Studies On Recognition Of Pyrophosphate And Oxalate In Water

Supramolecular chemistry is a science of study on the intermolecular interactionsbetween two or more chemical species which could form a complicated and orderedsupramolecular system with certain functions. In which, one of the most importantbranches of supramolecular chemistry is Molecular recognition. It is a fundamentalcharacteristic of biochemical systems and plays an important role in biological processes.Study on molecular recognition using artificial receptors to construct the biomimeticsystem or chemical models is one of the challenges in the frontiers of bioorganic chemistryand supramolecular chemistry. Chemosensors is plays an important role in molecularrecognition. Fluorescence chemosensors are widely used to detect metal ions and anionsbecause of their high selectivity, sensitivity and simplicity. Colorimetric sensors are populardue to their capability to detect analyte by the naked eye without resorting to theinstruments. In this thesis, a series of new optical chemosensing ensembles weresynthesized and investigated for their applications in the detection of pyrophosphate （PPi）or Oxalate. The details are as follows:1. The Structure characteristic of anions and the principles and methods of designingchemosensor were briefly introduced. In the anion recognition, some more flexible andnovel designed anion chemosensor were reviewed, which lay the first stone for this thesis.2. A new chemosensing ensemble CE1was construction by Receptor2-1and eosin Y.CE1shows a highly selective recognition to pyrophosphate through an obviousfluorescence increase, whereas, other anions such as CH₃COO,HSO₄, NO₃, H₂PO₄,HPO42, PO43, NCS, I, Cl,Br, F, citrate, tartrate, oxalate, malonate, succinate andglutarate did not induce obvious fluorescence intensity changes. The recognition process isnot significantly affected by other coexisting anions. Standard competition assays showedthat Receptor2-1and pyrophosphate formed a1:1stoichiometric complex, the associationconstant is K_S=1.17×10⁵M^-1。A new chemosensing ensemble CE1was construction by Receptor2-1andchromeazurol S. CE1shows a highly selective recognition of oxalate through an obviouscolor change from blue to yellow.whereas, other dicarboxylates such as malonate,succinate, fumarate, maleate, glutarate, adipate, phthalate, isophthalate and terephthalate donot induce any noticeable color changes. The recognition process is not significantlyaffected by other coexisting dicarboxylates. Standard competition assays showed thatReceptor2-1and oxalate formed a1:1stoichiometric complex, the association constant is K_S=（1.85±0.1）×10⁴M^-1.3. A new-type fluorescence chemosensing ensemble CE3showed a highly selectiverecognition towards pyrophosphate in water was synthesized by Dinuclear Zin ComplexReceptor3-1with eosin Y. This highly selective pyrophosphate recognition process of CE3is hardly influenced by other coexisting anions （I, Cl, Br, F, CH3COO, HSO4, NO3，NCS），except HPO₄^2-, PO₄^3-, H₂PO₄^-. Standard competition assays showed that Receptor3-1and pyrophosphate formed a1:1stoichiometric complex, the association constant is KS=2.33×105M-1.4. A new-type fluorescence chemosensing ensemble CE4showed a highly selectiverecognition towards pyrophosphate in water was synthesized by incorporating bis-（2-pyridine methyl） amine into Ferrocene with eosin Y. Standard competition assays showedthat Receptor4-1and pyrophosphate formed a1:1stoichiometric complex, the associationconstant is K_a=（1.93±0.1）×10⁴M^-1. This highly selective pyrophosphate recognitionprocess of CE4is hardly influenced by other coexisting anions(I^-, Cl^-, Br^-, HPO₄^2-, CH₃COO^-,F^-, PO₄^3-,H₂PO₄^-)...