NBO, HOMO, LUMO analysis and vibrational spectra (FTIR and FT Raman) of 1-Amino 4-methylpiperazine using ab initio HF and DFT methods

•FT-IR and Raman spectra of 1-Amino-4-methylpiperazine were recorded and analyzed.•The complete vibrational assignments and spectroscopic analysis were made.•The HOMO, LUMO energy gap were theoretically predicted.•Stability, charge delocalization analyzed by using NBO theory.•Electrostatic potential of 1-Amino4-methylpiperazine was calculated.

Experimental FTIR and FT-Raman spectroscopic analysis of 1-Amino-4-methylpiperazine (1A4MP) have been performed. A detailed quantum chemical calculations have been carried out using ab initio HF and density functional theory calculations (B3LYP) with 6-311+G(d,p) basis set. The atomic charges, electronic exchange interaction and charge delocalization of the molecule have been performed by natural bond orbital (NBO) analysis. Electron density distribution and frontier molecular orbitals (FMOs) have been constructed at B3LYP/6-311+G(d,p) level to understand the electronic properties. The charge density distribution and site of chemical reactivity of the molecule have been obtained by mapping electron density isosurface with electrostatic potential surfaces (ESP). The electronic properties, HOMO and LUMO energies were measured by time-dependent TD-DFT approach. The dipole moment (μ), polarizability (α), anisotropy polarizability (Δα) and hyperpolarizability (β) of the molecule have been reported.

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