Original Articles: 2015 Vol: 7 Issue: 2
DFT analysis of vibrational spectra of 1,3-dihydro-7-nitro-5-phenyl-2H-1,4- benzodiazepin-2-one
Abstract
The fourier transform infrared and fourier transform raman spectra of 1,3-dihydro-7-nitro-5-phenyl-2h-1,4- benzodiazepin-2-one (abbreviated as 3d7nbp) are recorded in the regions 4000–400 and 4000–100 cm-1, respectively. The appropriate theoretical spectrograms for the ir and raman spectra of the title molecule are also constructed. The calculated results show that the predicted geometry can well reproduce the structural parameters. Predicted vibrational frequencies have been assigned and compared with experimental ir spectra and they supported each other. stability of the molecule arising from hyperconjugative interactions, charge delocalization and intramolecular hydrogen bond-like weak interaction has been analyzed using natural bond orbital (nbo) analysis by using b3lyp/6-31g(d,p) method. The results show that electron density (ed) in the σ* and π*antibonding orbitals and second-order delocalization energies e (2) confirm the occurrence of intramolecular charge transfer (ict) within the molecule. The first order hyperpolarizability (βtotal) of this molecular system and related properties (β, μ, and δα) are calculated using hf/6-31g (d,p) and b3lyp/6-31g(d,p) methods based on the finite-field approach. on the basis of vibrational analyses, the thermodynamic properties of the title compound at different temperatures have been calculated, revealing the correlations between, , and vs. temperature.