Synthesis, spectral, and single crystal X-ray structural studies on (2,2 '-bipyridyl)bis(dimethyldithiocarbamato) zinc(II) and (1,10-phenanthroline)bis(dimethyldithiocarbamato)zinc(II)

Synthesis, spectral, and single crystal X-ray structural studies on (2,2'-b ipyridyl)bis (dimethyldithiocarbamato)zinc(II) (1) and (1,10-phenanthroline )bis(dimethyldithiocarbamato)zinc(II)(2) complexes are reported in this pap er. The complex (1) crystallizes in the orthorhombic lattice, space group P een, a = 18.456(3), b = 6.529(2), and c = 17.092(2) Angstrom. The complex ( 2) crystallizes in the monoclinic space group C2/c, a = 13.372(2), b = 13.8 50(2), c = 24.680(3) Angstrom, and beta = 102.71(4)degrees. IR spectra of t he complexes (1) and (2) show the thioureide v(C-N) bands at 1489 and 1510 cm(-1), respectively, which are lower than the value observed for the paren t bisdithiocarbamate. Reduction in the thioureide stretching frequency is d ue to the increase in coordination around the zinc ion and the resultant in crease in electron density. Thermal studies indicate that the 1,10-phenanth roline adduct is marginally more stable than the other complex. X-ray cryst al structures of the two adducts show them to be octahedrally coordinated a nd monomeric in nature. The Zn-S distances are longer than those observed i n the parent bisdithiocarbamate. The thioureide C-N bond distances in (1) a nd in (2) indicate the partial double bond character. The most important st ructural changes as a result of the adduct formation are observed in the Zn -S bond distances and S-Zn-S bond angles, in terms of very significant incr eases in Zn-S bond distances and reductions in S-Zn-S angles, compared to t he parent bisdithiocarbamate. The observed changes are indicative of a stro ng steric force in operation in the adducts rather than electronic effects.