Structural, vibrational spectroscopic studies and quantum chemical calculations of n-(2,4-dinitrophenyl)-l-alanine methyl ester by density functional theory

• Published in: Journal of molecular structure 2015-05, Vol.1088, p.70-84
• Main Authors: Govindarasu, K., Kavitha, E.
• Format: Article
• Language: English
• Subjects: FT-Raman; FTIR; N-(2,4-dinitrophenyl)-l-alanine methyl ester; NBO; TD-DFT; UV–Vis
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2015.02.008

[Display omitted] •The FTIR and FT-Raman spectra of Dnp-ala-ome were reported.•The first order hyperpolarizability was calculated.•UV–Vis spectra were recorded and compared with calculated values.•Electronegativity and electrophilicity index values also calculated. In this paper, the vibrational wavenumbers of N-(2,4-dinitrophenyl)-l-alanine methyl ester (abbreviated as Dnp-ala-ome) were obtained from ab initio studies based on the density functional theory approach with B3LYP and M06-2X/6-31G(d,p) level of theories. The optimized geometry and structural features of the most potential nonlinear optical crystal Dnp-ala-ome and the vibrational spectral investigations have been thoroughly described with the FT-Raman and FT-IR spectra supported by the DFT computations. FT-IR (4000–400cm–1) and FT-Raman spectra (3500–50cm–1) in the solid phase and the UV–Vis spectra that dissolved in ethanol were recorded in the range of 200–800nm. The Natural population analysis and natural bond orbital (NBO) analysis have also been carried out to analyze the effects of intramolecular charge transfer, intramolecular and hyperconjugative interactions on the geometries. The effects of frontier orbitals, HOMO and LUMO, transition of electron density transfer have also been discussed. The first order hyperpolarizability (β0) and related properties (β, α0 and Δα) of Dnp-ala-ome were calculated. In addition, molecular electrostatic potential (MEP) was investigated using theoretical calculations. The chemical reactivity and thermodynamic properties (heat capacity, entropy and enthalpy) of at different temperature are calculated.