Synthesis And Ion Recognition Of Chemosensors Based On Carbazole And Naphthol Derivatives

Supramolecular chemistry play a crucial role in life and information sciences. Molecular recognition is one of most parts of supramolecular chemistry. Fluorescence based sensors for metal ion and anions have been of interest due to their ability to detect metal ions selectivity, sensitivity and simplicity. Among the biologically pivotal metal ions and anions, Cu2+, Zn2+ and oxalate are particularly important due to the crucial roles they take part in chemical, environmental and biological processes.With this in mind, we describe the synthesis, characterization, and selective recognition behavior of a series of novel optical chemosensors for their applications in the detection of Cu2+, Zn2+ and oxalate. The details are as follows:1. Briefly introduced the concept of design methods for chemical sensors, molecularrecognition, and the principles of chemical sensors for Cu2+ and Zn2+.2. A new carbazole-based Schiff base L1 was synthesized and applied as a highly selective and sensitive fluorescent probe for Cu2+ in H2O-DMSO(8/2, v/v, pH = 7.4) solution. L1 exhibits an excellent selectivity to Cu2+ over other examined metal ions. L1 and Cu2+ forms a 1:2 binding ratio complex with detection limit of 9.5μM.3. A new 2,7-naphtalenediol-based sensor L2 was synthesized. And the dinuclear zinc complex Zn2L2 was prepared, which exhibits an selectivity to oxalate with C-IDA. In water solution(HEPES 10 mM pH = 7.4), a colorimetric chemosensing ensemble(CE1) was construct with pyrocatechol violet(PV) and Zn2L2. When addition of oxalateto CE1 solution induced a noticeable color change from blue to yellow. Except malonate behaves a slight interference, other dicarboxylates produce no significant influenceon oxalate recognition process.4. A new carbazole-based fluorescent sensor L3 has been developed. In CH3CN-H2O(1/1, v/v, HEPES 10 mM, pH = 7.4) solution, L3 displays selective and ratiometricresponses to Zn2+. The formed dinuclear Zn2+ complex Zn2L2 was further applied as a receptor for oxalate. Through constructing a chemosensing ensemble(CE2) with chromeazurol S as an indicator, a colorimetric recognition of oxalate in water solution was achieved through IDA. And other dicarboxylates have no infuluces on oxalate recognition process.5. A new Binol and 8-aminoquinoline based Schiff L4 was synthesized and appliedas a highly selective and sensitive fluorescent probe for Zn2+ in H2O-DMSO(1/1, v/v,HEPES 10 mM, pH = 7.4) solution.The formed Zn2+ complex ZnL4 was further applied as a receptor for oxalate with a significant fluorescence quenched. While other dicarboxylates produce no significant influence on oxalate recognition process. The “OFF–ON–OFF” fluorescence sensing behaviour of L4 observed in the presence of Zn2+ and oxalate may find applications in Hela cells.