Crystal structure, vibrational and optical properties of a new Bi(III) halide complex: [C6H16N2]5Bi2Br10(BiBr6)2·2H2O

A new Bi(III) halide complex, [C6H16N2]5Bi2Br10(BiBr6)2·2H2O has been synthesized at room temperature in the presence of 1,4-dimethylpiperazine by slow evaporation technique and characterized by physicochemical methods. It crystallizes in a triclinic centrosymmetric space group, P-1. The crystal lattice is composed of two types of anionic entities [Bi2Br10]4− and [BiBr6]3− surrounded by 1,4-dimethylpiperazine-1,4-diium cations and water molecules. The anionic part was found for the first time in halobismuthate(III) solid complexes. In the crystal, the components are linked by C-H…Br(Ow) and Ow-H…Br hydrogen bonds to built three-dimensional network. The vibrational absorption bands were identified by Infrared and Raman spectroscopy. The 13C and 15N CP-MAS NMR spectra are in agreement with the X-ray structure. Intermolecular hydrogen bonding was investigated by means of the Hirshfeld surfaces. The percentages of hydrogen bonding interactions are analyzed by Fingerprint plots of Hirshfeld surface. The optical properties of this compound were studied by UV–Vis and luminescence spectroscopy. The DSC curve shows that this compound is stable below melting point.