N-(2-Hydroxyethyl)-N-methyldithiocarbamato Complexes of Nickel(II) with Phosphorus Donor Ligands

Planar nickel(II) complexes involving N-(2-Hydroxyethyl)-N-methyldithiocarbamate, such as [NiX(nmedtc)(PPh3)] (X = Cl, NCS; PPh3 = triphenylphosphine), and [Ni(nmedtc)(P-P)]ClO4(P-P = 1,1-bis(diphenylphosphino)methane(dppm); 1,3-bis(diphenylphosphino)propane (1,3-dppp); 1,4-bis(diphenylphosphino)butane(1,4-dppb) have been synthesized. The complexes have been characterized by elemental analyses, IR and electronic spectroscopies. The increased vC-N value in all the complexes is due to the mesomeric drift of electrons from the dithiocarbamate ligands to the metal atom. Single crystal X-ray structure of [Ni(nmedtc)(1,3-dppp)]ClO4 center dot H2O is reported. In the present 1,3-dppp chelate, the P-Ni-P angle is higher than that found in 1,2-bis(diphenylphosphino)ethane-nickel chelates and lower than 1,4-bis(diphenylphosphino)butane-nickel chelates, as a result of presence of the flexible propyl back bone connecting the two phosphorus atoms of the complex.