@article {2405, title = {Effects of sulfuric acid and ammonium sulfate coatings on the ice nucleation properties of kaolinite particles}, journal = {Geophysical Research Letters}, volume = {36}, year = {2009}, note = {ISI Document Delivery No.: 401YZTimes Cited: 17Cited Reference Count: 28Eastwood, Michael L. Cremel, Sebastien Wheeler, Michael Murray, Benjamin J. Girard, Eric Bertram, Allan K.}, month = {Jan}, pages = {5}, type = {Article}, abstract = {The onset conditions for ice nucleation on H2SO4 coated, (NH4)(2)SO4 coated, and uncoated kaolinite particles at temperatures ranging from 233 to 246 K were studied. We define the onset conditions as the relative humidity and temperature at which the first ice nucleation event was observed. Uncoated particles were excellent ice nuclei; the onset relative humidity with respect to ice (RHi) was below 110\% at all temperatures studied, consistent with previous measurements. H2SO4 coatings, however, drastically altered the ice nucleating ability of kaolinite particles, increasing the RHi required for ice nucleation by approximately 30\%, similar to the recent measurements by Mohler et al. [2008b]. (NH4)(2)SO4 coated particles were poor ice nuclei at 245 K, but effective ice nuclei at 236 K. The differences between H2SO4 and (NH4)(2)SO4 coatings may be explained by the deliquescence and efflorescence properties of (NH4)(2)SO4. These results support the idea that emissions of SO2 and NH3 may influence the ice nucleating properties of mineral dust particles. Citation: Eastwood, M. L., S. Cremel, M. Wheeler, B. J. Murray, E. Girard, and A. K. Bertram (2009), Effects of sulfuric acid and ammonium sulfate coatings on the ice nucleation properties of kaolinite particles, Geophys. Res. Lett., 36, L02811, doi: 10.1029/2008GL035997.}, keywords = {AEROSOLS, AQUEOUS-SOLUTIONS, crystallization, GOETHITE, MINERAL DUST, NUCLEI, TEMPERATURES}, isbn = {0094-8276}, url = {://000262981800002}, author = {Eastwood, M. L. and Cremel, S. and Wheeler, M. and Murray, B. J. and Girard, E. and Bertram, A. K.} } @article {2460, title = {Hydrophobicity/Hydrophilicity of 1-Butyl-2,3-dimethyl and 1-Ethyl-3-methylimodazolium Ions: Toward Characterization of Room Temperature Ionic Liquids}, journal = {Journal of Physical Chemistry B}, volume = {113}, number = {44}, year = {2009}, note = {ISI Document Delivery No.: 510QMTimes Cited: 2Cited Reference Count: 52Kato, Hitoshi Miki, Kumiko Mukai, Tomohiro Nishikawa, Keiko Koga, Yoshikata}, month = {Nov}, pages = {14754-14760}, type = {Article}, abstract = {We continue to experimentally characterize the constituent ions of room temperature ionic liquids in terms of their interactions with H2O. By using the so-called 1-propanol probing methodology, we experimentally index the relative hydrophobicity/hydrophilicity of a test ion. In this paper, we examine 1-butyl-2,3 dimethylimidazolium (abbreviated as [C(4)C(1)mim](+)) and 1-ethyl-3-methylimidazolium ([C(2)mim](+)). We found that [C(4)C(1)mim](+) dissociates completely in dilute aqueous solution less than 0.006 mol fraction, and hence, its hydrophobicity/hydrophilicity could be determined. The results indicate that [C(4)C(1)mim](+) is highly amphiphilic with much stronger hydrophobicity and hydrophilicity than normal ions. Our earlier similar studies indicated the same conclusion for such typical constituent ions as 1-butyl-3-methylimidazolium ([C(4)mim](+)) PF6-, CF3SO3-, and N(SO2CF3)(2)(-). Hence, we suggest that the constituent ions of room temperature ionic liquids that we have studied so far are all amphiphiles with much stronger hydrophobicity and hydrophilicity than normal ions. We found, furthermore, that the hydrophobicity and hydrophilicity of [C(4)C(1)mim](+) are stronger than those for [C(4)mim](+). A possible reason for higher hydrpohilicity is discussed in terms of strong acidic character of H on the C(2) of the imidazolium ring, which tends to attract the delocalized positive charge toward itself oil forming a hydrogen bond to H2O. On replacing it with CH3 in [C(4)C(1)mim](+), the lack of acidic H enhances the positive charge in the vicinity of N-C-N in the ring that interacts with the surrounding H2O strongly to an induced dipole of O of the H2O. For [C(2)mim](+), we found it does not dissociate completely, even in dilute aqueous solution, and hence, we could not characterize it within the present methodology.