From Terminal to Spiro-Phosphonium Acceptors, Remarkable Moieties to Develop Polyaromatic NIR Dyes.
Chemistry
; 29(44): e202301073, 2023 Aug 04.
Article
in En
| MEDLINE
| ID: mdl-37212544
ABSTRACT
Phosphonium-based compounds gain attention as promising photofunctional materials. As a contribution to the emerging field, we present a series of donor-acceptor ionic dyes, which were constructed by tailoring phosphonium (A) and extended π-NR2 (D) fragments to an anthracene framework. The alteration of the π-spacer of electron-donating substituents in species with terminal -+ PPh2 Me groups exhibits a long absorption wavelength up to λabs =527â
nm in dichloromethane and shifted the emission to the near-infrared (NIR) region (λ=805â
nm for thienyl aniline donor), although at low quantum yield (Φ<0.01). In turn, the introduction of a P-heterocyclic acceptor substantially narrowed the optical bandgap and improved the efficiency of fluorescence. In particular, the phospha-spiro moiety allowed to attain NIR emission (797â
nm in dichloromethane) with fluorescence efficiency as high as Φ=0.12. The electron-accepting property of the phospha-spiro constituent outperformed that of the monocyclic and terminal phosphonium counterparts, illustrating a promising direction in the design of novel charge-transfer chromophores.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Chemistry
Journal subject:
QUIMICA
Year:
2023
Document type:
Article
Affiliation country:
Finland