Photosensitized, energy transfer-mediated organometallic catalysis through electronically excited nickel(II)

• Autores: Eric R. Welin, Daniela M. Arias Rotondo
• Localización: Science, ISSN 0036-8075, Vol. 355, Nº 6323, 2017, págs. 380-385
• Idioma: inglés
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• Resumen

  • Transition metal catalysis has traditionally relied on organometallic complexes that can cycle through a series of ground-state oxidation levels to achieve a series of discrete yet fundamental fragment-coupling steps. The viability of excited-state organometallic catalysis via direct photoexcitation has been demonstrated. Although the utility of triplet sensitization by energy transfer has long been known as a powerful activation mode in organic photochemistry, it is surprising to recognize that photosensitization mechanisms to access excited-state organometallic catalysts have lagged far behind. Here, we demonstrate excited-state organometallic catalysis via such an activation pathway: Energy transfer from an iridium sensitizer produces an excited-state nickel complex that couples aryl halides with carboxylic acids. Detailed mechanistic studies confirm the role of photosensitization via energy transfer.