Design,Synthesis And Cell Imaging Research Of Small Molecular Fluorescence Probe

Fluorescent probe technique has been attracted more and more attention due to the high sensitivity,operational simplicity,and instantaneous response.In this dissertation,three series of fluorescent small molecular probes,based on quinoline,benzimidazole and rhodamine,have been designed and synthesized,toward the application of the detection and recognition of metal ions in cell.In addition,the binding machanisms of these probes and target metal ions were systematically investigated in details by NMR,HR-MS analysis,and density functional theory?DFT?calculations.Detailed contents of each chapter were listed as below:1.In the seconde chapter,a novel and simple fluorescent probe QLSA based on quinoline was designed and synthesized,which can selectively recognize Zn²⁺.After binding with Zn²⁺,remarkable fluorescence emission enhancement at 581 nm can be observed,with a larger Stokes shift?171 nm?.This probe could detect Zn²⁺with better specificity over other common metal ions,and the limit of detection was found to be 21nM.Moreover,the proposed sensing machanisms of QLSA and Zn²⁺was systematically investigated by ¹H NMR,HR-MS analysis,and DFT calculations.Further application of QLSA in fluorescence imaging was studied in HeLa cell byconfocal fluorescence microscopy,suggesting that the sensor was proved to be a useful tool for tracking Zn²⁺levels in vivo.2.In the third chapter,a simple sensor QLBA based on benzimidazole was synthesized and evaluated as an efficient fluorescence chemosensor for the selective recognition of Cu²⁺.This sensor could detect Cu²⁺with obvious fluorescence quenching.In the sensing process,the quinolone unit N,amide and the benzimidazole unit N atom could coordinate the center Cu?II?and form one six-membered ring and one five-membered ring,which would stabilize the complex.The proposed sensing machanisms of QLBA and Cu²⁺was systematically investigated in detail by ¹H NMR,HR-MS analysis,and DFT calculations.In addition,the obtained QLBA-Cu²⁺could be used as one new sensor for S^2-.Moreover,this probe was also used to detect Cu²⁺and S^2-in real sample,and displayed good imaging characteristics for the detection of Cu²⁺and for the recognition of S^2-in living cells.3.In the fourth chapter,a simple Schiff base?BMSA?prepared from salicylaldehyde and 2-?1H-benzo[d]imidazol-2-yl?aniline was evaluated as an efficient fluorescent probe for the selective recognition of Al³⁺and Cu²⁺over other common metalions.This sensor could detect Al³⁺in CH₃OH/PBS with distinct emission red-shift and Cu²⁺in CH₃OH/Tris-HCl with obvious fluorescence quenching.The proposed sensing machanisms of BMSA and Al³⁺/Cu²⁺was systematically investigated in detail by ¹H NMR,HR-MS analysis,and DFT calculations.In addition,the obtained BMSA-Al³⁺complex could be used as a new probe for the detection of F^-and BMSA-Cu²⁺could be used as a new sensor for S^2-.BMSA was also used to recognize Al³⁺/Cu²⁺in cell.4.In the fifth chapter,we designed and synthesized two rhodamine B derivatives RhBOP and RhBEP.RhBEP could be used as a chemosensor to detect Fe³⁺,which was combined by rhodamine B and o-phthalic anhydride with a simple ethylenediamine chain.Once the Fe³⁺ion encountered the chemosensor RhBEP,the heteroatoms O of the rhodamine spirocyclic and o-phthalic anhydride unit could act as chelating sites for Fe³⁺,and the spirolactam ring turned open,leading to fluorescence turn-on.The proposed sensing machanisms of RhBEP and Fe³⁺was systematically investigated in detail by FTIR,¹H NMR,HR-MS,and fluorescence reversibility analysis.In order to enlarge the application scope of this chemosensor,this sensor was also used to detect iron ions in real sample and to recognize iron ions in cell imaging,providing important basis for further broadening the research on fluorescence detection of iron ions.