Studies On The Design, Assembly, And Applications Of Organic/Inorganic Hybrid Supramolecular Nanosensors

One of the most important subjects in supramolecular chemistry is about recognition, while a subject molecule selectively combined with another object to have some new special functions. The specific interaction between target molecule and the selected receptor normally involves noncovalent bonding, such as hydrophobic forces, van der Waals forces, hydrogen bonding, π-π interactions, hydrophobic effect, and electromagnetic effects et.al. The specific physical or chemical properties changes as optical or electrical properties of the system will come out after the recognition process. Different chemical informations as structural and behavioral variations will occur usually, accompanied with the chemical changes. Selective sensors can be designed to recognize, separate and detect ions, small molecules and macro biomolecules in the environment or biosystems.Nanomaterials have many unique physical and chemical properties, so they can be used as scaffold units of the recognization process, showing a great potential to be applied to the ions and moleculars recognition and detection. A crucial point in the design of nanosensing systems is the immobilization of the specific receptors onto a proper platform. This immobilization can be carried out by different methods, depending on the nature of the receptors and the nanomaterial, which constitute the sensing platform. By combining organic molecular and different nanomatericals, we can solve the water-solubility and biotoxicity, then give the hybrid materials a great potential at environmental monitoring, optical markers, and disease diagnosis-treatment. Based on combining the organic molecules and different nanoparticles, herein we have designed and constructed three functional nanosystems to different ions, and investigated the process and mechanism of the recognition process.This thesis presents a developing method for multi-functional nanosensors based on the development of novel functional organic molecular, different synthetic and assembly methods, and novel recombination measures. Three parts are involved in this thesis. Firstly, the design, synthetic, and application of small molecule fluorescence chemical sensors based on organic molecular, and the exploration of multi-functions. Secondly, the assembly of nanosensors through combination of chemical sensors with nanomaterials through covalent graft or supramolecular interaction and the stuidies of fluorescence sensing properties and development of biological applications have been performed. Finally, based on the research of nanosensors, by hybridization magnetic nano materials with metal organic framework (MOFs), we build a novel hybrid assembly material called nanoextractor, realizing the applications of MOFs materials in separation science. Four parts are included in this thesis.1. Two rhodamine sensors (RBCDTA and RBCTA) are obtained based on the principles of Fluorescence Resonance Energy Transfer (FRET). They can be used in the sensing of Hg2+and Ga3+under different excitations in ethanol solution.2. A multifunctional nanosensor designed by importing metal binding sites and hydrogen bonds attached to the chromophore, is prepared from silica nanoparticles. It works well in the continuous recognition of Hg2+, H2PO4-, and S " in aqueous solution via different combination mechanisms, and successfully suffices intracellular imaging. The nanosensor was very applicable in a relatively wide pH range (pH6to8) in water.3. Fluorescent carbon quantum dots have been efficiently prepared and isolated from a common carbon source, candle soot. And then, driven by the need to detect trace amounts of H2PO4-in water, a highly selective and ultrasensitive complex of calix[4]arene-derivative with Zn2+modified carbon nanosensor CQDs@L-Zn2+has been assembled for H2PO4-recognition at the4.85ppm level from aqueous solution, with excellent discrimination against other organic and inorganic anions.4. We found a K+ion-templated assembly with tripodal ligand L and then synthesized an unique3D MOF that features a binodal3,6-connected net with the pyrite (pyr) topology, which, for the first time, has been identified in a coordination network driven by an alkali metal. The observed interactions of L and K+could serve as a model for building novel and highly selective receptors for alkali metal ions. There is a self-extraction found in channels of the MOF. Furthermore, a magnetic nanoextractor was designed to solve the water solubility, thus allowing its application in aqueous medium to selectively separate K+ions. The K+-induced self-assembly of a novel MOF and its enhanced separation ability in channels of the MOF itself may lead a new route for the measuring and detaching of ions by nanoextractors.