Synthesis and structures of iron(III) complexes based on azo derivatives of 5-oxo- and 5-thioxopyrazole

New potentially tridentate ligands, viz., 3-methyl-1-phenyl-4-(quinolin-8-ylhydrazono)pyrazol-5(1H)-one and 3-methyl-1-phenyl-4-(quinolin-8-ylhydrazono)pyrazole5(1H)-thione (LH), and their complexes with Wit were synthesized. The structures of the ligands and metal chelates (FeL(2)A; A = ClO4 or FeCl4) were studied by H-1 NMR spectroscopy and magnetochemistry. The FeL(2)A complex (A = FeCl4) was investigated by X-ray diffraction. These low-spin complexes have pseudooctahedral structures with the N4X2 ligand environment (X = O or S).