159696-08-9Relevant academic research and scientific papers
Iridium μ-imido/amido A-frame complexes
Ye, Changqing,Sharp, Paul R.
, p. 55 - 59 (2008/10/08)
The reaction of Ir2Cl2(CO)2(μ-dppm)2 (dppm = bis(diphenylphosphino)methane) with 2 equiv of LiNHR yields Ir2(μ-NR)(CO)2(μ-dppm)2, 1 (R = p-tolyl, Ph, p-BrC6H4, p-NO2C6H4), or its tautomer Ir2(μ-NHR)(CO)2(μ-dppm)-(μ-dppm-H), 2 (dppm-H = bis(diphenylphosphino)methanide; R = Et, But). NMR data suggest that 1 (R = p-tolyl, Ph, p-BrC6H4) are in equilibrium with small amounts of 2 in polar solvents. An X-ray structural determination of 1 (R = p-tolyl) shows that the imido nitrogen atom links two iridium atoms at the apex of an A-frame complex. A very short N-C distance in the imido group suggests extensive N-lone pair donation to the tolyl ring. Crystals of 1 (R = p-tolyl) from benzene are tetragonal (P43) with a = 21.337(1) A?, c = 14.478(2) A?, and Z = 4. With the exception of R = p-NO2C6H4, p-BrC6H4, and Et, the complexes react with 1 equiv of CO at ambient temperature to form Ir2(CO)3(μ-dppm)2 as the major metal containing product. For R = Et, the reaction generates the unstable isocyanate complex Ir2(μ-EtNCO)(CO)2(μ-dppm)2. All of the complexes react with excess CO (2 atm) yielding Ir2(CO)4(μ-dppm)2 and amine except for the p-NO2C6H4 complex, which gives a complex mixture of products.
