da Silva, Elaine F.
Siqueira, Leonardo J. A.
Alves, Wagner A.
Total Authors: 3
 Univ Fed Rural Rio de Janeiro, Dept Quim, Inst Ciencias Exatas, BR-23890000 Seropedica, RJ - Brazil
 Univ Fed Sao Paulo, Inst Ciencias Quim Farmaceut & Ambientais, Lab Mat Hibridos, Dept Ciencias Exatas & Terra, BR-04042002 Sao Paulo - Brazil
Total Affiliations: 2
Web of Science Citations:
Hydrogen bonding between pyridazine (PRD) and formamide (FA) molecules has been investigated both experimentally by Raman spectroscopy on their binary mixtures and theoretically by DFT calculations on various gas-phase PRD:FA clusters. The band at 1160 cm(-1) of PRD was used for the first time as a marker for monitoring the degree of complexation. Upon dilution with FA, a new band at 1169 cm(-1) is observed and attributed to hydrogen-bonded PRO. The Raman experiments were complemented by OFT calculations and the corresponding structures, vibrational spectra and binding energies were determined. The most stable species were found to be the 1:2 PRD:FA complexes and such stoichiometry is in excellent agreement with the experimental determination. The shift to higher frequency observed to the prominent modes of PRO may be related to a shortening of the NC and CC bonds, upon complexation, which causes a decrease in the electron delocalization in PRO ring. (C) 2010 Elsevier B.V. All rights reserved. (AU)