Synthesis, Anion Recognition And Bioactivities Of Novel Triazoliums

The extensive potential application of triazole in medicinal, agricultural and chemical fields and the recognition of anions which play an important role in biology, medicine and environment science, received considerable attention. Many fluorescent chemosensors follow the approach of the covalent attachment of signaling subunits, the coordination site binds the anions with high selectivity and the signaling subunits are to act as a signal transducer with sensitive optical response. Our aim is to research and develop a series of novel triazolium fluorescent receptors, investigate their ability to bind selectively anions and evaluate biological activities of target molecules.On the basis of extensively reading literatures about the research and application of triazoles in medicinal, agricultural and chemical fields, this thesis designed and synthesized a series of new types of triazoles and their triazolium salts (mono-/bis-triazolium salts). The novel triazoles were synthesized starting from fluorescent naphthol or carbazole. The reaction of naphthol or carbazole with dibromides in the presence of base gave 1-(2-bromoethoxy)naphthalene or 9-(4-(bromomethyl) benzyl)-9H- carbazole, and then N-alkylated with 1H-1,2,4-triazole to produce target triazoles, after that quatemized with a series of alkyl bromides or dibromides to afford to corresponding to desired triazolium compounds in high yields. All the new compounds were confirmed by ¹H NMR, ¹³C NMR, MS and IR..Fluorescence spectrum titration was employed to investigate the molecular recognition ability of mono/bis-triazolium to four anions (AcO^- ,p-OOCPhCOO^2- , Cl^- and I^-) in dimethyl sulfoxide. The binding constants K_s (dm³Â·mol^-1) were calculated. The experimental results indicated that mono-triazolium hosts 70a and 70c showed weak selective recognition to anions. In contrast, bis-triazoliums displayed better anion recognition, especially terephthalate (p-OOCPhCOO^2-). The interaction of other receptors such as 71a and 72b-e with anions (e.g. p-OOCPhCOO^2-) was also investigated by fluorescence spectrum. The order of selectivity of different receptors is 72a > 71a > 72c, 72e > 71b. The obtained fluorescence data indicate that 1:1 stoichiometry complex is formed between bis-triazolium hosts with four anions separately.The antifungal and antibacterial activities against C. albicans, S. aureus, E. coli. were evaluated. The experimental results showed that 69a and 70a possess good activities against S. aureus, 67, 68, 69b and 70b don't give obvious biological activity, while all the bis-triazolium compounds displayed good activity against S. aureus, E. coli, especially 72e.