Nickel(II) and Palladium(II) complexes of dithiomalonamides: ligand which favor the formation of pi-conjugation systems in the coordination.

The spectra (IR and NMR) of the nickel(II) and palladium(II) complexes of dithiomalonamide (Hdtma) and N,N′-diphenyldithiomalonamide (Hdpdtma) are discussed in the light of the structure of the bis(N,N′-diphenyldithiomalonamidato) nickel(II) di(N,N-dimethylformamide)solvate. The compound crystallizes in the triclinic space group P-1 (No. 2) with a=11.113(2), b=10.173(2), c=9.912(1) Å, a=74.47(6), β=108.83(7), γ=114.10(7)°, Z=1 (R=0.0495 and Rw=0.052). The crystals consist of discrete [Ni(dpdtma)2] and N,N-dimethylformamide (DMF) molecules. The nickel atom is chelated by two centrosymmetrically related ligands via sulfur atoms in an approximately squareplanar arrangement. The ligand moiety in the nickel coordination forms a π-conjugation system. The DMF solvate molecules are involved in hydrogen bonding with the NH groups of the ligand.