Metal derivatives of azoles. Part V. Platinum(II) and palladium(II) pyrazolates as a new type of neutral bidentate ligands

Abstract

The complexes (L—L)M(pz)2 {(L—L) = (Ph2PCH2)2, M = Pt, Pd; (L—L) = 2,2′-dipyridine, M = Pt} and (L—L)M(pz′)2 {(L—L = (Ph2PCH2)2, M = Pt; (L—L) = 2,2′-dipyridine, M = Pt, Pd} where pzH = pyrazole and pz′H = 3,5-dimethylpyrazole, behave as ligands towards suitable acceptors affording 1:1 or 1:2 adducts.The 1:1 adducts are obtained by reaction with group IIB metal halides, cobalt(II) chloride, copper(II), or zinc(II) sulphate and are likely to be binuclear complexes, (ligand)MX2, with two pyrazolato anions bridging the different metals.The nature of the 1:2 adducts [(ligand)2M′][BF4]2 (M′ = Zn, Ni, Co) as well as of the adduct (dipy)Pt(pz)2•2Rh(CO)2Cl, are discussed.