Synthesis of C2-Symmetric Dimeric ReI Peptide Complexes



The reaction of [Re(CO)3(H2O)3]Br or [Re(CO)5Cl] with two peptides, glycylglycine, or glycylalanine were investigated. Each reaction produced a unique, well-defined product. Structural elucidation showed the formation of chiral compounds with the formula [Re(CO)3(Gly-Xxx-O)]2, Xxx = Gly (1), Ala (2). Each dimer displays C2 symmetry and a nearly rectangular shape. The ligands are bound through the amine and amide carbonyl at a rhenium center and through the pendant carboxylate to the adjacent rhenium center. Both products are fully characterized by X-ray structure elucidation.