Visible Light Photoredox Catalysis Using Ruthenium Complexes in Chemical Biology

Abstract

The development of bioorthogonal reactions have had a transformative impact in chemical biology and the quest to expand this toolbox continues. Herein we review recent applications of ruthenium‐catalyzed photoredox reactions used in chemical biology.

Coupling of DNA Circuit and Templated Reactions for Quadratic Amplification and Release of Functional Molecules

“…[27][28][29] The ground-state stability of the catalyst coupled to its excited state reactivity is key to its bioorthogonal chemistry. 30 Upon photoexcitation with 450 nm light and intersystem crossing, the Ru(II) * reacts with a stoichiometric reducing agent (NaAsc or NADPH in a biological environment) to afford a Ru(I) complex, a powerful single electron transfer (SET) reductant. The pyridinium linker is an excellent acceptor in a SET reaction leading to elimination of the coumarin and the pyridinium with a reduced benzylic position.…”

Enhanced SNP-sensing using DNA-templated reactions through confined hybridization of minimal substrates (CHOMS)

“…The reaction makes use of a ruthenium-photocatalyzed immolation of a pyridinium linker to uncage a pro-uorophore. 46 The choice of this reaction was based on its fast kinetics, its biorthogonality 47 and the fact that the guide DNAs do not need to exchange on the template in order to achieve amplication. While a templated reaction with sandwich probes has been reported, 37 it explored the benet of a double ligation reaction to suppress the background signal arising from the hydrolysis of a labile quencher.…”

Photochemical Methods for Peptide Macrocyclisation

“…This makes photoredox catalysis more compatible with biological speciest hat may suffer damage under UV irradiation. [53,[126][127][128] Furthermore, with indirect (and therefore asynchronous)E Tf rom the donor to the acceptor through the intermediary of the photocatalyst, more complex and varied chemistries are accessible. [129][130][131] The first reports of peptidem acrocyclisation under photoredox catalysis came from the Nolg roup, as part of their development of photocatalysedt hiol oxidations to form disulfides.…”

“…It also gives greater flexibility over chromophore structure, allowing the use of catalysts that absorb lower energy visible light to which all natural amino acids are transparent. This makes photoredox catalysis more compatible with biological species that may suffer damage under UV irradiation [53, 126–128] . Furthermore, with indirect (and therefore asynchronous) ET from the donor to the acceptor through the intermediary of the photocatalyst, more complex and varied chemistries are accessible [129–131] …”