We present an all atom potential energy function for the simulation of proteins and nucleic acids. This work is an extension of the CH united atom function recently presented by S.J. Weiner et al. J. Amer. Chem. Soc., 106, 765 (1984). The parameters of our function are based on calculations on ethane, propane, n−butane, dimethyl ether, methyl ethyl ether, tetrahydrofuran, imidazole, indole, deoxyadenosine, base paired dinucleoside phosphates, adenine, guanine, uracil, cytosine, thymine, insulin, and myoglobin. We have also used these parameters to carry out the first general vibrational analysis of all five nucleic acid bases with a molecular mechanics potential approach.

An all atom force field for simulations of proteins and nucleic acids.

In this review the phenomenon of proton conductivity in materials and the elements of proton conduction mechanismsproton transfer, structural reorganization and diffusional motion of extended moietiesare discussed with special emphasis on proton chemistry. This is characterized by a strong proton localization within the valence electron density of electronegative species (e.g., oxygen, nitrogen) and self-localization effects due to solvent interactions which allows for significant proton diffusivities only when assisted by the dynamics of the proton environment in Grotthuss and vehicle type mechanisms. In systems with high proton density, proton/proton interactions lead to proton ordering below first-order phase transition rather than to coherent proton transfers along extended hydrogen-bond chains as is frequently suggested in textbooks of physical chemistry. There is no indication for significant proton tunneling in fast proton conduction phenomena for which almost barrierless proton transfer is suggest...

Proton Conductivity: Materials and Applications

Hydrogen bonding in solids correlation of spectroscopic and crystallographic data

Publisher Summary This chapter describes the essence of the catalytic chemistry of heteropoly compounds in solution and in the solid state. The catalytic properties of heteropoly compounds have drawn wide attention, owing to the versatility of these compounds as catalysts, which has been demonstrated both by successhl large-scale applications and by promising laboratory results. Heteropolyanions are polymeric oxoanions formed by condensation of more than two different mononuclear oxoanions. Heteropolyanions formed from one kind of polyanion are called isopolyanions. Acidic elements such as Mo, W, V, Nb and Ta, which are present as oxoanions in aqueous solution, tend to polymerize by dehydration at low pH, forming polyanions and water.Heteropoly catalysts can be applied in various ways. They are used as acid as well as oxidation catalysts. They are used in various phases, as homogeneous liquids, in two-phase liquids (in phase-transfer catalysis), and in liquid-solid and in gas-solid combinations, etc.

Catalytic Chemistry of Heteropoly Compounds

Conducting polymers prepared by oxidative polymerization: polyaniline

Proton transfer and superionic conductivity in solids and gels

Infrared and Raman study of polyaniline Part II: Influence of ortho substituents on hydrogen bonding and UV/Vis—near-IR electron charge transfer

Equilibrium of the protonic species in hydrates of some heteropolyacids at elevated temperatures

Infrared and Raman study of polyaniline Part I. Hydrogen bonding and electronic mobility in emeraldine salts

Une attribution des frequences fondamentales de l’imidazole situees entre 1 700 et 250 cm–1 est proposee. L’etude des spectres d’absorption de ce compose dans divers etats physiques et du dichroisme d’un cristal oriente a permis d’identifier les vibrations A' et A". L’attribution des bandes aux vibrations des groupements CH, NH et du noyau a ete effectuee en examinant les spectres infrarouges a l’etat solide et Raman en solutions aqueuses des quatre especes isotopiques de l’imidazole. Les perturbations des frequences fondamentales dues a l’association et le couplage vibrationnel sont discutes. Les frequences des vibrations externes entre 200 et 30 cm–1 ont ete determinees en absorption.

Spectres de vibration de l’imidazole, de l’imidazole (D)-1, de l’imidazole (D3)-2,4,5 et de l’imidazole (D4) - Partie I : Région entre 4 000 et 1 700 cm–1

Alexandre Novak

Papers

Proton transfer and superionic conductivity in solids and gels

Infrared and Raman study of polyaniline Part II: Influence of ortho substituents on hydrogen bonding and UV/Vis—near-IR electron charge transfer

Equilibrium of the protonic species in hydrates of some heteropolyacids at elevated temperatures

Infrared and Raman study of polyaniline Part I. Hydrogen bonding and electronic mobility in emeraldine salts

Spectres de vibration de l’imidazole, de l’imidazole (D)-1, de l’imidazole (D3)-2,4,5 et de l’imidazole (D4) - Partie I : Région entre 4 000 et 1 700 cm–1