190650-49-8Relevant academic research and scientific papers
Stoichiometric and catalytic H/D incorporation by cationic iridium complexes: A common monohydrido-iridium intermediate
Yung, Cathleen M.,Skaddan, Marc B.,Bergman, Robert G.
, p. 13033 - 13043 (2007/10/03)
A mechanistic study of the Stoichiometric and catalytic H/D exchange reactions involving cationic iridium complexes is presented. Strong evidence suggests that both Stoichiometric and catalytic reactions proceed via a monohydrido-iridium species. Stoichiometric deuterium incorporation reactions introduce multiple deuterium atoms into the organic products when aryliridium compounds Cp*PMe3Ir(C6H4X)(OTf) (X = H, o-CH3, m-CH3, p-CH3) react with D2. Multiple deuteration occurs at the unhindered positions (para and meta) of toluene, when X = CH3. The multiple-deuteration pathway is suppressed in the presence of an excess of the coordinating ligand, CH3CN. The compound Cp*PMe3IrH(OTf) (1-OTf) is observed in low-temperature, Stoichiometric experiments to support a monohydrido-iridium intermediate that is responsible for catalyzing multiple deuteration in the stoichiometric system. When paired with acetone-d6, [Cp*PMe3IrH3][OTf] (4) catalytically deuterates a wide range of substrates with a variety of functional groups. Catalyst 4 decomposes to [Cp*PMe3Ir(η3-CH 2C(OH)CH2)][OTf] (19) in acetone and to [Cp*PMe 3IrH(CO)]-[OTf] (1-CO) in CH3OH. The catalytic H/D exchange reaction is not catalyzed by simple H+ transfer, but instead proceeds by a reversible C-H bond activation mechanism.
Alkylation of iridium via tandem carbon-hydrogen bond activation/decarbonylation of aldehydes. Access to complexes with tertiary and highly hindered metal-carbon bonds
Alaimo, Peter J.,Arndtsen, Bruce A.,Bergman, Robert G.
, p. 2130 - 2143 (2008/10/08)
Reactions between Cp*(PMe3)Ir(Me)OTf (1) and aldehydes (RCHO) proceed with high selectivity to give the hydrocarbyl carbonyl salts [Cp*(PMe3)Ir(R)(CO)][OTf] (R = Me (2), Et (3), n-Pr (4), c-Pr (5), Ph (6), 1-ethylpropyl (7), p-tolyl (8), mesityl (9), 2-(Z)-1-phenylpropenyl (10), vinyl (13), t-Bu (14), 1-adamantyl (17)). This tandem C-H bond activation/decarbonylation reaction provides access to the first isolated tertiary alkyl complexes of iridium. X-ray diffraction studies were performed on mesityl complex 9, tert-butyl derivative 15, and 1-adamantyl compound 18. Decarbonylation of cyclopropyl complex 5 results in irreversible opening of the cyclopropyl ring. This reaction has provided useful information concerning the mechanism of C-H activation of cyclopropane by 1. Hydride reduction of the p-tolyl carbonyl salt 8 has provided an example of a rare transition-metal formyl complex, Cp*-(PMe3)Ir(p-tolyl)(CHO) (28).
