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Model studies of interactions between amino acids and carboxylic acids: a pcilo mo study of the effects of hydration on hydrogen bonding and proton transfer in the system acetic acid - imidazole

✍ Scribed by Milan Remko; Ludovit Krasnec

Publisher: Elsevier Science
Year: 1980
Weight: 480 KB
Volume: 18
Category: Article
ISSN: 0378-4487
DOI: 10.1016/0378-4487(80)80057-4

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✦ Synopsis

The semi-empirical PCILO (Perturbative Configuration Interaction using Localized Orbitals) method has been used to study intermolecular hydrogen bonding and proton transfer in the acetic acid -imidazole system. The effect of specific hydration on the proton potential functions was investigated (within the so-called supermolecule approach) in the system acetic acid -imidazole x nH20 (n=2,4), The proton potential functions, calculated at equilibrium distances R 0 with a . . . N, single-minimum were found. The PCILO calculations at the longer R. *.. N = 0.30 nm distance indicate the double-minimum potentials. The second minimum is observed in the isolated acetic acid -imidazole system as a saddle point and with increasing hydration (by two and four water molecules) crosses to the second, less stable minimum.

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