Designs Of Fluorescent Chemosensors For Micro Water Content And Hydroxylated Organotins

Many important processes concerned in chemistry,biology and material science usually occur in micro systems.As a strong tool for exploring these systems, fluorescent chemosensors(FCSs) convert the subtle molecular interactions or processes to visible signals,making the vivid output of the chemical or biological information in the explored systems available to the researchers.Fluorescence is highly applicable to advanced researches in life sciences since it is hurtless to organisms and can be measured in real time and/or real space.Therefore,FCS is attracting much current research interest.On the basis of our previous works concerning optical chemosensors,this dissertation is aimed at developing FCSs for some environmental and biological species important yet less reported.Meanwhile, novel sensing mechanisms are emphasized in our researches.This dissertation consists of four chapters summarized as follows:In chapter 1,a general introduction to FCSs was presented.Emphasis was paid on the developments of FCSs for micro water content in organic solvents and toxic transition metal cations.Based on the analysis of the relative literatures,the objective of this dissertation was proposed.In chapter 2,we described a novel fluorescent probe for micro water content in aprotic organic solvents based on Pb₄Br₁₁^3- clusters.The indicator fluorophore exists in a special local environment which is highly sensitive and accessible to water.A linear decrease of fluorescence intensity and synchronous blue shift of the excitation band were observed with increasing water content.Meanwhile,there was also a good linearity between the Stokes' shift value(SSV) and the water concentration. The new water-sensing mechanism and SSV-based signaling mode make the developed probe greatly suitable for applications in routine analytical processes.In chapter 3,a specific FCS for hydroxylated organotins(HOTs) was developed.A simple Schiff base fluorophore was found to show a highly selective fluorescence response to HOTs in aqueous solution.The new receptor nicely combines the binding character of an o-hydroxyl Schiff base for the transition metal and boronic acid for the vicinal diol.Addition of HOTs induced a sensitive fluorescence enhancement of the receptor at physiological pH.This is the first report of a fluorescent receptor for hydroxylated metal species.In chapter 4,some of the primary experiments on chiral recognition of amino acids with optical probes were summarized.