Synthesis, crystal structure, and characterization of thiophene-3-carboxaldoxime complexes with cobalt(II), nickel(II) and copper(II) halides

The reaction of cobalt(II), nickel(II), copper(II) chlorides and bromides with thiophene-3-carboxaldoxime (3TCOH) leads to a series of new complexes: [CoCl2(3TCOH)4], [CoBr2(3TCOH)4], [NiCl2(3TCOH)4], [NiBr2(3TCOH)4], [CuCl2(3TCOH)4], [CuBr2(3TCOH)2] respectively. The crystal structures of [CoBr2(3TCOH)4], [NiBr2(3TCOH)4] have been determined by X-ray diffraction methods showing octahedral complex species. In all complexes, the oxime functional group remains protonated and the coordination occurs through the nitrogen atom of the oxime moiety.