Synthesis of a &mgr;,eta(2)-Disulfide-Bridged Hexanuclear Ru(II)-Na Cluster Formed from the Reductive Coupling of a &mgr;,eta(1)-Disulfide-Bridged Dinuclear Ru(III) Complex.

Abstract

Upon reduction of the disulfide-bridged complex [{Ru(III)Cl(P(OMe)(3))(2)}(2)(&mgr;,eta(1)-S(2))(&mgr;-Cl)(2)] (3) with Na metal in THF, the hexanuclear cluster complex [Na(2)Ru(II)(4)(P(OMe)(3))(4)(&mgr;-Cl)(4)(&mgr;(4)-Cl)(2)(&mgr;,eta(2)-S(2))(2)(&mgr;-P(OMe)(3)-P,O)(4)].THF (4) was obtained, and the X-ray crystal structure was solved. The crystal is triclinic with space group P&onemacr;. The cell constants are a = 14.927(3) Å, b = 21.063(7) Å, c = 11.802(4) Å, alpha = 93.81(3) degrees, beta = 94.73(2) degrees, gamma = 69.24(2) degrees, V = 3455(1) Å(3), and Z = 2. Compound 4 is a hexanuclear cluster in the crystal, having two units of dinuclear compound 3, bridged by two Na ions. Each Na ion is coordinated by two terminal chlorides, two bridging chlorides, and two phosphite oxygen atoms of the starting compound 3. The other notable feature of 4 is that the disulfide ligand originally in a &mgr;,eta(1)-bridging mode in 3 has been rotated by 90 degrees in 4 and bridges the two Ru atoms in a &mgr;,eta(2)-mode. The S-S distances of 4, 2.050(8) and 2.046(8) Å, are significantly longer than that in 3, 1.971(4) Å, and one of the two sulfur atoms of the disulfide ligand more strongly coordinates to one of the dinuclear Ru atoms, while the other coordinates more strongly to the other Ru atom. Therefore the four Ru-S distances are as follows: Ru(1)-S(1), 2.524(5) Å; Ru(1)-S(2), 2.334(5) Å; Ru(2)-S(1), 2.350(5) Å; Ru(2)-S(2), 2.527(5) Å. The same is observed for the other Ru(3)-Ru(4) dinuclear unit. The Na-Cl distances are normal, and the Na-O distances (2.37(1)-2.45(1) Å) are close to usual Na-O(carboxylate) distances.