π-Cyclopentadienyl complexes containing transition-metal–cadmium bonds

Abstract

The π-cyclopentadienyl complexes [(π-C₅H₅)M(CO)₃]₂Cd (M = Mo or W) have been prepared. These readily undergo exchange with cadmium halides in methanol solution at room temperature to give species of the type (π-C₅H₅)M(CO)₃CdX (X = Cl, Br, or I). In contrast to the corresponding mercury derivatives, the cadmium complexes, [π-C₅H₅M(CO)₃]₂Cd, form stable adducts with a number of amines. These are of the type [(π-C₅H₅)M(CO)₃]₂CdL₂(L = unidentate amine) and [(π-C₅H₅)M(CO)₃]₂CdL′(L′= bidentate amine). Similar adducts are formed by (π-C₅H₅)M(CO)₃CdX, but these are more difficult to isolate. The complexes [(π-C₅H₅)Mo(CO₃)]₂Cd and (π-C₅H₅)Mo(CO)₃Cdl form 1:1 and 1:2 adducts with tetramethylammonium iodide.