Authors:	Sittel, Steven Naumann, Robert Heinze, Katja
Title:	Molecular rubies in photoredox catalysis
Online publication date:	14-Nov-2022
Year of first publication:	2022
Language:	english
Abstract:	The molecular ruby [Cr(tpe)2]3+ and the tris(bipyridine) chromium(III) complex [Cr(dmcbpy)3]3+ as well as the tris(bipyrazine)ruthenium(II) complex [Ru(bpz)3]2+ wereemployed in the visible light-induced radical cation [4+2] cycloaddition (tpe = 1,1,1-tris(pyrid-2-yl)ethane, dmcbpy = 4,4′-dimethoxycarbonyl-2,2′-bipyridine, bpz = 2,2′-bipyrazine), while [Cr(ddpd)2]3+ serves as a control system (ddpd = N,N′-dimethyl N,N′-dipyridin-2-ylpyridine-2,6-diamine). Along with an updated mechanistic proposal for the CrIII driven catalytic cycle based on redox chemistry, Stern-Volmer analyses, UV/Vis/NIR spectroscopic and nanosecond laser flash photolysis studies, we demonstrate that the very weakly absorbing photocatalyst [Cr(tpe)2]3+ outcompetes [Cr(dmcbpy)3]3+ and even [Ru(bpz)3]2+ in particular at low catalyst loadings, which appears contradictory at first sight. The high photostability, the reversible redoxchemistry and the very long excited state lifetime account for the exceptional performance and even reusability of [Cr(tpe)2]3+ in this photoredox catalytic system.
DDC:	540 Chemie 540 Chemistry and allied sciences
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 09 Chemie, Pharmazie u. Geowissensch.
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-8198
Version:	Published version
Publication type:	Zeitschriftenaufsatz
Document type specification:	Scientific article
License:	CC BY
Information on rights of use:	https://creativecommons.org/licenses/by/4.0/
Journal:	Frontiers in chemistry 10
Pages or article number:	887439
Publisher:	Frontiers Media
Publisher place:	Lausanne
Issue date:	2022
ISSN:	2296-2646
Publisher DOI:	10.3389/fchem.2022.887439
Appears in collections:	DFG-491381577-G