Primary Investigation Of Optical Molecular Chemosensors For NO, Hg²⁺ And Cu²⁺

Optical molecular chemosensors (OMCSs) that convert molecular recognition into highly sensitive and easily detected optical signals have emerged in the field of analytical chemistry as an application of the research on molecular recognition. OMCS has become one of the current scientific fronts and have been actively investigated in recent years due to their unique importance and merits in probing the composition, structure or evolution of environmental or biological microsystems. Much considerable efforts have been focused on the research of the OMCS that based on the irreversible and specific reactions due to their high selectivity and nice sensitivity. Along this line, this research on the optical molecular chemosensors was conducted and a series of OMCSs have been successfully developed in this dissertation based on a variety of irreversible and specific reactions. This dissertation consists of six chapters summarized as follows:In chapter 1, a general introduction to the concept, the development of optical molecular chemosensors was presented. Emphasis was focused on the developments of optical molecular chemosensors for nitric oxide, mercury ion and copper ion. Then, based on the reports of interrelated literatures and the experimental results we had obtained, the objective of this dissertation was proposed.In chapter 2, a novel colorimetric and fluorimetic chenosensor for nitric oxide in aqueous solution based on a rhodamine B spirolactam ramification was developed. The NO-mediated transformation of diamine into benzotriazole and water sensitive behavior of the activated derivatives of carboxylic acids, acylbenzotriazole would serves as the foundation for a novel chemosensor for NO in aqueous solution. Therefore, we synthesized a series of rhodamine B spirolactam ramifications and studied their sensing performance for NO in aqueous solution, and discussed its reaction mechanism in detail. The developed chemosensor showed high specificity and sensitivity for NO in aqueous solution due to the NO-induced irreversible reaction above-mentioned.In chapter 3, the detection performance of the chemosensor developped in chapter 2 for nitrite ion was studied. The chemosensor possesses the specificity and high selectivity for nitrite ion ion in aqueous solution due to its similar NO2--induced irreversible reaction with NO's mentioned in chapter 2.In chapter 4, A Hg²⁺ selective ratiometric fluorescence sensor based on the mechanism of intramolecular fluorescence resonance energy transfer (FRET) was designed and synthesized. Then, the sensing performance of the sensor was studied and investigated. The developed sensor exhibited great ratiometric fluorescence enhancement and remarkable yellow-magenta color change toward Hg²⁺ with excellent selectivity in aqueous acetone solution, and the ratiometric fluorescence response to Hg²⁺ was not interfered by other metal cations including Fe3+, Co²⁺, Ni²⁺, Cr3+, Zn²⁺, Pb²⁺, Cd²⁺, Ca²⁺, Mg²⁺, Ba²⁺ and Mn²⁺. The linear range and the detection limit for fluorescence ratiometric method of Hg²⁺ were 1.0 - 10.0×10-6 mol/L and 5×10-8 mol/L, respectively.In chapter 5, two derivatives of Dansylhydrazine were designed and synthesized based on the metal ion-promoted hydrolyzation, and DANSH's and the synthsizd compounds'sensing performance to mercury ion and copper were investigated. DANSH and the synthsizd compounds displayed the specificity and high selectivity for Cu²⁺, Hg²⁺ in aqueous solution, repectively, due to the metal ion-promoted hydrolyzation reaction's high specifcity.In chapter 6, the studies on other compounds as optical molecular chemosensors in my experiments were summarized. I hope it would be helpful for other people who engage in the research of this field.