title: Computational study of noncovalent complexes between formamide and formic acid.
abstract: The geometries and binding energies of 1:1, 1:2, and 1:4 formic acid-formamide complexes (FA-FMA) are calculated by quantum chemical procedures. Vibrational spectra and intermolecular distances of the most stable FA-FMA dimers as well as the influence of the basis set superposition error (BSSE) on the geometries and energies of the dimers are also discussed. All FA-FMA dimers are optimized at the B3LYP/cc-pVTZ, the MP2/cc-pVDZ, aug-cc-pVDZ, cc-pVTZ, and aug-cc-pVTZ levels of theory to study the influence of the level of theory on the calculated geometries and energies. CCSD(T)/cc-pVTZ single-point calculations at the MP2/aug-cc-pVTZ-optimized geometries were performed as reference for estimating the quality of lower level calculations. These calculations allow us to qualitatively describe the competition between different types of hydrogen-bonding interactions in FA-FMA complexes. FA-FMA dimers are compared to other formamide complexes and to the FA-FMA crystal structure.
authors.affiliation: Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, D-44780 Bochum, Germany, and Laboratorio de Química Computacional y Teórica, Facultad de Química, Universidad de la Habana, 10400, Cuba.
authors.forename: Elsa
authors.initials: E
authors.lastname: Sánchez-García
authors.forename: Luis A
authors.initials: LA
authors.lastname: Montero
authors.forename: Wolfram
authors.initials: W
authors.lastname: Sander