Synthesis of and theoretical research on some azine derivatives and investigation of their antimicrobial activities

This study includes experimental, theoretical and antimicrobial investigations on 1-(diphenylmethylene)-2-(4-methoxybenzylidene)hydrazine (5), 1-(3,5-dimethoxybenzylidene)-2-(diphenylmethylene)hydrazine (6) and 1-(diphenylmethylene)-2-(2,3,4-trimethoxybenzylidene)hydrazine (7). The structures of the compounds, synthesized by the microwave method, were determined by spectroscopic methods and elemental analysis. Conformational analysis, ground state structure, Fourier-transform infrared spectra (FT-IR) and nuclear magnetic resonance (NMR) spectra of the compounds were determined using density the functional theory (DFT) calculations in the theoretical research. Based on the B3LYP/6-31G(d,p) level, the conformers from the torsional barrier scanning were optimized. The B3LYP/6-311++G .(d,p) was used to determine the harmonic vibrational frequencies, potential energy distribution (PED), infrared intensities, and NMR chemical shifts of the most stable conformers. The experimental findings were compared with the theoretically expected spectral data. The antibacterial activity of the prepared compounds was tested in vitro against nine bacteria and one yeast species. The antimicrobial activity of the compounds was tested by minimum inhibitory concentration (MIC) and agar well diffusion method. Compound 7 showed good activity against the bacteria and yeast, while 5 and 6 showed no antimicrobial activity. Compound 7 showed zone of inhibition values in the range of 10-15 mm against Klebsiella pneumonia, Pseudomonas aeruginosa and Salmonella typhimurium The results indicated that compound 7 was effective against bacteria.