| In recent years, the research on chemical probes based on organic carrier remains veryactive， and searching for new fluorophores with improved sensitivity and selectivity as wellas design of probes with both detection and removal function is still a challenge for theanalytical research efforts. To improve the sensitivity, selectivity or the reusibility of probes,following the general design principles and signal transmission mechanisms of thefluorescence probes, combining with the sucessfulresearch results of our laboratory as well asusing a variety of new materials, in this dissertation, a series of novel fluorescent probes weredesigned and synthesized for metal ions and small biological molecules detection, which werebased on aggregation induced emission, the extraction and separation as well as cut-off typedesign. The details are summarized as follows:1. In chapter2, based on the advantages of aggregation induced emission oftetraphenylethylene, we designed and synthesized a novel compound1(DEDA-TPE) for thedetection of aluminium ion. It was found that ethanol was the best solvent for theAl3+-triggered aggregation of DEDA-TPE compared with other solvents. In the solution ofVwater/Vethanol=1:9, the probe showed high selectivity and sensitivity towards aluminum ion.Job’s method was employed to determine the binding stoichiometry of DEDA-TPE and Al3+.It showed that the complex of DEDA-TPE and Al3+exhibited a maximum fluorescenceemission at485nm, when the molecular fraction of Al3+was closed to0.5.. This indicatedthat a1:1stoichiometry is possible for the binding mode of DEDA-TPE and Al3+. Theaggregation was verified by the dynamic light scattering (DLS) results, with an Al3+concentration-dependent size observed. It was also directly confirmed by SEM analyses.2. In chapter3, based on the advantages of aggregation induced emission oftetraphenylethylene, we designed and synthesized a novel compound2(TSB-TPE) for thedetection of zinc ion. It was found that N, N-Dimethlformamide (DMF) was the best solventfor the Zn2+-triggered aggregation of TSB-TPE compared with other solvents. In the solutionof Vwater/VDMF=1:9, the sensor showed high selectivity and sensitivity towards zinc ion. Job’smethod was employed to determine the binding stoichiometry of TSB-TPE and Zn2+. Itshowed the complex of TSB-TPE and Zn2+exhibited a maximum fluorescence emission at485nm, when the molecular fraction of Zn2+was closed to0.3.. This indicated that a1:1and1:2stoichiometry are possible for the binding mode of TSB-TPE and Zn2+. The aggregation was verified by the dynamic light scattering (DLS) results, with a Zn2+concentration-dependent size observed.3. In chapter4, A novel aggregation-induced emission-based fluorescent probe3(SAA)for Zn2+was designed and simply synthesized by condensation of salicylaldehyde withaqueous hydrazine. The experimental conditions were first optimized. It was found that N,N-Dimethlformamide (DMF) was the best solvent for the Zn2+-triggered aggregation of SAAcompared with other solvents. The emission intensity was gradually increased, accompaniedby the simultaneous red shift of the maximum emission peak with increasing Zn2+concentrations. A red shift about45nm was achieved when Zn2+concentration is100μM.Compared with other Zn2+fluorescent probes based on aggregation-induced emission (AIE),SAA can detect a lower concentration of Zn2+with a detection limit of0.1μM. Compound1also exhibited good selectivity toward Zn2+. The aggregation was verified by the dynamiclight scattering (DLS) results, with a Zn2+concentration-dependent size observed. It was alsodirectly confirmed by TEM analyses.4. In chapter5, we have developed a novel fluoroionphore-ionic liquid hybrid-basedstrategy for design of an efficient bifunctional sensing system for detection and removal ofheavy metal ions(HMIs) with improved performance via the synergistic extraction effect. Bychoosing Hg2+as a model HMI, a rhodamine-based target-specific ionic liquid compound4(RQI) was designed and synthesized, which can both detect and remove Hg2+from aqueoussamples. This new system could provide obviously improved sensitivity by simply increasingthe aqueous-to-ionic liquid phase volume ratio. Such bifunctional RQI possesses severalunique advantages compared to previously reported methods. First, the novel RQI is endowedwith both detection and removal function, and the two tasks can be completed in a one-stepoperation, which is simple, economical, convenient, and nontoxic to the environment.Moreover, selectively induced by Hg2+, the RQI molecule exhibits an easily distinguished“off-on” visual change for instrument-free detection of Hg2+, which is more convenient forthe general public than other instrument-based methods. Most importantly, the bifunctionalRQI design provides a general platform for various HMIs, thus holding promise for a broadspectrum of applications.5. Mesoporous silicon SBA-15silica is an excellent support for constructing fluorescentsurface sensors. In chapter6, we reported a two-step surface reaction involved strategy toconstruct efficient fluorescent surface sensors for metal ions by clicking fluoroionophores5(PANA) onto azide-functionalized SBA-15. Our experimental results indicate that such astrategy exhibits an obviously higher loading efficiency within commercial SBA-15than apreviously reported strategy. As a proof-of-concept, a newly designed alkynefunctionalized Hg2+fluoroionophore was grafted onto SBA-15to form a fluorescent Hg2+surface sensor. Itshows improved sensitivity and selectivity than the fluoroionophore itself working in thesolution phase with a detection limit of2.0×10-8M for Hg2+.6. In chapter7, based on the fact that thiol compounds can cut off the S-S bond, wedesigned and synthesized a dual fluorophore fluorescence probe compound6(PNA)containing pyrene and naphthalimide derivatives. With the introduction of thiol compounds,S-S bond was cut off, fluorescent intensities of pyrene and naphthalimide derivatives wereboth enhanced in different degrees. PNA showed high selectivity towards thiol compounds,with no interferences observed for non-sulfhydryl amino acids. We also examined theresponses of PNA on common metal ions, the results showed that PNA showed no responseon several kinds of metal ions. |
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