Study Of The Synthesis Of Phenylboronic Acid-based Fluorescent Probes And Their Applications

According to relevant references in recent years, this paper deals with the study of fluorescent probes based on phenylboronic acid. Fluorescent probes play the important role in analytical biochemistry, environment monitoring, disease diagnosis, medicine screening, and so on. Fluorescence probes can identify specific target molecules. Upon binding with target molecules, the optical properties of the fluorescent probes will be changed, which can be used to identify target molecules. In this paper, phenylboronic acid-based fluorescent probes for detecting D-fructose, CIO-and were designed and synthesized. In addition, a salophene-based chemosensor for Zn2+ was developed. This dissertation consists of three chapters summarized as follows:In chapter 1, a general introduction to the research progress on phenylboronic acid-based fluorescent probes was presented. Boronic acid-based fluorescent reporter can identify saccharides which play the important role in biochemistry process. Therefore, they are often designed for saccharides. Based on literature reported in these years, the objective of this dissertation was proposed.In chapter 2, a phenylboronic acid-based fluorescent sensor for D-fructose, 2-(1H-benzo[d]imidazol-2-yl)phenylboronic acid (1), was designed and synthesized. Compound 1 is a weak fluorescent compound and was synthesized via the two-step reaction of 2-formylphenylboronic acid with o-phenylenediamine. Upon mixing with D-fructose under neutral aqueous conditions, boronic acids bind with diol moieties of D-fructose with high affinity through reversible boronate, hence leading to a dramatic increase in fluorescence emission of the reaction mixture. Based on the above mechanism, a fluorogenic method for the determination of D-fructose was developed.In chapter 3, the application of compound 1 as a fluorescent probe for CIO- was investigated. The boronate group in probe 1 can be readily oxidized by CIO- to yield the corresponding hydroxyl group. Before the oxidation occurred, the ESIPT process was switched off, the probe 1 showed only fluorescence emission maximum at 415nm. Upon treatment with ClO- under neutral aqueous conditions, the boronic acids moieties of the probe 1 was transformed to the corresponding hydroxyl group, which in turn leading to the ESIPT process of the probe was switched on. Accordingly, it was observed that the fluorescence emission at 415nm showed "turn-off", while the fluorescence emission at 454nm showed "turn on". The proposed probe showed excellent selectivity toward ClO-.In chapter 4, a schiff-based fluorescent chemosensor 2 for Zn2+ was designed and synthesized. Compound 2 is a non-fluorescent compound and was synthesized via the one-step reaction of o-phenylenediamine with o-vanillin in ethanol. However, upon mixing with Zn2+ in 30%(v/v)aqueous ethanol, a "turn-on" fluorescence emission is observed due to the formation of a 1:1 complex 2-Zn2+. Based on the above mechanism, a fluorogenic method for the determination of Zn2+ was developed. The proposed method is simple, fast and sensitive.