92365-77-0Relevant academic research and scientific papers
Probing metal-metal bond reactivity in a series of acetylene-bridged binuclear complexes and the structure of a methyl isocyanide adduct, [Rh2Cl(CNMe)2(μ-CF3C2CF 3)(Ph2PCH2PPh2)2][BF 4]
Cowie, Martin,Dickson, Raymond S.,Hames, Barry W.
, p. 1879 - 1890 (2008/10/08)
The reactions of [Rh2Cl2(μ-HFB)(DPM)2] (1), [Rh2I2(μ-HFB)(DPM)2] (2), and [Rh2Cl2(μ-DMA)(DPM)2] (3) (HFB = hexafluoro-2-butyne, DMA = dimethyl acetylenedicarboxylate) with CO, SO2, and CNMe have been investigated. With CO and SO2 the complexes [Rh2X2(μ-L)(μ-acetylene)(DPM)2] (X = Cl, I; L = CO, SO2) are obtained in which these ligands have inserted into the metal-metal bonds. The carbonyl group is more tightly bound than SO2, and the iodo complex binds these groups stronger than the analogous chloro complex. These ligands are also more tightly bound when the accompanying bridging group is DMA instead of HFB. Reactions of compounds 1, 2, and 3 with CNMe proceed first by terminal attack to give the 1:1 adducts [Rh2X2(CNMe)(μ-acetylene)(DPM)2]. Subsequent reaction with additional CNMe yields either [Rh2X(CNMe)2(μ-acetylene)(DPM)2][X] or [Rh2X2(CNMe)2(μ-acetylene)(DPM) 2], and further reaction yields [Rh2(CNMe)4(μ-acetylene)(DPM)2][X] 2. The 1:1 and 2:1 adducts are each present in two isomeric forms whose relative abundance depends on the halide and the bridging acetylene groups present. No briding isocyanide groups are observed. The structure of one of the 2:1 adducts, as the BF4- salt [Rh2Cl(CNMe)2(μ-HFB)(DPM)2][BF4] has been structurally characterized by X-ray techniques. This compound crystallizes in the space group P21/n with a = 16.366 (3) A?, b = 18.685 (3) A?, c = 20.425 (4) A?, β = 104.35 (1)°, V = 6051.1 A?3, and Z = 4. On the basis of 6800 unique observations and 367 parameters varied, the structure refined to R = 0.059 and Rw = 0.097. The complex has a bridging hexafluoro-2-butyne group, accompanying Rh-Rh bond, and a terminal Cl on one Rh center with two terminal CNMe groups on the other. This geometry is very similar to those proposed for the other isocyanide products.
