Hydrogen Bonds Between Phthalimide and Hydrogen Fluoride: A Theoretical Study

B3LYP/6-31++G(d, p) theoretical calculations were performed to obtain the binding energies and molecular properties of the 1: 1 and 1: 2 hydrogen complexes involving a phthalimide as a proton acceptor and hydrogen fluoride. The calculations revealed the existence of two and three stable structures for the 1: 1 and 1: 2 complexes, respectively. A good linear correlation was found between the binding energies and the H-bond lengths of these complexes. The binding energies were corrected using both the BSSE and ZPE corrections. The vibrational changes that take place in the HF acid after complexation with phthalimide followed the usual behavior: the HF stretching frequency was shifted downward whereas its IR intensity was considerably heightened. Furthermore, the two HF bending modes, which are pure rotations of the isolated HF molecule, showed an appreciable infrared-active intensity upon H-bond formation. (C) 2011 Wiley Periodicals, Inc. Int J Quantum Chem 111: 1387-1394, 2011