Structural, vibrational, optical properties and theoretical studies of new noncentrosymmetric material: Bis(2-Amino-5-(methylthio)-1,3,4-thiadiazol-3-ium) pentachloroantimonate

A new non-centrosymmetric Sb(III) halide complex with formula (C3H6N3S2)(2)SbCl5 (complex 1) has been synthesized by reaction between antimony trioxide (Sb2O3) and 2-Amino-5-(methylthio)-1,3,4-thiadiazole (AMT,) in an aqueous solution of hydrochloric acid. Single crystal X-ray diffraction analysis shows that this compound crystallizes in orthorhombic system with the non-centrosymmetric space group Pna2(1). Its crystal structure consists of isolated (C3H6N3S2)(+) cations and square pyramidal shape [SbCl5](2-) anions. The anions are disposed to form a polymeric chain in which each subunit is connected to the others through a Cl bridge. The organic cations are connected to these chains via H-bonding N-H center dot center dot center dot Cl and C-H center dot center dot center dot Cl. The intermolecular interactions which ensure the cohesion between different entities were analyzed by DFT calculations and Hirshfeld surface analysis. Ab-initio DFT calculations were also used to investigate geometric and electronic properties of complex 1 and AMT. Absorption, photoluminescence and infrared spectroscopy have been carried out. DFT calculations with different functionals have been used to gain a better insight into its vibrational and optical properties and a good agreement was found between experiments and calculations. The thermal stability of compound was studied by thermal analysis. Published by Elsevier B.V.