}, keywords = {1-BUTYL-3-METHYLIMIDAZOLIUM BROMIDE, AGGREGATION BEHAVIOR, ALKYL CHAIN-LENGTH, APPROACH, AQUEOUS-SOLUTIONS, HOFMEISTER SERIES, MIXING SCHEMES, MOLECULAR-ORGANIZATION, partial molar enthalpy, PHYSICOCHEMICAL PROPERTIES, THERMODYNAMIC}, isbn = {1520-6106}, url = {://000271105600027}, author = {Kato, H. and Miki, K. and Mukai, T. and Nishikawa, K. and Koga,Yoshikata} } @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 {2342, title = {A novel functional polymer with tunable LCST}, journal = {Macromolecules}, volume = {41}, number = {14}, year = {2008}, note = {ISI Document Delivery No.: 326NJTimes Cited: 13Cited Reference Count: 44Zou, Yuquan Brooks, Donald E. Kizhakkedathu, Jayachandran N.}, month = {Jul}, pages = {5393-5405}, type = {Article}, abstract = {Poly(N-[(2,2-dimethyl-1,3-dioxolane)methyl]acrylamide) (PDMDOMA), a novel thermo-responsive polymer containing pendant dioxolane groups was synthesized via atom transfer radical polymerization (ATRP). Water soluble PDMDOMAs with controlled molecular weight and narrow molecular weight distribution were obtained. GPC-MALLS and MALDI-TOF-MS analysis verified the controlled nature of polymerization. It was found that an aqueous solution of PDMDOMA has a lower critical solution temperature (LCST) around 23 degrees C. The LCST of PDMDOMA was finely tuned over a wide temperature range by the partial hydrolysis of the acid labile dioxolane side group to form diol moieties (PDMDOMA diols). Unlike the traditional way of controlling LCST by copolymerization, the advantage of this method is that a series of thermo-responsive polymers with different LCST can be prepared from a single batch of polymer with comparable molecular weight profiles. The LCST of the resulting PDMDOMA diols increased almost linearly up to 28 mol \% of diol in the copolymer and the LCST disappeared above 43 mol \% diol content. The diol moiety generated during the hydrolysis was further oxidized to create aldehyde functionalities along the polymer backbone (PDMDOMA-aldehyde). The NMR analysis indicates that the aldehyde groups in the polymer exist in equilibrium with their covalent hydrates in water. The presence and reactivity of aldehyde groups on the PDMDOMA-aldehyde was verified by reaction with propylamine and aniline. The LCST of PDMDOMA-aldehyde did not change significantly compared to the precursor diol polymer. However, the propylamine or aniline derivatives showed a dramatic decrease in the LSCT possibly due to an increase in the hydrophobic character. The LCST of PDMDOMA-propylamine and PDMDOMA-aniline derivatives depends on the composition and nature of the attached groups. The structure of PDMDOMA and its derivatives were fully characterized by H-1, C-13, and 2D HMQC NMR, GPC-MALLS, and MALDI-TOF-MS.}, keywords = {2-(2-METHOXYETHOXY)ETHYL METHACRYLATE, AQUEOUS-SOLUTIONS, N-ISOPROPYLACRYLAMIDE, OLIGO(ETHYLENE GLYCOL) METHACRYLATE, POLYMERS, PROTEINS, SMART, SOLID TUMORS, STIMULI-RESPONSIVE POLYMERS, TEMPERATURE, TRANSFER RADICAL POLYMERIZATION}, isbn = {0024-9297}, url = {://000257665900045}, author = {Zou, Y. Q. and Brooks, D. E. and Kizhakkedathu, J. N.