Cargando…
A Pyridyl-1,2-azaborine Ligand for Phosphorescent Neutral Iridium(III) Complexes
[Image: see text] A novel 1,2-azaborine (i.e., 4-methyl-2-(pyridin-2-yl)-2,1-borazaronaphthalene, 1a) has been synthesized and used for the first time as a B–N alternative to common cyclometalating ligands to obtain neutral phosphorescent iridium(III) complexes (i.e., 2a, 3, and 4) of general formul...
Autores principales: | , , , , , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical Society
2023
|
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9906742/ https://www.ncbi.nlm.nih.gov/pubmed/36696253 http://dx.doi.org/10.1021/acs.inorgchem.2c04449 |
_version_ | 1784884038771671040 |
---|---|
author | Baschieri, Andrea Aleotti, Flavia Matteucci, Elia Sambri, Letizia Mancinelli, Michele Mazzanti, Andrea Leoni, Enrico Armaroli, Nicola Monti, Filippo |
author_facet | Baschieri, Andrea Aleotti, Flavia Matteucci, Elia Sambri, Letizia Mancinelli, Michele Mazzanti, Andrea Leoni, Enrico Armaroli, Nicola Monti, Filippo |
author_sort | Baschieri, Andrea |
collection | PubMed |
description | [Image: see text] A novel 1,2-azaborine (i.e., 4-methyl-2-(pyridin-2-yl)-2,1-borazaronaphthalene, 1a) has been synthesized and used for the first time as a B–N alternative to common cyclometalating ligands to obtain neutral phosphorescent iridium(III) complexes (i.e., 2a, 3, and 4) of general formula [Ir(C(∧)N)(2)(N(∧)NB)], where C(∧)N indicates three different cyclometalating ligands (Hppy = 2-phenylpyridine; Hdfppy = 2-(2,4-difluoro-phenyl)pyridine; Hpqu = 2-methyl-3-phenylquinoxaline). Moreover, the azaborine-based complex 2a was compared to the isoelectronic C=C iridium(III) complex 2b, obtained using the corresponding 2-(naphthalen-2-yl)pyridine ligand 1b. Due to the dual cyclometalation mode of such C=C ligand, the isomeric complex 2c was also obtained. All new compounds have been fully characterized by NMR spectroscopy and high-resolution mass spectrometry (MS), and the X-ray structure of 2a was determined. The electronic properties of both ligands and complexes were investigated by electrochemical, density functional theory (DFT), and photophysical methods showing that, compared to the naphthalene analogues, the azaborine ligand induces a larger band gap in the corresponding complexes, resulting in increased redox gap (basically because of the highest occupied molecular orbital (HOMO) stabilization) and blue-shifted emission bands (e.g., λ(max) = 523 vs 577 nm for 2avs2b, in acetonitrile solution at 298 K). On the other hand, the (3)LC nature of the emitting state is the same in all complexes and remains centered on the pyridyl-borazaronaphthalene or its C=C pyridyl-naphthalene analogue. As a consequence, the quantum yields of such azaborine-based complexes are comparable to those of the more classical C=C counterparts (e.g., photoluminescence quantum yield (PLQY) = 16 vs 22% for 2avs2b, in acetonitrile solution at 298 K) but with enhanced excited-state energy. This proves that such type of azaborine ligands can be effectively used for the development of novel classes of photoactive transition-metal complexes for light-emitting devices or photocatalytic applications. |
format | Online Article Text |
id | pubmed-9906742 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2023 |
publisher | American Chemical Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-99067422023-02-08 A Pyridyl-1,2-azaborine Ligand for Phosphorescent Neutral Iridium(III) Complexes Baschieri, Andrea Aleotti, Flavia Matteucci, Elia Sambri, Letizia Mancinelli, Michele Mazzanti, Andrea Leoni, Enrico Armaroli, Nicola Monti, Filippo Inorg Chem [Image: see text] A novel 1,2-azaborine (i.e., 4-methyl-2-(pyridin-2-yl)-2,1-borazaronaphthalene, 1a) has been synthesized and used for the first time as a B–N alternative to common cyclometalating ligands to obtain neutral phosphorescent iridium(III) complexes (i.e., 2a, 3, and 4) of general formula [Ir(C(∧)N)(2)(N(∧)NB)], where C(∧)N indicates three different cyclometalating ligands (Hppy = 2-phenylpyridine; Hdfppy = 2-(2,4-difluoro-phenyl)pyridine; Hpqu = 2-methyl-3-phenylquinoxaline). Moreover, the azaborine-based complex 2a was compared to the isoelectronic C=C iridium(III) complex 2b, obtained using the corresponding 