Molecular potential, cation binding, and hydration properties of the carboxylate anion. Ab initio studies with an extended polarized basis set

The carboxylat anion, involved in the structure of numerous compounds of biological interest, participates in a number of intermolecular interactions involving water, cations, and other cellular constituents. A set of ab initio SCF computations have been carried out with an extended polarized basis set on HCOO – , its molecular electrostatic potential, and its interaction with Li + , Na + , K + , and H 2 O. The results are compared with those of a minimal good quality basis set. An evaluation of the basis set superposition error is made in the two basis as well as that of the contribution of the dispersion energy to the hydration. The analogies and differences in the nucleophilic character of the formate and the phosphate groups are discussed.