A Facile Route to Carbonylhalogenometal Complexes (M = Rh, Ir, Ru, Pt) by Dimethylformamide Decarbonylation

Dimethyl formamide (DMF) can be a convenient source of the carbonyl ligand in the coordination chemistry of rhodium, ruthenium, iridium, and platinum. We have undertaken a thorough study concerning the course of this reaction. In a first step, DMF-containing complexes are produced, which is usually accompanied by chloride redistribution. Then, upon refluxing, carbonyl species in the same oxidation state are obtained, presumably as a result of HCl-mediated DMF decomposition. Provided that water levels are kept low, reduction can occur to provide the complexes [NH2(CH3)2][RhCl2(CO)2], [NH2(CH3)2][RuCl3(CO)2(DMF)], [RuCl2(CO)2(DMF)2], and [NH2(CH3)2][IrCl2(CO)2]. In the case of platinum, reduction is not effective and [NH2(CH3)2][PtCl3(CO)] is obtained. No carbonylpalladium species can be synthesized in this way, the reaction producing copious amounts of colloidal metal. Adding phosphanes to these chlorocarbonyl-containing solutions allows easy, one-step syntheses of a variety of complexes.