| Fluorescent probes are a class of molecules that have been intelligently designed to convert their binding/reaction with a target molecule into an optical signal and to identify and label the target molecule through changes in the fluorescent signal（wavelength,intensity,lifetime,etc.）.They are characterized by high sensitivity,high resolution and good selectivity.In recent years,thick-ringed molecules have attracted much attention in the field of probes due to their unique fluorescence properties,outstanding thermal stability,and chemical stability.The introduction of one or more nitrogen atoms into a thick-ringed molecule can enhance the reactivity of the thick-ringed molecule,easy modification,high photostability,high thermal stability,and high luminescence ability compared with the thick-ring molecule,Nitrogen-containing thick-ring molecules have the advantages of more reactive sites,easy modification,high photostability,high thermal stability,and strong luminescence compared to thick-ring molecules,so it is very important to study the design of nitrogen-containing thick-ring molecules as fluorescent probes.The common nitrogen-containing thick-ring fluorescent molecules include perylene derivatives,1,8-naphthalene diimide,pyrene,quinoline,anthocyanine,etc.The use of nitrogen-containing thick-ring molecules as a matrix for the preparation of fluorescent probes with different groups to detect different systems has obvious advantages over thick-ring molecules.However,these nitrogen-containing thick-ring molecules have aπ-πconjugation effect and tend to aggregate in solution,leading to fluorescence bursts and limiting their application.To solve this problem,this thesis adopts the method of combining the nitrogen-containing thick-ring fluorescent guest molecule and the main molecule（cucurbit[n]urils）,allowing the nitrogen-containing thick-ring molecule to enter the cavity of cucurbit[n]urils to construct a new supramolecular host-guest system.Not only can the self-aggregation of nitrogen-containing thick-ring molecules be inhibited and the negative effects of interactions and energy transfer processes between nitrogen-containing thick-ring molecules be mitigated,thereby improving the fluorescence properties of nitrogen-containing thick-ring molecules,but the constructed supramolecular host-guest systems can be combined to form new fluorescent probes,and their host-guest systems have been given new applications for research due to the dynamic and reversible nature of the non-covalent interactions present.In this thesis,three water-soluble nitrogen-containing thick-ring molecules were synthesized using perylene and 1,8-Naphthalenedicarboxamide as the parent molecules.Based on these water-soluble nitrogen-containing thick-ring derivatives,physicochemical methods such as nuclear magnetic resonance techniques,ultraviolet absorption visible spectroscopy,fluorescence emission spectroscopy,and isothermal titration calorimetry were applied to study the properties of the nitrogen-containing thick-ring molecules and the host and guest formed by the nitrogen-containing thick-ring should fluorescence with cucurbiturils.The experiments and the results of the studies are as follows:Perylenetetracarboxylic acid derivatives were designed and synthesized using perylene as the parent material,namely the fluorescent probe PDI-C4,were designed and synthesized using perylene as the parent material.The detection performance of PDI-C4 was investigated by NMR techniques,UV-absorption visible spectroscopy,and isothermal titration calorimetry.The experimental results show that PDI-C4 can recognize three basic amino acids using p H response,and its detection limits for arginine,lysine,and histidine are 2.33×10-6 mol·L-1,2.18×10-6mol·L-1and 2.19×10-6 mol·L-1 respectively.PDI-C4 is prepared into dye test strips to detect arginine in the concentration range of 1.0×10-2 mol·L-1,1.0×10-3 mol·L-1,1.0×10-4 mol·L-1,1.0×10-5 mol·L-1,indifferent concentrations of test strips show different fluorescent colors,which can be used for colorimetric application of arginine concentration;based on the p H-responsive nature of PDI-C4,the fluorescence colors of PDI-C4 colors range from red to green fluorescence in the alkaline range p H=10～14,which enables the detection of integer p H values of alkaline aqueous solutions,the p H meter has good photostability and reversibility.PDI-C6,a nitrogen-containing thick ring compound,was synthesized using perylene as the parent material,and the PDI-C6@Q[8]supramolecular host-guest system was constructed to inhibit the aggregation of PDI-C6 based on the self-aggregation characteristics of perylene derivatives.Two blue fluorescent substances,7-hydroxycoumarin,and quinine sulfate,with complementary fluorescent colors and different binding modes to the PDI-C6@Q[8]system,were also selected to construct two orthogonally tuned fluorescent supramolecular ternary systems,system A（PDI-C6@Q[8]@7-hydroxycoumarin）and system B（PDI-C6@Q[8]@quinine sulfate）,using a supramolecular approach to control the emission to produce white light.The ternary system was studied by NMR techniques,UV-absorption visible spectroscopy,and other methods.The results show that:PDI-C6 and Q[8]binding ratio of 1:2,system A can provide bright white emission,7-hydroxy coumarin does not enter into the cavity of Q[8]and formsπ-πconjugation with the thick ring part of PDI-C6,the fluorescence emission of system A can be controlled by temperature,and a smart temperature control switch in the range of 30℃to 100℃is developed;system B,this system due to quinine sulfate can enter the cavity of Q[8]making it possible to provide white light emission over a wide concentration range in comparison to system A.This white light emission also performs well in polymeric substrates for LED,3and D printing,while showing red and white fluorescence under white light and 365nm UV light respectively for anti-counterfeiting applications.The nitrogen-containing thick-ring compound NBA was synthesized using 1,8-Naphthalenedicarboxamide as the parent compound,and the detection of trivalent iron ions by a 1,8-Naphthalenedicarboxamide derivative（NBA）guest molecular probe was investigated using fluorescence and UV spectroscopy,NMR hydrogen spectroscopy;as well as the recognition performance and mechanism of the fluorescent probe constructed with Q8]for tautomers of dichromate anions,trivalent iron ions,silver ions,and nitrobenzene phenols.The results show that in an aqueous solution,NBA can detect trivalent iron ions with a detection limit of 1.5×10-6 mol·L-1;meanwhile,NBA can be encapsulated into the Q[8]cavity to form a1:2 host-guest complex,and using the host-guest fluorescent probe detection to identify three isomers of nitrobenzene phenols,dichromate anions,the detection limits of its probes for m-nitrophenol and p-nitrophenol are 7.8×10-6 mol·L-1、1.8×10-6 mol·L-1、3.56×10-6mol·L-1,and3.56×10-6mol·L-1or the detection of the anion Cr2O72-.The mechanism is based on the sudden extinction caused by the energy resonance transfer of the three nitrophenols,dichromate,ions,and the NBA@Q[8]host-guest fluorescent probe,which causes different degrees of quenching due to the different degrees of energy resonance of the three nitrophenols,e of differentiation;also the NBA@Q[8]system can detect trivalent iron ions and silver ions with detection limits of 2.6×10-6 mol·L-1and 3.5×10-6 mol·L-1,respectively.These studies have achieved fluorescence methods for the detection of three isomers of nitrobenzophenol,dichromate,trivalent iron ions,and silver ions in a single system. |
PDF Full Text Request