Synthesis, Structure, and Ligand-Based Reduction Reactivity of Trivalent Organosamarium Benzene Chalcogenolate Complexes (C5Me5)2Sm(EPh)(THF) and [(C5Me5)2Sm((mu)-EPh)]2

To compare the ligand-based reduction chemistry of (EPh)- ligands in a metallocene environment to the sterically induced reduction chemistry of the (C5Me5)- ligands in (C5Me5)3Sm, (C5Me5)2Sm(EPh) (E = S, Se, Te) complexes were synthesized and treated with substrates reduced by (C5Me5)3Sm: cyclooctatetraene; azobenzene; phenazine. Reactions of PhEEPh with (C5Me5)2Sm(THF)2 and (C5Me5)2Sm produced THF-solvated monometallic complexes, (C5Me5)2Sm(EPh) (THF), and their unsolvated dimeric analogues, [(C5Me5)2Sm((mu)-EPh)]2, respectively. Both sets of the paramagnetic benzene chalcogenolate complexes were definitively identified by X-crystallography and form homologous series. Only the (TePh)- complexes show reduction reactivity and only upon heating to 65 °C.