} } @article {1440, title = {The effects of chloride salts of some cations on the molecular organization of H2O. Towards understanding the Hofmeister series. II}, journal = {Bulletin of the Chemical Society of Japan}, volume = {79}, number = {9}, year = {2006}, note = {ISI Document Delivery No.: 097WCTimes Cited: 7Cited Reference Count: 42Koga, Yoshikata Katayanagi, Hideki Davies, James V. Kato, Hitoshi Nishikawa, Keiko Westh, Peter}, month = {Sep}, pages = {1347-1354}, type = {Article}, abstract = {We use the thermodynamic behaviour of I-propanol (1P) as a probe in ternary 1P-salt-H2O systems to elucidate the effect of a salt on the molecular organization of H2O. For salts, we have chosen CaCl2, NH4Cl, and (CH3)(4)NCl (TMAC). Having fixed the counter anion at Cl-, we compare here mainly the effects of chosen cations on H2O. Together with an earlier study on NaCl, we found that Ca2+, Na+, and NH4+ are hydrated by a number of H2O molecules and leave the bulk H2O away from the hydration shell unperturbed. The hydration numbers were found to be 6.4 +/- 1.6, and 1.2 +/- 0.4, for Ca2+ and NH4+, respectively with the hydration number 5.2 for Na+, the result of a simulation study, chosen as a reference. Thus, a salting out (also referred to as structure making, stabilizing, or kosmotropic) tendency would decrease in the order; Ca2+ > Na+ > NH4+. TMA(+), on the other hand, showed a more hydrophilic characteristics than the probing 1P. Thus, TMA(+) is rather chaotropic (salting in, structure breaking or destabilizing) within this methodology.}, keywords = {AQUEOUS-SOLUTIONS, EXCESS CHEMICAL-POTENTIALS, HEAT-CAPACITIES, INTERMOLECULAR INTERACTIONS, MIXING SCHEMES, PARTIAL MOLAR ENTHALPIES, TETRAALKYLAMMONIUM HALIDES, TETRAMETHYL UREA, THERMODYNAMIC APPROACH, WATER MIXTURES}, isbn = {0009-2673}, url = {://000241479100004}, author = {Koga,Yoshikata and Katayanagi, H. and Davies, J. V. and Kato, H. and Nishikawa, K. and Westh, P.} } @article {1627, title = {Toward understanding the Hofmeister series. 3. Effects of sodium halides on the molecular organization of H2O as probed by 1-propanol}, journal = {Journal of Physical Chemistry A}, volume = {110}, number = {5}, year = {2006}, note = {ISI Document Delivery No.: 011VUTimes Cited: 15Cited Reference Count: 42}, month = {Feb}, pages = {2072-2078}, type = {Article}, abstract = {We investigated the effects of NaF, NaCl, NaBr, and NaI on the molecular organization of H2O by a calorimetric methodology developed by us earlier. We use the third derivative quantities of G pertaining to I-propanol (1P) in ternary 1P-asalt-H2O as a probe to elucidate the effects of a salt on H2O. We found that NaF and NaCl worked as hydration centers. The hydration numbers were 19 +/- 2 for NaF and 7.5 +/- 0.6 for NaCl. Furthermore, the bulk H2O away from the hydration shell was found unaffected by the presence of Na+, F-, and Cl-. For NaBr and NaI, in addition to the hydration to Na+, Br- and I- acted like a hydrophilic moiety such as urea. Namely, they formed a hydrogen bond to the existing H2O network and retarded the fluctuation nature of H2O. These findings were discussed with respect to the Hofmeister ranking. We suggested that more chaotropic anions Br- and I- are characterized as hydrophiles, whereas kosmotropes, F- and Cl-, are hydration centers.}, keywords = {25-DEGREES-C, AQUEOUS-SOLUTIONS, CHEMICAL-POTENTIALS, DIELECTRIC-SPECTROSCOPY, INTERMOLECULAR INTERACTIONS, LIQUID WATER, MIXING SCHEMES, NONELECTROLYTES, partial molar enthalpy, TERT-BUTYL ALCOHOL}, isbn = {1089-5639}, url = {://000235297400050}, author = {Westh, P. and Kato, H. and Nishikawa, K. and Koga,Yoshikata} } @article {1202, title = {Effect of an "ionic liquid" cation, 1-butyl-3-methylimidazolium, on the molecular organization of H2O}, journal = {Journal of Physical Chemistry B}, volume = {109}, number = {18}, year = {2005}, note = {ISI Document Delivery No.: 924MMTimes Cited: 46Cited Reference Count: 46}, month = {May}, pages = {9014-9019}, type = {Article}, abstract = {The excess partial molar enthalpy of 1-propanol (1P), H-1P(E), was measured at 28 \° C in the ternary mixture of 1P-1-butyl-3-methylimidazolium chloride ([bmim]Cl)-H2O in the H2O-rich