Photoswitchable Hydride Transfer from Iridium to 1-Methylnicotinamide Rationalized by Thermochemical Cycles
| Autor: | Andrew G. Walden, Catherine L. Pitman, Alexander J. M. Miller, Seth M. Barrett |
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| Rok vydání: | 2014 |
| Předmět: |
Models
Molecular Niacinamide Chemistry Hydride Photodissociation Molecular Conformation Temperature chemistry.chemical_element General Chemistry Iridium Photochemical Processes Photochemistry Biochemistry Catalysis chemistry.chemical_compound Colloid and Surface Chemistry Excited state Thermochemical cycle Acetonitrile Selectivity Hydrogen |
| Zdroj: | Journal of the American Chemical Society. 136:14718-14721 |
| ISSN: | 1520-5126 0002-7863 |
| DOI: | 10.1021/ja508762g |
| Popis: | Visible light-triggered hydride transfer from [Cp*Ir(bpy)(H)](+) (1) to organic acids and 1-methylnicotinamide (MNA(+)) is reported (Cp* = pentamethylcyclopentadienyl; bpy = 2,2'-bipyridine). A new thermochemical cycle for determining excited-state hydride donor ability (hydricity) predicted that 1 would be an incredibly potent photohydride in acetonitrile. Phototriggered H2 release was indeed observed from 1 in the presence of various organic acids, providing experimental evidence for an increase in hydricity of at least 18 kcal/mol in the excited state. The rate and product selectivity of hydride transfer to MNA(+) are photoswitchable: 1,4-dihydro-1-methylnicotinamide forms slowly in the dark but rapidly under illumination, and photolysis can also produce doubly reduced 1,4,5,6-tetrahydro-1-methylnicotinamide. |
| Databáze: | OpenAIRE |
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