Cesium Cation Complexation by a Flavin Receptor via Self-Assembly and Deprotonation

This study focuses on the self-assembly of a new flavin compound and its scaffolding function for a Cs⁺ ion. 7,8-Dimethyl-10-[4′-(methoxycarbonyl)­phenyl]-isoalloxazine (FlH–MB) displays self-assembly in a DMSO solution and has strong dependence on the solvent. In the DMSO solution, both the resulting scaffold and the deprotonation of FlH–MB were demonstrated to induce complex formation with a Cs⁺ ion, which was investigated by UV–vis, ¹H NMR, and fluorescence titrations. This complex formation involves both Coulombic and cation−π interactions through the Fl^– site in an Fl^––MB dimer.