TITANIUM AND VANADIUM COMPLEXES OF 4-[1-( HENYL-METHYLIDENE]-3-METHYL-1-PHENYL-PYRAZOL-5-ONE - STRUCTURE OF HENYL-METHYLIDENE]-3-METHYL-1-PHENYL-PYRAZOL-5-ONE

By reaction of 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one with benzoylh ydrazine the tridentate diacidic ligand 4-[1 -(N'-benzoylhydrazino)-1- phenyl-methylidene] -3-methyl-1-phenyl-pyrazol-5-one (H(2)L) is formed which gives complexes ML(2) with tetravalent titanium and vanadium io ns. The ligand and its complexes were characterized by mass spectrosco py. The vanadium(IV) complex can be oxidised and reduced electrochemic ally The chemical bonding in the titanium(IV) complex and in the ligan d was studied by IR and C-13 NMR spectroscopy. The molecular structure of 4-[1-(N'-benzoylhydrazino)-1 henyl-methylidene]-3-methyl-1-phenyl- pyrazol-5-one was determined by X-ray analysis. Crystal data: a = 9.15 9(3) Angstrom, b = 11.014(4) Angstrom, c = 11.136(5) Angstrom, alpha = 90.11(2)degrees, beta = 101.84(3)degrees, gamma = 113.01(2)degrees; s pace group P (1) over bar, Z = 2.