Phenylboronic Acid-Based Adsorbent Materials And Fluorescent Probes

Phenylboronic acid exhibits diverse chemical properties:(a)it is a lewis acid;(b)it forms cyclic esters with cis-diols reversibly;(c)it is oxidized by hydrogen peroxide to form phenol;(d)it coordinates with metal ions.Based on its diverse chemical properties,phenylboronic acid has been widely used in the areas of adsorbent materials and fluorescent probes.Phenylboronic acid-functionalized materials are used for the enrichment of cis-diols,exhibiting the advantages of universality,high selectivity,reversibility,simpilicity and mass spectrometry compatibility,but they also have some disadvantages,such as narrow applicable p H range and low adsorption efficiency.Phenylboronic acid-based fluorescent probes are used for the detection of lewis bases,cis-diols,hydrogen peroxide and metal ions.This dissertation mainly focuses on the application of phenylboronic acid in the areas of adsorbent materials and fluorescent probes,and the main works are as follows:(a)A phenylboronic acid-functionalized material was prepared with a wide applicable p H range.A binary boronic acid is prepared via the reaction of cyanuric chloride with 3-aminophenylboronic acid,and then is grafted onto attapulgite.There exists a strong electron-deficient 1,3,5-triazine ring in the binary boronic acid,widening the applicable p H range of the material.This material can enrich cis-diols at p H ? 5.0,covering the p H of common biological samples,such as blood,saliva,tear and urine.Finally,the material is applied to the enrichment of nucleosides in urine.(b)A very simple and high-efficiency method was proposed for improving the adsorption efficiency of phenylboronic acid-functionalized materials.Imidazolium-based ionic liquid(IMIL)is coated on phenylboronic acid-functionalized material via physical adsorption.After coating IMIL,cis-diols first transfer from sample to IMIL,and then are adsorbed on phenylboronic acid-functionalized material.Due to the abundant interactions of IMIL,the concentration of cis-diols in IMIL is higher than that in sample,leading to that more cis-diols are adsorbed on phenylboronic acid-functionalized material.This method doesn't require complex material modification and is significantly effective,and thus is very simple and high-efficiency.Finally,IMIL-coated phenylboronic acid-functionalized material is applied to the enrichment of nucleosides in urine.(c)A simple and inexpensive ratiometric fluorescent probe was designed for fructose.The probe consists of 10-hydroxybenzo[h]quinoline(HBQ)which shows emission at 572 nm and 3-pyridylboronic acid(PDBA)whose complex with HBQ gives emission at 500 nm.With adding fructose,the reaction of fructose with PDBA inhibits the complexation of HBQ with PDBA.Requiring no sysnthesis as HBQ and PDBA are commercial available with low-cost,this probe is very simple and inexpensive.Finally,the probe is applied to the detection of fructose in food.(d)An enzymatic fluorescent glucose probe was synthesized with a novel response mechanism.The probe consists of ammonium-modified tetraphenylethylene(TPEA)with the feature of aggregation-induced emission and phenylboronic acid-functionalized polyanion(BAP)that induces the aggregation of TPEA via electrostatic interaction.With adding glucose and glucose oxidase,the produced H2O2 converts phenylboronic acid into weaker acid phenol,which reduces the negatively charges on BAP,resulting in the disaggregation of TPEA.Other phenylboronic acid-based enzymatic fluorescent glucose probes rely on the electronic difference between phenylboronic acid and phenol,but this probe relies on the acidic difference between phenylboronic acid and phenol,providing a new perspective for designing phenylboronic acid-based enzymatic glucose probes in future.Finally,the probe is applied to the detection of glucose in serum.(e)A highly selective fluorescent probe was synthesized for tyrosinase.The probe consists of resorufin as the fluorophore and phenylboronic acid pinacol ester as the receptor.With adding tyrosinase,the adjacent position of phenylboronic acid pinacol ester is hydroxylated,followed by 1,6-rearrangement-elimination to release resorufin.This probe exhibits high selectivity toward tyrosinase,and shows no response to other biological substances including reactive oxygen species.Finally,the probe is applied to the detection of tyrosinase in cells.