J. Chem. Soc. Perkin II, 2671-2675 (1998)

DOI: 10.1039/A804677H

A computational approach to intermolecular proton transfer in the solid state: assistance by proton acceptor molecules

Ab initio (B3LYP/6-311++G**) calculations have been carried out on the proton transfer of 2H-tetrazole and 5-phenyl-2H-tetrazole with and without the assistance of different nitrogen bases (hydrogen cyanide, ammonia and imidazole). In the absence of base, the proton transfer barrier amounts to 210 kJ mol–1 while in the presence of ammonia it is lowered to 119 kJ mol–1. Moreover, the inclusion of a solvent cavity of the Onsager type, which increases the first barrier, decreases the second one to 67 kJ mol–1 (for ε = 5) which is consistent with experimental data for irbesartan (a 5-aryl-2H-tetrazole derivative).