Synlett 2019; 30(07): 792-798
DOI: 10.1055/s-0037-1611716
letter
© Georg Thieme Verlag Stuttgart · New York

Electronically Divergent Triscyclometalated Iridium(III) 2-(1-naphthyl)pyridine Complexes and Their Application in Three-Component Methoxytrifluoromethylation of Styrene

Rachael E.N. Njogu
a   Centre for Analysis and Synthesis, Department of Chemistry, P.O. Box 124, SE-22100 Lund University, Sweden   Email: ola.wendt@chem.lu.se
d   Department of Chemistry, University of Nairobi, P.O Box 30197, KE-00100 Nairobi, Kenya
,
b   Department of Chemistry and Molecular Biology, P.O. Box 462, SE-40530 University of Gothenburg, Sweden   Email: carl.wallentin@chem.gu.se
,
Yuxi Tian
c   Chemical Physics, Department of Chemistry, Lund University, P.O Box 124, SE-22100, Sweden
,
Lydia W. Njenga
d   Department of Chemistry, University of Nairobi, P.O Box 30197, KE-00100 Nairobi, Kenya
,
David K. Kariuki
d   Department of Chemistry, University of Nairobi, P.O Box 30197, KE-00100 Nairobi, Kenya
,
Amir O. Yusuf
d   Department of Chemistry, University of Nairobi, P.O Box 30197, KE-00100 Nairobi, Kenya
,
Ivan Scheblykin
c   Chemical Physics, Department of Chemistry, Lund University, P.O Box 124, SE-22100, Sweden
,
Ola F. Wendt*
a   Centre for Analysis and Synthesis, Department of Chemistry, P.O. Box 124, SE-22100 Lund University, Sweden   Email: ola.wendt@chem.lu.se
,
b   Department of Chemistry and Molecular Biology, P.O. Box 462, SE-40530 University of Gothenburg, Sweden   Email: carl.wallentin@chem.gu.se
› Author Affiliations
We would like to acknowledge funding from the International Science Program (KEN 01), the Swedish Research Council (2014-04046, 621-2014-3935, 2017-00748), and the Carl Tryggers Foundation (CTS 16: 490) for a fellowship for P.F.
Further Information

Publication History

Received: 09 November 2018

Accepted after revision: 08 January 2019

Publication Date:
08 February 2019 (online)


These authors contributed equally.

Published as part of the Special Section 10th EuCheMS Organic Division Young Investigator Workshop

Abstract

A systematic study of the photophysical and electrochemical properties of triscyclometalated homoleptic iridium(III) complexes based on 2-(1-naphthyl)pyridine (npy) ligands is presented. A systematic investigation of ligand substitution patterns showed an influence on the lifetime of the excited state, with slight changes in the absorption and emission spectral features. Specifically, the emission lifetime of a complex of an npy ligand substituted with a strongly electron-withdrawing trifluoromethyl group was longer than that of the corresponding complex with the electronically nonperturbed ligand (3.7 μs versus 1.5 μs). Electronically complementary ligands and complexes with ­orthogonal configurations showed slightly shorter excited state lifetimes compared with unsubstituted npy (1.4–3.0 μs). All complexes displayed reversible or quasireversible redox-couple processes, with the complex of the trifluoromethylated ligand showing the highest ground-state oxidation potential E1/2 ox [Ir(III)/Ir(IV) = 0.95 V vs. SCE in CH2Cl2]. This study showed that these complexes can be used as efficient photoredox catalysts, as demonstrated by their application in a regioselective methoxytrifluoromethylation in which the npy complexes showed equal or better performance compared with the archetypical photo­redox catalyst tris[2-phenylpyridinato]iridium(III).

Supporting Information

 
  • References and Notes

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