Preparation and structural characterization of the palladium(0)-carbonyl complexes (R2PC2H4PR2)Pd(CO)(2) and {(R2PC2H4PR2)Pd}(2)(mu-CO)

(d(i)ppe)Pd(C2H4) and (d(t)bpe)Pd(C2H4) react with an excess of CO to affor d the novel tetrahedral Pd-0-dicarbonyl complexes (d(i)ppe)Pd(CO)(2) (1) an d (dtbpe)Pd(CO)(2). Partial CO elimination from 2 yields dinuclear {(dtbpe) Pd}(2)(mu-CO) (3), containing a single bridging carbonyl ligand. 3 represen ts the smallest cluster containing the Pd-2(mu-CO) group and, as such, is a lso the simplest model compound for CO adsorption on a Pd(100) surface; The rmolysis of 3 produces a carbonyl-free product which is assumed to be the d inuclear species {(dtbpe)Pd}(2) (4). The molecular structures of 2 and 3 ha ve been determined, and the solids are furthermore characterized by CP-MAS NMR spectra.