Synthesis and characterization of square planar nickel(II) complexes with p-fluorobenzaldehyde thiosemicarbazone derivatives

New thiosemicarbazone nickel complexes (1-7), derived from p-fluorobenzaldehyde and differently substituted thiosemicarbazides, were synthetized and characterized by means of NMR and IR techniques. The p-fluorobenzaldehyde 4-ethylthiosemicarbazone Et-Hfbt (1) and its complex [Ni(Et-fbt)(2)] (2) were also characterized by X-ray diffractometry. Molecule 1 consists of two units: the p-fluorobenzaldehyde residue and the thiosemicarbazonic chain. In the reaction of 1 with NiAc2. 4H(2)O, complex 2 was afforded. The molecular structure of 2 consists of the neutral complexes [Ni(Et-fbt)(2)] with the metal not lying on a symmetry centre, with two consequently independent ligand molecules; the coordination results in a square planar geometry slightly twisted towards a tetrahedron, involving the sulfur and the hydrazine nitrogen atoms of the two ligands in a trans configuration. (C) 2001 Elsevier Science B.V. All rights reserved.