Ab Initio Studies of Electron Acceptor–Donor Interactions with Blue‐ and Red‐Shifted Hydrogen Bonds

Abstract

Abstract The features of blue‐ and red‐shifted electron acceptor–donor ( ACH/B) hydrogen bonds have been compared by using quantum chemical calculations. The geometry, the interaction energy and the vibrational frequencies of both blue‐ (ACH=F 3 CH, Cl 3 CH with B=FCD 3 ) and red‐shifted (ACH=F 3 CH, Cl 3 CH with B=NH 3 and ACH=CH 3 CCH with B=FCD 3 , NH 3 ) complexes were obtained by using ab initio MP2(Full)/6‐31+G(d,p) calculations with the a priori basis‐set superposition error (BSSE) correction method. One‐dimensional potential energy and dipole moment functions of the dimensionless normal coordinate Q 1 , corresponding to the CH stretching mode of ACH, have been compared for both types of complexes. Contributions of separate components of the interaction energy to the frequency shift and the effect of electron charge transfer were examined for a set of intermolecular distances by using the symmetry‐adapted perturbation theory (SAPT) approach and natural bond orbitals (NBO) population analysis.