composition range. From these data we evaluated what we call the 1P-1P enthalpic interaction function, H-1P-1P(E). Its changes induced by addition of (bmim]Cl of the pattern of H-1P-1P(E) were used as a probe to elucidate the effect of [bmim]Cl on the molecular organization of H2O. It was found that the effect of Cl- was not conspicuous within this methodology, and the observed dependence is predominantly due to the hydration of [bmim](+). The changes in the \χ(1P)-dependence of H-1P-1P(E) were compared with those brought about by temperature increase, or by the addition of fructose or glycerol. It was found that the effect of [bmim](+) is similar to that of fructose or increased temperature. We speculate that in the H2O-rich composition region a number of H2O molecules are attracted to the delocalized positive charge of the imidazolium ring and the bulk of H2O is influenced in such a manner that the global hydrogen bond probability is reduced.}, keywords = {25-DEGREES-C, ALKANE-MONO-OLS, AQUEOUS-SOLUTIONS, fluctuations, HEXAFLUOROPHOSPHATE, MIXING SCHEMES, PARTIAL MOLAR ENTHALPIES, SOLVENTS, TERT-BUTANOL MIXTURES, WATER SOLUTIONS}, isbn = {1520-6106}, url = {://000228982900071}, author = {Miki, K. and Westh, P. and Nishikawa, K. and Koga,Yoshikata} } @article {1201, title = {Hydrophobicity vs hydrophilicity: Effects of poly(ethylene glycol) and tert-butyl alcohol on H2O as probed by 1-propanol}, journal = {Journal of Physical Chemistry B}, volume = {109}, number = {41}, year = {2005}, note = {ISI Document Delivery No.: 974SQTimes Cited: 8Cited Reference Count: 33}, month = {Oct}, pages = {19536-19541}, type = {Article}, abstract = {The enthalpic interaction between 1-propanol (IP) molecules, H-1P- 1P(E), was evaluated in 1P-poly(ethleneglycol) (PEG)-H2O and 1P-tert-butyl alcohol (TBA)-H2O ternary mixtures. The model-free and experimentally accessible quantity, H-1P-1p(E), indicates the effect of an additional 1P on the actual enthalpic situation of 1P in the mixture. It was shown earlier that the composition dependence of H-1P-1P(E) reflects the process how 1P modifies H2O. This H-1P-1P(E) pattern changes in the presence of a third component, PEG or TBA. The effects of PEG or TBA on the molecular organization of H2O were elucidated from these induced changes. Together with previous similar studies for the effects of methanol (ME), 2-propanol (2P), ethylene glycol (EG), and glycerol (Gly), we suggest a method and hence a possible scaling for sorting out hydrophobicity vs hydrophilicity of these alcohols by the changes induced to the loci of the maxima in H-1P-1P(E). We show that hydrophilicity scales with the number of oxygen, regardless of whether O is the ether -O- or the hydroxyl -OH. Hydrophobicity also scales with the number of carbon atoms for alcohols without a methyl group. For those with methyl groups, the hydrophobicity seems proportional to the total number of carbon with a different proportionality factor from those without methyl group.}, keywords = {25-DEGREES-C, ALKANE-MONO-OLS, AQUEOUS-SOLUTIONS, EXCESS CHEMICAL-POTENTIALS, GLYCEROL, HOFMEISTER SERIES, MIXING SCHEMES, MOLECULAR-ORGANIZATION, PARTIAL MOLAR ENTHALPIES, THERMODYNAMIC APPROACH}, isbn = {1520-6106}, url = {://000232612100072}, author = {Miki, K. and Westh, P. and Koga,Yoshikata} } @article {1177, title = {Thermodynamic properties of water in the water-poor region of binary water plus alcohol mixtures}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {83}, number = {5}, year = {2005}, note = {ISI Document Delivery No.: 930KOTimes Cited: 2Cited Reference Count: 54}, month = {May}, pages = {420-429}, type = {Article}, abstract = {In our previous thermodynamic studies, we suggested that alcohol molecules in water-poor water + alcohol mixtures exist as alcohol clusters in a form similar to the pure alcohols. Here, we use calorimetry and densitometry to investigate how H2O