X-RAY PHOTOELECTRON SPECTRAL STUDY OF THE PLANAR NIS4, NIS2PCL AND NIS2P2 CHROMOPHORES AND X-RAY CRYSTAL-STRUCTURE OF NEDITHIOCARBAMATOBIS(TRIPHENYLPHOSPHINE)NICKEL(II) PERCHLORATE TRIPHENYLPHOSPHINE MONOHYDRATE

An X-ray photoelectron spectral study on the complexes bis(diethyldith iocarbamato) nickel(II), Ni(dedtc)(2) (1), bis(diethanoldithiocarbamat o) nickel(II), Ni (deadtc)(2) (2), chlorodiethyldithiocarbamatotriphen ylphosphine nickel(II), Ni(dedtc)Cl (PPh(3)) (3) and diethyldithiocarb amatobis(triphenylphosphine) nickel(II) perchlorate, [Ni(dedtc)(PPh(3) )(2)]ClO4 (4) with NiS4, NiS4 (electron-withdrawing alkyl substituent) NiS2PCl and NiS2P2 chromophores, respectively was made. All the chrom ophores except NiS2P2 showed similarity in binding energy values with respect to various core level electrons. The nickel 2p(3/2) binding en ergy value for the NiS2P2 chromophore was significantly different (854 .1 eV), indicating an excessive positive charge on the nickel ion. Thi s observation is in line with solution studies by cyclic voltammetry. A one-electron reduction potential was observed to be the minimum for the NiS2P2 chromophore compared to the others. Alkyl substitution does not alter the binding energy values of the nickel 2p(3/2) level as ob served earlier. Highly significant negative Delta E values for sulfur 2p electron binding energies indicate the localization of electronic c harge on sulfur. Also, the crystal structure of the complex [Ni(pipdtc )(PPh(3))(2)]ClO4(PPh(3)). H2O (pipdtc = piperidine dithiocarbamate) p repared by the reaction between Ni(pipdtc)(2) and PPh(3) in CH2Cl2-CH3 OH was determined.