Electron density distribution studies on ZnS4N2 chromophore in solution and solid phases: XPS and cyclic voltammetric studies on 1,10-phenanthroline and 2,2 '-bipyridine adducts of bis(piperidinecarbodithioato-S,S ')zinc(II). Single crystal X-ray structure of (2,2 '-bipyridine)bis(piperidinecarbodithioato-S,S ')zinc(II)

(1,10-phenanthroline)bis(piperidinecarbodithioato-S,S')zinc(II), [Zn(pipdtc )(2)(1,10-phen)] (1) and (2,2'-bipyridine)bis(piperidinecarbodithioatao-S,S ')zinc(II), [Zn(pipdtc)(2)(bipy)] (2) adducts were prepared and the crystal structure of 2 is reported. The Zn-S distances in 2 are longer than those in Zn(dtc)(2) complexes. The presence of an additional neutral ligand cause s an increase of the Zn-S bond lengths. S2p binding energies show a signifi cant reduction in value compared to the parent dithiocarbmate [Zn(pipdtc)(2 )](3), indicating the weakening of the Zn-S bond on adduct formation. The o bserved reduction in binding energy is due to the increased electron densit y on the metal in the adducts. The cyclic voltammetric study on the complex es also show an increase of electron density on zinc in the adducts compare d to Zn(pipdtc)(2). The S-Zn-S angle in the adduct shows a reduction due to increased coordination around zinc, The thioureide C-N distance of 1.343(1 3) Angstrom in compound 2 is in line with the nu C-N observed at 1469 cm(-1 ). (C) 1999 Elsevier Science Ltd. All rights reserved.