Stoichiometric and catalytic H/D incorporation by cationic iridium complexes: a common monohydrido-iridium intermediate
| Autor: | Robert G. Bergman, Cathleen M. Yung, Marc B. Skaddan |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Reaction mechanism
Stereochemistry Ligand Cationic polymerization Carboxylic Acids chemistry.chemical_element General Chemistry Deuterium Iridium Biochemistry Toluene Medicinal chemistry Catalysis chemistry.chemical_compound Colloid and Surface Chemistry chemistry Alcohols Isotope Labeling Organometallic Compounds Amines Stoichiometry Hydrogen |
| Zdroj: | Journal of the American Chemical Society. 126(40) |
| ISSN: | 0002-7863 |
| Popis: | 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 CpPMe(3)Ir(C(6)H(4)X)(OTf) (X = H, o-CH(3), m-CH(3), p-CH(3)) react with D(2). Multiple deuteration occurs at the unhindered positions (para and meta) of toluene, when X = CH(3). The multiple-deuteration pathway is suppressed in the presence of an excess of the coordinating ligand, CH(3)CN. The compound CpPMe(3)IrH(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-d(6)(), [CpPMe(3)IrH(3)][OTf] (4) catalytically deuterates a wide range of substrates with a variety of functional groups. Catalyst 4 decomposes to [CpPMe(3)Ir(eta(3)-CH(2)C(OH)CH(2))][OTf] (19) in acetone and to [CpPMe(3)IrH(CO)][OTf] (1-CO) in CH(3)OH. The catalytic H/D exchange reaction is not catalyzed by simple H(+) transfer, but instead proceeds by a reversible C-H bond activation mechanism. |
| Databáze: | OpenAIRE |
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