Complexes of nickel(II) with substituted thioureas

A series of Ni(II) complexes with methyl-, ethyl-, and sym-dimethyl-, sym-diethyl-, and sym-di-n-butyl- thioureas and halide, perchlorate, and thiocyanate anions have been prepared and characterized. Spectral and magnetic studies show that compounds NiL 4 X 2 (L = N,N′-dimethyl and N,N′-diethylthiourea, X = halide) are tetragonally distorted octahedral species with a singlet ground state and a thermally populated triplet excited state. The remaining compounds are octahedral. Infrared evidence shows sulfur bonding of the disubstituted ligands to the metal, but suggests nitrogen coordination of the methylthiourea compounds.