METAL-COMPLEXES OF 4,5-DIMETHYLPYRAZOLE-3-CARBOXALDEHYDE PHENYLTHIOSEMICARBAZONE

Several new transition metal complexes derived from 4,5-dimethyl-3-carboxaldehyde phenylthiosemicarbazone, LH, have been synthesized. The complexes are of stoichiometry, [CoL2]X, X = Cl-, Br-, ClO4- or NO3- [MnL2] and [CuXnLm], X = Cl-, Br-, NCS- or N3-; n = 1 or 0; m = 1 or 2 and L = the anion of LH. All complexes have been characterized by elemental analysis, spectral (i.r., electronic, NMR, ESR) and magnetic measurements. The ligand acts as tridentate monobasic co-ordinated to the metal ion via azomethine, pyrazole (N2) nitrogen atoms and the thiolo-sulphur. The ligand field and ESR parameters are used to interpret the nature of bonding of LH with the metal ion, ground state and the ligand field strength of LH and the various co-ordinated simple ions. The coupling constants of various co-ordinated nuclei with copper (II) are estimated from ESR spectra of copper (II) complexes.