@article {2673, title = {Structures of Water Molecules at the Interfaces of Aqueous Salt Solutions and Silica: Cation Effects}, journal = {Journal of Physical Chemistry C}, volume = {113}, number = {19}, year = {2009}, note = {ISI Document Delivery No.: 443FLTimes Cited: 6Cited Reference Count: 53Yang, Zheng Li, Qifeng Chou, Keng C.}, month = {May}, pages = {8201-8205}, type = {Article}, abstract = {Structures of water molecules at water/silica interfaces, in the presence of alkali chloride. were investigated using infrared-visible sum frequency vibrational spectroscopy. Significant perturbations of the interfacial water structure were observed on silica surfaces with the NaCl concentration as low as 1 x 10(-4) M. The cations, which interact with the Silica Surface via electrostatic interaction, play key roles in Perturbing the hydrogen-bond network of water molecules at the water/silica interface. This cation effect becomes saturated at concentrations around 10(-2) to 10(-1) M, where the sum frequency generation peaks at 3200 and 3400 cm(-1) decrease by 75\%. Different alkali cation species (Li+, Na+, and K+) produce different magnitudes of perturbation, with K+ > Li+ > Na+. This order can be explained by considering the effective ionic radii of the hydrated cations and the electrostatic interactions between the hydrated cations and silica Surfaces. The interfacial water structure associated with the 3200 cm(-1) band is more vulnerable to the cation perturbation, Suggesting that the more ordered water structure on silica is likely associated with the vincinal silanol groups, which create a higher local surface electrical field on silica.}, keywords = {ADSORPTION, charge, DYNAMICS SIMULATIONS, ELECTROLYTE INTERFACE, hydration, INTERFACE, LIQUID WATER, SOLID/LIQUID, SUM-FREQUENCY SPECTROSCOPY, SURFACE, vibrational spectroscopy}, isbn = {1932-7447}, url = {://000265895500034}, author = {Yang, Z. and Li, Q. F. and Chou, K. C.} } @article {911, title = {"Icebergs" or no "Icebergs" in aqueous alcohols?: Composition-dependent mixing schemes}, journal = {Journal of Physical Chemistry A}, volume = {108}, number = {17}, year = {2004}, note = {ISI Document Delivery No.: 814TNTimes Cited: 22Cited Reference Count: 38}, month = {Apr}, pages = {3873-3877}, type = {Article}, abstract = {The classical concept of "iceberg formation" is modified by our recent thermodynamic studies. The local enhancement of the hydrogen-bond network of H2O in the immediate vicinity of small nonelectrolyte solutes (i.e., the "iceberg formation") is still correct. However, the hydrogen-bond probability of bulk H2O away from solutes is reduced progressively, as the solute composition increases. When the hydrogen-bond probability of bulk H2O is reduced to the bond percolation threshold of the hexagonal ice connectivity, the hydrogen-bond percolation is lost and a qualitatively different mixing scheme sets in, whereby the solution consists of two kinds of clusters. In the solute-rich region, solute molecules form Clusters of its own kind. Thus, the "iceberg, formation" is basically correct within a narrow range in the H2O-rich region for small nonelectrolyte solutes. Thus, reference made to the "iceberg" concept in recent literatures should be clarified in terms of the concentration range and the size of solute in question.}, keywords = {2-BUTOXYETHANOL, BUTANOL, fluctuations, hydration, HYDROPHOBIC SURFACES, MIXTURES, PARTIAL MOLAR VOLUMES, TERT-BUTYL ALCOHOL, WATER-RICH REGION, X-RAY-SCATTERING}, isbn = {1089-5639}, url = {://000220997100023}, author = {Koga,Yoshikata and Nishikawa, K. and Westh, P.