Thermal behaviour and optical properties of a new dimeric 1D mixed halide hybrid material [CuBrCl(C2H8N2)

Abstract

A new organic–inorganic copper-based hybrid material containing ethylendiamine as organic part and mixed bromide/chloride as halide ions has been synthesized and crystallographically characterized. At room temperature, this new compound adopts the monoclinic symmetry (space group P21/m) and presents the following unit-cell parameters: a = 6.927(3) Å, b = 5.884(3) Å, c = 8.399(4) Å, β = 94.856(13)°, V = 341.1(2)Å3 and Z = 2. The 1D structure of the title compound consists of infinite dimeric chains running along the crystallographic b axis. These chains are constructed from dimeric units [Cu2Br2Cl2(C2H8N2)2] linked together by sharing (Br/Cl) atoms. N-H…Br/Cl hydrogen bonds guarantee the connection between the dimeric chains and the cohesion of the structure. The thermogravimetric analysis shows that this new hybrid material decomposes in two stages giving rise to the copper oxide as final residue. The UV–visible absorption shows that the new complex undergoes three optical absorption bands at 238, 317 and 686 nm, respectively. From the gap energy value of 2.92 eV it can be concluded that the new mixed halide compound is a semiconductor material.