@article {2536, title = {Reversible decomposition of mono(alpha-hydroxy)phosphines and their reaction with alpha,beta-unsaturated aldehydes}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {87}, number = {4}, year = {2009}, note = {ISI Document Delivery No.: 431IGTimes Cited: 4Cited Reference Count: 24Moiseev, Dmitry V. Marcazzan, Paolo James, Brian R.}, month = {Apr}, pages = {582-590}, type = {Article}, abstract = {{The mono (alpha-hydroxy) phosphines R2PCH(OH)R{\textquoteright} (R = Ph, R{\textquoteright} = H, Et, CH2Ph, Ph, p-X-C6H4; R = cyclohexyl, R{\textquoteright} = Ph) are prepared under solvent-free conditions by a 1:1 reaction of Ph2PH with the appropriate aldehyde, and their stabilities (with respect to reversible dissociation into reactants), studied in DMSO, Et2O, and MeOH, increase with decreased basicity of the hydroxyphosphine; for example, for the Ph2PCH (OH) C6H4-p-X phosphines, stability decreases in the order:X = CN > Cl > F > H > Me > OMe. A 1:1 room-temperature reaction of the (alpha-hydroxy) phosphines (except for R{\textquoteright} = H) with cinnamaldehyde in DMSO slowly yields the known mono-and di-phosphines Ph2PCH(Ph)CH2CHO (4a) and Ph2PCH(Ph)CH2CH(PPh2)OH (10a), and the corresponding R{\textquoteright}CHO aldehyde. In MeOH, the sequentially formed intermediates}, keywords = {(alpha-hydroxy)phosphines, alpha, beta-unsaturated aldehydes, CHEMISTRY, CHLORIDE, diphenylphosphine, FORMALDEHYDE, hydrophosphination, LIGNIN, NUCLEAR MAGNETIC-RESONANCE, PHOSPHONIUM CHLORIDE, TERTIARY PHOSPHINES, TETRAKIS(HYDROXYMETHYL)PHOSPHONIUM, TRIS(HYDROXYMETHYL)PHOSPHINE, WATER}, isbn = {0008-4042}, url = {://000265054200007}, author = {Moiseev, D. V. and Marcazzan, P. and James, Brian R.} } @article {2397, title = {Simulation of Water Adsorption on Kaolinite under Atmospheric Conditions}, journal = {Journal of Physical Chemistry A}, volume = {113}, number = {27}, year = {2009}, note = {ISI Document Delivery No.: 466WNTimes Cited: 5Cited Reference Count: 61Croteau, T. Bertram, A. K. Patey, G. N.}, month = {Jul}, pages = {7826-7833}, type = {Article}, abstract = {Grand canonical Monte Carlo calculations are employed to investigate water adsorption on kaolinite at 298 and 235 K. Both basal planes (the Al and Si surfaces) as well as two edge-like surfaces are considered. The general force field CLAYFF is used together with the SPCIE and TIP5P-E models for water. Problems that occur in single slab simulations due to arbitrary truncation of the point charge lattice are identified, and a working remedy is discussed. The edges and the Al surface adsorb water at subsaturation in the atmospherically relevant pressure range. The Si surface remains dry up to saturation. Both edges have a very strong affinity for water and adsorb continuously up to monolayer coverage. The Al surface has a weaker affinity for water but forms a subsaturation monolayer. On the Al surface, the monolayer is formed in an essentially sharp transition, and strong hysteresis is observed upon desorption. This indicates collective behavior among the water molecules which is not present for the edges. Binding energies of singly adsorbed water molecules at 10 K were determined to understand the differences in water uptake by the four kaolinite surfaces. Binding energies (SPC/E) of -21.6, -46.4, -73.5, and -94.1 kJ/mol, were determined for the Si surface, Al surface, unprotonated edge, and protonated edge, respectively. The water monolayer on the Al surface, particularly at 235 K, exhibits hexagonal patterns. However, the associated lattice parameters are not compatible with ice 1h. Water density and hydrogen bonding in the monolayers at both 298 and 235 K were also determined to better understand the structure of the adsorbed water.}, keywords = {ADSORBED, CLAY-MINERALS, COMPUTER-SIMULATION, DYNAMICS, HYDROGEN-BOND, ICE FORMATION, INITIO MOLECULAR-DYNAMICS, LIQUID WATER, MINERAL DUST, MONTE-CARLO SIMULATIONS, NITRIC-ACID, WATER}, isbn = {1089-5639}, url = {://000267694800018}, author = {Croteau, T. and Bertram, A. K. and Patey, G. N.} } @article {2474, title = {Spectrum of Excess Partial Molar Absorptivity. I. Near Infrared Spectroscopic Study of Aqueous Acetonitrile and Acetone}, journal = {Journal of Physical Chemistry B}, volume = {113}, number = {35}, year = {2009}, note = {ISI Document Delivery No.: 487EETimes Cited: 4Cited Reference Count: 22Koga, Yoshikata Sebe, Fumie Minami, Takamasa Otake, Keiko Saitow, Ken-ichi Nishikawa, Keiko}, month = {Sep}, pages = {11928-11935}, type = {Article}, abstract = {We study the mixing schemes or the molecular processes occurring in aqueous acetonitrile (ACN) and acetone (ACT) by near-infrared spectroscopy (NIR). Both solutions (any other aqueous solutions) are not free from strong and complex intermolecular interactions. To tackle such a many-body problem, we first use the concept of the excess molar absorptivity, epsilon(E), which is a function of solute mole fraction in addition to that of wavenumber, nu. The plots of F E calculated from NIR spectra for both aqueous solutions against nu showed two clearly separated bands at 5020 and 5230 cm(-1); the former showed negative and the latter positive peaks. At zero and unity mole fractions of solute, epsilon(E) is identically zero independent of v. Similar to the thermodynamic excess functions, both negative and positive bands grow in size from zero to the minimum (or the maximum) and back to zero, as the mole fraction varies from 0 to 1. Since the negative band{\textquoteright}s nu-locus coincides with the NIR spectrum of ice, and the positive with that of liquid H2O, we suggest that on addition of solute the "ice-likeness" decreases and the "liquid-likeness" increases, reminiscent of the two-mixture model for liquid H2O. The modes of these variations, however, are qualitatively different between ACN-H2O and ACT-H2O. The former ACN is known to,let as a hydrophobe and ACT as a hydrophile from Our previous thermodynamic studies. To see the difference more clearly, we introduced and calculated the excess partial molar absorptivity of ACN and ACT, epsilon(E)(N), and epsilon(E,)(T) respectively. The mole fraction dependences of epsilon(E)(N) and epsilon(E)(T) show qualitatively different behavior and are consistent with the detailed mixing schemes elucidated by our earlier differential thermodynamic studies. Furthermore, we found in the H2O-rich region that the effect of hydrophobic ACN is acted on the negative band at 5020 cm(-1), while that of hydrophilic ACT is on the positive high-energy band. Thus, the present method of analysis adds more detailed insight into the difference between a hydrophobe and a hydrophile in their effects on H2O.}, keywords = {2-DIMENSIONAL CORRELATION SPECTROSCOPY, 25-DEGREES-C, CHEMICAL-POTENTIALS, ENTHALPIES, ENTROPIES, HYDROGEN-BONDS, MIXTURES, NON-ELECTROLYTES, TEMPERATURE, WATER}, isbn = {1520-6106}, url = {://000269252700016}, author = {Koga,Yoshikata and Sebe, F. and Minami, T. and Otake, K. and Saitow, K. and Nishikawa, K.} } @article {2302, title = {Experimental determination of the third derivative of G. I. Enthalpic interaction}, journal = {Journal of Chemical Physics}, volume = {129}, number = {21}, year = {2008}, note = {ISI Document Delivery No.: 379XWTimes Cited: 2Cited Reference Count: 19Westh, Peter Inaba, Akira Koga, Yoshikata}, month = {Dec}, pages = {4}, type = {Article}, abstract = {The solute (i)-solute interaction in terms of enthalpy, H-i-i(E)=N(partial derivative H-2(E)/partial derivative n(i)(2))=(1-x(i))(partial derivative H-2(E)/partial derivative n(i)partial derivative x(i)), the third derivative of G, was experimentally determined using a Thermal Activity Monitor isothermal titration calorimeter for aqueous solutions of 2-butoxyethanol (BE) and 1-propanol (1P). This was done using both calorimetric reference and sample vessels actively. We simultaneously titrate small and exactly equal amounts of solute i (=BE or 1P) into both cells which contain the binary mixtures at an average mole fraction, x(i), which differs by a small amount Delta x(i). The appropriate amount of titrant delta n(i) was chosen so that the quotient (delta H-E/delta n(i)) can be approximated as (partial derivative H-E/partial derivative n(i)), and so that the scatter of the results is reasonable. delta H-E is the thermal response from an individual cell on titration, and we measure directly the difference in the thermal response between the two cells, Delta(delta H-E). The resulting quotient, Delta(delta H-E)/delta n(i)/Delta x(i), can be approximated as (partial derivative H-2(E)/partial derivative n(i)partial derivative x(i)) and hence provides a direct experimental avenue for the enthalpy interaction function. We varied the value of Delta x(i) to seek its appropriate size. Since H-E contains the first derivative of G with respect to T, the result is the third derivative quantity. Thus we present here a third derivative quantity directly determined experimentally for the first time.}, keywords = {AQUEOUS-SOLUTIONS, calorimetry, DYNAMICS, enthalpy, fluctuations, H2O, HOFMEISTER SERIES, LIQUID MIXTURES, MOLECULAR-ORGANIZATION, organic compounds, SOLVATION, WATER}, isbn = {0021-9606}, url = {://000261430900001}, author = {Westh, P. and Inaba, A. and Koga,Yoshikata} } @article {2218, title = {Hydrophobic interactions in urea - Trimethylamine-N-oxide solutions}, journal = {Journal of Physical Chemistry B}, volume = {112}, number = {35}, year = {2008}, note = {ISI Document Delivery No.: 342RDTimes Cited: 2Cited Reference Count: 25Paul, Sandip Patey, G. N.}, month = {Sep}, pages = {11106-11111}, type = {Article}, abstract = {The influence of osmolytes urea and trimethylemine-N-oxide (TMAO) on hydrophobic interactions is investigated employing molecular dynamics simulations. These osmolytes are of interest because of their opposing influence on proteins in solution; the denaturing effect of urea can be countered with TMAO. A neopentane pair is used to model typical nonpolar entities. Binary water-urea and water-TMAO as well as ternary water-urea-TMAO systems are considered. Neopentane-neopentane potentials of mean force, neopentane-water, and neopentane-osmolyte distribution functions are reported. Urea is found to have only modest influence on the neopentane-neopentane potential of mean force, but the hydrophobic attraction is completely destroyed by the presence of TMAO. It is shown that TMAO tends to act as a simple "surfactant" displacing water and urea (if it is present) from the first solvation shell of neopentane. It is likely the surfactant-like influence of TMAO that accounts for the elimination of the hydrophobic attraction. The implications of Our results for explanations of the action of TMAO in protein solutions are discussed.}, keywords = {AQUEOUS UREA, FORCE, MOLECULAR-DYNAMICS, OSMOLYTES, POTENTIALS, PROTEIN DENATURATION, SIMULATIONS, WATER}, isbn = {1520-6106}, url = {://000258800300046}, author = {Paul, S. and Patey, G. N.} } @article {2064, title = {Ice nucleation on mineral dust particles: Onset conditions, nucleation rates and contact angles}, journal = {Journal of Geophysical Research-Atmospheres}, volume = {113}, year = {2008}, note = {ISI Document Delivery No.: 375WPTimes Cited: 16Cited Reference Count: 62Eastwood, Michael L. Cremel, Sebastien Gehrke, Clemens Girard, Eric Bertram, Allan K.}, month = {Nov}, pages = {9}, type = {Article}, abstract = {An optical microscope coupled to a flow cell was used to investigate the onset conditions for ice nucleation on five atmospherically relevant minerals at temperatures ranging from 233 to 246 K. Here we define the onset conditions as the humidity and temperature at which the first ice nucleation event was observed. Kaolinite and muscovite were found to be efficient ice nuclei in the deposition mode, requiring relative humidities with respect to ice (RHi) below 112\% in order to initiate ice crystal formation. Quartz and calcite, by contrast, were poor ice nuclei, requiring relative humidities close to water saturation before ice crystals would form. Montmorillonite particles were efficient ice nuclei at temperatures below 241 K but were poor ice nuclei at higher temperatures. In several cases, there was a lack of quantitative agreement between our data and previously published work. This can be explained by several factors including the mineral source, the particle sizes, the surface area available for nucleation, and observation time. Heterogeneous nucleation rates (J(het)) were calculated from the measurements of the onset conditions (temperature and RHi) required from ice nucleation. The Jhet values were then used to calculate contact angles (theta) between the mineral substrates and an ice embryo using classical nucleation theory. The contact angles measured for kaolinite and muscovite ranged from 6 degrees to 12 degrees, whereas for quartz and calcite, the contact angles ranged from 25 degrees to 27 degrees. The reported Jhet and q values may allow for a more direct comparison between laboratory studies and can be used when modeling ice cloud formation in the atmosphere.}, keywords = {AFRICAN DUST, AMMONIUM-SULFATE PARTICLES, CIRRUS CLOUDS, CUBIC ICE, GENERATED LIQUID AEROSOLS, HETEROGENEOUS NUCLEATION, MICROPHYSICS, NUCLEI, SOOT, WATER}, isbn = {0148-0227}, url = {://000261144800007}, author = {Eastwood, M. L. and Cremel, S. and Gehrke, C. and Girard, E. and Bertram, A. K.} } @article {2169, title = {Serendipitous syntheses of Rh(H)(2)Cl(PRPh2)(3) complexes, and their crystal structures, where R = Me, Cy (cyclohexyl)}, journal = {Inorganica Chimica Acta}, volume = {361}, number = {7}, year = {2008}, note = {ISI Document Delivery No.: 304ETTimes Cited: 4Cited Reference Count: 40Lorenzini, Fabio Patrick, Brian O. James, Brian R.