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Recent applications of [Cu(dap)2]Cl in visible light-mediated photoredox catalysis

Citation

Olding, A and Nicholls, TP and Bissember, AC, Recent applications of [Cu(dap)2]Cl in visible light-mediated photoredox catalysis, Australian Journal of Chemistry, 71, (7) pp. 547-548. ISSN 0004-9425 (2018) [Contribution to Refereed Journal]


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DOI: doi:10.1071/CH18046

Abstract

Since 2008, visible light-mediated photoredox catalysis has enjoyed a renaissance in organic synthesis.[15] The most commonly employed metal-based photoredox catalysts typically utilise second- and third-row transition metals featuring polypyridyl ligand systems such as [Ru(bpy)3]Cl2 (1).[1] In contrast, the synthetic applications of copper-based photoredox catalysts have received much less attention.[6] A class of photoactive homoleptic, phenanthroline-based copper(I) complexes, including [Cu (dap)2]Cl (2), were first prepared some 35 years ago (Chart 1).[7,8] This class of complexes share several interesting properties that can be exploited to facilitate chemical transformations. The absorption of a photon in the visible range leads to a metal-to-ligand charge transfer (MLCT) excited state. Subsequent intersystem crossing (ISC) results in spin inversion and allows access to long-lived triplet photoexcited states.[9] In its photoexcited state, complex 2 is a strong reductant (-1.43 V versus saturated calomel electrode) capable of reducing organic acceptor molecules via single electron transfer (SET) processes.[8] The ensuing CuIIspecies can undergo a second SET process to oxidise an organic donor molecule, which reduces the catalyst back to its ground state and closes the catalytic cycle.[1] The coordinatively unsaturated nature of these copper(I) complexes typically provides lower coordinative stability relative to saturated octahedral complexes (e.g. 1). Also, in the ground state, these copper(I) complexes typically exhibit a distorted tetrahedral coordination geometry. Upon photoexcitation, oxidation of the metal centre occurs as a result of the population of the MLCT excited state. This causes a flattening distortion that results in a more square-planar coordination geometry. These two factors are primarily responsible for reducing excited state lifetimes. The present focus article aims to highlight recent applications of [Cu(dap)2]Cl in organic synthesis.

Item Details

Item Type:Contribution to Refereed Journal
Keywords:photoredox catalysis, copper
Research Division:Chemical Sciences
Research Group:Organic Chemistry
Research Field:Organic Chemical Synthesis
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Chemical Sciences
UTAS Author:Olding, A (Mr Angus Olding)
UTAS Author:Nicholls, TP (Mr Thomas Nicholls)
UTAS Author:Bissember, AC (Dr Alex Bissember)
ID Code:127419
Year Published:2018
Web of Science® Times Cited:3
Deposited By:Chemistry
Deposited On:2018-07-26
Last Modified:2018-07-30
Downloads:1 View Download Statistics

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