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

[Image: see text] 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, (1)H NMR, and fluorescence titrations. This complex formation involves both Coulombic and cation−π interactions through the Fl(–) site in an Fl(–)–MB dimer.