Comparative Reductive Reactivity of SmI2 with TmI2 in the Synthesis of Lanthanide Arene Complexes

Arene complexes of divalent samarium, [(C6R6)Sm(AlCl3I)2]n (C6R6 = C6H5Me (1); C6Me6 (2)), were obtained by reaction of unsolvated SmI2 with AlCl3 in toluene and hexamethylbenzene. Crystallization of the tetrahalo-aluminate lanthanide arene complexes gave single crystals that showed disorder in the Cl and I positions by X-ray crystallography, but provided detailed information on η6-arene coordination to SmII. The more strongly reducing lanthanide diiodide TmI2 did not form analogous products under the same conditions, but the reaction of TmI2 with AlCl3 in toluene in the presence of naphthalene formed the trivalent arene complex (C6H5Me)Tm(AlCl4-xIx)3 (3).