Structural and spectroscopic studies on dimerization and solvent-ligand complexes of Theobromine

Abstract

The solvent effects on structure and vibrational modes of Theobromine (TBR) were examined by using theoretical and experimental methods. Solvent-ligand complexes of TBR were handled in detail for Dimethylsulfoxide (DMSO) and Ethanol (EtOH) solvents. Density Functional Theory (DFT) was used for theoretical calculations. Polarized continuum model (PCM) was employed to characterize the solvent effects in implicit and explicit investigations. After the optimized molecular structures are determined in vacuum and solvent media, the wavenumbers and intensities of the vibrational frequencies were also computed in detail. Experimental FT-IR spectra of TBR in DMSO and EtOH solutions were recorded and compared with solid phase data. The results show that the structural and vibrational properties of TBR are affected by the solvent effect. Experimental and theoretical results show also that TBR may exist in dimer form in solid phase and it is bonded by hydrogen bonds with the solvent molecules in solutions.