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

Njogu, Rachael E.N. ; Fodran, Peter ; Tian, Yuxi LU ; Njenga, Lydia W. ; Kariuki, David K. ; Yusuf, Amir O. ; Scheblykin, Ivan LU ; Wendt, Ola F. LU and Wallentin, Carl Johan LU (2019) In Synlett 30(7). p.792-798
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 μ s). Electronically complementary ligands and complexes... (More)


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 μ s). 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 E
1/2

ox
[Ir(III)/Ir(IV) = 0.95 V vs. SCE in CH
2
Cl
2
]. 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 photo redox catalyst tris[2-phenylpyridinato]iridium(III).

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
iridium catalysis, ligands, naphthylpyridines, oxytrifluoromethylation, photoredox catalysis, styrene
in
Synlett
volume
30
issue
7
pages
7 pages
publisher
Georg Thieme Verlag
external identifiers
  • scopus:85064269316
ISSN
0936-5214
DOI
10.1055/s-0037-1611716
language
English
LU publication?
yes
id
86f35fbe-1e88-4525-8a9a-edbdaecc7fb0
date added to LUP
2019-05-03 14:59:26
date last changed
2020-01-13 01:42:53
@article{86f35fbe-1e88-4525-8a9a-edbdaecc7fb0,
  abstract     = {<p><br>
                                                         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 μ s). 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 E                              <br>
                            <sub>1/2</sub><br>
                                                                                       <br>
                            <sup>ox</sup><br>
                                                          [Ir(III)/Ir(IV) = 0.95 V vs. SCE in CH                              <br>
                            <sub>2</sub><br>
                                                          Cl                              <br>
                            <sub>2</sub><br>
                                                          ]. 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 photo redox catalyst tris[2-phenylpyridinato]iridium(III).                         <br>
                        </p>},
  author       = {Njogu, Rachael E.N. and Fodran, Peter and Tian, Yuxi and Njenga, Lydia W. and Kariuki, David K. and Yusuf, Amir O. and Scheblykin, Ivan and Wendt, Ola F. and Wallentin, Carl Johan},
  issn         = {0936-5214},
  language     = {eng},
  month        = {01},
  number       = {7},
  pages        = {792--798},
  publisher    = {Georg Thieme Verlag},
  series       = {Synlett},
  title        = {Electronically Divergent Triscyclometalated Iridium(III) 2-(1-naphthyl)pyridine Complexes and Their Application in Three-Component Methoxytrifluoromethylation of Styrene},
  url          = {http://dx.doi.org/10.1055/s-0037-1611716},
  doi          = {10.1055/s-0037-1611716},
  volume       = {30},
  year         = {2019},
}