Synthesis And Photophysical Properties Of Tripod BODIPY Compounds Bearing Bis-Fluorophore

Fluorescence imaging and spectroscopy are nowadays indispensable tools in various fields of modern science and medicine, including materials scienc e, analytical and environmental chemistry, clinical diagnostics and biotechnology. So the design, synthesis, and application of novel fluorescent indicators continue to be topics of a vibrant, highly multidisciplinary research area. In this paper, five novel tripod BODIP Y compounds bearing bis-fluorophore and amine or phenolic derivatives were synthesized via stepwise nucleophilic substitution of cyanuric chloride. All the five compounds have been characterized by HRMS, 1H NMR, 13 C NMR, and IR. And their photophysical properties have also been measured.First,the appropriate reaction conditions were found through exploring the reaction temperatures and the reaction time. The optimized reaction conditions were obtained as follows: the third chlorine atom of the bis-aldehyde-containing intermediate can be substituted by nucleophilic reagents at low temperatures ahead of the complexation with BF3×OEt2. The two steps can be performed in one-reactor, resulting in a simplif ied process and less reaction time. The reaction temperature, reaction mechanism, and reactivity of the nucleophilic reagent were also investigated:(1) The third chlorine of the cyanuric chloride has been successfully substituted by the phenolic nucleophilic reagent at room temperature or even low temperature. This work proved that the activity of the third chlorine atom within the uncoordinated bis-fluorophore precursor can be dramatically enhanced.(2) A proposed mechanism for the increased activity of the bis-substituted intermediate was discussed.(3) The yield of the nucleophilic substitution of the third chlorine by amine was much higher than that by the nucleophilic phenolic reagents.Next, the UV-Vis and fluorescence spectra of the dyes obtained in this paper showed that :(1) The maximum absorption wavelength of the five novel dyes were all 502 nm in the methylene chloride solvent.(2) The range of the fluorescence quantum yields of compounds 1-5 were 48.54%~62.79%.At last, attempts to explore the synthetic routes of unsymmetrical structures containing two different BODIP Y f luorophores have also been made in this paper. Even though all the trials failed, some constructive ideas for the subsequent work have been put forward.