Preparation and reactivity of a compartmental Schiff-base samarium dinuclear complex

SmI2(THF)5 acted as a reducing agent in the reaction with phenylenebis(3,5-But4salicylidene)iminatosodium, (3,5-But4salophen)Na2(THF)2, to yield a dimeric compound [Sm2(SB-SB)(THF)3]·2toluene (2) [SB-SB = C-C bonded 3,5-But4salophen dimer] arising from the reductive C-C coupling of two imine functional groups of two 3,5-But4salophenSm units. Complex 2 reacts with MeLi, resulting in a novel oxo-bridged dimer, {[(Me2-SB)Sm(μ-CH3)Li(THF)][(Me2-SB)S m(μ-CH3 )Li(THF)2Li(THF)2]}(μ-O)(μ-Li)3 (3) [Me2SB = phenylenebis(3,5-But4salycyl)dimethyldiamidato], featuring alkylation of both Sm atoms and arising from cleavage of the C-C bond connecting the two units, as well as complete reduction of the imine groups of the two salophen ligands and THF deoxygenation. Similar cleavage of the connecting C-C bond of complex 2 was also observed during the reaction with dry O2 to form a distorted cuboid cluster in which four Sm atoms are bridged by four hydroxyl groups, [(3,5-But4salophen)Sm(OH)]4·4toluene (4). The structures of complexes 2, 3, and 4 were elucidated by X-ray crystallography.