DFT Calculations on the Molecular Structure, Vibrational and Chemical Shift Assignments of 4-Allyl

Abstract

The molecular geometry, vibrational frequencies, gauge including atomic orbital (GIAO) 1H and 13C chemical shift values and several thermodynamic parameters of 4-allyl-2-(morpholin-4-ylmethyl)-5-(pyridin-4-yl)-2,4-dihydro-3H-1,2,4-triazole-3-thione in the ground state were calculated using density functional methods (BLYP and B3LYP) with the 6-31G(d) basis set. The results of the optimized molecular structure are given and compared with experimentally obtained X-ray diffraction. The computed vibrational frequencies were used to determine the types of molecular motions associated with each of the experimental bands observed. Vibrational mode assignments of the title compound were carried out using a total energy distribution calculation. The calculated 1H and 13C chemical shift values are compared with the experimental values. The molecular frontier orbital energies of the title compound were calculated using the BLYP and B3LYP/6-31G(d) levels. The obtained data for the title compound provided its molecular structure, while the IR and NMR analyses provide a basis for the future design of efficient materials containing a 1,2,4-triazole core. © 2011 King Fahd University of Petroleum and Minerals.