Synthesis And Application Of AIE Functionalized Mesoporous And Layered Materials

Inorganic porous materials are excellent carriers for loading guest molecules due to their unique properties such as ordered pore structure and large surface area. Inorganic porous materials functionalized with organic groups combine the advantages of porous materials and organic functional groups, and have been widely used in catalysis, adsorption, biomedicine, and so on. Since the first material with intriguing aggregation induced emission (AIE) was discovered, many AIE molecules have been synthesized and widely used as efficient electroluminescent materials, sensitive chemosenors, bioprobes, and so on. Restriction of intramolecular rotation is the main cause for the AIE effect, therefore we proposed that after these molecules were introduced into mesoporous materials with rigid skeleton, their internal rotation would be largely restricted, leading to highly emission. In this thesis, based on inorganic mesoporous materials as well as layered phosphates, we developed AIE functionalized inorganic-organic hybrid materials through post grafting, co-condensation and ion exchange, and systematically explored their applications in drug delivery, chemical detection, cell imaging, etc. The main results of this thesis include the following sections:We modified mesoporous SBA-15with AIE luminogen tetraphenylethene (TPE) for the first time through post grafting method and explored their applications in drug delivery and explosive detection. The internal rotation of AIE molecules was largely restricted by the rigid inorganic skeleton, leading to strong blue emission, so the composite materials exhibit typical AIE-like characteristics. The fluorescence intensity of the materials enhanced with the increasing amount of the drug adsorbed on the materials. When the drug release reached equilibrium, the fluorescence intensity can almost return to the initial value, showing great potential for biomedical application. In addition, such materials show high sensing performance to explosive molecules, e.g., picric acid (PA). When the amount of TPE modified on SBA-15reaches to0.067mmol/g, the quenching constant is about2.5×105M-1, much higher than that of TPE molecules. This is because PA molecules can quickly diffuse into the pores and be effectively adsorbed around fluorophores (TPE) via acid-base interaction, enhancing the fluorescence quenching efficiency. Furthermore, the materials are recyclable by washing with proper solvents, which is a key factor for future practical application. In addition, we fabricated AIE functionalized mesoporous silica nanoparticles, which are excellent solid-state sensors for2,4-dinitrotoluene (DNT) saturated vapors, with the fluorescence quenched by80%in30seconds, showing an extremely sensitive detection efficiency. The materials also have better detection ability for HC1gas with the fluorescence quenching, and can be recovered by NH3gas. Therefore, AIE luminogen-functionalized mesoporous materials promise to be excellent fluorescence probes for potential applications in biomedicine as well as chemical and explosive detections.The organic phosphate based on AIE molecule was fabricated into bioactive hydroxyapatite (HAP) by a one-pot condensation process with P-O-Ca covalent bond to form hollow mesoporous nanocapsules of ellipsoidal morphology. The as-prepared AIE luminogen bridged mesostructured HAP exhibits strong blue luminescence and good biocompatibility, and shows a high ibuprofen (IBU) storage capacity and favorable drug release behavior compared to pure mesoporous HAP. More importantly, the fluorescence intensity changes with the amount of drug molecules adsorbed to the materials, suggesting that the drug release may be tracked and monitored by the change of luminescence intensity, showing potential for bioapplications.AIE cation (TPEN) was successfully intercalated into layered nano a-ZrP by ion exchange to form organic-inorganic hybrid materials with the interlayer distance expanded to19.6A. The obtained materials emit strong blue fluorescence centered at474nm in aqueous media because internal rotation of AIE molecules was largely restricted caused by electrostatic interactions. This material can serve as an effective fluorescence visualizer for HeLa cells and sensitive fluorescent sensor for the detection of explosive PA in a water solution with the quenching constant of about1.0 ×105M-1.In addition, we prepared amino-modified mesoporous HAP and carboxyl-modified mesoporous titanium phosphate materials by co-concentration. Compared to pure mesoporous HAP, the amino-modified mesoporous HAP with larger surface area and smaller particles sizes, shows higher drug loading and relatively slower release rate. Carboxyl group functionalized mesoporous titanium phosphate shows better coordination for palladium, with the formation of the palladium particle size of about3nm, exhibiting better catalytic activity in the Suzuki coupling reaction.