Pentasulfide S5(2-) as the first tridentate chelating ligand in Ru(P(OE)3)3S5(E = Me and Et).
Room temperature stirring of H2Ru(P(OE)3)4 (E = Me and Et) and elemental sulfur in benzene afforded the optically active compounds Ru(P(OMe)3)3S5 (1) and Ru(P(OEt)3)3S5 (2). Compounds 1 and 2 are crystallized in the trigonal space group P31 with a = 14.231(10) A, c = 10.24(1) A, V = 1794(2) A3, and Z = 3, and orthorhombic space group P212121 with a = 15.393(5) A, b = 18.126(6) A, c = 12.421(4) A, V = 3465(1) A3, and Z = 4, respectively. Solutions of 1 and 2 did not show any optical activity since the bulk materials are racemic mixtures. The X-ray analyses also reveal that in both compounds polysulfide S5(2-) ion acts as a novel tridentate ligand, resulting in an asymmetric bicyclic RuS5 unit having three- and five-membered rings around the ruthenium atom. Fragmentation of the S5(2-) ring to S2- ion was observed in the presence of sulfur-abstracting reagents such as PR3 (R = Ph, OMe, and OEt) and also to S2(2-) ion when the compounds were reacted with RuCl2(P(OE)3)4 (E = Me and Et).
Department of Chemistry, Advanced Research Center for Science and Engineering, Waseda University, Tokyo, Japan.
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Hossain
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Matsumoto