In-situ Synthesis Of Benzothiadiazolyl Tetrazolium Complexes And Their Response To External Environment Such As PH

Currently,because of deverse sensing mechanisms,coordination polymers?CPs?have developed rapidly in fluorescence detection area,especially for the emission change of ligand triggered by the external envirement.As we known,benzothiadiazole?BTD?is an excellent fluorophore,whilst tetrazole?Tz?group can show various coordination modes,which also is able to expose uncoordinated N active sites.Interestingly,tetrazole complex can be easily prepared by in-situ hydrothermal synthesis method,which is environmentally friendly,simple to operate and easy to prepare some special structures that are not available by the conventional method.Inspired by these,in this theme,a series of new BTD-Tz complexes 1-7?complexes 1,5,6 and 7 are isostructural?were synthesized by different cyanobenzothiadiazole precursors?PL₁,PL₂ and PL₃?in the in-situ hydrothermal condition,which was modulated by the ratio of sodium azide and metal salt.Subsequently,the structures and photophysical propeties of these new complexes were studied in detail,and the interaction between complex and external envirement,such as pH of environment,metal ion or anion,was further investigated.Herein,for example,complexes 1,2 and 4 were sensitive to the acidic condition,where the fluorescence was distinctly quenched at the condition of pH=2.On the other hand,because of its unique dual emission and the influence of coordinated azide,complex 3was sensitive to the alkaline environment,where the ratio of two emission peaks was varied by pH.In addition,the interaction between complex and metal ion as well as the interaction between complex and anion were studied by the fluorescence spectroscopy.