interacts with alcohol clusters in water-poor binary aqueous mixtures of 12 different alcohols. The composition dependence of the measured excess partial molar enthalpy and volume of water (H-W(E) and V-W(E)), along with entropy data calculated from H-W(E) and literature data for excess chemical potentials, showed that in water-poor solutions of small alcohols such as methanol, ethanol, and 1-propanol, mutual water-water interactions are endothermic, but entropically favorable. Conversely, in long-chain solvents such as 1-octanol and 1-decanol, the interaction is exothermic and entropically unfavorable. We suggest that these observations reflect water-alcohol hydrogen bonding in short-chain solvents and water clustering with more hydrogen bonding than in pure water or "dewetting" in mixtures of the longer alcohols, respectively. The composition dependence of H-W(E) was also used to locate anomalies that specify the boundary between the mixing schemes characterizing the intermediate and the water-poor regions of alcohol + water mixtures.}, keywords = {25-DEGREES-C, ALKANE-MONO-OLS, aqueous alkane-mono-ols, AQUEOUS-SOLUTIONS, BUTANOL MIXTURES, DILUTE-SOLUTIONS, entropy and, EXCESS ENTHALPY, excess partial molar enthalpy, MIXING SCHEMES, PARTIAL MOLAR VOLUMES, RICH REGION, TERT-BUTYL ALCOHOL, VOLUME}, isbn = {0008-4042}, url = {://000229414900003}, author = {Liltorp, K. and Westh, P. and Koga,Yoshikata} } @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 {860, title = {Muonium formation as a probe of radiation chemistry in sub- and supercritical carbon dioxide}, journal = {Journal of Physical Chemistry A}, volume = {108}, number = {52}, year = {2004}, note = {ISI Document Delivery No.: 882FPTimes Cited: 5Cited Reference Count: 97}, month = {Dec}, pages = {11613-11625}, type = {Article}, abstract = {Muonium (Mu = mu(+)e(-)), which can be considered a light isotope of the H atom, has been observed for the first time in supercritical CO2 (ScCo2). It is Unreactive on a time scale of a few microseconds and over a wide density range from well below to well above the CO2 critical density rho(c) = 0.47 g/cm(3). The fraction of muon polarization in muonium, P-Mu, does not vary significantly at low densities but changes quickly at the highest densities, approaching zero. This density dependence is reflected in a concomitant increase observed in the lost fraction of polarization, P-L, demonstrating that the dynamics of Mu formation and depolarization in ScCO2 is a direct probe of radiolysis effects in the terminal muon radiation track. In marked contrast to previous studies in hydrogen-containing solvents, C2H6 and H2O, over comparable density ranges, the diamagnetic fraction, P-D, was found to be almost independent of density in CO2, attributed to the formation of the stable solvated MuCO(2)(+) molecular ion in this hydrogen-free solvent. The differing density dependences of both the Mu and the diamagnetic fraction in Co-2, in comparison with the rather similar trends seen for both in C2H6 and H2O, supports previous claims of a significant role played by proton (muon) transfer reactions in the competing processes involved in Mu formation in hydrogen-containing solvents. In addition to this being the first report of radiolysis effects accompanying energetic positive muons stopping in ScCO2, it is the only report of end of track effects in this solvent, which has many applications in nuclear waste management and green chemistry. With a mass intermediate between that of the electron, which has provided most radiation-chemistry studies in ScCO2 to date, and the proton (or alpha-particle), implanted muons provide a unique data set, characteristic of higher LET radiation, that may be relevant to radiolysis effects induced in ScCO2 by alpha decay from heavy nuclei, for which there are no comparable studies.