Solvent effect on intramolecular hydrogen bonds in push-pull conjugated molecules

A series of molecules leading to resonance-assisted hydrogen bonding has been investigated by means of Becke's three-parameter functional and the gradient-corrected functional of Lee, Yang, and Parr/6-311G(d,p) computations. The solvent (carbon tetrachloride) is simulated by the self-consistent reaction field model. The influence of the molecular structure on the intramolecular proton transfer is analyzed. The effect of the solvent on the geometry of the hydrogen bonds and on the frequency of the stretching modes of the groups involved in these bonds is noticeable. A linear relationship between the vibrational frequency and the bond length is found. (C) 2003 Wiley Periodicals, Inc.