DFT CALCULATIONS AND SPECTROSCOPIC STUDY ON TRIGONELLINE, A BIOLOGICALLY ACTIVE COMPOUND OF FENUGREEK
Keywords:
MEP - Molecular electrostatic potential, NBO - Natural bond orbitals, NLO - nonlinear optics,HOMO- Higher occupied molecular orbital, LUMO- Lower unoccupied molecular orbital, TD-DFT- Time dependent density functional theory.Abstract
Fenugreek (Trigonella foenum-graecum) is a medicinal plant which is widely used for its pharmacological properties. Fenugreek seeds have been extracted by soxhlet extraction method with the solvent ethanol for an alkaloid Trigonelline. In this present study extracts have been subjected to FT-Infrared and FT-Raman analysis for the structural determination of different functional groups present in spices. Quantum chemical computations such as the molecular geometry, vibrational frequencies, UV-Vis spectroscopic parameters, HOMO-LUMO energies, molecular electrostatic potential (MEP), natural bond orbitals (NBO), nonlinear optics (NLO) and thermodynamic properties of title molecule have been calculated by using DFT/B3LYP method with 6-311++G (d,p) basis set in ground state for the first time. The obtained results show that the calculated spectroscopic data are in a good agreement with experimental data.
The time dependent DFT (TD-DFT) method was employed to predict its electronic properties, such as electronic transitions by HOMO and LUMO energies, various global reactivity and selectivity descriptors (chemical hardness, chemical potential, softness, electrophilicity index) also calculated.
