Coordinating Behaviour of 4-Cyano-5-Aminopyrazole Ligand: Synthesis and Physico-Chemical Studies of Some Transition Metal Complexes ML4CI2(M = Fe, Co, Ni, Cu, L = HCNNH2pz)

摘要

Reactions of 4-cyano-5-aminopyrazole HCNNH2pz (L) with anhydrous MCl2give the complexes ML4Cl2(M = Fe, Co, Ni, Cu) which also can be prepared from M(PPh3)2Cl2 (M = Co, Ni). The complexes are soluble in most non-polar solvents. Experimentally determined molecular weights suggest that they are monomeric in solution. The i.r., #x3BC;eff and the bands exhibited in reflectance and electronic spectra at room temperature are consistent with octahedral geometries. IR spectra contain bands characteristic of the pyrazole ring and substituents. The M-N and M-Cl stretching vibrations appear at their expected frequencies. The complexes derived from M(PPh3)2Cl2 (M = Ni, Co) do not exhibit a characteristic band expected at Ca. 500 cm#x2212;1for the PPh3group.