}, month = {May}, pages = {2123-2130}, type = {Article}, abstract = {Reactions of RhCl(cod)(THP) (cod = 1,5-cyclooctadiene; THP = P(CH2OH)(3)) with PMePh2 or PCyPh2 (Cy = cyclohexyl) in acetone/MeOH solution under H-2 surprisingly form the complexes cis,mer-Rh(H)Cl-2(PRPh2)(3) (R = Me or Cy); both complexes are characterized by crystallography (the first structures in which the hydride ligands of such dihydrido-chloro-trisphosphine complexes have been located), and by detailed H-1 and P-31 NMR spectroscopy. The key role of the THP in the observed chemistry is discussed. (C) 2007 Elsevier B.V. All rights reserved.}, keywords = {CRYSTALLOGRAPHY, ETHYLENE, EXCHANGE, HOMOGENEOUS CATALYTIC HYDROGENATION, hydride, hydride complexes, NMR, PARAHYDROGEN-INDUCED POLARIZATION, PHOSPHINE COMPLEXES, rhodium, RHODIUM(I), SPECTROSCOPY, TERTIARY PHOSPHINES, WATER, WILKINSONS CATALYST}, isbn = {0020-1693}, url = {://000256093500040}, author = {Lorenzini, F. and Patrick, B. O. and James, Brian R.} } @article {1382, title = {Deposition ice nucleation on soot at temperatures relevant for the lower troposphere}, journal = {Journal of Geophysical Research-Atmospheres}, volume = {111}, number = {D4}, year = {2006}, note = {ISI Document Delivery No.: 021EPTimes Cited: 36Cited Reference Count: 43}, month = {Feb}, pages = {9}, type = {Article}, abstract = {The ice nucleating efficiency of many important atmospheric particles remains poorly understood. Here we investigate the ice nucleation properties of a range of soot types including soot that has been treated with atmospherically relevant amounts of ozone. We focus on deposition nucleation below water saturation and at temperatures ranging from 243 to 258 K. For our experimental conditions, ice nucleation never occurred at temperatures above 248 K and below water saturation. Below 248 K, ice occasionally formed in our experiments with no indication of the formation of water droplets prior to ice formation. However, even at these temperatures the relative humidity with respect to ice (RHi) was close to water saturation when ice nucleation was observed, suggesting water nucleation may have occurred first followed by ice nucleation during the condensation process. We also performed a complimentary set of experiments where we held soot particles at 248 K and RHi = 124 +/- 4\%, which is just below water saturation, for a period of 8 hours. From these measurements we calculated an upper limit of the heterogeneous ice nucleation rate coefficient of 0.1 cm(-2) s(-1). If the number of soot particles is 1.5 x 10(5) L-1 in the atmosphere ( which corresponds to urban-influenced rural areas), then the number of ice particles produced below water saturation at these conditions is at most 0.1 particles L-1 on the basis of our upper limit. We conclude from our studies that deposition nucleation of ice on most types of soot particles is not important in the Earth{\textquoteright}s troposphere above 243 K and below water saturation.}, keywords = {ACID, AEROSOL, CARBON, CLOUDS, crystallization, CRYSTALS, deliquescence, EXHAUST, PARTICLES, WATER}, isbn = {0148-0227}, url = {://000235966800008}, author = {Dymarska, M. and Murray, B. J. and Sun, L. M. and Eastwood, M. L. and Knopf, D. A. and Bertram, A. K.} } @article {1513, title = {The interaction of patterned solutes in binary solvent mixtures}, journal = {Journal of Chemical Physics}, volume = {124}, number = {9}, year = {2006}, note = {ISI Document Delivery No.: 019IHTimes Cited: 1Cited Reference Count: 44}, month = {Mar}, pages = {11}, type = {Article}, abstract = {Mean solute-solute forces and solute-induced solvent structure are investigated for pairs of chemically patterned (patched) solutes in binary mixtures near demixing coexistence. The isotropic and anisotropic hypernetted-chain integral equation theories as well as a superposition approximation are solved and compared. The patched solutes consist of one end that favors the majority species in the mixture while the other end favors the minority species. A wide range of patch sizes is considered. The isotropic and anisotropic theories are found to be in good agreement for most orientations, including the most attractive and most repulsive configurations. However, some differences arise for asymmetrical orientations where unlike ends of the solute particles face each other. In contrast, superposition often gives a rather poor approximation to the mean force, even though the results obtained for the solvent densities agree qualitatively with the anisotropic theory. The mean force is sensitive to small differences in the densities particularly near demixing. For patched solutes the influence of demixinglike behavior is evident both in the orientational dependence and in the range of the mean force acting between solutes. (c) 2006 American Institute of Physics.}, keywords = {BRIDGE DIAGRAM SERIES, FLUID, HARD-SPHERES, HYDROPHOBIC SURFACES, LENNARD-JONES, LIQUID MIXTURES, MACROPARTICLES, PHASE-TRANSITION, RANGE, SPHERICALLY INHOMOGENEOUS FLUIDS, WATER}, isbn = {0021-9606}, url = {://000235828300034}, author = {Overduin, S. D. and Patey, G. N.} } @article {1558, title = {Measurements of the vapor pressure of cubic ice and their implications for atmospheric ice clouds}, journal = {Geophysical Research Letters}, volume = {33}, number = {17}, year = {2006}, note = {ISI Document Delivery No.: 081QHTimes Cited: 17Cited Reference Count: 38Shilling, J. E. Tolbert, M. A. Toon, O. B. Jensen, E. J. Murray, B. J. Bertram, A. K.}, month = {Sep}, pages = {5}, type = {Article}, abstract = {Under conditions commonly found in Earth{\textquoteright}s atmosphere, water can form two solid phases; hexagonal ice (I-h) and cubic ice (I-c). Recent reports have suggested that Ic may form in the atmosphere under a wider range of conditions than previously believed. In light of these reports, the formation of Ic has been suggested as one contributing factor for in-situ observations of persistent in-cloud supersaturations in cold cirrus. However, an accurate evaluation of the contribution of Ic formation to the observed supersaturations requires knowledge of the saturation vapor pressure of Ic, which has not been measured. In this manuscript, we report direct measurements of the vapor pressure of Ic over the temperature range 180 - 190 K. Over this temperature range, the vapor pressure of the cubic phase is 10.5 +/- 2.5\% higher than that of the hexagonal phase. Field measurements of in-cloud supersaturations made during CRYSTAL-FACE are also re-analyzed and discussed.}, keywords = {AMORPHOUS WATER ICE, ASTROPHYSICAL IMPLICATIONS, CIRRUS CLOUDS, ELECTRON DIFFRACTION, FORMS, GLASSY, HEXAGONAL ICE, LOW-TEMPERATURE, SPECTRA, WATER, X-RAY-DIFFRACTION}, isbn = {0094-8276}, url = {://000240331600005}, author = {Shilling, J. E. and Tolbert, M. A. and Toon, O. B. and Jensen, E. J. and Murray, B. J. and Bertram, A. K.} } @article {1499, title = {New oligophosphines and (hydroxymethyl)phosphonium chlorides}, journal = {Inorganic Chemistry}, volume = {45}, number = {7}, year = {2006}, note = {ISI Document Delivery No.: 028HCTimes Cited: 6Cited Reference Count: 46}, month = {Apr}, pages = {2917-2924}, type = {Article}, abstract = {{The new oligophosphines [H2P(CH2)(2)](2)PH, [H2P(CH2)(2)P(H)CH2](2), and {[(H2P(CH2)(2)](2)PCH2}(2) have been made by hydrophosphination of diethyl vinylphosphonate (2) with H2P(CH2)(2)PH2 (1), using different ratios of 2/1, followed by LiAlH4 reduction of the phosphonate intermediates; the three phosphonate precursors were obtained as oils of varying purity (similar to 90-95\%) in low (similar to 20\%) to almost quantitative yield. The tri-, tetra-, and hexaphosphines were then treated with formaldehyde in the presence of hydrochloric acid to generate the corresponding water-soluble (hydroxymethyl)phosphonium chlorides {(HOCH2)(3)P[(CH2)(2)P(CH2OH)(2)](n)(CH2)(2)P(CH2PH)(3)}Cl-m (n = 1}, keywords = {ALDEHYDES, BRIGHTNESS STABILIZING AGENTS, COMPLEXES, CRYSTAL-STRUCTURE, DERIVATIVES, FORMALDEHYDE, LIGANDS, phosphines, SALTS, WATER}, isbn = {0020-1669}, url = {://000236476700018}, author = {Moiseev, D. and James, Brian R. and Patrick, B. O. and Hu, Thomas Q.} } @article {1499, title = {New oligophosphines and (hydroxymethyl)phosphonium chlorides}, journal = {Inorganic Chemistry}, volume = {45}, number = {7}, year = {2006}, note = {ISI Document Delivery No.: 028HCTimes Cited: 6Cited Reference Count: 46}, month = {Apr}, pages = {2917-2924}, type = {Article}, abstract = {{The new oligophosphines [H2P(CH2)(2)](2)PH, [H2P(CH2)(2)P(H)CH2](2), and {[(H2P(CH2)(2)](2)PCH2}(2) have been made by hydrophosphination of diethyl vinylphosphonate (2) with H2P(CH2)(2)PH2 (1), using different ratios of 2/1, followed by LiAlH4 reduction of the phosphonate intermediates; the three phosphonate precursors were obtained as oils of varying purity (similar to 90-95\%) in low (similar to 20\%) to almost quantitative yield. The tri-, tetra-, and hexaphosphines were then treated with formaldehyde in the presence of hydrochloric acid to generate the corresponding water-soluble (hydroxymethyl)phosphonium chlorides {(HOCH2)(3)P[(CH2)(2)P(CH2OH)(2)](n)(CH2)(2)P(CH2PH)(3)}Cl-m (n = 1}, keywords = {ALDEHYDES, BRIGHTNESS STABILIZING AGENTS, COMPLEXES, CRYSTAL-STRUCTURE, DERIVATIVES, FORMALDEHYDE, LIGANDS, phosphines, SALTS, WATER}, isbn = {0020-1669}, url = {://000236476700018}, author = {Moiseev, D. and James, Brian R. and Patrick, B. O. and Hu, Thomas Q.} } @article {1227, title = {Hydration number of glycine in aqueous solution: An experimental estimate}, journal = {Journal of Chemical Physics}, volume = {123}, number = {23}, year = {2005}, note = {ISI Document Delivery No.: 996ADTimes Cited: 6Cited Reference Count: 31}, month = {Dec}, pages = {6}, type = {Article}, abstract = {An experimental estimate of hydration number, N-H, of glycine in aqueous solution is given by using the calorimetric methodology developed by us earlier, which is briefly reviewed. We found N-H to be 7 +/- 0.6 for glycine presumably in the zwitter ion form, 10 +/- 1 for sodium glycinate, and 5 +/- 0.4 for glycine hydrochloride. Both glycine and sodium glycinate seem to work purely as a hydration center without altering the nature of the bulk H2O away from the hydration shell. Glycine hydrochloride, in addition to the role of hydration center, seems also to act as a typical hydrophilic species such as polyols, urea, or polyethylene glycols. Hence, the effect of the latter on H2O is of a long range, like other hydrophilic species. (c) 2005 American Institute of Physics.}, keywords = {25-DEGREES-C, fluctuations, H2O, INTRAMOLECULAR PROTON-TRANSFER, MIXING SCHEMES, MOLECULAR-ORGANIZATION, NONELECTROLYTES, PARTIAL MOLAR ENTHALPIES, TAUTOMERIZATION, WATER}, isbn = {0021-9606}, url = {://000234145900026}, author = {Parsons, M. T. and Koga,Yoshikata} } @article {1151, title = {Tris(pyronato)- and tris(pyridonato)-ruthenium(III) complexes and solution NMR studies}, journal = {Inorganic Chemistry}, volume = {44}, number = {19}, year = {2005}, note = {ISI Document Delivery No.: 964EGTimes Cited: 7Cited Reference Count: 25}, month = {Sep}, pages = {6529-6535}, type = {Article}, abstract = {{The water-soluble Ru-III maltolato, ethylmaltolato, and pyridonato complexes, Ru(O-O{\textquoteright})(3) (O-O{\textquoteright} = ma (1a), etma (1b), pyd (2a)), were synthesized (Hma = 3-hydroxy-2-methyl-4-pyrone}, keywords = {CRYSTAL, LIGANDS, RUTHENIUM(II), WATER}, isbn = {0020-1669}, url = {://000231860900012}, author = {Kennedy, David C and Wu, A. and Patrick, B. O. and James, Brian R.} } @article {957, title = {Deliquescence of malonic, succinic, glutaric, and adipic acid particles}, journal = {Journal of Geophysical Research-Atmospheres}, volume = {109}, number = {D6}, year = {2004}, note = {ISI Document Delivery No.: 809FPTimes Cited: 32Cited Reference Count: 46}, month = {Mar}, pages = {8}, type = {Article}, abstract = {In order to understand and predict the role of organic particles in the atmosphere their deliquescence behavior must be understood. Using an optical microscope coupled to a flow cell, we investigated the deliquescence of malonic, succinic, glutaric, and adipic acid particles with sizes ranging from 2 to 40 mm. Deliquescence relative humidities were determined for temperatures ranging from 293 to 243 K. Over this temperature range both succinic acid and adipic acid deliquesced at approximately 100\% relative humidity, whereas malonic acid and glutaric acid deliquesced at significantly lower relative humidities. These results are generally in good agreement with previous studies and are within 3\% of calculations based on the UNIQUAC (universal quasi-chemical) Functional Group Activity Coefficients (UNIFAC) model and recently published interaction parameters. Our studies also include measurements at temperatures below the eutectic temperatures. At these temperatures, ice did not nucleate; rather the particles underwent deliquescence to form metastable solution droplets. This indicates that solid dicarboxylic acids are not good ice nuclei above 243 K and hence will probably not play a role in ice cloud formation at these temperatures.}, keywords = {AEROSOL, AEROSOL PHASE, AMAZON BASIN, AMMONIUM-SULFATE, atmospheric chemistry, ATMOSPHERIC PARTICLES, CIRRUS CLOUD FORMATION, deliquescence, dicarboxylic acid, DICARBOXYLIC-ACIDS, HYGROSCOPIC GROWTH, ice, NUCLEATION, optical microscopy, PHASE-TRANSITIONS, STRATOSPHERIC TEMPERATURES, WATER}, isbn = {0148-0227}, url = {://000220622900002}, author = {Parsons, M. T. and Mak, J. and Lipetz, S. R. and Bertram, A. K.} } @article {913, title = {Effects of Na2SO4 and NaClO4 on the molecular organization of H2O}, journal = {Journal of Physical Chemistry A}, volume = {108}, number = {10}, year = {2004}, note = {ISI Document Delivery No.: 801KFTimes Cited: 11Cited Reference Count: 16}, month = {Mar}, pages = {1635-1637}, type = {Letter}, abstract = {We study thermodynamic behaviors of 1-propanol (abbreviated as 1P) in ternary 1P-salt-H2O in order to elucidate the effects of salt on the molecular organization of H2O. We determine the excess partial molar enthalpy of 1P, H-1P(E), as a function of the mole fraction of 1P, x(1P), and the salt. We examine the x(1P) dependence of H-1P(E), and changes induced by the presence of salt are used to elucidate the effect of the salt on the molecular organization of H2O. We previously found that an NaCl ion pair binds 7 to 8 molecules of H2O, but has no effect on H2O outside of the hydration shell. Na2SO4 and NaClO4, on the other hand, modify the molecular organization of H2O each in different ways. In particular, ClO4- seems to participate in the hydrogen bond network of H2O and to retard the degree of fluctuation inherent in liquid H2O.