2-(naphthalen-2-yl)pyridine ligand 1b. Due to the dual cyclometalation mode of such C=C ligand, the isomeric complex 2c was also obtained. All new compounds have been fully characterized by NMR spectroscopy and high-resolution mass spectrometry (MS), and the X-ray structure of 2a was determined. The electronic properties of both ligands and complexes were investigated by electrochemical, density functional theory (DFT), and photophysical methods showing that, compared to the naphthalene analogues, the azaborine ligand induces a larger band gap in the corresponding complexes, resulting in increased redox gap (basically because of the highest occupied molecular orbital (HOMO) stabilization) and blue-shifted emission bands (e.g., λ(max) = 523 vs 577 nm for 2avs2b, in acetonitrile solution at 298 K). On the other hand, the (3)LC nature of the emitting state is the same in all complexes and remains centered on the pyridyl-borazaronaphthalene or its C=C pyridyl-naphthalene analogue. As a consequence, the quantum yields of such azaborine-based complexes are comparable to those of the more classical C=C counterparts (e.g., photoluminescence quantum yield (PLQY) = 16 vs 22% for 2avs2b, in acetonitrile solution at 298 K) but with enhanced excited-state energy. This proves that such type of azaborine ligands can be effectively used for the development of novel classes of photoactive transition-metal complexes for light-emitting devices or photocatalytic applications. American Chemical Society 2023-01-25 /pmc/articles/PMC9906742/ /pubmed/36696253 http://dx.doi.org/10.1021/acs.inorgchem.2c04449 Text en © 2023 The Authors. Published by American Chemical Society https://creativecommons.org/licenses/by/4.0/Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Baschieri, Andrea Aleotti, Flavia Matteucci, Elia Sambri, Letizia Mancinelli, Michele Mazzanti, Andrea Leoni, Enrico Armaroli, Nicola Monti, Filippo A Pyridyl-1,2-azaborine Ligand for Phosphorescent Neutral Iridium(III) Complexes |
title | A Pyridyl-1,2-azaborine Ligand for Phosphorescent
Neutral Iridium(III) Complexes |
title_full | A Pyridyl-1,2-azaborine Ligand for Phosphorescent
Neutral Iridium(III) Complexes |
title_fullStr | A Pyridyl-1,2-azaborine Ligand for Phosphorescent
Neutral Iridium(III) Complexes |
title_full_unstemmed | A Pyridyl-1,2-azaborine Ligand for Phosphorescent
Neutral Iridium(III) Complexes |
title_short | A Pyridyl-1,2-azaborine Ligand for Phosphorescent
Neutral Iridium(III) Complexes |
title_sort | pyridyl-1,2-azaborine ligand for phosphorescent
neutral iridium(iii) complexes |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9906742/ https://www.ncbi.nlm.nih.gov/pubmed/36696253 http://dx.doi.org/10.1021/acs.inorgchem.2c04449 |
work_keys_str_mv | AT baschieriandrea apyridyl12azaborineligandforphosphorescentneutraliridiumiiicomplexes AT aleottiflavia apyridyl12azaborineligandforphosphorescentneutraliridiumiiicomplexes AT matteuccielia apyridyl12azaborineligandforphosphorescentneutraliridiumiiicomplexes AT sambriletizia apyridyl12azaborineligandforphosphorescentneutraliridiumiiicomplexes AT mancinellimichele apyridyl12azaborineligandforphosphorescentneutraliridiumiiicomplexes AT mazzantiandrea apyridyl12azaborineligandforphosphorescentneutraliridiumiiicomplexes AT leonienrico apyridyl12azaborineligandforphosphorescentneutraliridiumiiicomplexes AT armarolinicola apyridyl12azaborineligandforphosphorescentneutraliridiumiiicomplexes AT montifilippo apyridyl12azaborineligandforphosphorescentneutraliridiumiiicomplexes AT baschieriandrea pyridyl12azaborineligandforphosphorescentneutraliridiumiiicomplexes AT aleottiflavia pyridyl12azaborineligandforphosphorescentneutraliridiumiiicomplexes AT matteuccielia pyridyl12azaborineligandforphosphorescentneutraliridiumiiicomplexes AT sambriletizia pyridyl12azaborineligandforphosphorescentneutraliridiumiiicomplexes AT mancinellimichele pyridyl12azaborineligandforphosphorescentneutraliridiumiiicomplexes AT mazzantiandrea pyridyl12azaborineligandforphosphorescentneutraliridiumiiicomplexes AT leonienrico pyridyl12azaborineligandforphosphorescentneutraliridiumiiicomplexes AT armarolinicola pyridyl12azaborineligandforphosphorescentneutraliridiumiiicomplexes AT montifilippo pyridyl12azaborineligandforphosphorescentneutraliridiumiiicomplexes |