Emission of Protonated Riboflavin Induced by Inhibition of Out-of-plane Vibration in a Rigid Polymer Network

The Journal of Physical Chemistry B, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 22, 2025

Chromophores incorporated into rigid polymer matrices may exhibit novel photophysical properties distinct from those in liquid solutions. In this work, we explored the decay path of second ππ* state (2ππ*) riboflavin poly(vinyl alcohol) (PVA) solutions and films with various acidities. Highly efficient internal conversion 2ππ* to lowest (1ππ*) induced by slight in-plane motion is demonstrated all PVA films, irrespective environmental acidity rigidification. Ground-state protonation occurs highly acidic film, cationic species emits fluorescence around 460 nm, contrast ultrafast nonradiative relaxation aqueous solution. The emission originate rather than 1ππ* state. 2ππ*-1ππ* protonated be out-of-plane impeded a network, resulting anti-Kasha fluorescence.

Language: Английский

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Fluorescence Enhancement of Nonemissive Monodeprotonated Luteolin in a Poly(vinyl alcohol) Film

The Journal of Physical Chemistry B, Journal Year: 2024, Volume and Issue: 128(45), P. 11328 - 11334

Published: Nov. 1, 2024

Solid polymer matrixes can modulate the electronic states of embedded chromophores and have been widely used in flexible optoelectronic optical materials. Luteolin is one most common natural flavonoids, its neutral monodeprotonated forms are nonemissive aqueous solution induced by ultrafast excited-state proton transfer (ESPT) followed nonradiative relaxation. In this study, we incorporated luteolin into poly(vinyl alcohol) (PVA) films studied their fluorescence behaviors. Neutral coexist PVA film. Weak steady-state peaking at about 440 nm observed for first time. addition, film exhibits obvious 500 nm, with a quantum yield as high 0.4 lifetime long 2.4 ns. Time-dependent density functional theory calculations determined that ESPT barrierless but needs to surmount barrier, explaining distinct emission properties. These results indicate modulation ability both ground-state deprotonation ESPT, broadening application areas solid matrix.

Language: Английский

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The Enhanced Proton-Accepting Ability of Bound Water in Poly(vinyl alcohol) Films

The Journal of Physical Chemistry B, Journal Year: 2025, Volume and Issue: unknown

Published: March 25, 2025

Poly(vinyl alcohol) (PVA) films have been widely used as flexible matrixes in advanced optical materials. Most studies concern the rigidification strategy of PVA films, while physicochemical properties inside bound water are ignored. In this study, we employed lumichrome fluorescent probe to explore acid–base property water, which was demonstrated exhibit an enhanced proton-accepting ability than bulk evidenced by promoted deprotonation ground state. Decreasing content a film is further improve ability. Different from that solution, selective prototropism determined induced formation anchored lumichrome–PVA complex through three hydrogen bonds. This work first points out opening new avenue for development materials based on proton transfer.

Language: Английский

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The enhanced excited-state intramolecular proton transfer energy barrier of flavonols induced by deprotonation

Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy, Journal Year: 2025, Volume and Issue: unknown, P. 126146 - 126146

Published: March 1, 2025

Language: Английский

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