Design,Synthesis and Application of Novel Borondipyrromethene Reaction-based Fluorescent Probes
Author:Li Lan Qing
Supervisor:wang ling yun
Fluorescent chemosensors have been widely applied in many diverse fields such as biology,physiology,pharmacology,and environmental sciences.Among fluorescent probe based on different fluorophores,BODIPY-based fluorescent probes have been developed because of its relatively high chemical and photostability,high fluorescence quantum yield,and easy modification.BODIPY-based fluorescent probes for cations,anions,small neutral molecules as well as biomacromolecules attract more attention.Compared with BODIPY,pyrrolopyrrole aza-BODIPY with big conjugated structure and emission in the near-infrared region have unique advantages in the field of bioimaging.Here,a series of BODIPY reaction-based fluorescent probes for F~-,CN~-and amines detection were designed and synthesized.Design,synthesis method and application research of novel boron-dipyrromethene reaction-based fluorescent probes are the main issue as follows.(1)Boron-dipyrromethene dyes(BODIPY-CN)with strong red solid-state photoluminescence were designed and synthesized,which used as reaction-based fluorescent probes for the detection of cyanide.BODIPY-CN achieves rapid detection of cyanide anion within 60 s.It shows that the color changes from yellow to purple when CN~-is added to BODIPY-CN.The maximum emission intensity is quenched96%.BODIPY-CN can be used as a fluorescent and colorimetric probe for the detection of cyanide with rapid detection and high selectivity.Moreover,only one dicyanovinyl group is introduced to BODIPY-CN,and it can reduce symmetry and planarity of target dye.Appending bulky Br atom on the meso-phenyl ring is expected to inhibitπ-πstacking and prevent emission quenching caused by intermolecular stacking.BODIPY-CN that efficiently emits in red region in the solid state was achieved.(2)A novel multifunctional fluorescent probe(TPA-BODIPY)was synthesized by Suzuki reaction,TPA-BODIPY could be applied as a colorimetric and fluorescent chemosensor for F~-and CN~-with no interference from each other.The addition of F~-and CN~-to TPA-BODIPY induced a rapid color change from yellowish green to yellow and flesh,emission intensity is quenched 89%and 94%,respectively.TPA-BODIPY overcomes the shortcomings of traditional probes which can only identify single species.The BODIPY moiety is presumably decomposed by the cyanide anions in a different way compared to fluoride anions in the detection of F~-and CN~-ions.(3)A new Boron-dipyrromethene derivative(Boryl-BODIPY)contained two different Lewis acidic boron center binding sites(BODIPY core and boronate)had been designed and synthesized as a multifunctional fluorescent probe,which can differentiate interfering cyanide and fluoride ions simultaneously by distinct color and fluorescent changes.The addition of F~-and CN~-to Boryl-BODIPY induced a rapid color change from rose pink to indigo and faint pink,respectively.At the same time,the emission color of the Boryl-BODIPY changed from orange yellow to indigo and green in presence of F~-and CN~-,respectively.Fluoride would bind with boronate and simultaneously induces decomposition of the BODIPY moiety,while cyanide anions only attack B-N bond of BODIPY cores.The two different interaction induce different UV-vis and emission change.(4)Two novel near-infrared pyrrolopyrrole aza-BODIPY luminogens(PPAB-2and PPAB-3)with aggregation-enhanced emission characteristics were synthesized by facile synthesis routes.One or two triphenylethylene were introduced and successfully converted them from aggregation-caused quenching to aggregation induced emission molecules.PPAB feature excellent photostability characteristics.The nanoparticles for bioimaging with water solubility were prepared through nanoprecipitation in the presence of Pluronics F127 as the stabilizer.(5)A new pyrrolopyrrole aza-BODIPY compound(PPAB-Py)were designed and synthesized,which can be used as a reaction-based fluorescent probe for biogenic amines detection such as putrescine and cadaverine with high selectivity.Other primary amines,secondary,tertiary amines,aromatic amines,amide,ester,alcohols have no interference.225 nm hypsochromic shift in the absorption maximum and 12-fold fluorescence enhancement in comparison with PPAB-Py were achieved.The limits of detection as low as ppb.PPAB-Py can be used as highly selective and ultrasensitive probe for the detection of BAs by a synchronous colorimetric and fluorescent turn-on process.PPAB-Py underwent the following stepwise chromophore decomposition reaction:a kinetic-control B-N bond cleavage of PPAB-Py is initiated by diamines as the first step reaction,and then two following fast step reactions occurred,i.e.transimination and hydrolysis,to generate much smaller conjugated molecules.It is the first time to report the stepwise chromophore decomposition reaction and to design a novel unique strategy for biogenic amines detection.This unique chemical strategy provides new ideas for the design of new PPAB fluorescent probes.(6)The application of PPAB-Py based on nanoaggregates in amine detection was studied.It exhibits high selectivity response to n-hexylamine with low detection limit(2.53 nM).The addition of n-hexylamine to PPAB-Py nanoaggregates induced a rapid color change from green to yellow,and fluorescence“Turn on”changes were observed.Other biogenic amines,primary amines,secondary,tertiary amines,aromatic amines,amide,ester,alcohols have no interference.PPAB-Py underwent decomposition induced by n-hexylamine,and then a fast hydrolysis reaction occurred,following by colorimetric and fluorescent change.