97487-40-6Relevant academic research and scientific papers
Hydroxy- and hydrido-bridged binuclear complexes of iridium: Synthesis, characterization, and attempts to model binuclear water-gas shift catalysts. Structure of [Ir2(CO)2(μ-OH·Cl)(Ph2PCH 2PPh2)2]
Sutherland, Bruce R.,Cowie, Martin
, p. 1637 - 1648 (2008/10/08)
The reaction of trans-[IrCl(CO)(DPM)]2 with excess NaOH yields [Ir2(CO)2(μ-OH·Cl)(DPM)2] which upon treatment with HBF4·Et2O gives [Ir2(CO)2(μ-OH)(DPM)2][BF4]. Reaction of the former product with CO produces the binuclear Ir(0) complex [Ir2(CO)4(DPM)2] which after flushing with N2 yields [Ir2(CO)3(DPM)2]. Reaction of [Ir2(CO)2(μ-OH)(DPM)2][BF4] with CO produces [Ir2(CO)2(μ-H)(μ-CO)(DPM)2][BF 4]. This latter complex reacts with HBF4·Et2O to give [Ir2(H)(CO)2(μ-H)(μ-CO)-(DPM)2][BF 4]2 which rearranges with time yielding the isomeric complex [Ir2(H)2(CO)3(DPM)2][BF 4]2. Reaction of either of these dihydrides with CO produces [Ir2(CO)4(μ-H)2(DPM)2][BF 4]2 and [Ir2(CO)4(μ-CO)(DPM)2][BF4] 2 in the ratio 9:1, the latter product resulting from reductive elimination of H2. Refluxing [Ir2(H)2(CO)3(DPM)2][BF 4]2 in CH3CN also produces some H2 elimination and the formation of [Ir2-(CO)2(CH3CN) 2(μ-CO)(DPM)2][BF4]2. Reaction of [Ir2(CO)4(μ-CO)(DPM)2][BF4] 2 with OH- yields [Ir2-(CO)2(μ-H)(μ-CO)(DPM)2][BF 4] whereas reaction of [Ir2(CO)2(CH3CN)2(μ-CO)(DPM) 2][BF4]2 with OH- gives a mixture of this hydride and the bridging hydroxide complex [Ir2(CO)2(μ-OH)(DPM)2][BF4]. This chemistry is discussed and related to a model water-gas shift cycle. The related rhodium complex [Rh2(CO)2(μ-OH)(DPM)2]+ is shown to be a WGS catalyst precursor under mild conditions, although it seems that metal hydrides and not hydroxides are the catalytically important species. The complex [Ir2(CO)2(μ-OH·Cl)(DPM)2] crystallizes in the space group P212121 with a = 14.762 (2) A?, b = 25.583 (4) A?, c = 13.770 (3) A?, and Z = 4 and was refined to R = 0.043 and Rw = 0.065 based on 2650 unique observed reflections and 223 variables.
