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). 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)SmBr(2)(dme) (3) and (dpp-Bian)SmI(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)SmISC(S)NMe(2) (5). Compound 4 and tBuOK react with the formation of the iodine-bridged dimer (dpp-Bian)SmI(OtBu)(THF) (6). Complexes 1 and 2 have been characterized by (1)H NMR spectroscopy and complexes 2-6 by their molecular structures, which were determined by single-crystal X-ray diffraction.