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Exploiting Charge-Transfer States for Maximizing Intersystem Crossing Yields in Organic Photoredox Catalysts.

ABSTRACT: A key feature of prominent transition-metal-containing photoredox catalysts (PCs) is high quantum yield access to long-lived excited states characterized by a change in spin multiplicity. For organic PCs, challenges emerge for promoting excited-state intersystem crossing (ISC), particularly when potent excited-state reductants are desired. Herein, we report a design exploiting orthogonal ?-systems and an intermediate-energy charge-transfer excited state to maximize ISC yields (?ISC) in a highly reducing ( E0* = -1.7 V vs SCE), visible-light-absorbing phenoxazine-based PC. Simple substitution of N-phenyl for N-naphthyl is shown to dramatically increase ?ISC from 0.11 to 0.91 without altering catalytically important properties, such as E0*.

SUBMITTER: Sartor SM

PROVIDER: S-EPMC5920652 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature

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Exploiting Charge-Transfer States for Maximizing Intersystem Crossing Yields in Organic Photoredox Catalysts.

Sartor Steven M SM McCarthy Blaine G BG Pearson Ryan M RM Miyake Garret M GM Damrauer Niels H NH

Journal of the American Chemical Society 20180402 14

A key feature of prominent transition-metal-containing photoredox catalysts (PCs) is high quantum yield access to long-lived excited states characterized by a change in spin multiplicity. For organic PCs, challenges emerge for promoting excited-state intersystem crossing (ISC), particularly when potent excited-state reductants are desired. Herein, we report a design exploiting orthogonal π-systems and an intermediate-energy charge-transfer excited state to maximize ISC yields (Φ<sub>ISC</sub>) i ...[more]

PMID: 29595966

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