}, keywords = {25-DEGREES-C, AQUEOUS-SOLUTIONS, MIXING SCHEMES, PARTIAL MOLAR ENTHALPIES, THERMODYNAMIC APPROACH, WATER}, isbn = {1089-5639}, url = {://000220094100001}, author = {Koga,Yoshikata and Westh, P. and Nishikawa, K.} } @article {901, title = {Mixing schemes in ionic liquid-H2O systems: A thermodynamic study}, journal = {Journal of Physical Chemistry B}, volume = {108}, number = {50}, year = {2004}, note = {ISI Document Delivery No.: 879CXTimes Cited: 78Cited Reference Count: 33}, month = {Dec}, pages = {19451-19457}, type = {Article}, abstract = {We studied the hydration characteristics of room-temperature ionic liquids (IL). We experimentally determined the excess chemical potentials, mu(i)(E), the excess partial molar enthalpies, H-i(E), and the excess partial molar entropies S-i(E) in IL-H2O systems at 25 degreesC. The ionic liquids studied were 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4) and the iodide ([bmim]l). From these data, the excess (integral) molar enthalpy and entropy, H-m(E) and S-m(E), and the IL-IL enthalpic interaction, H-IL-IL(E), were calculated. Using these thermodynamic data, we deduced the mixing schemes, or the "solution structures", of IL-H2O systems. At infinite dilution IL dissociates in H2O, but the subsequent hydration is much weaker than for NaCl. As the concentration of IL increases, [bmim]l ions and the counteranions begin to attract each other up to a threshold mole fraction, x(IL) = 0.015 for [bmim]BF4 and 0.013 for [bmim]l. At still higher mole fractions, IL ions start to organize themselves, directly or in an H2O-Mediated manner. Eventually for x(IL) > 0.5-0.6, IL molecules form clusters of their own kind, as in their pure states. We show tha HI-L-IL, a third derivative of G, provided finer details than H-i(E) and S-i(E) second derivatives, which in turn gave more detailed information than H-m(E) and S-m(E), first derivative quantities.}, keywords = {25-DEGREES-C, AQUEOUS SODIUM-CHLORIDE, ENTHALPIES, GLYCEROL, H2O, METHANOL, MIXTURES, MOLECULAR-ORGANIZATION, SOLVENTS, WATER}, isbn = {1520-6106}, url = {://000225695100058}, author = {Katayanagi, H. and Nishikawa, K. and Shimozaki, H. and Miki, K. and Westh, P. and Koga,Yoshikata} } @article {912, title = {Toward understanding the Hofmeister series. 1. Effects of sodium salts of some anions on the molecular organization of H2O}, journal = {Journal of Physical Chemistry A}, volume = {108}, number = {40}, year = {2004}, note = {ISI Document Delivery No.: 858TGTimes Cited: 18Cited Reference Count: 28}, month = {Oct}, pages = {8533-8541}, type = {Article}, abstract = {We studied a detailed thermodynamic behavior of 1-propanol (abbreviated as 1P) in mixed solvents of aqueous Na2SO4, NaOOCCH3, and NaClO4, and NaSCN. We measured the excess partial molar enthalpy of 1P, H-1P(E), in these mixed solvents at various initial salt concentrations. We then evaluated what we call the enthalpic interaction, H-1P-1P(E) = (partial derivativeH(1P)(E)/partial derivativen(1P)), where n(1P) is the amount of 1P. The composition dependence of H-1P-1P(E) changes in a characteristic manner on addition of a specific salt. This induced change in the behavior of H-1P-1P(E) is used to elucidate the effect of the salt on the molecular organization of H2O. Na+ ion seems to hydrate a number less than seven or eight molecules of H2O, leaving the bulk H2O outside the hydration shell unperturbed. SO42- also hydrates a number less than 26 H2O molecules with a concomitant increase in the degree of fluctuation of the bulk H2O. Na2SO4 as a whole hydrates the total of 26 H2O. CH3COO- ion modifies H2O in a similar manner as an alcohol. Cl- ion hydrates a number less than seven or eight H2O molecules leaving the bulk H2O in the same state as in pure H2O. NaCl as a whole hydrates the total of seven or eight molecules of H2O. ClO4- and SCN- participate in hydrogen bonding with the hydrogen bond network of H2O keeping its connectivity intact. However, they reduce the degree of fluctuation inherent in liquid H2O. Thus, each ion has its own unique manner of modifying H2O, except that ClO4- and SCN- modify H2O in almost the same way. Therefore, it seems fair to state that the phenomenological net result manifested as the Hofmeister series is due to multifacetted factors working in the holistic manner, and a single or a small number of parameters is not sufficient to explain its effect.}, keywords = {1-PROPANOL, 25-DEGREES-C, ALKANE-MONO-OLS, AQUEOUS-SOLUTIONS, fluctuations, MIXING SCHEMES, PARTIAL MOLAR ENTHALPIES, THERMODYNAMIC APPROACH, WATER}, isbn = {1089-5639}, url = {://000224214100050}, author = {Koga,Yoshikata and Westh, P. and Davies, J. V. and Miki, K. and Nishikawa, K. and Katayanagi, H.} } @article {655, title = {Effect of ethylene glycol on the molecular organization of H2O in comparison with methanol and glycerol: A calorimetric study}, journal = {Journal of Solution Chemistry}, volume = {32}, number = {9}, year = {2003}, note = {ISI Document Delivery No.: 742ZVTimes Cited: 8Cited Reference Count: 25}, month = {Sep}, pages = {803-818}, type = {Article}, abstract = {Excess partial molar enthalpies of ethylene glycol, H-EG(E), in binary ethylene glycol-H2O, and those of 1-propanol, H-IP(E), in ternary 1-propanol-ethylene glycol (or methanol)-H2O were determined at 25degreesC. From these data, the solute-solute interaction functions, H-EG-EG(E)=N(partial derivativeH(EG)(E)/partial derivativen(EG)) and H-1P-1P(E)=N(partial derivativeH(1P)(E)/partial derivativen(1P)), were calculated by graphical differentiation without resorting to curve fitting. Using these, together with the partial molar volume data, the effect of ethylene glycol on the molecular organization of H2O was investigated in comparison with methanol and glycerol. We found that there are three concentration regions, in each of which the mixing scheme is qualitatively different from the other regions. Mixing scheme III operative in the solute-rich region is such that the solute molecules are in a similar situation as in the pure state, most likely in clusters of its own kind. Mixing scheme II, in the intermediate region, consists of two kinds of clusters each rich in solute and in H2O, respectively. Thus, the bond percolation nature of the hydrogen bond network of liquid H2O is lost. Mixing scheme I is a progressive modification of liquid H2O by the solute, but the basic characteristics of liquid H2O are still retained. In particular, the bond percolation of the hydrogen bond network is still intact. Similar to glycerol, ethylene glycol participates in the hydrogen bond network of H2O via-OH groups, and reduces the global average of the hydrogen bond probability and the fluctuations inherent in liquid H2O. In contrast to glycerol, there is also a sign of a weak hydrophobic effect caused by ethylene glycol. However, how these hydrophobic and hydrophilic effects of ethylene glycol work together in modifying the molecular organization of H2O in mixing scheme I is yet to be elucidated.}, keywords = {25-DEGREES-C, ALKANE-MONO-OLS, AQUEOUS-SOLUTIONS, CHEMICAL-POTENTIALS, effect on the, enthalpic interaction, enthalpy, ethylene glycol-H2O, excess partial molar, methanol-, MIXING SCHEMES, molecular organization of H2O, or glycerol-H2O, PARTIAL MOLAR ENTHALPIES, TERT-BUTANOL MIXTURES, THERMODYNAMIC APPROACH, VOLUMES, WATER}, isbn = {0095-9782}, url = {://000186548700004}, author = {Koga,Yoshikata} } @article {587, title = {Excess chemical potential and partial molar enthalpy of 2-iso-butoxyethanol in aqueous solution at 20 degrees C}, journal = {Thermochimica Acta}, volume = {397}, number = {1-2}, year = {2003}, note = {ISI Document Delivery No.: 642RNTimes Cited: 0Cited Reference Count: 14}, month = {Feb}, pages = {75-80}, type = {Article}, abstract = {Vapour pressures were determined at 20degreesC for aqueous 2-iso-butoxyethanol (ME). Partial pressures and hence, the excess chemical potentials of iBE were calculated by the Boissonnas method. Excess partial molar enthalpies were measured, and the excess partial molar entropies of iBE were then calculated at 20degreesC. These data and their mole fraction dependence indicated that there are three mixing schemes operative, in the same way as in aqueous 2-n-butoxyethanol (nBE) studied extensively by us. The details of each mixing schemes are identical, but the locus of the transition between mixing schemes I and II occurs at a smaller mole fraction than for aqueous nBE. This suggests that iBE is a stronger hydrophobic solute than nBE, which is consistent with the common understanding. (C) 2002 Elsevier Science B.V. All rights reserved.}, keywords = {2-BUTOXYETHANOL, 2-iso-butoxyethanol-H2O, 2-ISOBUTOXYETHANOL, 2-n-butoxyethanol-H2O, 25-DEGREES-C, a stronger hydrophobicity than 2-n-butoxyethanol, ALCOHOL, BUTYL, enthalpic interaction functions, excess partial molar enthalpy and entropy, LAW REGION, MIXING SCHEME, MIXTURES, THERMODYNAMIC PROPERTIES, three mixing schemes identical with, VAPOR-PRESSURES, WATER}, isbn = {0040-6031}, url = {://000180803100010}, author = {Cheung, C. M. W. and Chan, K. P. Y. and Koga,Yoshikata} } @article {717, title = {Non-ideality of methanol solution{\textquoteright}s of artificial serum in the mole fraction range from 5 x 10(-4) to 5 x 10(-3) at 25 degrees C}, journal = {Fluid Phase Equilibria}, volume = {207}, number = {1-2}, year = {2003}, note = {ISI Document Delivery No.: 683WUTimes Cited: 0Cited Reference Count: 20}, month = {May}, pages = {301-317}, type = {Article}, abstract = {Vapour pressure and excess partial molar enthalpy were measured at 25 degreesC for solutions of methanol in H2O and artificial serum solutions. The mole fraction range studied was from 5 x 10(-4) to 5 x 10(-3). From the vapour pressure data, the partial pressures were determined by the Barker{\textquoteright}s and Boissonnas{\textquoteright} methods. Various thermodynamic functions were then calculated from them. The curve-fitting (Barker{\textquoteright}s method) gave the osmotic coefficients very close to unity in all the cases, including serum solutions. The purely numerical method without resorting to any fitting function (Boissonnas{\textquoteright} method), on the other hand, produced the osmotic coefficient significantly larger than unity in serum solutions studied. This is consistent with the findings by the earlier freezing point depression study on ethanol in human blood serum solutions. The partial molar enthalpy data indicated highly non-ideal behaviours also, particularly in serum solutions. The detailed mechanism causing non-ideality even at this dilute concentration range is yet to be elucidated. (C) 2003 Elsevier Science B.V. All rights reserved.}, keywords = {ALBUMIN, AQUEOUS-SOLUTIONS, Barker{\textquoteright}s and Boissonnas methods, BINDING, chemical potential, data analysis by, DILUTE, LAW REGION, methanol in H2O and serum with bovine serum, osmotic coefficient, partial molar enthalpy, VAPOR-PRESSURES, WATER}, isbn = {0378-3812}, url = {://000183174700020}, author = {Ralloff, K. P. G. and Westh, P. and Purssell, R. A. and Pudek, M. and Koga,Yoshikata} } @article {332, title = {A differential vapor-pressure equipment for investigations of biopolymer interactions}, journal = {Journal of Biochemical and Biophysical Methods}, volume = {50}, number = {2-3}, year = {2002}, note = {ISI Document Delivery No.: 510CETimes Cited: 7Cited Reference Count: 47}, month = {Jan}, pages = {269-288}, type = {Article}, abstract = {The design and performance of an equipment for the measurement of vapor pressures over liquid or solid samples is presented. The equilibrium pressure difference, DeltaP, between a sample and a reference of known vapor pressure is recorded as a function of composition and/or temperature. Through the use of high-accuracy capacitance manometers and a leak-tight system of stainless steel pipes, below-scaled valves and metal-gasket fittings, DeltaP can be measured with a resolution of about 0.5 mubar (0.05 Pa) in some applications. This sensitivity level, along with other features of the equipment, particularly a "gas-phase titration" routine for changing the cell composition, makes it effective for the investigations of several types of biopolymer interactions. These include isothermal studies of net affinities such as the adsorption of water to proteins or membranes, the preferential interaction of biopolymers with the components of a mixed solvent. the partitioning of solutes between a membrane and the aqueous bulk and the weak. specific binding of ligands to macromolecules. Furthermore, a temperature-scanning mode allows real-time elucidation of such interactions at thermally induced conformational changes in biopolymers. Selected examples of these applications are presented and discussed. (C) 2002 Elsevier Science B.V. All rights reserved.}, keywords = {25-DEGREES-C, ALCOHOLS, BINDING, BOVINE SERUM-ALBUMIN, CALORIMETER, differential, hydration, LIQUID-EQUILIBRIA, preferential interaction, static vapor pressure, temperature scanning, TEMPERATURES, THERMODYNAMICS, titration, WATER, weak binding}, isbn = {0165-022X}, url = {://000173190500016}, author = {Andersen, K. B. and Koga,Yoshikata and Westh, P.