Ab initio and AIM studies on intramolecular dihydrogen bonds

Ab inito calculations on molecules with intramolecular dihydrogen bonds have been performed at MP2/6-311++G(d,p) level of theory. The O-H bond for these systems is the proton donator and the H-B bond of BH3- group is the acceptor within B-H...H-O H-bridge. Different geometrical, energetic and topological parameters derived from the theory of Bader have been studied. The correlation analysis shows that there is no the meaningful delocalization of electrons within the ring formed by the intramolecular H-bridge. The properties of the bond critical points of H+delta...H-delta contacts and the properties of the ring critical points are useful parameters for the description of the unconventional H-bond analysed in this study. (C) 2003 Elsevier Science B.V. All rights reserved.