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Synthesis And Self-assembly Of Chiral Low-molecular-weight Organogelators And Construction Of Inorganic Nanostructures Templated By Organogels

Posted on:2006-07-30Degree:DoctorType:Dissertation
Country:ChinaCandidate:P C XueFull Text:PDF
GTID:1101360155953634Subject:Organic Chemistry
Abstract/Summary:PDF Full Text Request
Nowadays, the design, synthesis and study of gelation properties of low-molecular-weight gelators have been received much attentions because of the diversity of structures of gelators, which may induce the gelators to self-assemble into various dimensional and morphologic suparstructures in organic solvents directed by nanocovalent interactions such as H-bonding, van der Walls, π-πstacking ect. We may construct functional organogel with special nanostructures through introduction some functional groups to the organogelators. The organogels have numerous potential applications in hardeners of solvents and drug delivery systems. Very recently, organogels were applied as novel media to produce various inorganic nanostructures, such as linear fibers, lamellar and helical fibers structures, which give us an opportunity to prepare various novel inorganic nanomaterials. We synthesized several organogelators consisting of cholesterol groups and investigated their gelation properties, furthermore, used their gels as templates to produce various inorganic nanomaterials. Some creative results were obtained. The main results were outlined as following: (1) Dicholesterol derivative consisting of salicylideneaniline moieties was synthesized, and its gelation property was studied in organic solvents. It was found that it was good gelator and the organogelators packed with unimolecular repeating layer into lamellar structure. Moreover, strong green fluorescence in gel state could be observed and very weak fluorescence in sol state was invisible by our naked eye. This enhanced fluorescence emission was ascribed to the restriction of the molecular motions and the formation of J-aggregate. (2) Synthesis and gelation properties of a series of dicholesterol derivatives consisting of Schiff'base moieties were investigated. It found that their gel abilities possessed obvious odevity, which was related with their chemical structures. Moreover, we successed in constructing CuS nanofibers with different helical pitches, and firstly affirmed that binding sites between metal ions and gel fibers could be tunned by the solvent, which induced the difference of morphologies of inorganic nanostructures. (3) A organogelator of cholesterol derivative with amide groups was synthesized. Gelator self-assembled into one-dimensional nanofibers with dimolecular repeating layer in ethanol. The CdS nanofibers with an approximate 60 nm outer diameters and 4-6 nm inner diameters were prepared using organogel fibers as template. On one hand, one can obtain useful information on how the gel molecule and inorganic precursor interacted, which induced the transformation of the arrangement of gelator molecule. On the other hand, it was confirmed that the formation of pearl-necklace CdS nanofibers consisting of porous network particles was on base of the...
Keywords/Search Tags:Low-molecular-weight
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