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

• DOI: 10.1021/acs.jpcb.4c08370
• Publication Date: 2025-01-22T13:13:04Z
• Authors: Siyu Hou; Qin Yu; Xiaolan Cheng; Mengrong Hu; Zheng Li; Jian Luo

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.