} } @article {472, title = {Forces between chemically patterned plates immersed in binary liquid mixtures}, journal = {Journal of Chemical Physics}, volume = {117}, number = {7}, year = {2002}, note = {ISI Document Delivery No.: 579WWTimes Cited: 9Cited Reference Count: 31}, month = {Aug}, pages = {3391-3397}, type = {Article}, abstract = {Grand canonical Monte Carlo calculations are used to investigate the phase behavior of a binary mixture of Lennard-Jones particles confined between planar, parallel, chemically patterned plates. Attention is focused on the influence of surface-induced transitions on the net force acting between the plates. In addition to the stable and metastable bulk states that play a crucial role for homogeneous surfaces, for certain patterns and surface separations a bridge phase analogous to that recently reported for one-component systems is observed. It is found that bridge phase formation leads to strongly attractive plate-plate forces that are equal in magnitude to those observed for homogeneous surfaces. The significance of our results for the interaction and behavior of nonuniform macroparticles in solution is discussed. (C) 2002 American Institute of Physics.}, keywords = {CHARGED HARD-SPHERES, HYDROPHOBIC SURFACES, LENNARD-JONES FLUID, MACROPARTICLES, MONTE-CARLO, PHASE-TRANSITION, STATISTICAL-MECHANICS, WALLS, WATER}, isbn = {0021-9606}, url = {://000177202300048}, author = {Overduin, S. D. and Patey, G. N.} } @article {431, title = {In situ extract ion/preconcentration of PCBs and PAHs from aqueous samples using polytetrafluoroethylene tubing}, journal = {Analyst}, volume = {127}, number = {6}, year = {2002}, note = {ISI Document Delivery No.: 565YATimes Cited: 5Cited Reference Count: 23}, month = {Jun}, pages = {730-734}, type = {Article}, abstract = {In situ extraction/preconcentration of organics from water samples was accomplished using polytetrafluoroethylene (PTFE) tubing. Polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) were concentrated inside the tubing by flowing aqueous samples through it. The adsorbed PCBs and PAHs were then recovered by solvent desorption. The eluent was subsequently analyzed using gas chromatography with electron capture detection (GC-ECD) or gas chromatography with flame ionization detection (GC-FID). Multiple samples were simultaneously processed to concentrate organics onto several PTFE tubings. Analyses of seawater and surface microlayers using this technique demonstrated that organics in the surface microlayers were elevated with respect to those in the water column, consistent with previous findings.}, keywords = {CHROMATOGRAPHY, MASS-SPECTROMETRY, MICROEXTRACTION, MICROLAYER, POLYCYCLIC AROMATIC-HYDROCARBONS, SOLID-PHASE EXTRACTION, WATER}, isbn = {0003-2654}, url = {://000176396800008}, author = {Li, X. F. and Cullen, W. R. and Reimer, K. J.} } @article {421, title = {Mixing schemes in ternary aqueous solutions - Thermodynamic approach}, journal = {Journal of Thermal Analysis and Calorimetry}, volume = {69}, number = {3}, year = {2002}, note = {ISI Document Delivery No.: 604BRTimes Cited: 8Cited Reference Count: 282nd International Symposium on the New Frontiers of Thermal Studies of MaterialsNOV 25-27, 2001SUZUKAKEDAI, JAPAN}, pages = {705-716}, type = {Proceedings Paper}, abstract = {The enthalpic interaction functions introduced by us earlier were evaluated in some ternary aqueous solutions. They are determined purely experimentally without resorting to any model system. From them, the pair interaction coefficients based on the virial expansion were evaluated, which will serve for a future theoretical development based on the McMillan-Mayer theory of solution. Secondly, our new methodology of using the mole fraction dependence of the enthalpic interaction function as a probe to elucidate the effect of a third component on the molecular organization is introduced. The conclusions for selected third components in ternary aqueous 1-propanol are reviewed.}, keywords = {25-DEGREES-C, effect of selected solutes on the molecular organization of H2O, enthalpic interaction functions, ENTROPIES, EXCESS CHEMICAL-POTENTIALS, H2O, MOLECULAR-ORGANIZATION, pair interaction coefficients, PARTIAL MOLAR ENTHALPIES, ternary aqueous solutions, TERT-BUTANOL, TETRAMETHYL UREA, the, VOLUMES, WATER}, isbn = {1418-2874}, url = {://000178596200002}, author = {Koga,Yoshikata} } @article {5219, title = {Binding of small alcohols to a lipid bilayer membrane: does the partitioning coefficient express the net affinity?}, journal = {Biophysical Chemistry}, volume = {89}, number = {1}, year = {2001}, note = {ISI Document Delivery No.: 397WQTimes Cited: 13Cited Reference Count: 55}, month = {Jan}, pages = {53-63}, type = {Article}, abstract = {The total vapor pressures at 26 degreesC of binary (water-alcohol) and ternary (water-alcohol-vesicle) systems were measured for sis short chain alcohols. The vesicles were unilamellar dipalmitoyl phosphatidylcholine (DMPC). The data was used to evaluate the effect of vesicles on the chemical potential of alcohols expressed as the preferential binding parameter of the alcohol-lipid interaction, Gamma (23). This quantity is a thermodynamic (model-free) measure of the net strength of membrane-alcohol interactions. For the smaller investigated alcohols (methanol, ethanol and 1-propanol) Gamma (23) was negative. This is indicative of so-called preferential hydration, a condition where the affinity of the membrane for water is higher than the affinity for the alcohol. For the longer alcohols (1-butanol, 1-pentanol, 1-hexanol) Gamma (23) was positive and increasing with increasing chain length. This demonstrates preferential binding, i.e. enrichment of alcohol in the membrane and a concomitant depletion of the solute in the aqueous bulk. The measured values of Gamma (23) were compared to the number of alcohol-membrane contacts specified by partitioning coefficients from the literature. It was found that for the small alcohols the number of alcohol-membrane contacts is much larger than the number of preferentially bound solutes. This discrepancy, which is theoretically expected in cases of very weak binding, becomes less pronounced with increasing alcohol chain length, and when the partitioning coefficient exceeds approximately 3 on the molal scale (10(2) in mole fraction units) it vanishes. Based on this, relationships between structural and thermodynamic interpretations of membrana partitioning are discussed. (C) 2001 Elsevier Science B.V. All rights reserved.}, keywords = {energy of interaction, ETHANOL, free, lipid membranes, membrane partitioning, MODEL, NONELECTROLYTE PARTITION, PHASE, PHOSPHATIDYLCHOLINE, preferential binding, protein stability, SOLUTES, THERMODYNAMICS, vapor pressure, VAPOR-PRESSURE, WATER}, isbn = {0301-4622}, url = {://000166721200005}, author = {Westh, P. and Trandum, C. and Koga,Yoshikata} } @article {5102, title = {Bis(mercapto) and hydrido(thiolate) complexes of Ru(II)-dppm (dppm = Ph2PCH2PPh2)}, journal = {Inorganica Chimica Acta}, volume = {320}, number = {1-2}, year = {2001}, note = {ISI Document Delivery No.: 472CETimes Cited: 6Cited Reference Count: 33}, month = {Aug}, pages = {184-189}, type = {Article}, abstract = {From a mixture of cis- and trans-Ru(SH)(2)(dppm)(2) (4), formed from reaction of H2S with trans-Ru(H)Cl(dppm)(2) (2), a crystal of cis-4 has been isolated and its structure determined by X-ray analysis. The mercapto protons are located within the centrosymmetric structure, although the S-atoms are partially disordered (S - H similar to 1.06 Angstrom). The thiolate complexes, trans-Ru(H)SR(dppm)(2) (R = Ph, 5a; C6F5, 5b), have been isolated from reaction of trans-2 with 1 equiv. of RSH. trans-Ru(H)SH(dppm)(2) (3) has been isolated from reaction of H2S with a mixture of cis- and trans-Ru(H)(2)(dppm)(2) (1). An improved synthetic route for 1 is presented. (C) 2001 Elsevier Science B.V. All rights reserved.}, keywords = {CHEMISTRY, COMPLEXES, crystal structures, CRYSTAL-STRUCTURE, DERIVATIVES, DINUCLEAR RHODIUM COMPLEXES, hydrido complexes, HYDROFORMYLATION, MECHANISMS, MERCAPTO, PHOSPHINE COMPLEXES, ruthenium complexes, RUTHENIUM(II), THIOLATO, WATER}, isbn = {0020-1693}, url = {://000170965000025}, author = {Khorasani-Motlagh, M. and Safari, N. and Pamplin, C. B. and Patrick, B. O. and James, Brian R.} } @article {5150, title = {Sugar-pendant diamines}, journal = {Journal of Organic Chemistry}, volume = {66}, number = {11}, year = {2001}, note = {ISI Document Delivery No.: 435ZDTimes Cited: 19Cited Reference Count: 62}, month = {Jun}, pages = {3783-3789}, type = {Article}, abstract = {A set of 1,3-propanediamine derivatives connected to carbohydrates (5) has been prepared in four steps from peracetylated sugar and 1,3-dibromo-2-propanol in 60-73\% yields. D-Glucose, D-mannose, D-galactose, D-xylose, D-ribose, and maltose are utilized as sugar molecules in this work. The diamine moiety was connected to the C1 carbon of the glycopyranose ring via an O-glycoside bond. All of the anomeric configurations and sugar puckering conformations, except in the D-maltose derivative, were determined by X-ray crystallography of the diazido or dibromo precursors. While glycosidation of peracetylated galactopyranose with 1,3-dibromo-2-propanol in the presence of boron trifluoride afforded both anomers, the neighboring group participation of the 2-acetoxy group yielded a single anomer for the other substrates. This method has been used to synthesize a library of sugar-pendant diamines including an OH-protected derivative (6), and an N,N {\textquoteright} -diisopropyl-substituted derivative (7). A similar series of reactions using 2,3-dibromo-1-propanol gave ethylenediamine-type derivatives (11), and bis(bromomethyl)bis(hydroxymethyl)methane (12) gave bisglucose-pendant derivatives (16).}, keywords = {BINDING-PROPERTIES, C-2 EPIMERIZATION, CARBON SKELETON, D-GLUCOSE, ETHYLENEDIAMINE, LIGANDS, N-GLYCOSIDES, NICKEL(II) COMPLEXES, PHOTOCYTOTOXICITY, WATER}, isbn = {0022-3263}, url = {://000168911300018}, author = {Mikata, Y. and Shinohara, Y. and Yoneda, K. and Nakamura, Y. and Esaki, K. and Tanahashi, M. and Brudzinska, I. and Hirohara, S. and Yokoyama, M. and Mogami, K. and Tanase, T. and Kitayama, T. and Takashiba, K. and Nabeshima, K. and Takagi, R. and Takatani, M. and Okamoto, T. and Kinoshita, I. and Doe, M. and Hamazawa, A. and Morita, M. and Nishida, F. and Sakakibara, T. and Orvig, Chris and Yano, S.} } @article {5159, title = {A thermodynamic study of 1-propanol-glycerol-H2O at 25 degrees C: Effect of glycerol on molecular organization of H2O}, journal = {Journal of Solution Chemistry}, volume = {30}, number = {11}, year = {2001}, note = {ISI Document Delivery No.: 514HPTimes Cited: 29Cited Reference Count: 36}, month = {Nov}, pages = {1007-1028}, type = {Article}, abstract = {The excess chemical potential, partial molar enthalpy, and volume of 1-propanol were determined in ternary mixtures of 1-propanol-glycerol-H2O at 25degreesC. The mole fraction dependence of all these thermodynamic functions was used to elucidate the effect of glycerol on the molecular organization of H2O. The glycerol molecules do not exert a hydrophobic effect on H2O. Rather, the hydroxyl groups of glycerol, perhaps by forming clusters via its alkyl backbone with hydroxyl groups pointing outward, interact with H2O so as to reduce the characteristics of liquid H2O. The global hydrogen bond probability and, hence, the percolation nature of the hydrogen bond network is reduced. In addition, the degree of fluctuation inherent in liquid H2O is reduced by glycerol perhaps by participating in the hydrogen bond network via OH groups. At infinite dilution, the pair interaction coefficients in enthalpy were evaluated and these data suggest a possibility that the interaction is mediated through H2O.}, keywords = {1-propanol-glycerol-H2O, AQUEOUS-SOLUTIONS, CHEMICAL-POTENTIALS, effect of glycerol on H2O, enthalpy of 1-propanol, ENTROPIES, excess chemical potential, fluctuations, interactions, INTERMOLECULAR, INTERMOLECULAR INTERACTIONS, MIXING SCHEMES, partial molar, PARTIAL MOLAR ENTHALPIES, partial molar volume of 1-propanol, TERT-BUTANOL, VOLUMES, WATER}, isbn = {0095-9782}, url = {://000173433400005}, author = {Parsons, M. T. and Westh, P. and Davies, J. V. and Trandum, C. and To, E. C. H. and Chiang, W. M. and Yee, E. G. M. and Koga,Yoshikata} } @article {4843, title = {Chirally modified zeolites as reaction media: Photochemistry of an achiral tropolone ether}, journal = {Organic Letters}, volume = {2}, number = {2}, year = {2000}, note = {ISI Document Delivery No.: 278ZETimes Cited: 49Cited Reference Count: 26}, month = {Jan}, pages = {119-121}, type = {Article}, abstract = {[GRAPHICS] Zeolites modified with chiral inductors serve as media for performing chiral induction during photochemical reactions of organic molecules. The photochemical behavior of achiral tropolone ethyl phenyl ether illustrates this unique feature of a zeolite.}, keywords = {AROMATICS, benzene, CATION-PI INTERACTIONS, CHEMISTRY, interactions, ION, MODEL, MOLECULE, STATE ORGANIC-PHOTOCHEMISTRY, WATER}, isbn = {1523-7060}, url = {://000085018200006}, author = {Joy, A. and Scheffer, J. R. and Ramamurthy, V.} } @article {4920, title = {Electrospray ionization of alkali and alkaline earth metal species. Electrochemical oxidation and pH effects}, journal = {Journal of Mass Spectrometry}, volume = {35}, number = {8}, year = {2000}, note = {ISI Document Delivery No.: 347MUTimes Cited: 7Cited Reference Count: 49}, month = {Aug}, pages = {981-989}, type = {Article}, abstract = {The utility of electrospray ionization mass spectrometry (ESI-MS) for characterizing dissolved metal species has generated considerable interest in the use of this technique for metal speciation, However, the development of accurate speciation methods based on ESI-R;IS requires a detailed understanding of the mechanisms by which dissolved metal species are ionized during electrospray. We report how the analysis of alkali and alkaline earth metal species pro,ides new information about some of the processes that affect electrospray ion yield. Selected metal ions and organic ligands were combined in 50:50 water-acetonitrile buffered with acetic acid or ammonium acetate and analyzed by flow injection ESI-MS using mild electrospray conditions. Species formed by alkali metal ions with thiol and oxygen-donating ligands were detected in acidic and neutral pH solutions. Electrochemical oxidation of N,N-diethyldithiocarbamate and glutathione during electrospray was indicated by detection of the corresponding disulfides as protonated or alkali metal species, The extent of ligand oxidation depended on solution pH and the dissociation constant of the thiol group, Tandem mass spectrometric experiments suggested that radical cations such as [NaL](+.) (where L = N,N -diethyldithiocarbamate) can be generated by in-source fragmentation of disulfide species. Greater complexation of alkali metals at neutral pH tvas indicated by a corresponding decrease in the relative abundance of the free metal ion, The number of alkali metal ions bound by glutathione and phthalic acid also increased with increasing pH, in accordance with thermodynamic equilibrium theory. Alkaline earth metal species were detected only in acidic solutions, the absence of 8-hydroxyquinoline complexes being attributed to their relative instability and subsequent dissociation during electrospray, Hence, accurate speciation by ESI-MS depends on experimental conditions and the intrinsic properties of each analyte, Copyright (C) 2000 John Wiley \&; Sons, Ltd.