Ground and excited state dipoles and polarizabilities of the chromophores N-methyl-6-oxyquinolinium betaine (MQ) and coumarin 153 (C153) in solution have been evaluated using time-dependent density functional theory (TD-DFT). A method for determining the atomic polarizabilities has been developed; the molecular dipole has been decomposed into atomic charge transfer and polarizability terms, and...

Room temperature ionic liquids (RTILs) are a new class of solvents. Their main interest is related to their “green” properties (non-volatile, non-flammable, etc.), but also from the variability of their physico-chemical properties (stability, hydrophobicity, viscosity) as a function of the RTIL cationic and anionic components. In the frame of the nuclear fuel reprocessing, RTILs are particularl...

Cochran, H.D., Cummings, P.T. and Karaborni, S., 1992. Solvation in supercritical water. Fluid Phase Equilibria, 71: 1-16. The aim of this work is to determine the solvation structure in supercritical water compared with that in ambient water and in simple supercritical solvents. Molecular dynamics studies have been undertaken of systems that model ionic sodium and chloride, atomic argon, and m...

Selected theoretical methods, basis sets and solvation models have been tested in their ability to predict (31)P NMR chemical shifts of large phosphorous-containing molecular systems in solution. The most efficient strategy was found to involve NMR shift calculations at the GIAO-MPW1K/6-311++G(2d,2p)//MPW1K/6-31G(d) level in combination with a dual solvation model including the explicit conside...

This paper describes a generalized method to establish the values of the five solvation parameters of solutes, which reflect, together with the five solvation parameters of solvents, the intermolecular forces involved in solutions and in some biological phenomena. The tool applied for this purpose is a simplified molecular topology (SMT), which principally takes into account, for each atom of a...

The interaction of myelin basic protein (MBP) from the bovine central nervous system with Ca2+ and Mg2+ ions, named as M2+, was studied by isothermal titration calorimetry at 27 degrees C in aqueous solution. The extended solvation model was used to reproduce the enthalpies of MBP+M2+ interactions. The solvation parameters recovered from the extended solvation model were attributed to the struc...

A Gaussian solvent-exclusion model for the solvation free energy is developed. It is based on theoretical considerations and parametrized with experimental data. When combined with the CHARMM 19 polar hydrogen energy function, it provides an effective energy function (EEF1) for proteins in solution. The solvation model assumes that the solvation free energy of a protein molecule is a sum of gro...

In this contribution we report studies on enzymatic activity of alpha-chymotrypsin (CHT) upon complexation with cationic cetyltrimethylammonium bromide (CTAB) micelle. With picosecond time resolution, we examined solvation dynamics at the interface of CHT-micelle complex, and rigidity of the binding. We have used 5-(dimethyl amino) naphthalene-1-sulfonyl chloride (dansyl chloride; DC) that is c...

The ability of the GROMOS96 force field to reproduce partition constants between water and two less polar solvents (cyclohexane and chloroform) for analogs of 18 of the 20 naturally occurring amino acids has been investigated. The estimations of the solvation free energies in water, in cyclohexane solution, and chloroform solution are based on thermodynamic integration free energy calculations ...

Water solvation dynamics of polar species both in the bulk and in the hydration layers of proteins and self-organized assemblies have been discussed. Recent studies have revealed that while water solvation dynamics in the bulk is ultrafast and is mostly complete within 1 ps, this can slow down by as much as 2–3 orders of magnitude in the hydration layers of these systems. In this Report we disc...