}, keywords = {AQUEOUS-SOLUTIONS, CROSS-SECTIONS, EXCESS ELECTRON-TRANSPORT, GAS-PHASE, LIQUID WATER, MAGNETIC-RESONANCE, ORGANIC FREE-RADICALS, PRESSURE-DEPENDENCE, relaxation, SOLVENT ANIONS, SPIN}, isbn = {1089-5639}, url = {://000225924800018}, author = {Ghandi, K. and Bridges, M. D. and Arseneau, D. J. and Fleming, Donald G.} } @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 {595, title = {Formulation of benzoporphyrin derivatives in pluronics}, journal = {Photochemistry and Photobiology}, volume = {77}, number = {3}, year = {2003}, note = {ISI Document Delivery No.: 656FVTimes Cited: 10Cited Reference Count: 9}, month = {Mar}, pages = {299-303}, type = {Article}, abstract = {This study investigates the potential of Pluronics for the formulation of tetrapyrrole-based photosensitizers, with a particular focus on B-ring benzoporphyrin derivatives. The B-ring derivatives have a high tendency to aggregate in aqueous solutions, and this poses a significant formulation problem. Pluronics are ABA-type triblock copolymers composed of a central hydrophobic polypropylene oxide section with two hydrophilic polyethylene oxide sections of equal length at either end. Out of a range of different commercially available block copolymers studied, it was found that the longer the hydrophobic block, the better the stabilization of tetrapyrrolic drugs in monomeric form in aqueous suspensions. Of these the best performance was observed in the micelle-forming Pluronic P123. Micelle size determination by laser light scattering confirmed that particle size in stable Pluronic formulations was around 20 nm. Pluronics such as L122 formed emulsions spontaneously without the need for emulsion stabilizers; emulsions were highly stable at ambient temperatures over several days and also highly effective as potential drug delivery agents.}, keywords = {AGGREGATION, AQUEOUS-SOLUTIONS, SURFACTANTS, THERMODYNAMICS}, isbn = {0031-8655}, url = {://000181598800010}, author = {Chowdhary, R. K. and Chansarkar, N. and Sharif, I. and Hioka, N. and Dolphin, D.} } @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 {399, title = {Studies of a benzoporphyrin derivative with Pluronics}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {80}, number = {10}, year = {2002}, note = {ISI Document Delivery No.: 623LCTimes Cited: 14Cited Reference Count: 22}, month = {Oct}, pages = {1321-1326}, type = {Article}, abstract = {The synthetic route for the benzoporphyrin derivatives produces two regioisomers in equimolar quantities (ring A and B isomers). A derivative of the A-ring product, BPD-MA (benzoporphyrin-derivative monoacid ring A, verteporfin), has recently been approved in North America and Europe for the treatment of age-related macular degeneration. The B-ring isomers, contrary to the A-ring isomers, exhibit high aggregation in many formulations, which results in inadequate drug delivery for clinical uses. To avoid aggregation, a non-ionic surfactant polymer such as a Pluronic - poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) - may be used as a formulation excipient. The triblock polymer investigated here is designated P123 (or poloxamer 403). When used to formulate a monoacid benzoporphyrin B-ring derivative (2), a critical micelle concentration of P123 in water occurred at approximately 0.015 to 0.03\%. The apparent pK(a) of compound 2 was dependent on its concentration in P123, and decreased as the molar ratio (P123:2) increased. High concentrations of P123 and neutral pH were found to be the best conditions to maintain the drug in its monomeric form. Kinetic studies suggest that the aggregate of 2 contains several molecules, and is formed by a catalyzed self-assembly process. Samples with 1 mg mL(-1) of drug, at pH = 7.4, and 4.8\% of Pluronic showed satisfactory capacity to load and keep monomers stable. This formulation has potential PDT applications.