Study on vibrational spectra and structure of 4-mercaptopyridine monomer and dimer using density functional theory

The optimized molecular structure and vibrational frequencies of 4-mercaptopyridine monomer and dimer were studied by density functional theory using B3LYP method with the 6-311++G(d, p) basis set On the basis of the calculations, the assignments of vibrational spectra were performed on monomer and dimer, and the change in structure and vibrational spectrum of dimer as well as the intermolecular force of forming dimer were investigated. It was found that the two pyridine ring planes are vertical to each other, and the dimer was formed through H-bonding, which is between the nitrogen on one ring and the hydrogen of SH moieties on another. Furthermore, the structure and vibrational spectrum of the dimer have some changes with respect to those of the monomer.