}, keywords = {cell, COMPLEXES, electrochemical oxidation, ELECTROPHORESIS, electrospray ionization, ION-TRAP, MASS-SPECTROMETRY, metal speciation, OLIGONUCLEOTIDES, PEPTIDES, pH effects, PROTEINS, STOICHIOMETRY, thiol ligands, WATER}, isbn = {1076-5174}, url = {://000088934400006}, author = {Ross, A. R. S. and Ikonomou, M. G. and Orians, K. J.} } @article {4895, title = {Forces between like-charged walls in an electrolyte solution: A comparison of McMillan-Mayer results for several models}, journal = {Journal of Chemical Physics}, volume = {113}, number = {7}, year = {2000}, note = {ISI Document Delivery No.: 344XYTimes Cited: 8Cited Reference Count: 28}, month = {Aug}, pages = {2851-2855}, type = {Article}, abstract = {The interaction of like-charged walls immersed in aqueous solutions with monovalent counterions is investigated at the McMillan-Mayer (MM) level of description. The net pressure acting between the walls is obtained by applying the anisotropic hypernetted-chain theory. The MM approach requires solvent-averaged ion-ion potentials of mean force as input. Results based on "realistic" models for Na+ and Cl- in water are available in the literature and these are used in the present calculations. The wall-wall interactions obtained can differ dramatically from the primitive model (dielectric continuum solvent) case. For some models attractive wall-wall forces are observed at small separations. The MM theory is found to be rather sensitive to details of the counterion-counterion potential of mean force, and different models for the same counterion can give qualitatively different results. At present it is difficult to evaluate the relative accuracy of the different models that have been proposed. However, the results presented here give at least an idea of the interesting possibilities that lie in the physically realistic range. (C) 2000 American Institute of Physics. [S0021-9606(00)50331-6].}, keywords = {APPROXIMATION, DOUBLE-LAYER, FORCE, HARD-SPHERES, IMAGE INTERACTIONS, INHOMOGENEOUS COULOMB FLUIDS, MEAN, MOLECULAR-DYNAMICS, PLANAR SURFACES, SODIUM-CHLORIDE, WATER}, isbn = {0021-9606}, url = {://000088787400034}, author = {Otto, F. and Patey, G. N.} } @article {4747, title = {A proton nuclear magnetic resonance relaxation study of C12E6/D2O}, journal = {Journal of Physical Chemistry B}, volume = {104}, number = {37}, year = {2000}, note = {ISI Document Delivery No.: 355JYTimes Cited: 8Cited Reference Count: 25}, month = {Sep}, pages = {8782-8791}, type = {Article}, abstract = {Aqueous solutions of the nonionic surfactant, n-dodecylhexaoxyethylene glycol [C12H25(OCH2CH2)(6)OH], termed C12E6, form various phases at room temperature: there is a micellar phase at high water content, hexagonal, cubic, and lamellar mesophases at intermediate water contents, and an isotropic phase at very low water content. Proton nuclear magnetic resonance (NMR) T-1(-1) relaxation rates have been measured for the C12E6/D2O system as a function of composition, spectral frequency, and temperature. The results are interpreted in terms of the possible molecular motions for the C12E6 molecule in the different phases. A review of relaxation theory is presented with special attention to molecular exchange between sites that are associated with different relaxation rates.}, keywords = {CHAIN, CYCLING, LYOTROPIC LIQUID-CRYSTAL, NMR-RELAXOMETRY, PHASES, POTASSIUM PALMITATE, REPTATION, SPIN-LATTICE RELAXATION, SURFACTANTS, SYSTEM, WATER}, isbn = {1089-5647}, url = {://000089383600004}, author = {Burnell, E. E. and Capitani, D. and Casieri, C. and Segre, A. L.} } @article {4458, title = {Electronic spectra of YOH and YOD in the visible region: Strong vibronic coupling between the (B)over-tilde(1)II and (C)over-tilde(1)Sigma(+) states}, journal = {Journal of Molecular Spectroscopy}, volume = {196}, number = {1}, year = {1999}, note = {ISI Document Delivery No.: 208RCTimes Cited: 7Cited Reference Count: 41}, month = {Jul}, pages = {45-69}, type = {Article}, abstract = {Laser excitation spectra of yttrium monohydroxide, YOH, have been recorded in the 500-625 nm wavelength region. Rotational analysis of bands of YOH and YOD has shown that the ground state is (X) over tilde(1)Sigma(+), with the structure r(0)(Y-O) = 1.948(6) Angstrom, r(0)(O-H) = 0.920(6) Angstrom; the bending frequency (nu(2), pi) is 313.73 cm(-1) (237.43 cm(-1) in YOD) and the Y-O stretching frequency (nu(3), sigma(+)) is 673.83 cm(-1) (655.34 cm(-1)). Two excited electronic states have been identified; they are assigned as (B) over tilde(1)Pi (16 449 cm(-1)) and (C) over bar(1)Sigma(+) (18 509 cm(-1)). Unusually strong vibronic coupling through the bending vibration occurs between these two states, which causes their vibrational structures to be highly irregular; assignments have only been possible following extensive wavelength-resolved fluorescence experiments. The vibronic coupling raises the bending frequency of the (C) over tilde(1)Sigma(+) state to 457 cm(-1) and reduces that of the lower Born-Oppenheimer component of the (B) over tilde(1)Pi state (which has A{\textquoteright} symmetry in the C, point group) to the extent that the molecule becomes nonlinear, with a potential barrier at the linear configuration of about 120 cm(-1). The presence of the potential barrier is clearly demonstrated by the level structure of YOD, where the Sigma(+) vibronic component of the 010 vibrational level (linear molecule notation) lies 1.4 cm(-1) below the 000 level. The upper Born-Oppenheimer component, which has A " symmetry, is unaffected; its bending frequency is similar to that of the ground state. Perturbations occur in both the (B) over tilde(1)Pi and (C) over tilde(1)Sigma(+) states; some of these represent local interactions between the two of them, but others are caused by higher vibrational levels of lower-lying "dark" electronic states. Over 40 ground state vibrational levels have been identified for both YOH and YOD from the wavelength-resolved fluorescence spectra. (C) 1999 Academic Press.}, keywords = {15-K, laser spectroscopy, METHYLIDYNE, ORBITAL ANGULAR-MOMENTUM, RESONANCE, SYSTEM, TRANSITION, TRIATOMIC-MOLECULES, VANADIUM, WATER}, isbn = {0022-2852}, url = {://000081004300006}, author = {Adam, A. G. and Athanassenas, K. and Gillett, D. A. and Kingston, C. T. and Merer, A. J. and Peers, J. R. D. and Rixon, S. J.} } @article {4711, title = {Enzymatic methylation of arsenic compounds. VII. Monomethylarsonous acid (MMA(III)) is the substrate for MMA methyltransferase of rabbit liver and human hepatocytes}, journal = {Toxicology and Applied Pharmacology}, volume = {158}, number = {1}, year = {1999}, note = {ISI Document Delivery No.: 216QCTimes Cited: 80Cited Reference Count: 33}, month = {Jul}, pages = {9-15}, type = {Article}, abstract = {Inorganic arsenite is methylated by some, but not all, animal species to dimethylarsinic acid (DMA), The monomethyl compound containing arsenic in an oxidation state of +3 has been proposed as an intermediate. Using highly purified arsenic methyltransferase from rabbit liver and the partially purified enzyme from Chang human liver hepatocytes, the activity of methylarsonic acid (MMA(V)) and methylarsonous acid (MMA(III)) as a substrate has been characterized by Michaelis-Menten kinetics. The rabbit liver enzyme has a greater affinity for MMA(III) (K-m = 0.92 x 10(-5) M) than MMA(V) (K-m = 7.0 x 10(-5) M) since the smaller the K, the greater the affinity. In addition, a dithiol, reduced lipoic acid or dithiothreitol, appears to be more active than GSH in satisfying the thiol requirement of the enzyme. Although investigators have been unable to detect the arsenic methyltransferase in surgically removed human liver, its presence in Chang human hepatocytes now has been established. The K-m for MMA(III), 3.04 x 10(-6), using MMAIII methyltransferase from Chang human hepatocytes was not greatly different from that of the rabbit liver enzyme, (C) 1999 Academic Press.}, keywords = {BINDING, CYTOSOL, IN-VITRO, INVITRO, METABOLISM, TOXICITY, WATER, WEST-BENGAL}, isbn = {0041-008X}, url = {://000081452500002}, author = {Zakharyan, R. A. and Ayala-Fierro, F. and Cullen, W. R. and Carter, D. M. and Aposhian, H. V.} } @article {4613, title = {Excess partial molar enthalpy of 1-propanol in 1-propanol-NaCl-H2O at 25 degrees C: The effect of NaCl on molecular organization of H2O}, journal = {Journal of Physical Chemistry B}, volume = {103}, number = {15}, year = {1999}, note = {ISI Document Delivery No.: 189YNTimes Cited: 23Cited Reference Count: 26}, month = {Apr}, pages = {2981-2983}, type = {Article}, abstract = {Excess partial molar enthalpies of l-propanol, H-1p(E), in 1-propanol-NaCl-H2O were measured directly, accurately, and in small increments in mole fraction of 1-propanol, x(1P), at 25 degrees C in the range x(NaCl) < 0.04 x(NaCl) is the mole fraction of NaCl. The enthalpic interaction function, H-1P-1P(E), between l-propanol molecules was then evaluated. H-1P-1P(E) is a convenient, model-free measure for the intermolecular interaction in terms of enthalpy. The behavior of these thermodynamic quantities was compared with that of the binary 1-propanol-H2O. Based on the knowledge accumulated in our laboratory on the binary aqueous l-propanol, the effect of NaCl on H2O became apparent. Our tentative conclusions are that (1) a NaCl molecule "binds" to seven or eight molecules of H2O on dissolving into H2O, and (2) the reminder of bulk H2O away from solute NaCl is not affected and stays almost the same as pure H2O.}, keywords = {2-BUTOXYETHANOL, AQUEOUS SODIUM-CHLORIDE, CLUSTERS, EQUILIBRIUM, fluctuations, INTERMOLECULAR INTERACTIONS, LYSOZYME, SPECTROSCOPY, vibrational, VOLUMES, WATER}, isbn = {1089-5647}, url = {://000079934100023}, author = {Matsuo, H. and To, E. C. H. and Wong, D. C. Y. and Sawamura, S. and Taniguchi, Y. and Koga,Yoshikata} } @article {4611, title = {A H-1-NMR study of the permeation of glycolic acid through phospholipid membranes}, journal = {Biochimica Et Biophysica Acta-Biomembranes}, volume = {1416}, number = {1-2}, year = {1999}, note = {ISI Document Delivery No.: 162BFTimes Cited: 10Cited Reference Count: 31}, month = {Jan}, pages = {333-338}, type = {Article}, abstract = {The transmembrane permeability coefficient of the alpha-hydroxyacid, glycolic acid, has been measured for egg phosphatidylcholine large unilamellar vesicles. The determination of the vesicle concentration independent first-order rate constant for membrane transport and the permeability coefficient were made using an NMR technique employing shift agents. Both the temperature dependence and the dependence on cholesterol content were investigated. The activation energy and the Arrhenius pre-exponential factor were found to be dependent on the cholesterol content. A marked increase in both parameters was observed up to 20 mol\% cholesterol, with a further, small increase up to 50\%. The pH dependence of permeability was also investigated. An increase in permeability is observed with a decrease in pH, providing a possible explanation for the effectiveness of glycolic acid in skin treatment. (C) 1999 Published by Elsevier Science B.V. All rights reserved.}, keywords = {ACETIC-ACID, acne, aging of the, BILAYER-MEMBRANES, CHOLESTEROL, CHOLESTEROL CONTENT, glycolic acid, H-1-NMR, HUMAN ERYTHROCYTES, LAIDLAWII-B-CELLS, LARGE UNILAMELLAR VESICLES, lipid, NONELECTROLYTE, NUCLEAR MAGNETIC-RESONANCE, permeability, SKIN, transmembrane permeability, TRANSPORT, WATER}, isbn = {0005-2736}, url = {://000078324700030}, author = {Males, R. G. and Herring, F. G.} } @article {4710, title = {Synthesis and characterization of AlPO4-36: a novel aluminophosphate molecular sieve with ATS structure}, journal = {Microporous and Mesoporous Materials}, volume = {32}, number = {3}, year = {1999}, note = {ISI Document Delivery No.: 261CDTimes Cited: 16Cited Reference Count: 32}, month = {Dec}, pages = {241-250}, type = {Article}, abstract = {AlPO-36, the parent member of the ATS, molecular sieve structure type, has been synthesized hydrothermally from gels containing only Al and P oxides. Four series of syntheses were carried out to determine the best conditions for the preparation of AlPO-36 free of AlPO-H3, Characterization of the synthesis products was performed using X-ray diffraction (XRD), chemical analysis, scanning electron microscopy (SEM), N-2 adsorption, X-ray photoelectron spectroscopy (XPS) and Al-27 and P-31 MAS NMR. X-ray powder diffraction patterns are comparable to those previously reported for MAPO-36. (C) 1999 Elsevier Science B.V. All rights reserved.}, keywords = {ADSORPTION, Al-27 and P-31 MAS NMR, AlPO-36, ATS structure type, FRAMEWORK TOPOLOGY, molecular sieves, scanning electron microscopy, SOLID-STATE NMR, THERMAL-STABILITY, VPI-5, WATER, XPS, XRD}, isbn = {1387-1811}, url = {://000083989500002}, author = {Zahedi-Niaki, M. H. and Xu, G. Y. and Meyer, H. and Fyfe, C. A. and Kaliaguine, S.