Construction Of A New Functionalized Calix[4]arene Optical Probe And Detection Of Uranyl Ions

Calixarene is a type of calix-like phenolic macrocyclic compound,which are usually composed of four or more methylene bridged phenol units,calix[4]arene is one of the most widely used.Due to the calix[4]arene has a unique cavity structure and adjustable structure,as well as the the upper and lower edges which can improving coordination ability by derivatizing,the calix[4]arene has advantages in the construction of specific probes and the preparation of optical nanomaterials.Spiropyran is a well-known photochromic compound,which is composed of a benzopyran ring and an indoline ring.Exogenous stimulis such as p H,metal ions,temperature,and light can cause the C-O bond and the C-N bond in the spiropyran molecule broken to form a ring-opening,and the metal ion is complexed with the ring-opened spiropyran to form a complex.The changes in the optical signal of the spiropyran before and after can be used to quantitatively analyze the metal ions.In this study,spiropyrans were selected to derivatize calix[4]arenes.Using the changes of optical signal before and after the complexation of uranyl ions and spiropyran,a new type of calix[4]arene optical probe for detecting UO₂²⁺was constructed,and a new method for detecting UO₂²⁺was established through experiments.The first chapter of this article briefly introduces the significance of the detection of uranyl ions in the environment and the current research progress on the detection methods of uranyl ions at home and abroad.At the same time,the development and application of calix[4]arenes and spiropyrans are briefly described,with emphasis on elaboration The research progress of fluorescence detection of uranyl ions is reviewed,and the purpose and main content of this research are put forward at the same time.Synthesize a novel calix[4]arene optical probe through five steps.Firstly,functionalize the lower edge of p-tert-butyl calix[4]arene and introduce propyne groups;secondly,synthesize spiropyran azidesulfonate molecules step by step,and finally connect the two parts through click chemistry.Meanwhile,characterizing each product by NMR,MS,FT-IR.The second chapter introduces the experimental process of the five-step synthesis of a novel calix[4]arene optical probe.First,functionalize the lower edge of p-tert-butylcalix[4]arene and introduce propyne groups;secondly,synthesize spiropyran azidesulfonate molecules step by step,and finally connect the two parts through click chemistry.At the same time,NMR,MS,and FT-IR were used to characterize each product.In the third chapter,by scaning the synthesized calix[4]arene optical probe with ultraviolet-visible spectrophotometer and fluorescence spectrophotometer to study its ability to recognize UO₂²⁺.The experimental results prove that the calix[4]arene-sulfonic acid spiropyran optical probe has a good response to UO₂²⁺.A new method for detecting UO₂²⁺is established based on this.In the p H 6.0 Na Ac-HAc buffer solution,absorption and fluorescence showed good response.Under UV conditions,the linear range of detection is 20～200n M,the detection limit is 10.17n M,the linear equation is:ΔA=0.0022c（n M）+0.017,and the correlation coefficient is r=0.9939.Under the fluorescence conditions,the linear range of detection is 40～180n M,the detection limit is 14.81n M,the linear regression equation isΔF=1.9941c（n M）-29.04,and the correlation coefficient is r=0.984.