} } @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 {2871, title = {SYNTHESES OF 2-DEOXY-2-FLUORO MONOSACCHARIDE AND OLIGOSACCHARIDE GLYCOSIDES FROM GLYCALS AND EVALUATION AS GLYCOSIDASE INHIBITORS}, journal = {Carbohydrate Research}, volume = {249}, number = {1}, year = {1993}, note = {ISI Document Delivery No.: MD387Times Cited: 41Cited Reference Count: 34}, month = {Oct}, pages = {77-90}, type = {Article}, abstract = {Several fluorinated oligosaccharides, including 2-deoxy-2-fluoro derivatives of cellobiose, maltose, and maltotriose were synthesized by the action of fluorine or acetyl hypofluorite on the corresponding glycal peracetates. Temperature effects on the stereoselectivities of these reactions were examined. Addition of acetyl hypofluorite to several 2-substituted glycals in the gluco or galacto series gave 2,2-disubstituted arabino- or lyxo-hexose derivatives; 3,4,6-tri-O-acetyl-2-fluoro-D-glucal or the analogous galactal yielded 2-deoxy-2,2-difluoro arabino- or lyxo-hexose peracetates, whereas 2-acetoxy-3,4,6-tri-O-acetyl-D-glucal or the analogous galactal gave 2(R)-2-acetoxy-2-fluoro-arabino- or lyxo-hexose peracetates, respectively. 2-Acetamido-3,4,6-tri-O-acetyl-D-glucal gave 2(R)-2-acetamido-2-acetoxy-3,4,6-tri-O-acetyl-alpha-D-arabino-hexopyrano syl fluoride. 2,4-Dinitrophenyl 2-deoxy-2-fluoro-beta-cellobioside was an inactivator of the exoglucanase from Cellulomonas fimi while 2-deoxy-2-fluoro-alpha-maltosyl and alpha-maltotriosyl fluorides were slow substrates of human pancreatic alpha-amylase and rabbit muscle glycogen debranching enzyme, respectively.}, keywords = {ACETYL HYPOFLUORITE, beta-glucosidase, CATALYTIC FLEXIBILITY, DERIVATIVES, ENZYME, GLYCOSYLASES, hydration, INTERMEDIATE, MECHANISM}, isbn = {0008-6215}, url = {://A1993MD38700007}, author = {McCarter, J. D. and Adam,Michael J. and Braun, C. and Namchuk, M. and Tull, D. and Withers, S. G.} } @article {7389, title = {MONONUCLEAR AND DINUCLEAR PALLADIUM COMPLEXES CONTAINING 2-PYRIDYLPHOSPHINE LIGANDS, INCLUDING X-RAY CHARACTERIZATION OF PD2I2(MU-PPH2PY)2 AND A DIMETHYLACETYLENEDICARBOXYLATE A-FRAME COMPLEX PD2CL2(MU-PPY3)2(MU-MEO2C.C=C.CO2ME) PY = 2-PYRIDYL}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {70}, number = {3}, year = {1992}, note = {ISI Document Delivery No.: JD670Times Cited: 41Cited Reference Count: 48}, month = {Mar}, pages = {751-762}, type = {Article}, abstract = {{Dibromo- and diiodo[(2-pyridyl)phosphine]palladium(II) complexes are prepared by metathesis of cis-PdCl2(PPh3-npyn)2 species (n = 1-3) using the appropriate sodium halide; py = 2-pyridyl. NMR spectroscopy, particularly C-13{H-1}, is used to distinguish cis and trans isomers. The dinuclear complexes Pd2X2(mu-PPh3-npyn)2}, keywords = {(DINUCLEAR), 2-(DIPHENYLPHOSPHINO)PYRIDINE, BINUCLEAR COMPLEXES, bis(diphenylphosphino)methane, BRIDGING, CHEMISTRY, CRYSTAL, DIMETHYLACETYLENEDICARBOXYLATE ADDUCTS, hydration, LIGAND, MOLECULAR-STRUCTURE, palladium complexes, pyridylphosphines, RHODIUM COMPLEXES, RUTHENIUM(II)}, isbn = {0008-4042}, url = {://A1992JD67000009}, author = {Xie, Y. and Lee, C. L. and Yang, Y. P. and Rettig, S. J. and James, Brian R.} } @article {7152, title = {SYNTHESIS AND CHEMISTRY OF 2-PYRIDYL(PHOSPHINE) COMPLEXES OF PLATINUM(0)}, journal = {Journal of Organometallic Chemistry}, volume = {417}, number = {1-2}, year = {1991}, note = {ISI Document Delivery No.: GL228Times Cited: 23Cited Reference Count: 39}, month = {Oct}, pages = {277-288}, type = {Article}, abstract = {The complexes tetrakis[tri(2-pyridyl)phosphine]platinum(0), 1, and tris[2-(diphenylphosphino)pyridine]platinum(0), 2, are synthesized, and characterized by P-31{H-1} and Pt-195{H-1} NMR spectroscopy. The reactions of 1 and 2 with olefins (ethylene, maleic anhydride, diethyl maleate, and olefinic nitriles) are studied and some square-planar Pt(PR3)2(eta-2-olefin) species isolated (PR3 = the pyridylphosphine). No olefin hydration products are observed on heating the olefin complexes in aqueous solution. Oxidative addition of MeI to 1 and to 2 gives the trans-PtI(Me)(PR3)2 species. However, the trans-Pt(H)Cl(PR3)2 species is isolated only from reaction of 2 with gaseous HCl; the hydride reacts with acrylonitrile to form cis-PtCl(CH2CH2CN)(PR3)2.}, keywords = {2-(DIPHENYLPHOSPHINO)PYRIDINE, BINUCLEAR COMPLEXES, BRIDGING, CATALYSIS, hydration, LIGAND, MOLECULAR-STRUCTURE, palladium, PHOSPHINE COMPLEXES, RHODIUM(I), RUTHENIUM(II)}, isbn = {0022-328X}, url = {://A1991GL22800024}, author = {Xie, Y. and James, Brian R.} }