Lipophilic Red-Emitting Oligomeric Organic Dots for Moisture Detection and Cell Imaging

The development of self-assembled organic dots (ODs) with lipophilic fluorescent properties has significant potential in various applications, especially in sensing and bioimaging. Herein, we report a one-pot gram-scale synthesis of lipophilic red-emitting oligomeric L-ODs with high quantum yield (39.3%), which is prepared by a solvothermal condensation of o-phenylenediamine and L-tartaric acid. Interestingly, as-prepared ODs shows no solid and aqueous emission but intense red fluorescence in the majority of organic solvent. The titration of water indicates that ODs can be applied to the moisture detection of organic solvent. And since ODs exhibits excellent biocompatibility, it is successfully used as a lipophilic red-emitting imaging reagent. Furthermore, contrast experiment and theoretical simulation are adopted to reveal photoluminescence mechanism of L-ODs. Thus, the hydrogen-bond-induced red-shift of benzimidazole intermediate is thought to be the main reason for the intense red-emitting fluorescenc...