We describe the experimental investigation of time-resolved magnetic field effects in exciplex-forming organic donor-acceptor systems. In these systems, the photoexcited acceptor state is predominantly deactivated by bimolecular electron transfer reactions (yielding radical ion pairs) or by direct exciplex formation. The delayed fluorescence emitted by the exciplex is magnetosensitive if the re...

in this article, theoretical studies on the selective complexation of the halide ions (f¯, cl¯ and br¯) and ion pairs (na+f¯, na+cl¯ and na+br¯) with the cyclic nano-hexapeptide (cp) composed of l-proline have been performed in the gas phase. in order to calculate the dispersion interaction energies of the cp and ions, dft-d3 calculations at the m05-2x-d3/6-31g(d) level was employed. based on t...

a simple extractive spectrophotometric method has been developed for the estimation of miconazole nitratein both pure and pharmaceutical preparation. the method is based on the formation of ion-pair complex of thedrug with acidic dye bromothymol blue (btb) in acidic condition, followed by its extraction in organic solvent(chloroform). the absorbance was measured against the corresponding blank....

The ionic environment of biomolecules strongly influences their structure, conformational stability, and inter-molecular interactions. This paper introduces GIBS, a grand-canonical Monte Carlo (GCMC) simulation program for computing the thermodynamic properties of ion solutions and their distributions around biomolecules. This software implements algorithms that automate the excess chemical pot...

A general model has been developed for calculating the static dielectric constant of mixed-solvent electrolyte solutions. For mixtures of solvents without electrolyte components, the model is based on an empirical modification of the Kirkwood theory for multicomponent systems. For systems containing electrolytes, the model takes into account the effects of ions and ion pairs and, therefore, it ...

Pair association in Ionic Liquids is an important quantity that affects many of their physical and chemical properties. However, the association constant is a complex function of the component ions as well as of the solvent environment, and no single theory can compute or predict it with quantitative accuracy. In this work we analyze infinite-dilution association data from a number of recent co...

Intermolecular ion pairs (salt bridges) are crucial for protein-DNA association. For two protein-DNA complexes, we demonstrate that the ion pairs of protein side-chain NH3+ and DNA phosphate groups undergo dynamic transitions between distinct states in which the charged moieties are either in direct contact or separated by water. While the crystal structures of the complexes show only the solve...

Molecular dynamics simulations of supercritical electrolyte solutions with three different ion–water models are performed to study the anion–cation potential of mean force of an infinitely dilute aqueous NaCl solution in the vicinity of the solvent’s critical point. The association constant for the ion pair Na/Cl and the constant of equilibrium between the solvent-separated and the contact ion ...