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Molecular Environment Effects That Modulate the Photophysical Properties of Novel 1,3-Phosphinoamines Based on 2,1,3-Benzothiadiazole

We report synthesis, crystal structure, and photophysical properties of novel 1,3-phosphinoamines based on 4-amino-2,1,3-benzothiadiazole (NH(2)-btd): Ph(2)PCH(Ph)NH-btd (1) and Ph(2)P(E)CH(Ph)NH-btd, (E = O (2α and 2β·thf), S (3), Se (4)). Chalcogenides 2–4 exhibit bright emissions with a major ban...

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Detalles Bibliográficos
Autores principales: Khisamov, Radmir M., Ryadun, Alexey A., Konchenko, Sergey N., Sukhikh, Taisiya S.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9227927/
https://www.ncbi.nlm.nih.gov/pubmed/35744980
http://dx.doi.org/10.3390/molecules27123857
Descripción
Sumario:We report synthesis, crystal structure, and photophysical properties of novel 1,3-phosphinoamines based on 4-amino-2,1,3-benzothiadiazole (NH(2)-btd): Ph(2)PCH(Ph)NH-btd (1) and Ph(2)P(E)CH(Ph)NH-btd, (E = O (2α and 2β·thf), S (3), Se (4)). Chalcogenides 2–4 exhibit bright emissions with a major band at 519–536 nm and a minor band at 840 nm. According to TD-DFT calculations, the first band is attributed to fluorescence, while the second band corresponds to phosphorescence. In the solid state, room temperature quantum yield reaches 93% in the case of the sulphide. The compounds under study feature effects of the molecular environment on the luminescent properties, which manifest themselves in fluorosolvatochromism as well as in a luminescent response to changes in crystal packing and in contributions to aggregation effects. Specifically, transformation of solid 2β·thf to solvate-free 2β either by aging or by grinding causes crystal packing changes, and, as a result, a hypsochromic shift of the emission band. Polystyrene films doped with 2 reveal a bathochromic shift upon increasing the mass fraction from 0.2 to 3.3%, which is caused by molecular aggregation effects.