Department of Chemistry
Ratiometric pH responsive fluorescent probes operative on ESIPT
A series of C-8′-oxime-appended spirobenzopyrans 4a-4d were synthesized and developed as fluorescent pH ratiometric probes operative in HEPES/ACN (8:2, v/v) buffer solutions. Acidochromic conversion of spirobenzopyran to merocyanine open form can facilitate the subsequent enol-keto tautomerization giving dual emissive peaks via the excited state intramolecular proton transfer (ESIPT) mechanism. The pH titrations of 4a show a 68-fold increase in ratiometric intensities ratio (I645 nm/I 522 nm) when the pH was switched from 8.0 to 4.0 with a pK a value of 5.90. © 2013 Elsevier Ltd. All rights reserved.
ESIPT, pH sensing, Ratiometric fluorescent probe, Spirobenzopyran
Source Publication Title
Chan, Yim-Pan, Li Fan, Qihua You, Wing-Hong Chan, Albert W.M. Lee, and Shaomin Shuang. "Ratiometric pH responsive fluorescent probes operative on ESIPT." Tetrahedron 69.29 (2013): 5874-5879.