Synthesis and structures of 3,5-bis(trifluoromethyl)pyrazol derivatives of Rh(I), Ir(I), Pd(II) and Pt(II)

The reaction of 3,5-(CF3)2PzLi with [Rh(COD)Cl]2, IrCl(CO)3, [PdCl(η3-C3H5)]2 and PtCl2(COD) in diethylether solution at 0 °C results in the formation of [Rh(COD)(μ-3,5-(CF3)2Pz)]2 (1), [Ir(CO)2(μ-3,5-(CF3)2Pz)]2 (2), [Pd(η3-C3H5)(μ-3,5-(CF3)2Pz)]2 (3), and Pt(COD)(η1-3,5-(CF3)2Pz)2 (4), respectively (3,5-(CF3)2Pz=3,5-(CF3)2 pyrazolate; COD=1,5-cyclooctadiene). Compounds 1–3 are dimeric with bridging 3,5-(CF3)2Pz ligands while 4 is monomeric and features two η1-3,5-(CF3)2Pz groups. All compounds have been characterized by spectroscopic methods and their X-ray crystal structures have also been determined.