Spectral and magnetic studies of anomolous paramagnetic,nickel(II) complexes ofN-phenyl-2-[1-(2-pyridyl)ethylidene] hydrazinecarbothioamide

Summary Nickel(II) complexes ofN-phenyl 1-2-1-(2-pyridyl) ethylidene] hydrazinecarbothioamide (HL) of general composition NiLX] (where X=Cl, Br, OAc or NO₃ and L=deprotonated ligand) have been synthesized and characterized by elemental analysis, conductivity measurements, i. r. spectra, electronic spectra and magnetic measurements. The electronic spectra were recorded in Nujol and dimethylformamide (DMF) whereas magnetic susceptibilities were recorded in the range 80–300 K. A distorted tetrahedral geometry is indicated for all the complexes except the chloro-complex. The paramagnetic behaviour of square-planar NiLCl] is explained in terms of an equilibrium between the diamagnetic spin-paired ground state and low lying triplet state.