}, keywords = {AGGREGATION, AQUEOUS-SOLUTIONS, block copolymers, BPD, COPOLYMERS, DYNAMICS, formulation, micelles, PHOTODYNAMIC THERAPY, photodynamic therapy (PDT), PHOTOSENSITIZERS, photosensitizing drug, Pluronic, poloxamers, porphyrins, SURFACTANTS, THERMODYNAMICS}, isbn = {0008-4042}, url = {://000179703700007}, author = {Hioka, N. and Chowdhary, R. K. and Chansarkar, N. and Delmarre, D. and Sternberg, E. and Dolphin, D.} } @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 {4958, title = {Interactions in D-fructose-1-propanol-H2O: the effect of D-fructose on the molecular organization of liquid H2O}, journal = {Fluid Phase Equilibria}, volume = {171}, number = {1-2}, year = {2000}, note = {ISI Document Delivery No.: 349EQTimes Cited: 5Cited Reference Count: 27}, month = {May}, pages = {151-164}, type = {Article}, abstract = {Densities of binary aqueous solutions of D-fructose (abbreviated as FR hereinafter) were determined in a much wider mole fraction range than available in literature. In contrast to hydrophobic solutes, the partial molar volume of FR, V-FR, does not show an initial decrease on increasing the mole fraction of FR, x(FR). In order to learn more about the effect of FR on the molecular organization of liquid H2O, the excess chemical potentials and partial molar enthalpy of 1-propanol (1P) were determined in ternary 1P-FR-H2O system. Namely, the detailed thermodynamic behaviour of 1P in the ternary system was used as a probe to elucidate the effect of FR on liquid H2O. In comparison with earlier results of the temperature dependence of tert-butanol (TBA)-TBA interaction functions, addition of FR seems to have a similar effect of temperature increase on the molecular organization of H2O. We suggest that addition of FR tends to decrease the global average of hydrogen bond probability of H2O. (C) 2000 Elsevier Science B.V. All rights reserved.}, keywords = {25-DEGREES-C, AQUEOUS-SOLUTIONS, BUTYL ALCOHOL-SOLUTIONS, chemical potential, CHEMICAL-POTENTIALS, D-fructose-1-propanol-H2O, effect of beta-D-fructose on H2O, INTERMOLECULAR INTERACTIONS, MIXING SCHEME, PARTIAL MOLAR ENTHALPIES, partial molar enthalpy, TRANSITION, VOLUME, VOLUMES, WATER-RICH REGION}, isbn = {0378-3812}, url = {://000089031000011}, author = {To, E. C. H. and Westh, P. and Trandum, C. and Hvidt, A. and Koga,Yoshikata} } @inbook {4841, title = {Macromolecular crowding and its consequences}, booktitle = {International Review of Cytology - a Survey of Cell Biology, Vol 192}, series = {International Review of Cytology-a Survey of Cell Biology}, volume = {192}, year = {2000}, note = {ISI Document Delivery No.: BP32STimes Cited: 19Cited Reference Count: 30Review525 B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 USA}, pages = {155-170}, publisher = {Academic Press Inc}, organization = {Academic Press Inc}, address = {San Diego}, keywords = {AQUEOUS-SOLUTIONS, CYTOPLASM, DIAGRAMS, Flory-Huggins theory, incompatibilty, PHASE, PHASE-SEPARATION, PROTEINS, scaled particle theory, THERMODYNAMIC INCOMPATIBILITY}, isbn = {0074-7696}, url = {://000084720600006}, author = {Johansson, H. O. and Brooks, D. E. and Haynes, C. A.} } @article {4420, title = {Interactions in 1-propanol-urea-H2O: Chemical potentials, partial molar enthalpies, and entropies at 25 degrees C}, journal = {Journal of Physical Chemistry B}, volume = {102}, number = {52}, year = {1998}, note = {ISI Document Delivery No.: 153MQTimes Cited: 27Cited Reference Count: 31}, month = {Dec}, pages = {10958-10965}, type = {Article}, abstract = {The excess partial molar enthalpies of I-propanol were determined in aqueous urea solutions. The total vapor pressures of 1-propanol-urea-H2O were also measured. The numerical analysis applied in a previous paper (J. Phys. Chem. B 1998, 102, 5182) was used to calculate partial pressures and, hence, the excess chemical potentials of each component. Thus, the excess partial molar entropies of l-propanol were obtained. From these partial molar quantities, the