Cis versus trans arrangement of dithiocarbazate ligands in bis-chelated Ni and Cu complexes

The structures are described of two bis-chelated metal complexes of nickel(II) and copper(II) with S-n-hexyl 3-(1-phenylethylidene)dithiocarbazate Schiff bases in a cis configuration, namely, bis[S-n-hexyl 3-(1-phenylethylidene)dithiocarbazato-?² N ³,S]nickel(II), [Ni(C₁₅H₂₁N₂S₂)2], and bis[S-n-hexyl 3-(1-phenylethylidene)dithiocarbazato-?² N ³,S]copper(II), [Cu(C₁₅H₂₁N₂S₂)2]. In both complexes, the metals have distorted square-planar geometries. A search in the Cambridge Structural Database [Groom et al. (2016). Acta Cryst. B72, 171-179] for bis-chelated nickel(II) and copper(II) complexes with similar Schiff bases retrieved 55 and 36 hits for the two metals, respectively. An analysis of the geometrical parameters of complexes showing cis and trans configurations is reported and the values compared with those for the complexes described in this work.