Density functional analysis of molecular crystal: bis-l-Phenyl alanine mandelate

Abstract

A novel organic nonlinear four component molecular crystal bis-l-phenylalanine mandelate (BLPAMA) has been synthesized and single crystal has been grown by slow evaporation method in an aqueous solution at ambient temperature. The characterization studies support the formation of the neutral novel organic molecular crystal containing 68 atoms in a molecule. The experimental and theoretical density functional analysis (DFT) have been compared for the vibrational changes, dipolar interactions, 1H and 13C NMR values, UV-visible absorption pattern, HOMO-LUMO interactions, hyperconjugation effects, Natural Bond Orbital (NBO) and Natural Hybridisation Orbital (NHO) analysis. The molecular structure obtained from the solid state experimental data using ORTEP diagram has been compared with the gaseous state optimized stucture obtained from DFT data using Gaussian 98 software with MO6-31++(d,p) basis set. The DFT study of the title compound has confirmed the crystal formation through charge transfer mechanism, hydrogen bonding interactions and van der Waals forces of attraction. The stress and strain in the title compound leads to the low energy gap nonlinear molecular sheet formation. The title compound shows electrochemical activity due to the highly reactive and relatively unstable structure.