Competition in Non-Covalent Interactions

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

James Lisy of the University of Illinois; Urbana-Champaign is supported by a grant from the Experimental Physical Chemistry Program to continue his studies of non-covalent interactions of chemical and biochemical importance. These studies are on mass selected cluster ions produced in an upgraded thermionic source and a recently constructed electrospray source, using infrared photodissociation and collision induced dissociation (CID). Particular systems to be studied are: (1) hydrated complexes of alkali cations with crown ethers and peptides to establish whether the ion is ligated by the solvent or the peptide/ionophore; (2) cation-ligand systems such as phenol, where the ligand has two binding sites, to establish where binding preferentially occurs and (3) anion (Cl- and Br-) with model receptors such as perfluorobenzene and amines to determine relative bond strengths. The studies will lead to a greater understanding of the bonding between ions and solvent molecules. This will improve our knowledge at the fundamental molecular level and show how the solvation, in situations including those where there are multiple binding sites, can be either cooperative or competitive. The information obtained will have relevance to the condensed phase and, in particular, to biological systems where the solvent molecules sometimes have to be removed before a molecule can pass through a cell membrane.