Trinuclear pyrazolate complexes. Crystal structure of [(OC)2Rh(µ-pz)2Pd(µ-pz)2Rh(CO)2]

Abstract

The preparation and properties of trinuclear complexes containing pyrazolate and chloride as bridging ligands are reported. Representative formulae are [L₂M(µ-Cl)(µ-pz)Pd(µ-Cl)(µ-pz)ML₂][M = Rh, L₂= diolefin or (CO)₂; M = Ir, L₂= diolefin; M = Pd, L₂=η³-C₃H₅ or η³-C₄H₇]. These complexes react with the pyrazolate anion to give trinuclear homobridged compounds of formula [L₂M(µ-pz)₂Pd(µ-pz)₂ML₂]. The crystal structure of the carbonyl derivative [(OC)₂Rh(µ-pz)₂Pd(µ-pz)₂Rh(CO)₂] has been determined by single-crystal X-ray methods. Crystal are monoclinic, space group P2₁/c with cell constants a= 8.9281(5), b= 11.7961(6), c= 10.391 6(5)Å, β= 94.727(4)°, and Z= 2. The intermetallic distance palladium–rhodium is equal to 3.578 9(6)Å.