Room‐Temperature Phosphorescence‐active Boronate Particles: Characterization and Ratiometric Afterglow‐sensing Behavior by Surface Grafting of Rhodamine B
Mitsuki Hoshi, Ryuhei Nishiyabu, Yuichiro Hayashi, Shigeyuki Yagi, Yuji Kubo
Chemistry An Asian Journal
We found that boronate particles (BP), as a self‐assembled system prepared by sequential dehydration of benzene‐1,4‐diboronic acid with pentaerythritol, showed greenish room‐temperature phosphorescence (RTP). This emission was observed in both solid and dispersion state in water. To understand the RTP properties, X‐ray crystallographic analysis, and density functional theory (DFT) and time‐dependent DFT at M06‐2X/6‐31G(d,p) level were performed using 3,9‐dibenzo‐2,4,8,10‐tetraoxa‐3,9‐diboraspiro[5.5]undecane (1) as a model compound. Our interest in functionalizing the RTP‐active particles led us to graft Rhodamine B onto their surface. The resulting system emitted a dual afterglow via a Förster‐type resonance energy transfer process from the BP in the excited triplet state to Rhodamine B acting as an acceptor fluorophore. This emission behavior was used for ratiometric afterglow sensing of water content in THF with a detection limit of 0.28 %, indicating that this study could pave the way for a new strategy for developing color‐variable afterglow chemosensors for various analytes.
Fluorescence, Phosphorescence, Solid state, FRET, Chemical stability, Optical properties, Materials