Structural, vibrational, optical properties and theoretical studies of a new organic-inorganic material: Tris-acetoguanaminium hexachlorobismuthate monohydrate

In the present work, we investigate a self-assembly process which offers the possibility to construct organic-inorganic hybrid architectures by assembling halogenobismuthates(III) as building units and organic cations, in order to elaborate a new organic inorganic hybrid material with the formula {[H-guan](3)[BiCl6]center dot H2O} (H-guan(+): acetoguanaminium cation). The compound was synthesized by slow evaporation of aqueous solution at room temperature and characterized by X-ray single crystal diffraction, infrared and UV-vis absorption, scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Its structure consists of [BiCl6](3-) anions, showing distorted octahedral geometry, surrounded by three crystallographically independent acetoguanaminium [C4H8N5](+) cations and a water molecule. The crystal packing is governed by the formation of a number of N-H center dot center dot center dot Cl, N-H center dot center dot center dot N, N-H center dot center dot center dot O and O-H center dot center dot center dot Cl hydrogen bonds arranged in a three-dimensional network. The optical properties of the title compound were also investigated by both UV-vis and photoluminescence spectroscopy. DFT calculations at the B3LYP/LanL2DZ level have been carried out to gain a better insight into its vibrational and optical properties and a good agreement was found between experiments and calculations. TGA coupled to DSC analysis were carried out to study the thermal behavior of the prepared material.