Cinchona alkaloid copolymers as fluorimetric INHIBIT and colorimetric AND logic gates for detection of iodide

Agius, Nicola' and Ashton, Catherine J. and Willcock, Helen and Magri, David C. (2025) Cinchona alkaloid copolymers as fluorimetric INHIBIT and colorimetric AND logic gates for detection of iodide. RSC Advances, 15 (14). pp. 11121-11127. ISSN 2046-2069

Abstract

Four cinchona alkaloid-acrylamide water soluble copolymers with a mean hydrodynamic diameter of 3 nm were synthesised by free radical polymerization. The copolymers were characterised by 1H NMR, FTIR, GPC, DLS, UV-vis and fluorescence spectroscopy. A blue emission is observed with H + switching of 185 and 175-fold for the quinidine and quinine copolymers, and 21 and 11-fold for the cinchonine and cinchonidine copolymers, while the presence of Cl -, Br - or I - causes fluorescence quenching. In emission mode, the copolymers function as fluorescent H +, X --driven INHIBIT logic gates (where X = Cl -, Br - or I -). In absorbance mode, the copolymers function as colorimetric H +, I --driven AND logic gates in 1 : 1 (v/v) THF/water with a 76-fold enhancement. The solution colour changes from colourless to yellow with formation of new absorbance bands at 288 nm and 353 nm due to a π-anion non-covalent charge transfer interaction. The copolymers may be useful as selective iodide sensors for medical and analytical diagnostics.