} } @article {4208, title = {Analyte-additive interactions in nonaqueous capillary electrophoresis: a critical review}, journal = {Trac-Trends in Analytical Chemistry}, volume = {17}, number = {7}, year = {1998}, note = {ISI Document Delivery No.: 107HPTimes Cited: 54Cited Reference Count: 40}, month = {Aug}, pages = {424-434}, type = {Review}, abstract = {This article reviews the recent developments in nonaqueous capillary electrophoresis and discusses the effect of the solvent on analyte-additive interactions. When nonaqueous solvents are used, solvophobic interactions are generally weaker than those in water; therefore, those additives that can change the analyte mobility through electrostatic or donor-acceptor interactions should be further explored. (C) 1998 Elsevier Science B.V. All rights reserved.}, keywords = {ANIONS, CHIRAL SEPARATION, cohesion energy, density, dielectric constant, electron donor-acceptor interaction, FORMAMIDE, ION, MEDIA, nonaqueous capillary electrophoresis, SEPARATION SELECTIVITY, solvent effect, SOLVENTS, SURFACTANTS, WATER, ZONE ELECTROPHORESIS}, isbn = {0165-9936}, url = {://000075202300022}, author = {Bowser, M. T. and Kranack, A. R. and Chen, D. D. Y.} } @article {4433, title = {How dilute is the Henry{\textquoteright}s law region? II}, journal = {Journal of Physical Chemistry B}, volume = {102}, number = {25}, year = {1998}, note = {ISI Document Delivery No.: ZV967Times Cited: 13Cited Reference Count: 12}, month = {Jun}, pages = {4982-4987}, type = {Article}, abstract = {Vapor pressures for n-hexane-c-hexane were measured at extremely low concentrations of n-hexane. The vapor pressure data seemed to indicate within the experimental uncertainty that, in the range of the mole fraction of n-hexane x(nH) < 0.015, the solution obeys Henry{\textquoteright}s law. However, the excess partial molar enthalpy of n-hexane and c-hexane measured by a sensitive microcalorimeter showed that the Henry{\textquoteright}s law is not operative above x(nH) or x(cH) approximate to 2 x 10(-4), the lowest accessible for the calorimetry technique available at present. The excess partial molar enthalpies of the following solutes were also determined in aqueous solutions in an extremely dilute region. Within the experimental technique at our disposal, we could not locate a finite range of Henry{\textquoteright}s law. Thus, whether the solute-solute interaction becomes actually absent or whether such absence depends on the nature of the solvent (H2O or organic) cannot be addressed at present. For aqueous solutions, however, the lower limits of the mole fraction of a solute, above which the solutions behave as non-Henry-like, were found by an order of magnitude lower: 1 x 10(-5) for 2-butoxyethanol; 3 x 10(-5) for tert-butyl alcohol; 2 x 10(-5) for glycerol; 3 x 10(-5) for urea.}, keywords = {H2O, PERCOLATION, TERT-BUTANOL MIXTURES, VAPOR-PRESSURES, WATER}, isbn = {1089-5647}, url = {://000074360300017}, author = {Westh, P. and Haynes, C. A. and Koga,Yoshikata} } @article {4155, title = {Intermolecular interactions of lysozyme and small alcohols: A calorimetric investigation}, journal = {Journal of Physical Chemistry B}, volume = {101}, number = {29}, year = {1997}, note = {ISI Document Delivery No.: XM058Times Cited: 23Cited Reference Count: 34}, month = {Jul}, pages = {5755-5758}, type = {Article}, abstract = {Isothermal titration calorimetry was used to measure transfer enthalpies of hen egg white lysozyme from water to aqueous solutions of methanol, ethanol, 1-propanol, glycerol, and 2,2,2-trifluoroethanol. Excess partial molar enthalpies of lysozyme at infinite dilution in the alcoholic solvents, H-infinity(L)E, were calculated, and the dependence of H-infinity(L)E on the concentration of the alcohol, was utilized to elucidate the enthalpy of alcohol-protein interactions. Results show that, at low alcohol concentrations, alcohol-protein interactions are unfavorable in terms of enthalpy (endothermic), while at higher concentrations they are favorable (exothermic). The change from endothermic to exothermic interactions happened sharply over a narrow alcohol concentration interval, and was found to occur concurrently with denaturation of the protein in some but not all cases. Comparison of the present results with previous investigations of simple binary and ternary aqueous solutions suggests that the change of sign of the interaction enthalpy is related to the water-water hydrogen bonding properties in the alcohol mixtures. It is argued that modifications by the alcohol of the percolated hydrogen bond network govern the enthalpy of alcohol-lysozyme interactions in the most water-rich samples. This suggests that occupancy by the alcohol of a binding site on the surface of the protein may not be necessary for the alcohol to affect the properties of the protein. At higher alcohol concentrations the observed interaction enthalpies are dominated by direct ({\textquoteright}{\textquoteright}intrinsic{\textquoteright}{\textquoteright}) effects of protein-alcohol interactions, which are exothermic.}, keywords = {25-DEGREES-C, ENERGIES, GLOBULAR-PROTEINS, INDUCED REVERSIBLE DENATURATION, MIXTURES, MONOHYDRIC ALCOHOLS, STABILIZATION, THERMODYNAMIC INVESTIGATIONS, TRIFLUOROETHANOL, VAPOR-PRESSURES, WATER}, isbn = {1089-5647}, url = {://A1997XM05800021}, author = {Westh, P. and Koga,Yoshikata} } @article {3816, title = {Composition and distribution of polycyclic aromatic hydrocarbon contamination in surficial marine sediments from Kitimat Harbor, Canada}, journal = {Science of the Total Environment}, volume = {181}, number = {3}, year = {1996}, note = {ISI Document Delivery No.: UA427Times Cited: 95Cited Reference Count: 46}, month = {Mar}, pages = {265-278}, type = {Article}, abstract = {Surficial marine sediments from 20 sites within the Kitimat fjord system were analyzed for polycyclic aromatic hydrocarbons (PAHs), Levels of the sum of the 16 USEPA priority pollutant PAHs varied from below detection limits (ca, 1 mu g . g(-1)) to over 10 000 mu g . g(-1). Sediment PAH levels were highest in the immediate vicinity of a large aluminum smelter at the head of Kitimat Arm, and declined rapidly with increasing distance from the smelter. However, even at some of the more distant sites which are geographically isolated from the smelter PAH levels were elevated. The PAH distribution in the fjord system is consistent with a combination of aeolian and fluvial transport of PAHs emitted by the aluminum smelter at the head of Kitimat Arm. The mixture of PAHs present was qualitatively similar in all samples analyzed, including those from the distant sites. All aspects of the PAH composition are consistent with combustion generated PAHs. A correlation between PAH levels and sediment organic carbon was observed; however, this was only significant for highly contaminated sites in the harbor. This probably reflects the high organic content of particulate emissions from the smelter, rather than equilibrium partitioning of PAHs to sediment organic carbon within the harbor itself.}, keywords = {AIR, aluminum smelter, BAY, contamination, FLUXES, marine sediments, MEDITERRANEAN-SEA, POLLUTANTS, polycyclic aromatic hydrocarbons, sorption, WASHINGTON, WATER}, isbn = {0048-9697}, url = {://A1996UA42700011}, author = {Simpson, C. D. and Mosi, A. A. and Cullen, W. R. and Reimer, K. J.} } @article {3655, title = {Geometric factors in the structural and thermodynamic properties of copper(II) complexes with tripodal tetraamines}, journal = {Inorganic Chemistry}, volume = {35}, number = {26}, year = {1996}, note = {ISI Document Delivery No.: VZ074Times Cited: 60Cited Reference Count: 23}, month = {Dec}, pages = {7798-7803}, type = {Article}, abstract = {The tripodal tetramine ligands N(CH2CH2CH2NH2)(3) (trpn) and N[(CH2CH2CH2NH2)(2)(CH2CH2NH2)] (332) react with Cu(NO3)(2) . 3H(2)O in water to give light blue copper(II) complexes. These were characterized by X-ray crystallography to be the square-pyramidal binuclear Cu(II) species [Cu(trpn)(NO3)](2)(NO3)(2) and [Cu(332)(NO3)]2(NO3)(2) . 2H(2)O. Selected crystallographic details are as follows, respectively: formula C18H18Cu2N12O12, C16H18Cu2N12O14; M = 751.74, 759.72 Da; both triclinic; both ; a = 8.4346(8), 8.446(4) Angstrom; b = 9.0785(9), 8.744(3) Angstrom; c = 11.9310(12), 12.007(3) Angstrom; alpha = 94.50(1), 102.68(2)degrees; beta = 103.56(1), 94.79(3)degrees; gamma = 117.42(1), 117.69(4)degrees; V = 769.7(5), 748.2(13) Angstrom(3); both Z = 1; R = 4.16, 4.00; R(w) = 11.34, 6.74 for 2887 (I greater than or equal to 2 sigma(I)), 2457 (F-o(2) greater than or equal to 3 sigma(F-o(2))) structure factors and 199, 209 refined parameters. The binuclear complex dications exhibit a square pyramidal coordination geometry around the copper atoms. Three amine functions (one tertiary and two primary) are coordinated to one copper atom and the remaining primary amine arm bridges to the second copper center. Potentiometric and visible spectrophotometric studies show that a protonated square-pyramidal [Cu(HL)(H2O)(2)](3+) cation (L = trpn, 332, 322 (322 = N[(CH2CH2CH2NH2)(CH2CH2NH2)(2)])) predominates in the intermediate pH region, in contrast to the established trigonal-bipyramidal structure of the tren (tren = tris(2-aminoethyl)amine)) complex of Cu(II). Each [Cu(HL)(H2O)(2)](3+) has one protonated uncoordinated ligand arm which explains the formation of the binuclear species at neutral pH.}, keywords = {EXCHANGE, WATER}, isbn = {0020-1669}, url = {://A1996VZ07400050}, author = {DittlerKlingemann, A. M. and Orvig, Chris and Hahn, F. E. and Thaler, F. and Hubbard, C. D. and vanEldik, R. and Schindler, S. and Fabian, I.} } @article {3822, title = {Micelle-induced change of mechanism in the reaction of muonium with acetone}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {74}, number = {11}, year = {1996}, note = {ISI Document Delivery No.: WC124Times Cited: 1Cited Reference Count: 25}, month = {Nov}, pages = {1945-1951}, type = {Article}, abstract = {Muonium atoms add to the O atom of the carbonyl group of acetone to give the muonated free radical (CH3)(2)C-O-Mu when the reaction takes place in water or hydrocarbons, but not when the acetone is localized in micelles. Micelles have no effect on the formation of muonated cyclohexadienyl radicals when muonium reacts with benzene under similar conditions. The addition reaction with acetone appears to have been subsumed by a faster alternative reaction in the micellar environment. Evidence is presented for this interpretation rather than for an inhibition of the radical or for a shift in the muon level-crossing resonance spectrum with hydrogen (muonium) bonding, though major shifts are seen for the spectrum of this radical in pure solvents of widely different dielectric constant. It is suggested that muonium{\textquoteright}s {\textquoteright}{\textquoteright}abstraction{\textquoteright}{\textquoteright} reaction takes over in micelles because significant micelle-induced enhancement effects were previously observed in that type of reaction. The data are consistent with a I ate constant for the abstraction reaction of muonium with acetone in micelles of >6 x 10(8) M(-1) s(-1).}, keywords = {AQUEOUS-SOLUTIONS, H/Mu abstraction, H/Mu-addition, HYDROGEN-ATOMS, kinetic isotope effects, LEVEL-CROSSING-RESONANCE, micelle enhancement, muonium, radical formation, SOLUTES, SPECTROSCOPY, WATER}, isbn = {0008-4042}, url = {://A1996WC12400008}, author = {Stadlbauer, J. M. and Venkateswaran, K. and Gillis, H. A. and Porter, G. B. and Walker, D. C.} } @article {3860, title = {Study of a commercial SiO2 sol and gel by small angle x-ray scattering: Effect of sample thickness and interpretation by means of smoluchowski scheme}, journal = {Clays and Clay Minerals}, volume = {44}, number = {2}, year = {1996}, note = {ISI Document Delivery No.: UL994Times Cited: 4Cited Reference Count: 35}, month = {Apr}, pages = {197-213}, type = {Article}, abstract = {Ludox HS SiO2 sols at high concentrations show a peak in small angle x-ray scattering (SAXS) reminiscent to a {\textquoteright}{\textquoteright}structure.{\textquoteright}{\textquoteright} The appearance of such a peak was found to depend crucially on the thickness of the sample cell used for SAXS measurements. The thinner the cell used, the more prominent the peak. When the thickness was larger than 2 mm, it was no longer observable. When sols were treated with activated charcoal powders (in order to remove a surfactant) the peak became less prominent. For the cases where clear features for structure were absent (thick sample regime), the Smoluchowski scheme was utilized to study the nature of sols. Namely, the distribution of the Smoluchowski species were estimated by numerically calculating the size distribution of particles directly from SAXS data. The distribution was found basically bimodal, and the main distribution peak, particularly for dilute sols (less than 5 wt\%), was consistent with primary particles of SiO2. The second distribution peak was strongly dependent on the concentration of SiO2 particles. The observed trend was that the higher the concentration of SiO2 particles, the more prominent the second distribution peak and the locus of the maximum tended to move toward a smaller value in diameter. This behavior of the second distribution peak of the Smoluchowski species is no doubt a manifestation of the interparticle correlation. The observation of such behavior may provide a convenient means to characterize sols with interparticle correlation. This method was also applied for characterizing gels formed when the pH values were altered.}, keywords = {COLLOIDAL SILICA, dependence of sample thickness, Ludox HS SiO2, MIXTURES, MULTIPLE-SCATTERING, NEUTRON-SCATTERING, SAXS, SCHEME, Smoluchowski, STABILITY, structure in sol, SYSTEMS, WATER}, isbn = {0009-8604}, url = {://A1996UL99400005}, author = {Xu, Y. N. and Hiew, P. L. and Klippenstein, M. A. and Koga,Yoshikata} } @article {3681, title = {Synthesis of hydroxyl-footed cavitands}, journal = {Journal of Organic Chemistry}, volume = {61}, number = {4}, year = {1996}, note = {ISI Document Delivery No.: TX420Times Cited: 28Cited Reference Count: 30}, month = {Feb}, pages = {1505-1509}, type = {Article}, keywords = {CAVITIES, HOST GUEST COMPLEXATION, MOLECULAR VESSELS, WATER}, isbn = {0022-3263}, url = {://A1996TX42000050}, author = {Gibb, B. C. and Chapman, R. G. and Sherman, J. C.