One- And Two-Electron-Transfer Reactions Of (Dpp-Bian)Sm(Dme)(3)

The reduction of 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (dpp-Bian) with an excess of samarium in 1,2-dimethoxyethane (dme) affords the Sm-II complex (dpp-Bian)Sm(dme)(3) (1). The reaction of 1 with 0.5 mol equiv of 1,2-dibromostilbene proceeds with the formation of the dimeric Sm-III complex [(dpp-Bian)SmBr(dme)](2) (2). Oxidation of both the metal and the dpp-Bian ligand takes place if 1 is reacted with equimolar amounts of 1,2-dibromostilbene or iodine, yielding the monomeric Sm-III derivatives (dpp-Bian)SmBr2(dme) (3) and (dpp-Bian)Sml(2)(THF)(2) (4; THF = tetrahydrofuran), respectively. The reaction of 1 with 0.5 mol equiv of iodine followed by 0.5 mol equiv of tetramethylthiuram disulfide gives the Sm-III complex (dpp-Bian)Sml[SC(S)NMe2](dme) (5). Compound 4 and tBuOK react with the formation of the iodine-bridged dimer [(dpp-Bian)Sml(OtBu)(THF)](2) (6). Complexes 1 and 2 have been characterized by H-1 NMR spectroscopy and complexes 2-6 by their molecular structures, which were determined by single-crystal X-ray diffraction.