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Alkali metal complexes of an enantiopure iminophosphonamide ligand with bright delayed fluorescence

The enantiomerically pure ligand P,P-diphenyl-N,N′-bis((R)-1-phenylethyl)phosphinimidic amide (1; (R)-HPEPIA) was synthesized and subsequently deprotonated with alkali metal precursors to yield dimeric complexes [M(2){(R)-PEPIA}(2)] (M = Li (2), Na (3), K (4), Rb (5)). The cesium compound [M{(R)-PEP...

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Autores principales: Feuerstein, Thomas J., Goswami, Bhupendra, Rauthe, Pascal, Köppe, Ralf, Lebedkin, Sergei, Kappes, Manfred M., Roesky, Peter W.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Royal Society of Chemistry 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6510313/
https://www.ncbi.nlm.nih.gov/pubmed/31160950
http://dx.doi.org/10.1039/c9sc00629j
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author Feuerstein, Thomas J.
Goswami, Bhupendra
Rauthe, Pascal
Köppe, Ralf
Lebedkin, Sergei
Kappes, Manfred M.
Roesky, Peter W.
author_facet Feuerstein, Thomas J.
Goswami, Bhupendra
Rauthe, Pascal
Köppe, Ralf
Lebedkin, Sergei
Kappes, Manfred M.
Roesky, Peter W.
author_sort Feuerstein, Thomas J.
collection PubMed
description The enantiomerically pure ligand P,P-diphenyl-N,N′-bis((R)-1-phenylethyl)phosphinimidic amide (1; (R)-HPEPIA) was synthesized and subsequently deprotonated with alkali metal precursors to yield dimeric complexes [M(2){(R)-PEPIA}(2)] (M = Li (2), Na (3), K (4), Rb (5)). The cesium compound [M{(R)-PEPIA}] (6) crystallized as a cocrystal composed of dimeric ([Cs(2){(R)-PEPIA}(2)] (6(d)) and 1D-polymeric ([Cs{(R)-PEPIA}](n)) (6(p)) species in a 1 : 1 ratio. The coordination polymer 6(p) features a unique sinus-shaped configuration of repeating –Cs–N–P–N–Cs–N–P–N– units. Unusual photoluminescence (PL) properties were found for solid 1–6: in contrast to the fluorescent ligand 1, the alkali metal complexes show phosphorescence at low temperatures (<100 K) and thermally activated delayed fluorescence (TADF) above ∼150 K. The latter provides for PL quantum yields up to 36% (3) at ambient temperature. DFT calculations support that both 1 and 2–6(d) have similar singlet and triplet excited states with energy separations of a few tens of meV. The strongly enhanced intersystem crossing (ISC) in the metal complexes, resulting in TADF, is attributed to their dimeric structure. This suggests that the fluorophore dimerization may serve as a tool to effect ISC for the design of TADF emitters.
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spelling pubmed-65103132019-06-03 Alkali metal complexes of an enantiopure iminophosphonamide ligand with bright delayed fluorescence Feuerstein, Thomas J. Goswami, Bhupendra Rauthe, Pascal Köppe, Ralf Lebedkin, Sergei Kappes, Manfred M. Roesky, Peter W. Chem Sci Chemistry The enantiomerically pure ligand P,P-diphenyl-N,N′-bis((R)-1-phenylethyl)phosphinimidic amide (1; (R)-HPEPIA) was synthesized and subsequently deprotonated with alkali metal precursors to yield dimeric complexes [M(2){(R)-PEPIA}(2)] (M = Li (2), Na (3), K (4), Rb (5)). The cesium compound [M{(R)-PEPIA}] (6) crystallized as a cocrystal composed of dimeric ([Cs(2){(R)-PEPIA}(2)] (6(d)) and 1D-polymeric ([Cs{(R)-PEPIA}](n)) (6(p)) species in a 1 : 1 ratio. The coordination polymer 6(p) features a unique sinus-shaped configuration of repeating –Cs–N–P–N–Cs–N–P–N– units. Unusual photoluminescence (PL) properties were found for solid 1–6: in contrast to the fluorescent ligand 1, the alkali metal complexes show phosphorescence at low temperatures (<100 K) and thermally activated delayed fluorescence (TADF) above ∼150 K. The latter provides for PL quantum yields up to 36% (3) at ambient temperature. DFT calculations support that both 1 and 2–6(d) have similar singlet and triplet excited states with energy separations of a few tens of meV. The strongly enhanced intersystem crossing (ISC) in the metal complexes, resulting in TADF, is attributed to their dimeric structure. This suggests that the fluorophore dimerization may serve as a tool to effect ISC for the design of TADF emitters. Royal Society of Chemistry 2019-04-09 /pmc/articles/PMC6510313/ /pubmed/31160950 http://dx.doi.org/10.1039/c9sc00629j Text en This journal is © The Royal Society of Chemistry 2019 http://creativecommons.org/licenses/by/3.0/ This article is freely available. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence (CC BY 3.0)
spellingShingle Chemistry
Feuerstein, Thomas J.
Goswami, Bhupendra
Rauthe, Pascal
Köppe, Ralf
Lebedkin, Sergei
Kappes, Manfred M.
Roesky, Peter W.
Alkali metal complexes of an enantiopure iminophosphonamide ligand with bright delayed fluorescence
title Alkali metal complexes of an enantiopure iminophosphonamide ligand with bright delayed fluorescence
title_full Alkali metal complexes of an enantiopure iminophosphonamide ligand with bright delayed fluorescence
title_fullStr Alkali metal complexes of an enantiopure iminophosphonamide ligand with bright delayed fluorescence
title_full_unstemmed Alkali metal complexes of an enantiopure iminophosphonamide ligand with bright delayed fluorescence
title_short Alkali metal complexes of an enantiopure iminophosphonamide ligand with bright delayed fluorescence
title_sort alkali metal complexes of an enantiopure iminophosphonamide ligand with bright delayed fluorescence
topic Chemistry
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6510313/
https://www.ncbi.nlm.nih.gov/pubmed/31160950
http://dx.doi.org/10.1039/c9sc00629j
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