Experimental and theoretical investigation of the spectroscopic properties of 2- and 4-aminobenzylamine molecules

The experimental spectroscopic properties of 2-aminobenyzlamine (2ABA), and 4-aminobenyzlamine (4ABA) were investigated by FT-IR, FT-Raman, UV-Vis, and NMR techniques. The structural and spectroscopic data of the molecule have been obtained for two possible conformers from DFT/B3LYP with 6-311++G(d,p) basis set calculations. The geometry of the molecules 2ABA and 4ABA were fully optimized. The vibrational spectra of two molecules were calculated, and fundamental vibrations were assigned based on the potential energy distribution (PED) of the vibrational modes. The UV spectra of 2ABA, and 4ABA dissolved in ethanol were recorded in the range of 180-400 nm this solution and obtained as a theoretically. 1H and 13C NMR chemical shifts properties were predicted by using GIAO method and compared with the experimental data obtained in DMSO solution. Mulliken charges, and the electronic properties (like HOMO and LUMO energies) were presented as well and to investigate the effect of NH2 position of molecules based on benzylamine. The comparison of the theoretical results according to their experimental data, showing a good agreement with some minor differences. We wish this study to demonstrate and thoroughly to have insight into the effect of NH2 substitution in benzylamine derivatives.