NOVEL COFACIAL BIOCTAHEDRAL COMPLEXES OF RUTHENIUM - SYNTHESES AND PROPERTIES OF THE MIXED-VALENCE SPECIES [LRU2.5(MU-CL)3RU2.5L]2+, [LRU2.5(MU-BR)3RU2.5L]2+, [LRU2.5(MU-I)3RU2.5]2+, [LRU2.5(MU-OH)-3RU2.5L)2+ CRYSTAL-STRUCTURES OF [LRU2.5(MU-OH)3RU2.5L](PF6)2.H2O AND [LRUIV(MU-O)3RU-IVL](PF6)2.H2O (L = 1,4,7-TRIMETHYL-1,4,7-TRIAZACYCLONONANE)

Reaction of RuCl2(dmso)4 with 1, 4, 7-trimethyl-1, 4, 7-triazacyclononane (L; C9H21N3) in ethanol affords red-brown LRu(dmso)xCl2 (x = 1–2), which reacted with concentrated HX (X = Cl, Br, I) in the presence of air to yield LRuCl3•H2O, LRuBr3, and LRuI3. Treatment of these LRuX3 species with CF3SO3H yielded gaseous HX and deep blue solutions from which the mixed-valence complexes [L2Ru22.5(μ-X)3](CF3SO3)2 precipitated upon addition of ether. Blue [L2Ru22.5(μ-X)3](PF6)2 salts (X = Cl, Br, I) were isolated and characterized. Blue [L2Ru22.5(μ-OH)3](PF6)2•H2O was synthesized from an aqueous solution of [L2Ru2III(μ-O)(μ-CH3CO2)2](PF6)2 via reduction with zinc amalgam and exposure of the resulting yellow solution to air. Oxidation of this species with S2O82− at pH = 7 gave yellow [L2Ru2III(μ-OH)3](PF6)3, which reacted at pH 12 with O2 to yield green [L2Ru2IV(μ-O)3]- (PF6)2•H2O. The crystal structures of [L2Ru22.5(μ-OH)3](PF6)2•H2O (1) and [L2Ru2IV(μ-O)3](PF6)2•H2O (2) have been determined by X-ray analysis. Crystal data for 1: orthorhombic space group Pnma, a = 10.089 (2) Å, b = 16.134 (3) Å, c = 19.585 (4) Å, V = 3188 (1) Å3, Z = 4. Crystal data for 2: orthorhombic space group Pnma, a = 10.057 (5), b = 16.12 (1) Å, c = 19.237 (9) Å, V = 3118.7 (10) Å3, Z = 4. The {N3Ru(O)3RuN3} core in both structures possesses idealized D3h symmetry. The Ru–Ru distances in 1 and 2 are 2.401 (2) and 2.363 (2) Å, respectively. Electronic and ESR spectra have been recorded, and the magnetic properties of complexes have been investigated. The electrochemistry of mononuclear and binuclear species are reported. The cyclic voltammogram of 2 in CH3NO2 displays two reversible one-electron waves at E1 1/2 = −0.46 V and E21/2 = +1.12 V vs NHE, which correspond to the couples. © 1990, American Chemical Society. All rights reserved.