} } @article {3575, title = {COMPLEXES OF TRIVALENT METAL-IONS WITH POTENTIALLY HEPTADENTATE N4O3 SCHIFF-BASE AND AMINE PHENOL LIGANDS OF VARYING RIGIDITY}, journal = {Inorganic Chemistry}, volume = {34}, number = {8}, year = {1995}, note = {ISI Document Delivery No.: QT603Times Cited: 67Cited Reference Count: 47}, month = {Apr}, pages = {2164-2178}, type = {Article}, abstract = {{The synthesis and characterization of several potentially heptadentate N4O3 Schiff bases and amine phenols, as well as a series of their mononuclear and dinuclear complexes with indium and the lanthanides are reported. Schiff bases containing imidazolidine rings were the products of the known condensation reaction of triethylenetetramine with 3 equiv of 5-substituted salicylaldehydes to form H(3)api (5-H-substituent), H(3)Clapi (5-Cl-substituent), or H(3)Brapi (5-Br-substituent); KBH4 reduction of these Schiff bases gave the appropriate isomeric N4O3 amine phenols H-3(1,2,4-btt) and H-3(1,1,4,-btt), as well as an acetone adduct, H-3(1,2,4-ahi). The Schiff bases reacted with 1 equiv of a lanthanide (Ln(3+)) nitrate to produce mononuclear nine-coordinated [Ln(H(3)Xapi)-(NO3)(3)] complex wherein the ligand adopts a tridentate capping coordination mode, whereas the amine phenols formed mononuclear seven-coordinate complexes with the lanthanides and indium; homodinuclear complexes [LnL]2 were also obtained with the Schiff bases. The X-ray structures of the Schiff bases H(3)api and H(3)Clapi, the mononuclear amine phenol complexes Yb(1,2,4-btt) . 0.5CH(3)OH and In(1,1,4-btt), and the homodinuclear Schiff base complex [La(Brapi)](2) . 2CHCl(3) have been determined. Crystals of H(3)api (C27H30N4O3) are monoclinic, space group P2(1)/a}, keywords = {BRIDGES, CRYSTAL, ETHER, LANTHANIDE COMPLEXES, MOLECULAR-STRUCTURE, SALTS, TETRAHYDRATE, WATER, X-RAY}, isbn = {0020-1669}, url = {://A1995QT60300032}, author = {Yang, L. W. and Liu, S. and Wong, E. and Rettig, S. J. and Orvig, Chris} } @article {3266, title = {POTENTIOMETRIC, CALORIMETRIC, AND SOLUTION NMR-STUDIES OF A TRIDENTATE LIGAND WHICH HAS A MARKED PREFERENCE FOR FORMATION OF BIS(LIGAND) VERSUS MONO(LIGAND) LANTHANIDE COMPLEXES AND WHICH EXHIBITS HIGH SELECTIVITY FOR HEAVIER LANTHANIDES}, journal = {Journal of the American Chemical Society}, volume = {117}, number = {45}, year = {1995}, note = {ISI Document Delivery No.: TE739Times Cited: 69Cited Reference Count: 59}, month = {Nov}, pages = {11230-11238}, type = {Article}, abstract = {A new water-soluble N4O3 tripodal amine phenol ligand, tris(((2-hydroxy-5-sulfobenzyl)amino)ethyl)amine (H(3)TRNS) has been synthesized, and its complexation properties with six lanthanide(III) ions (Ln, Nd, Gd, Ho, Yb, Lu) have been probed. In water, the ligand coordinates in a tridentate fashion through the three phenolate oxygen atoms to give mono- and bis(ligand) complexes. The bis complexes are proposed to be 7-coordinate containing one bound water as evinced by O-17 NMR experiments on the Dy3+ complex. while the mono complexes are proposed to have a coordination number of eight or nine. The stepwise formation constants for the 1:1 and 2:1 (L:M) complexes have been measured at 25 degrees C (mu = 0.16 M NaCl) for Nd3+ (log K-1 = 6.41, log K-2 6.34), Gd3+ (log K-1 = 6.67, log K-2 = 7.69), Ho3+ (log K-1 = 7.67, log K-2 = 8.75), and Yb3+ (log K-1 = 8.53, log K-2 = 9.73). The formation constants show an increasing affinity and an unprecedented selectivity for the heavier lanthanides (beta(2(yb)) - beta(2(Nd)) = 10(5.5)). Furthermore, the stepwise stability constant for the 2:1 complex is increasingly greater than that for the 1:1 complexes of Gd3+, Ho3+, and Yb3+, while K-1 and K-2 for the 1:1 and 2:1 complexes of Nd3+ are approximately the same. Solution calorimetry shows that the selectivity for the heavier lanthanides is an enthalpic effect (Delta H-beta 2 = -45.11 (Yb) and -13.71 kJ . mol(-1) (Nd)), while the anomalous behavior in formation constants (K-2 > K-1) is predominantly entropic (Delta S-2 > Delta S-1) and is rationalized in terms of salvation of the complexes, Lanthanum(III) forms only the 1:1 complex (log K = 5.65) which precipitates from solution.}, keywords = {AGENTS, AMINE PHENOL LIGANDS, AQUEOUS, BIOLOGICAL-SYSTEMS, CHEMISTRY, EXCHANGE, HEPTADENTATE LIGANDS, METAL-IONS, NUCLEAR MAGNETIC-RESONANCE, probes, SHIFT-REAGENTS, WATER}, isbn = {0002-7863}, url = {://A1995TE73900021}, author = {Caravan, P. and Hedlund, T. and Liu, S. and Sjoberg, S. and Orvig, Chris} } @article {3401, title = {VAPOR-PRESSURES OF DILUTE AQUEOUS T-BUTYL ALCOHOL - HOW DILUTE IS THE HENRYS LAW REGION}, journal = {Journal of Physical Chemistry}, volume = {99}, number = {16}, year = {1995}, note = {ISI Document Delivery No.: QU828Times Cited: 18Cited Reference Count: 11}, month = {Apr}, pages = {6231-6233}, type = {Article}, abstract = {Vapor pressures of aqueous t-butyl alcohol (TBA) were determined at 25 degrees C by the static method in the mole fraction range, 0.000 068 < x(TBA) < 0.006. The partial pressures of TBA, p(TBA), and those of H2O, p(W), were calculated by a numerical integration method developed by Boissonnas. It was pointed out that this method inevitably introduces errors in the first few data points from the dilute end, which will be self-corrected after several data points. Together with the data obtained for the range x(TBA) > 0.002 in the previous work (J. Phys. Chem. 1990, 94, 7700), reliable values of the excess partial molar Gibbs function of TBA, G(m)(E)(TBA), were obtained. It was concluded that at the most dilute point measured, x(TBA) 0.000 068 (m(TBA) = 0.0038 mol/kg), the solution is not yet dilute enough for Henry{\textquoteright}s law to be obeyed.}, keywords = {25-DEGREES-C, MIXING SCHEME, PARTIAL MOLAR ENTHALPIES, TERT-BUTANOL MIXTURES, WATER}, isbn = {0022-3654}, url = {://A1995QU82800069}, author = {Koga,Yoshikata} } @article {3185, title = {INTRAMOLECULAR SELECTIVITY OF MUONIUM TOWARDS CHLORINATED AROMATIC-COMPOUNDS}, journal = {Hyperfine Interactions}, volume = {87}, number = {1-4}, year = {1994}, note = {ISI Document Delivery No.: PA118Times Cited: 0Cited Reference Count: 166th International Conference on Muon Spin Rotation/Relaxation/ResonanceMAY 31-JUN 11, 1993MAUI, HI}, pages = {947-952}, type = {Proceedings Paper}, abstract = {Muon resonance studies show that muonium atoms (Mu) in ethanol add selectively to certain C-sites of aromatic compounds containing -Cl and -OH substituents. The sites chosen seem to be those carrying the lowest electron density. This helps to characterize Mu as a nucleophile in addition reactions and, in this respect, Mu differs from ordinary H-atoms. The study shows no apparent inter-molecular selectivity between a pair of aromatic solutes in an equimolar mixture, but strong intra-molecular selectivity in an ether composed of those two aromatic rings. This difference between intra- and inter-molecular selectivity is interpreted as kinetic in origin - arising from the {\textquoteright}caging effect{\textquoteright} of the solvent and peculiar to reactions close to the diffusion-controlled limit.}, keywords = {ADDITION-REACTIONS, AQUEOUS-SOLUTIONS, BENZOIC-ACID, HYDROGEN ISOTOPES, LEVEL-CROSSING RESONANCE, Pyrazine, WATER}, isbn = {0304-3843}, url = {://A1994PA11800018}, author = {Venkateswaran, K. and Stadlbauer, J. M. and Laing, M. E. and Klugkist, J. and Chong, D. P. and Porter, G. B. and Walker, D. C.} } @article {3198, title = {THE RESPONSE OF THE INDUCTIVELY-COUPLED ARGON PLASMA TO SOLVENT PLASMA LOAD - SPATIALLY-RESOLVED MAPS OF ELECTRON-DENSITY OBTAINED FROM THE INTENSITY OF ONE ARGON LINE}, journal = {Spectrochimica Acta Part B-Atomic Spectroscopy}, volume = {49}, number = {12-14}, year = {1994}, note = {ISI Document Delivery No.: QD364Times Cited: 13Cited Reference Count: 40}, month = {Oct-Dec}, pages = {1231-1250}, type = {Article}, abstract = {A survey of spatially resolved electron number density (n(e)) in the tail cone of the inductively coupled argon plasma (ICAP) is presented: all of the results of the survey have been radially inverted by numerical, asymmetric Abel inversion. The survey extends over the entire volume of the plasma beyond the exit of the ICAP torch; It extends over distances of z = 5-25 mm downstream from the induction coil, and over radial distances of +/- 8 mm from the discharge axis. The survey also explores a range of inner argon flow rates (Q(IN)), solvent plasma load (Q(SPL)) and r.f. power: moreover, it explores loading by water, methanol and chloroform. Throughout the survey, n(e) was determined from the intensity of one, optically thin argon line, by a method which assumes that the atomic state distribution function (ASDF) for argon lies close to local thermal equilibrium (LTE). The validity of this assumption is reviewed. Also examined are the discrepancies between n(e) from this method and n(e) from Stark broadening measurements. With the error taken into account, the results of the survey reveal how time averaged values of n(e) in the ICAP respond over an extensive, previously unexplored range of experimental parameters. Moreover, the spatial information lends insight into how the thermal conditions and the transport of energy respond. Overall, the response may be described in terms of energy consumption along the axial channel and thermal pinch within the induction region. The predominating effect depends on the solvent plasma load, the solvent composition, the robustness of the discharge, and the distribution of solvent material over the argon stream.}, keywords = {ATOMIC EMISSION-SPECTROMETRY, DESOLVATION, EQUILIBRIUM, EXCITATION, GAS-FLOW, INTRODUCTION, NUMBER, SAMPLE, STATE DISTRIBUTION FUNCTION, TEMPERATURE DETERMINATION, WATER}, isbn = {0584-8547}, url = {://A1994QD36400009}, author = {Weir, D. G. J. and Blades, M. W.} } @article {3092, title = {SPECIATION OF ARSENIC COMPOUNDS BY HPLC WITH HYDRIDE GENERATION ATOMIC-ABSORPTION SPECTROMETRY AND INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY DETECTION}, journal = {Talanta}, volume = {41}, number = {4}, year = {1994}, note = {ISI Document Delivery No.: NJ813Times Cited: 94Cited Reference Count: 45}, month = {Apr}, pages = {495-502}, type = {Article}, abstract = {An arsenic specific detection system utilizing on-line microwave digestion and hydride generation atomic absorption spectrometry (MD/HGAAS) is described for arsenic speciation by using high performance liquid chromatography (HPLC). Both ion exchange chromatography and ion pair chromatography have been studied for the separation of arsenite, arsenate, monomethylarsonic acid (MMAA), dimethylarsinic acid (DMAA), and arsenobetaine (AB). When the commonly used mobile phases, phosphate and carbonate buffers at pH 7.5, are used on an anion exchange column, arsenite and AB co-elute. However, selective determination of these two arsenic compounds can be achieved by using the new detection system. Partial separation between arsenite and AB can be achieved by increasing the mobile phase pH to 10.3 and by using a polymer based anion exchange column. The detection limit obtained by using anion exchange chromatography with MD/HGAAS detection is approximately 10 ng/ml (or 200 pg for a 20-mul sample injection) for arsenite, DMAA and AB, 15 ng/ml (or 300 pg) for MMAA, and 20 ng/ml (or 400 pg) for arsenate. Complete separation of the five arsenic compounds is achieved on a reversed phase C18 column by using sodium heptanesulfonate as ion pair reagent. Comparable resolution between chromatographic peaks is obtained by using MD/HGAAS detection and inductively coupled plasma mass spectrometry (ICPMS) detection.}, keywords = {ELEMENT-SPECIFIC DETECTOR, IDENTIFICATION, ION CHROMATOGRAPHY, MUSCLE, ORGANOARSENIC COMPOUNDS, PERFORMANCE LIQUID-CHROMATOGRAPHY, QUANTITATION, REFERENCE MATERIAL, SEPARATION, TRACE-ELEMENTS, WATER}, isbn = {0039-9140}, url = {://A1994NJ81300003}, author = {Le, X. C. and Cullen, W. R. and Reimer, K. J.} } @article {3101, title = {STEPWISE HYDROLYSIS OF A TERMINAL NITROSYL LIGAND}, journal = {Journal of the American Chemical Society}, volume = {116}, number = {26}, year = {1994}, note = {ISI Document Delivery No.: QA288Times Cited: 18Cited Reference Count: 19}, month = {Dec}, pages = {12105-12106}, type = {Note}, keywords = {CHEMISTRY, COMPLEXES, CONVERSION, ELECTROCATALYTIC REDUCTION, MOLYBDENUM, NITRIC-OXIDE, TUNGSTEN, WATER}, isbn = {0002-7863}, url = {://A1994QA28800082}, author = {Legzdins,Peter and Rettig, S. J. and Sayers, S. F.} } @article {2851, title = {EXCESS PARTIAL MOLAR ENTHALPIES AND FREE-ENERGIES IN METHANOL ISOBUTANOL MIXTURES AT 20-DEGREES-C - THE EFFECT OF SIZE DIFFERENCE}, journal = {Thermochimica Acta}, volume = {230}, year = {1993}, note = {ISI Document Delivery No.: MW430Times Cited: 0Cited Reference Count: 10}, month = {Dec}, pages = {39-53}, type = {Article}, abstract = {The excess partial molar enthalpies, H(m)E(i), and free energies, G(m)E(i), (where i is methanol or isobutanol) were determined at 20.00-degrees-C in methanol-isobutanol mixtures. The Bhatia-March approach (J. Phys. F, 5 (1975) 1100), taking into account the size difference between the components within the framework of the conformational solution theory, was applied to explain the composition dependence of H(m)E(i) and G(m)E(i). It was reasonably successful : however, it did not seem to work for the other isomeric butanol and methanol mixtures.