The crystal structure, infrared, Raman and density functional studies of bis(2-aminophenyl) diselenide

Bis(2-aminophenyl) diselenide exhibits a broad spectrum of biological activity against viruses, bacteria, yeasts and pathogenic fungi. In this work, for the first time the structure of bis(2-NH2Ph)Se-2 has been determined by single crystal X-ray diffraction and vibrational spectroscopy methods. The compound crystallizes in the triclinic system, space group P (1) over bar. There are two symmetrically independent molecules, each containing two seleno-2-aminophenyl moieties bound by the diselenide bridge. The Se-Se distances are 2.3565(2) and 2.3600(3) angstrom. The N-H center dot center dot center dot N intermolecular hydrogen bonds contribute to the formation of the zig-zag chains along the b axis. The Raman and FT-IR spectra of the title compound are reported. Comprehensive theoretical studies have been performed by using density functional B3LYP method with the 6-311+G(d,p) basis set. The calculated atom distances, bond angles and vibrational frequencies are in good agreement with experiment. Detailed assignments of the spectra have been made on the basis of the calculated potential energy distribution, PED. The v(C-Se) stretching vibrations are assigned at 288 and 280 cm(-1) (Raman). The most intense and characteristic Raman band at 252 cm(-1) arises from the Se-Se stretching vibration. The presented vibrational assignment will be helpful in the spectroscopic studies of other organoselenium compounds. (C) 2011 Elsevier Ltd. All rights reserved.