Development of novel fluorescent chemosensors: 1. Fluorescence enhancement through conformational restriction as a signaling method for binding events. 2. Exploiting the modular design of biarylpyridine fluorophores for SAR and wavelength tuning. 3. Design and development of a fluorescent sensor for the explosive triacetone triperoxide.

摘要

In Chapter 1, we describe the development, synthesis, and analysis of several potential fluorescent chemosensors based on fluorescence enhancement through conformational restriction during a binding event. We conclude that fluorophore scaffolds based on compounds with high quantum yields are difficult to apply to our chemosensor design. Furthermore, highly substituted heteroaromatic fluorophores are not ideal scaffolds for efficient synthesis of analogs.; In Chapter 2, we discuss the development of a modular synthetic strategy for the generation of a small library of compounds for an SAR study. The minimum requirement to achieve similar emissive properties to our parent biarylpyridine based fluorescent chemosensor was a simple 2-arylpyridine fluorophore. The binding selectivity of the library components were less than that of the parent fluorophore by 1 to 2 orders or magnitude, with a single exception. We report the elucidation of a partial fluorescent chemosensor for Ca2+. Furthermore, the modular design of our fluorescent chemosensors was exploited to tune the emission wavelength. With various substituents in the 4-position of the pyridine ring, the emission wavelength was shifted nearly 100 nm from an unsubstituted fluorophore. This ability to tune the system at the 4-position of pyridine is significant because the changes are made at a position remote from the location of an appended binding site.; The foundation for the development of a fluorescent triacetone triperoxide (TATP) sensor has been set, and it is described in Chapter 3. The oxidizing ability of TATP to react with phosphines and phosphites was used as a signaling method. These compounds are non-emissive or are comparatively dark with respect to their oxidized counterparts. The exposure of phosphines, phosphonites and phosphites to oxidizing conditions, specifically TATP, generates the corresponding phosphine oxides, phosphonates and phosphates which show enhanced fluorescence. Studies of these types of organophosphorous compounds show that the future development of a TATP-specific sensor lies in phosphite development due to the sensitivity of phosphines to atmospheric oxygen.