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