Synthesis of (O2CEPh)1- ligands (E = S, Se) by CO2 insertion into lanthanide chalcogen bonds and their utility in forming crystallographically characterizable organoaluminum complexes [Me2Al(μ-O2CEPh)]2

CO2 inserts into the Sm-S and Sm-Se bonds of [(C5Me5)(2)Sm(mu-EPh)](2) (E = S, Se) to form the first crystallographically characterized (O2CEPh)(1-) complexes, [(C5Me5)(2)Sm(mu-O2CEPh)](2). These complexes are structurally analogous to [(C5Me5)(2)Sm(mu-O2CR)](2) complexes, but they are less soluble. This feature was utilized in the reaction of Me2AlCl with [(C5Me5)(2)Sm(mu-O2CEPh)](2), which forms crystallographically characterizable [Me2Al(mu-O2CEPh)](2) complexes. Such complexes could not be isolated from an analogous carboxylate reaction. [(C5Me5)(2)Sm(mu-O-2-CSePh)](2) decarboxylates in THF to form (C5Me5)(2)Sm(SePh)(THF). The loss of CO2 rather than COSe with formation of (C5Me5)(2)Sm(OPh)(THF) was established by (CO2)-C-13 studies and independent synthesis of (C5Me5)(2)Sm(OPh)-(THF) from (C5Me5)(2)Sm[N(SiMe3)(2)] and PhOH.