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

CO(2) inserts into the Sm-S and Sm-Se bonds of [(C(5)Me(5))(2)Sm(mu-EPh)](2) (E = S, Se) to form the first crystallographically characterized (O(2)CEPh)(1-) complexes, [(C(5)Me(5))(2)Sm(mu-O(2)CEPh)](2). These complexes are structurally analogous to [(C(5)Me(5))(2)Sm(mu-O(2)CR)](2) complexes, but they are less soluble. This feature was utilized in the reaction of Me(2)AlCl with [(C(5)Me(5))(2)Sm(mu-O(2)CEPh)](2), which forms crystallographically characterizable [Me(2)Al(mu-O(2)CEPh)](2) complexes. Such complexes could not be isolated from an analogous carboxylate reaction. [(C(5)Me(5))(2)Sm(mu-O(2)CSePh)](2) decarboxylates in THF to form (C(5)Me(5))(2)Sm(SePh)(THF). The loss of CO(2) rather than COSe with formation of (C(5)Me(5))(2)Sm(OPh)(THF) was established by (13)CO(2) studies and independent synthesis of (C(5)Me(5))(2)Sm(OPh)(THF) from (C(5)Me(5))(2)Sm[N(SiMe(3))(2)] and PhOH.