Experimental and computational study of the structure and spectroscopic properties of 1′,3′-Dihydrospiro[cyclohexane-1,2′-[2H]imidazo[4,5-b]pyridine]

• The molecular structure and vibrations were calculated using the HF and DFT methods.
• The molecule was screened for antimicrobial activity against Gram-positive and Gram-negative bacteria.
• NBO, NLO, NMR analysis for the title compound were carried out.

The optimized molecular geometry and vibrational frequencies of 1′,3′-Dihydrospiro[cyclohexane-1,2′-[2H]imidazo[4,5-b]pyridine] were calculated using Hartree Fock (HF) and Density Functional Theory (DFT) methods. The vibrational spectrum was experimentally recorded using Fourier Transform-Infrared (FT-IR). Gauge-independent atomic orbital (GIAO) 1H and 13C nuclear magnetic resonance (NMR) chemical shift values of the 1′,3′-Dihydrospiro[cyclohexane-1,2′-[2H]imidazo[4,5-b]pyridine] were calculated using DFT/B3LYP/6-311G + (d, p). The electronic properties such as HOMO-LUMO energies, absorption wavelengths, and excitation energy were investigated by time dependent DFT (TD-DFT) method with integral equation formalism-polarized continuum model (IEF-PCM). The mulliken charges on the atoms and second-order interaction energies were derived from NBO analysis. The electric dipole moment, the mean polarizability and the mean first hyperpolarizability values were also computed by using the DFT method. The effect of the molecule on pBR322 plasmid DNA was monitored by agarose gel electrophoresis experiments. The antimicrobial activities were tested by using minimal inhibitory concentration method (MIC).