Emerging Thermosensitive Probes Based on Triamino-Phenazinium Dyes

Temperature is an essential physical characteristic that influences all biological processes. Building on previous research on dialkylamino-functionalized rhodamine-based thermo-sensors, we investigate herein the thermosensitive properties of triamino-phenazinium dyes. Through a simple five-step synthetic route, we synthesized amino-phenazinium chromophores <b>6</b> and <b>7</b>, featuring diethylamine substituents at different positions. A comparative analysis of optical properties and thermosensitivity was conducted on these compounds and an isomer, <b>5</b>, in which butylamine moiety replaced the diethylamine group. The different emissive behaviors of the three fluorophores emphasize that not only the chemical nature but also the specific position of the alkylamine substituent play fundamental roles in the synthesis of highly emissive thermo-probes.