130495-84-0Relevant academic research and scientific papers
Structure and reactivity studies of the unusual peroxo-bridged complex, [Ir2I2(CO)2(μ-O2)(Ph 2PCH2PPh2)2]: The first compound having a peroxide moiety bridging a metal-metal bond
Xiao, Jianliang,Santarsiero, Bernard D.,Vaartstra, Brian A.,Cowie, Martin
, p. 3212 - 3220 (2007/10/02)
Reaction of the diiodo complex [Ir2I2(CO)(μ-CO)(dppm)2] (1; dppm = Ph2PCH2PPh2) with oxygen gives an unusual peroxo-bridged complex, [Ir2I2(CO)2(μ-O2)(dppm) 2] (2), in which the bridging dioxygen group is accompanied by a metal-metal bond. The reactivity of this species has been investigated. Thus, reaction of SO2 with 2 yields the sulfate-bridged compound [Ir2I2(CO)2(μ-SO4)(dppm) 2] (3), which is also produced in the reaction of 2 with CuSO4 and in the protonation of 2 with H2SO4, with release of H2O2. Reaction of 2 with NO2 and NO affords the nitrate-and nitrosyl-bridged compounds [Ir2I2(CO)2(μ-X)(dppm)2] [NO3] (X = NO3 (4a); NO (5)), respectively. The reaction with CO in CH2Cl2/CH3OH yields two compounds together with CO2. One of the species is identified as [Ir2(CO)2-(μ-CO)(μ-I)(dppm)2] [I], while the other one is shown to be a dioxygen compound, [Ir2I2(CO)2(μ-CO)(μ-O 2)(dppm)2] (6), formed via formal CO insertion into the Ir-Ir bond of 2. In contrast, isocyanides (RNC; R = iPr, tBu) are not oxidized by 2; instead the hydroxide-bridged methoxycarbonyl species [Ir2(CO2CH3)(RNC) 3(μ-CO)(μ-OH)(dppm)2][I]2 (R = iPr (7); tBu (8)) are obtained through involvement of the methanol solvent. Reaction of 2 with HCl yields two tetrahalide isomers [Ir2Cl2I2(CO)2(dppm)2] (9a,b). Attempted reactions with NO+, HBF4·OEt2, and CH3SO3CF3 gave rise to the hydroxide-bridged complex [Ir2I2(CO)2(μ-OH)(dppm)2] + (10), through involvement of adventitious water; although under dry conditions, reaction with NO+ yields 4, with the appropriate anion. The structures of 2 and 6 have been determined by X-ray crystallography. Complex 2 crystallizes in the tetragonal space group P41212 with a = 14.647(2) A?, c = 27.973(4) A?, V = 6001(1) A?3, and Z = 4 and has refined to R = 0.061 and Aw = 0.093 on the basis of 3585 observations and 169 parameters varied. Complex 6 crystallizes in the orthorhombic space group Pna21 with a = 30.110(8) A?, b = 15.678(6), c = 12.020(6) A?, V = 5674(7) A?3, and Z = 4 and has refined to R = 0.056 and Aw = 0.064 on the basis of 2598 observations and 328 parameters varied.
