Phosphinohydrazines. Part IV. Coordination compounds of N,N-dimethyl,N′-diphenylphosphinohydrazine and N,N-dimethyl-N′-diphenylthiophosphinatohydrazine

Abstract

A study of complexes of (a) N,N-dimethyl,N′-diphenylphosphinohydrazine, DPH, viz., Pd(DPH)Cl2, Pd(DPH)2Cl2, [Pd(DPH)2Cl]ClO4, Pt(DPH)2Cl2, Pt(DPH)Cl4, Hg(DPH)Cl2; (b) N,N-dimethyl,N´-diphenylthiophosphinatohydrazine, DPS, viz., Pd(DPS)Cl2, Pt(DPS)Cl4, Ag(DPS)NO3, Zn(DPS)Cl2, Cd(DPS)Cl2, and Hg(DPS)Cl2, and (c) N,N-dimethylhydrazine, DMH, viz., Zn(DMH)2Cl2 and Cd(DMH)Cl2, has been carried out using conductivity, molecular weight, infrared, and nuclear magnetic resonance measurements. DPH functions mostly as a unidentate ligand, with the phosphorus atom as the preferred donor site. Thus Pd(DPH)Cl2 is a chlorobridged dimer in solution in weakly polar solvents, while the monomeric form in polar solvents is of uncertain structure. A trans, four-coordinate structure is consistent for Pd(DPH)2Cl2. For [Pd(DPH)2Cl]ClO4, however, one DPH ligand is chelating through the phosphorus and terminal nitrogen atoms, while the second ligand is unidentate; the compound is a monomeric uni–univalent electrolyte in nitrobenzene. The ligand DPS appears to chelate via the sulfur and central nitrogen atoms, giving four-membered ring structures; a cis configuration is suggested for Pd(DPS)Cl2. Zn(DMH)2Cl2 is monomeric in solution, with the Me2N group coordinated to the metal.