interaction functions between a pair of solute molecules were calculated following the method developed by us ( J. Phys. Chern. B 1996, 100, 5172). All these data seem to indicate that urea molecules lock into the hydrogen bond network of H2O, keep the connectivity of hydrogen bond intact, but reduce the degree of fluctuation that is characteristic of liquid water. I-Propanol molecules modify the hydrogen bond network in the same manner with or without urea, and hence the same amount of 1-propanol is required to break down the connectivity, i.e., the loss of hydrogen bond percolation. However, the H2O-mediated interaction between l-propanol solutes is weakened since the hydrogen bond fluctuation responsible for such an interaction is reduced by the presence of urea.}, keywords = {AQUEOUS-SOLUTIONS, fluctuations, INTERMOLECULAR INTERACTIONS, KIRKWOOD-BUFF PARAMETERS, MIXING SCHEMES, MIXTURES, TERT-BUTYL ALCOHOL, UREA, WATER-RICH REGION, X-RAY-SCATTERING}, isbn = {1089-5647}, url = {://000077837200040}, author = {To, E. C. H. and Hu, J. H. and Haynes, C. A. and Koga,Yoshikata} } @article {4422, title = {Intermolecular interactions in tert-butyl alcohol dimethyl sulfoxide H2O: Chemical potentials, partial molar entropies and volumes}, journal = {Journal of Physical Chemistry B}, volume = {102}, number = {26}, year = {1998}, note = {ISI Document Delivery No.: ZY137Times Cited: 13Cited Reference Count: 28}, month = {Jun}, pages = {5182-5195}, type = {Article}, abstract = {The excess chemical potentials, the excess partial molar entropies, and the partial molar volumes in tert-butyl alcohol (TBA)-dimethyl sulfoxide (DMSO)-H2O mixtures were determined. These data, together with previously published excess partial molar enthalpies (Fluid Phase Equilib. 1997, 136, 207) were used to evaluate intermolecular interactions. The TBA-TBA and TBA-DMSO, and DMSO-DMSO interactions were found to be crucially dependent on the composition. The net interaction in terms of chemical potential is very intricate. For example, net interactions of DMSO with a hydrophobic moiety (represented here by TEA) change from attractive to repulsive as the composition changes. This suggests that general discussions of the affinity of DMSO for nonpolar groups (or surfaces) are meaningful only by specifying the composition region. The interactions in terms of enthalpy and entropy are an order of magnitude larger and strongly compensating. Anomalous changes in the enthalpic/entropic interactions and hence qualitative changes in the mixing scheme of the solution, previously described in respective binary TBA-H2O and DMSO-H2O systems, are also apparent in this ternary system. II was found that as the mole fraction, x(D), of DMSO (third component) increases, the transition in mixing scheme occurred at a progressively lower value of x(B). The behavior of partial molar volume indicated that as x(B) increases, the initial increase in the partial molar volume of H2O on increasing x(D), reminiscent to "iceberg formation", diminished. This suggests that existing TEA molecules already made their contribution to the "iceberg formation". The DMSO-DMSO interaction in terms of volume also showed that the transition occurred at a smaller value of x(D) than that for x(B) = 0. The boundary between the two mixing schemes in the present ternary mixture was a straight line in the x(D)-x(B) field, suggesting that the effect of TEA and DMSO on H2O, causing the transition in the mixing scheme, is additive.}, keywords = {AQUEOUS-SOLUTIONS, ENTHALPIES, HYDROPHOBIC INTERACTION, MIXING SCHEME, MIXTURES, NONELECTROLYTES, NONPOLAR SOLUTE PARTICLES, PERCOLATION, TRANSITION, WATER-RICH REGION}, isbn = {1089-5647}, url = {://000074590000026}, author = {Trandum, C. and Westh, P. and Haynes, C. A. and Koga,Yoshikata} } @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 {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.} }