}, keywords = {25 DEGREES C, ALLOYS, BUTANOL, CONCENTRATION FLUCTUATIONS, NA-CS, SYSTEMS, WATER}, isbn = {0040-6031}, url = {://A1993MW43000004}, author = {Lai, J. T. W. and Kam, J. S. C. and Lau, F. W. and Beach, L. J. and Koga,Yoshikata} } @article {2730, title = {INSERTIONS OF HETEROCUMULENES INTO THE M-C SIGMA-BONDS OF CP-ASTERISK-M(NO)(ARYL)2 (M=MO, W) COMPLEXES}, journal = {Organometallics}, volume = {12}, number = {10}, year = {1993}, note = {ISI Document Delivery No.: MC322Times Cited: 14Cited Reference Count: 32}, month = {Oct}, pages = {4234-4240}, type = {Note}, abstract = {{Treatment of the 16-valence-electron complexes Cp*M(NO)(aryl)2 (Cp* = eta5-C5Me5; M = Mo, W; aryl = phenyl (Ph), p-tolyl) with the heterocumulenes carbon disulfide, p-tolyl isocyanate, and carbon dioxide leads to the eta2-thiocarboxylate, eta2-amide-, and eta2-carboxylate-containing complexes, respectively, in 10-65\% isolated yields. Furthermore, Cp* W(NO) (eta2-S2C-Ph)(Ph) (1) reacts with trimethylphosphine to form Cp*W(NO)(eta2-S2C(PMe3)Ph)(Ph) (10), which contains a zwitterionic phosphonium betaine ligand. The solid-state molecular structure of 10-CH2Cl2 has been established by a single-crystal X-ray crystallographic analysis. Crystal data for Cp*W(NO)(eta2-S2C(PMe3)Ph)(Ph). CH2Cl2: monoclinic}, keywords = {ALKYL, CARBON BONDS, CO2, H-BONDS, ORGANOMETALLIC NITROSYL CHEMISTRY, REACTIVITY, TUNGSTEN, WATER, X-ray structure}, isbn = {0276-7333}, url = {://A1993MC32200074}, author = {Brouwer, E. B. and Legzdins,Peter and Rettig, S. J. and Ross, K. J.} } @article {2921, title = {MOLECULAR-SOLVENT MODEL FOR AN ELECTRICAL DOUBLE-LAYER - ASYMMETRIC SOLVENT EFFECTS}, journal = {Journal of Physical Chemistry}, volume = {97}, number = {49}, year = {1993}, note = {ISI Document Delivery No.: ML667Times Cited: 25Cited Reference Count: 36}, month = {Dec}, pages = {12909-12918}, type = {Article}, abstract = {Previous reference hypernetted-chain theoretical results for electrical double layers using a multipolar solvent with tetrahedral geometry are extended here to a more accurate water model having only C2v symmetry. This model exhibits a net polarization at a flat uncharged surface with the positive end of the dipoles inclined into the fluid; the resulting surface potential is compared with both computer simulation and experimental results for the free surface of liquid water. This model also responds differently to positively and negatively charged surfaces, both with and without electrolyte. This leads to an asymmetry in the differential capacitance of the electrical double layer.}, keywords = {APPROXIMATION, AQUEOUS-ELECTROLYTE SOLUTIONS, CHARGED SURFACES, HARD-SPHERES, LIQUID VAPOR INTERFACE, MIXTURES, ORIENTATIONAL STRUCTURE, PROPERTIES, SIMULATION, THERMODYNAMIC, WATER}, isbn = {0022-3654}, url = {://A1993ML66700045}, author = {Torrie, G. M. and Patey, G. N.} } @article {7295, title = {DECOMPOSITION OF ORGANOARSENIC COMPOUNDS BY USING A MICROWAVE-OVEN AND SUBSEQUENT DETERMINATION BY FLOW-INJECTION HYDRIDE GENERATION ATOMIC-ABSORPTION SPECTROMETRY}, journal = {Applied Organometallic Chemistry}, volume = {6}, number = {2}, year = {1992}, note = {ISI Document Delivery No.: HQ168Times Cited: 61Cited Reference Count: 33INTERNATIONAL CONF ON ENVIRONMENTAL AND BIOLOGICAL ASPECTS OF MAIN-GROUP ORGANOMETALS ( ICEBAMO )SEP 15-19, 1991PADUA, ITALYUNIV PADUA, ITALIAN CHEM SOC}, month = {Apr}, pages = {161-171}, type = {Proceedings Paper}, abstract = {Environmentally important organoarsenicals such as arsenobetaine, arsenocholine and tetramethylarsonium ion do not form volatile hydrides under the commonly used analytical conditions on treatment with borohydride and it has been difficult to determine their concentrations without further derivatization. This paper describes a rapid method which completely decomposes and oxidizes these arsenicals to arsenate by using potassium persulphate and sodium hydroxide with the aid of microwave energy. The quantitative decomposition of these species permits their determination at low nanogram levels, by hydride generation atomic absorption spectrometry (HG AA). A new hydride generator which has high efficiency and minimum dead volume and therefore is suitable for flow injection analysis (FIA) is also described. A system combining flow injection analysis, on-line microwave oven digestion, and hydride generation followed by atomic absorption measurement, is developed. This system is capable of performing analysis at a sample throughput of 100-120 per hour. Calibration curves were linear from 10 to 200 ng cm-3 of arsenic and the detection limit was 5 ng cm-3 for a 100-mu-l injection or 0.5 ng of arsenic. All ten organoarsenic compounds studied gave arsenate as the decomposition product, which was confirmed by using molybdenum blue photometric measurement.}, keywords = {ABSORPTION SPECTROMETRY, arsenic, arsenobetaine, atomic, DECOMPOSITION, DETERMINATION, DISSOLUTION, ENVIRONMENT, FLOW INJECTION ANALYSIS, HYDRIDE GENERATION, IDENTIFICATION, LIQUID-CHROMATOGRAPHY, MICROWAVE OVEN DIGESTION, MUSCLE REFERENCE MATERIAL, QUANTITATION, TRACE-ELEMENTS, WATER}, isbn = {0268-2605}, url = {://A1992HQ16800008}, author = {Le, X. C. and Cullen, W. R. and Reimer, K. J.} } @article {7384, title = {EXCESS PARTIAL MOLAR FREE-ENERGIES, ENTHALPIES, AND ENTROPIES IN 2-BUTANONE-H2O MIXTURES - SOLUTE SOLUTE INTERACTIONS}, journal = {Journal of Physical Chemistry}, volume = {96}, number = {24}, year = {1992}, note = {ISI Document Delivery No.: KA298Times Cited: 12Cited Reference Count: 19}, month = {Nov}, pages = {10025-10029}, type = {Article}, abstract = {The excess partial molar enthalpies, H(m)E(i), in 2-butanone (BUT)-H2O mixtures were measured at 4.20, 20.00, and 25.00-degrees-C (i = BUT or H2O). The vapor pressures were also measured by a static method at 20.00 and 25.00-degrees-C. From the latter data, the partial pressures and hence the excess partial molar Gibbs free energies, G(m)E(i), were calculated by the method. The excess partial molar entropies, S(m)E(i), were then calculated at 20.00 and 25.00-degrees-C. From the composition derivatives of these partial molar quantities, the nature of the solute-solute interactions was discussed in relation to the global information about the mixture: existence of phase separation, the way in which the phase boundary slants, and existence of azeotropy and addition compound.}, keywords = {2-BUTOXYETHANOL, 25-DEGREES-C, BUTYL ALCOHOL, MIXING SCHEME, SCATTERING, TERT-BUTANOL MIXTURES, TRANSITION, WATER}, isbn = {0022-3654}, url = {://A1992KA29800080}, author = {Wong, T. Y. H. and Wongmoon, K. C. and Beach, L. J. and Chuang, Y. F. and Koga,Yoshikata} } @article {7359, title = {ISOTOPE EFFECTS ON THE EXCESS PARTIAL MOLAR ENTHALPIES OF (XCH3(CH2)3O(CH2)2O(H OR D)+(1-X)(H2O OR D2O))}, journal = {Journal of Chemical Thermodynamics}, volume = {24}, number = {2}, year = {1992}, note = {ISI Document Delivery No.: HC049Times Cited: 9Cited Reference Count: 16}, month = {Feb}, pages = {159-165}, type = {Article}, keywords = {2-BUTOXYETHANOL, AQUEOUS-SOLUTION, WATER}, isbn = {0021-9614}, url = {://A1992HC04900007}, author = {Siu, W. W. Y. and Wong, T. Y. H. and Lai, J. T. W. and Chong, A. and Koga,Yoshikata} } @article {6959, title = {CONTINUUM ELECTROSTATIC INTERACTIONS BETWEEN PLANAR LATTICES OF DIPOLES AND THE POSSIBLE RELEVANCE TO THE HYDRATION FORCE}, journal = {Physical Review A}, volume = {43}, number = {6}, year = {1991}, note = {ISI Document Delivery No.: FD045Times Cited: 11Cited Reference Count: 37}, month = {Mar}, pages = {2953-2962}, type = {Article}, abstract = {The electrostatic interaction between two planar dipolar lattices in dielectric continua is investigated. If there are no dielectric images, the pressure is equally likely to be attractive or repulsive, depending upon the relative lateral displacement of the two lattices. In addition to perfect dipolar lattices, we consider the effects of real dipoles, of disorder, and of finite-sized domains. When the surfaces constitute the boundary between dielectric media, and when there are no correlations between the two surfaces, then there occurs a strong exponentially decaying repulsion due to the interaction between a lattice and its dielectric images. The relevance of this repulsion to the hydration force is discussed, and an experimental test that should discriminate between different theories for that force is proposed.}, keywords = {BILAYER SYSTEMS, DEPENDENCE, DOUBLE-LAYER, ELECTROLYTE-SOLUTIONS, MICA, MOBILE, MODEL, ORIENTABLE DIPOLES, polarization, SURFACES, WATER}, isbn = {1050-2947}, url = {://A1991FD04500037}, author = {Attard, P. and Patey, G. N.} } @article {7130, title = {THE CRYSTALLIZATION OF ALKALI-HALIDES FROM AQUEOUS-SOLUTION - AN APPLICATION OF DENSITY-FUNCTIONAL THEORY}, journal = {Journal of Chemical Physics}, volume = {95}, number = {1}, year = {1991}, note = {ISI Document Delivery No.: FT847Times Cited: 3Cited Reference Count: 23}, month = {Jul}, pages = {485-493}, type = {Article}, abstract = {Density-functional theory is applied to the problem of salt crystallization from solution and explicit results are given for model aqueous alkali-halide systems. Both direct- and Fourier-space methods of calculation are considered and it is found that only the direct (i.e., r space) method converges sufficiently rapidly to provide reliable results for ionic crystals at 25-degrees-C. It is shown that the density-functional method is capable of predicting crystallization, but that the solid-state parameters and, for some salts, the crystal structures obtained are in poor agreement with experiment or computer simulations. The calculated crystal/solution coexistence concentrations are found to be extremely sensitive to the short-range part of the interionic pair potentials. This is consistent with earlier observations that the activity coefficients of model aqueous alkali-halide solutions are very strongly dependent upon the short-range ion-ion interactions. Therefore, we do not believe that this sensitivity to details of the short-range interionic potentials is an artifact of theoretical approximations, but rather a real effect significantly influencing crystallization.}, keywords = {APPROXIMATION, INVARIANT EXPANSION, MEAN SPHERICAL MODEL, ORNSTEIN-ZERNIKE EQUATION, SIMULATION, SPHERES, TRANSITION, WATER}, isbn = {0021-9606}, url = {://A1991FT84700048}, author = {Ursenbach, C. P. and Patey, G. N.} } @article {7122, title = {MOLECULAR-SOLVENT MODELS OF ELECTRICAL DOUBLE-LAYERS}, journal = {Electrochimica Acta}, volume = {36}, number = {11-12}, year = {1991}, note = {ISI Document Delivery No.: GJ354Times Cited: 1Cited Reference Count: 17INTERDISCIPLINARY CONF ON ELECTRIFIED INTERFACESSEP 16-21, 1990ASILOMAR, CAAMER PHYS SOC, INT SOC ELECTROCHEM, IBM, US DOE, NATL SCI FDN, USN, OFF NAVAL RES}, pages = {1669-1675}, type = {Proceedings Paper}, abstract = {This paper summarizes some recent work directed towards the construction of a wholly molecular theory of the solution side of an electrical double layer using modern liquid state theory. The influence of surface charge on the solvent restructuring near the surface and the consequences of this for the ionic distributions in the double layer are discussed and related to the role of the continuum solvent description embodied in Gouy-Chapman theory.}, keywords = {APPROXIMATION, AQUEOUS-ELECTROLYTE SOLUTIONS, DOUBLE LAYER THEORY, INFINITE DILUTION, MOLECULAR MODELS, STATISTICAL MECHANICS, SURFACE, WATER}, isbn = {0013-4686}, url = {://A1991GJ35400004}, author = {Torrie, G. M. and Patey, G. N.} } @article {6778, title = {THE QUANTITATION OF BUTYLTIN AND CYCLOHEXYLTIN COMPOUNDS IN THE MARINE-ENVIRONMENT OF BRITISH-COLUMBIA}, journal = {Applied Organometallic Chemistry}, volume = {4}, number = {6}, year = {1990}, note = {ISI Document Delivery No.: EU195Times Cited: 29Cited Reference Count: 27}, month = {Nov-Dec}, pages = {581-590}, type = {Article}, abstract = {{A HPLC/GF AA procedure based on the use of C-18 columns is described for the quantitation of butyltin species in marine samples. When a mass spectrometer was used as detector (HPLC MS), evidence was obtained for the presence of other tin compounds in the samples. Extracts of samples were treated with CH3MgBr and examined by using GC MS; the presence of BU(n)SnMe4-n (n = 3-1}, keywords = {BUTYLTIN SPECIES, CYCLOHEXYLTIN SPECIES, CYHEXTIN, GC MS, HPLC AA, HPLC MS, LIQUID-CHROMATOGRAPHY, ORGANOTIN COMPOUNDS, OYSTERS, PLICTRAN, SAMPLES, SEAWATER, SPECIATION, SURFACE MICROLAYER, WATER}, isbn = {0268-2605}, url = {://A1990EU19500001}, author = {Cullen, W. R. and Eigendorf, G. K. and Nwata, B. U. and Takatsu, A.} } @article {6889, title = {QUANTUM PHENOMENA AND SOLVENT EFFECTS ON ADDITION OF HYDROGEN ISOTOPES TO BENZENE AND TO DIMETHYLBUTADIENE}, journal = {Berichte Der Bunsen-Gesellschaft-Physical Chemistry Chemical Physics}, volume = {94}, number = {11}, year = {1990}, note = {ISI Document Delivery No.: EU906Times Cited: 18Cited Reference Count: 4189TH GENERAL ASSEMBLY OF THE DEUTSCHE-BUNSEN-GESELLSCHAFT-FUR-PHYSIKALISCHE-CHEMIE ( ON THE 65TH BIRTHDAY OF THEODOR ACKERMANN ) : CHEMICAL ELEMENTAL REACTIONSMAY 24-26, 1990TUBINGEN, FED REP GERDEUT BUNSEN GESELL PHYS CHEM}, month = {Nov}, pages = {1224-1230}, type = {Proceedings Paper}, abstract = {Rate constants have been measured for the reaction of the light hydrogen isotope muonium with benzene and 2,3-dimethylbutadiene-1,3 in the gas phase and in several solvents. Comparison with H atom data reveals (1) appreciable kinetic isotope effects, (2) a strong contribution of tunnelling for the activated reaction with benzene, (3) encounter controlled reaction for Mu addition to the diene, (4) a mass dependence of the diffusion constant of hydrogen isotopes in solution, and (5) an enhancement of the rate constant in solution over that in the gas phase by a factor, except for water, of the inverse Ostwald solubility coefficient for hydrogen. The isotope-dependent reduction of the solvent effect in water is tentatively ascribed to the dynamics of the clathrate-like structure when the hydrogen atom reacts.}, keywords = {ATOM, DIFFUSION, electron, ELEMENTARY REACTIONS, GASES, ISOTOPE EFFECTS, KINETICS, LIQUIDS, muonium, radicals, RATE CONSTANTS, solutions, WATER}, isbn = {0005-9021}, url = {://A1990EU90600008}, author = {Roduner, E. and Louwrier, P. W. F. and Brinkman, G. A. and Garner, D. M. and Reid, I. D. and Arseneau, D. J. and Senba, M. and Fleming, Donald G.} }