Vibrational Spectroscopic [IR and Raman] Analysis and Computational Investigation [NMR, UV-Visible, MEP and Kubo gap] on L-Valinium Picrate

Abstract

In the present methodical study, FT-IR, FT-Raman and NMR spectra of the L-Valinium Picrate are recorded and the fundamental vibrational frequencies are tabulated and assigned. The Gaussian hybrid computational calculations are carried out by HF and DFT (LSDA, B3LYP and B3PW91) methods with 6-311++G(d,p) basis sets and the corresponding results are compared with experimental values. The existence of vanderwals interaction between L-Valine and picric acid is investigated. The Zwitterionic motion of hydrogen atom from phenol group of Picric acid to amino group of L-Valine is studied. The impact of this occurrence of motion in the molecular structure is also discussed. The vibrational sequence pattern of the weak interaction molecule is analyzed. Moreover, 13 C NMR and 1 H NMR are calculated by using the gauge independent atomic orbital (GIAO) method with B3LYP methods and the 6-311++G(d,p) basis set and their spectra are simulated and the chemical shifts related to TMS are compared. A study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, are performed by HF and DFT methods. The calculated HOMO and LUMO energies (kubo gap) are displayed in the figures which show that the occurring of charge transformation within the molecule. Besides frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) was performed. NLO properties related to Polarizability and hyperpolarizability is also discussed.