Synthesis, crystal structure, vibrational spectra, optical properties and theoretical investigation of bis (2-aminobenzimidazolium) tetraiodocadmate

The present research work accounts for a combined experimental and theoretical study on crystal structure and vibrational spectra of a new organic inorganic hybrid compound (C7H8N3)2CdI4. In fact, the single crystals of bis (2-aminobenzimidazolium) tetraiodocadmate (C7H8N3)2CdI4, were obtained by slow evaporation of an aqueous solution at room temperature and crystallized in the centrosymmetric space group P-1 of triclinic system. The infrared (IR) and Raman spectra of the title compound were recorded at room temperature and then analyzed. As for the vibrational spectra, they were also calculated theoretically by means of Gaussian 98 package of programs within the DFT framework using the B3LYP/LanL2DZ level of theory. The data thus obtained from vibrational wavenumber calculations were used to assign vibrational bands obtained in IR and Raman spectroscopy of the studied compound. Moreover, the geometrical parameters of the title compound are in agreement with the values of similar structures. The optical study was also investigated by UV–vis absorption. In fact, the organic–inorganic hybrid crystal thin film can be easily prepared by spin-coating method from the ethanol solution of the (C7H8N3)2CdI4 hybrid compound and it showed absorptions characteristics of CdI based layered perovskite centered at 288 and 388 nm.