A comparative study on FT-IR, conformational and electronic structure of 6-methylpurine

•The FT-IR spectra of the title compound have been recorded.•Frontier molecular orbitals analysis of the title compound was investigated by theoretical calculations.•The calculations for the optimization, analysis of molecular electrostatic potential, NBO, thermodynamic parameters are done.

In this work, the experimental and theoretical study on molecular structure and vibrational spectra of 6-methylpurine were studied. A detailed quantum chemical calculations have been performed by Hartree–Fock (HF) and density functional theory (DFT) methods (B3LYP) with 6-31++G(d,p) basis sets. Ultraviolet–visible (UV–Vis) spectra, thermodynamic properties and Natural Bond Orbital (NBO) analysis of the title compound in the ground state have been calculated using the Hartree–Fock (HF) and density functional theory (DFT) methods (B3LYP) with 6-31++G(d,p) basis set combination for the first time. The vibrational spectra were interpreted with the aid of normal coordinate analysis based on scaled density functional force field. The results show that the vibrational frequencies are in good agreement with the experimental data. In addition, not only were frontier molecular orbitals (HOMO and LUMO), molecular electrostatic potential (MEP) and density of the state (DOS) energy band gap values were predicted.

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