Development of Fluorescent Isocoumarin-Fused Oxacyclononyne - 1,2,3-Triazole Pairs.
Chemistry
; 29(47): e202300540, 2023 Aug 21.
Article
em En
| MEDLINE
| ID: mdl-37293937
ABSTRACT
Fluorescent isocoumarin-fused cycloalkynes, which are reactive in SPAAC and give fluorescent triazoles regardless of the azide nature, have been developed. The key structural feature that converts the non-fluorescent cycloalkyne/triazole pair to its fluorescent counterpart is the pi-acceptor group (COOMe, CN) at the C6 position of the isocoumarin ring. The design of the fluorescent cycloalkyne/triazole pairs is based on the theoretical study of the S1 state deactivation mechanism of the non-fluorescent isocoumarin-fused cycloalkyne IC9O using multi-configurational ab initio and DFT methodologies. The calculations revealed that deactivation proceeds through the electrocyclic ring opening of the α-pyrone cycle and is accompanied by a redistribution of electron density in the fused benzene ring. We proposed that the S1 excited state deactivation barrier could be increased by introducing a pi-acceptor group into a position that is in direct conjugation with the formed C=O group and has a reduced electron density in the transition state. As a proof of concept, we designed and synthesized two fluorescent isocoumarin-fused cycloalkynes IC9O-COOMe and IC9O-CN bearing pi-acceptors at the C6 position. The importance of the nature of a pi-acceptor group was shown by the example of much less fluorescent CF3 -substituted cycloalkyne IC9O-CF3 .
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Base de dados:
MEDLINE
Idioma:
En
Revista:
Chemistry
Assunto da revista:
QUIMICA
Ano de publicação:
2023
Tipo de documento:
Article
País de afiliação:
Federação Russa