| Supramolecular chemists have long been concentrating their strength and energy on the study of intermolecular secondary interactions, such as hydrogen-bonding, metal coordination interaction and host-guest interaction. Molecular recognition and self-assembly, which are based on weak supramolecular interactions, are two main branches of supramolecular chemistry. Accordingly, my research subjects in this thesis are generally classified into two parts, part 1:the selective recognition of biologically and environmentally important inorganic anions and metal cations based on disc-shape chemosensors bearing hexaazatriphenylene (HAT) core; part 2:the construction of single-layer two-dimensional supramolecular organic frameworks in water through the self-assembly of rigid vertexes and flexible edges.Fluoride anion exhibits beneficial effect on dental care and has been widely adopted in the treatment of osteoporosis, while excessive fluoride ion intake may lead to fluorosis, urolithiasis, and even cancer. In chapter two, a novel chemosensor for fluoride anion has been developed. This sensor, constructed by merging six phenolyl units into a HAT core, could recognize F- visually and spectroscopically with high selectivity over other anions, which was demonstrated by naked-eye experiment and UV-vis absorption spectroscopic study.Owing to its involvement in the vital process, copper ion plays key roles in the biological system as a cofactor for a variety of metalloenzymes. However, excessive accumulation of Cu2+ may lead to neurodegenerative diseases and environment pollution. In chapter three, a highly selective chemosensor bearing three salphen pockets fulfilled the recognition of Cu2+ via obvious color change and significant absorption enhancement upon the introduction of Cu2+. Notbally, the Cu-complex as formed from Cu2+ and 2-8 is capable of recognizing the existence of S2", which is toxic and even fatal once protoned to be HS- or H2S. Additionally, the coordination of chemosensor and Cu2+ led to the formation of coordination polymer which further generated nanospheres, as evidenced by SEM, TEM, AFM, PXRD, and EDX investigations.Silver ion, reported and proved to possess the advantage of sterilization and disinfection, may interfere the biological balance and normal growth or reproduction of benign microbes at the same time. Because of the duplicitous effects of the silver ion in biological and environmental systems, in chapter four, two fluorescent probes for Ag+, comprised of HAT skeleton and furan or thiophene motifs, were synthesized and characterized. In addition, the sensitivity and selectivity of both probes for silver ion were investigated through naked-eye experiment, UV-vis spectroscopy,1H NMR titration experiment and fluorescence spectroscopy, which demonstrated that thiophene-derivedprobe exhibited comparatively higher selectivity for Ag+ based on fluorescent quenching mechanism. Moreover, the detection limits and binding constants between probes and Ag+ were calculated by fitting fluorescent titration curves.Since the discovery of graphene, a prototype of two-dimensional (2D) polymers, the fabrication of synthetic 2D polymers has aroused considerable interest because it providesan access to exploring the unique properties and practical applications of 2D materials. In chapter five, single-layer two-dimensional supramolecular organic frameworks have been constructed in water through three-component self-assembly of rigid cross-shaped vertexes, flexible oligoethylene glycol edges, and cucurbit[8]uril (CB[8]) hosts, driven by CB [8]-encapsulation-enhanced donor acceptor interaction between viologen unit and 2,6-dihydroxynaphthalene or 1,4-dihydroxybenzene segment which were peripherally incorporated into the vertex and edge, respectively. |
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