Design,Synthesis And Application Of Organic Small Molecule Fluorescent Probes

Fluorescent techniques have been extensively employed to develop non-invasive methodologies for detecting analytes and understanding complex biological processes both in vitro and in vivo.A variety of fluorescent probes,organic chromophores,fluorescent proteins and very recently the developed organic dots based on organic semiconducting molecules or conjugated polymers,have been explored to accomplish the challenging detection and imaging tasks with desired outputs.However,fluorescence microscopy imaging technology requires fluorescent chromophores with high fluorescence efficiency,good light stability,and large stokes shift.The fluorescent probes often used in previous studies mainly include conventional fluorescent dyes,inorganic semiconductor quantum dots,silicon-based probes,conjugated organic semiconductor probes,and so on.However,these commonly used fluorescent dyes have some well-known shortcomings such as: hydrophobicity,easy aggregation quenching,photobleaching,self-toxicity,and some are easily disturbed by source background fluorescence,low signal to noise ratio,and are easily affected by the environment.The ?-conjugated organic molecular dyes provide an attractive platform in the nano-and micro-structures of organic photoelectrons.Organic small-molecule fluorescent dyes have become a rapid development of fluorescent dyes in biosensing applications due to the feasibility of design and the ease of control of synthesis.In the solid state,conventional organic dye molecules generally have the effect of concentration quenching fluorescence.All of the molecules we are going to introduce in this paper have unique photoluminescence properties and aggregation-induced fluorescence enhancement effects,all of which can avoid those problems.Nanostructures are prepared by a simple self-assembly process and their applications in biological imaging or other optical studies are discussed.Based on the application of organic small molecule fluorescent dyes,this paper is mainly carried out from the following aspects:First,according to the reports in the literature and in the application of this subject group to the Tao Youtian teacher to form a small organic molecule CPy has a good TADF effect,we designed and synthesized a new structure t Bu-CPy,that is,through the replacement of t-butyl,change Its energy level,through the study of its optical properties and its biological imaging,found that its nature is similar to that of CPy.It is also an organic small molecule dye with long-lived surface fluorescence.We have found that its emission wavelength is adjusted,which will It is a better innovation for t Bu-CPy research.Second,through the effects of molecular symmetry and substituent isomerization,four symmetrical two-photon fluorescent organic small molecules based on cyanostyrene conjugated centers were designed and synthesized: TPA-CN-F and TPA-CN-N,OMe-TPA-CN-F and OMe-TPA-CN-N.Third,Photophysical properties and aggregation state behaviors of four symmetrical two-photon fluorescent organic small molecules TPA-CN-F,TPA-CN-N,OMe-TPA-CN-F and OMe-TPA-CN-N Bioimaging applications are studied.In this dissertation,we focus on the regulation of the fluorescence properties of molecular materials,design materials,and realize a variety of optical properties of fluorescent nanoprobes,and perform corresponding biological imaging applications.