Self-assembiles Of Low-molecular-weight Gelators And As Template To Construct Nanofibers Of Metal Sulfide

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 amide 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) Chalcone derivatives consisting of amide moieties were synthesized, and their gelation properties were studied in organic solvents. It was found that they were good gelators and the organogelators packed with bimolecular repeating layer into nanofibers. We successed in constructing NiS nanostructures with various morphologic NiS such as helical or tubular using the gel fibers (compound 3b) as template in the ethanol-water. On one hand, one can obtain useful information on extent the gel molecule and inorganic precursor interacted, which impacted the transcription of gelator nanostructures into inorganic nanomaterials. On the other hand, the speed of NiS mineralization is very important for transcribing the gelator nanostructures into inorganic nanomaterials based on different sulfur source. (2) Synthesis and gelation properties of a series of alanine derivatives were investigated. The gelator (LAA) self-assembled into one-dimensional nanofibers in the ethanol-water. Several nanofibers of metal sulfide (M=Cu, Ag, Ni and Cd) were prepared using this hydrogel 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. The results indicated that interactions happened at acid between Cu and gelator molecule or at amide between M (M= Ag, Ni and Cd) and gelator molecule. On the other hand, CuS nanotubes were obtained from composited gel with approximate 150-500 nm outer diameters, however, CuS nanofibers were prepared from dispersed gel with 70-130 nm diameters. (3) Organogelators of glutamic acid derivatives and biglutamic acid derivatives with amide groups were synthesized. Gelators of glutamic acid derivatives self-assembled into one-dimensional nanofibers with dimolecularrepeating layer in ethanol-water through H-bond of amides and acids based the results of SAXRD and FT-IR. The CuS nanoribbons with widths of 30-60 nm were prepared using organogel fibers as template. Firstly, one can obtain useful information on how the gel molecule and inorganic precursor interacted, which induced the transformation of the arrangement of gelator molecule. Secondly, it was confirmed that the formation of CuS nanoribbons was on base of the continuous growth on the surface of the primary CuS nanoparticles distributed on the some points of the gel fibers. (4) Novel organogelators based on long chain substituted benzoic acid hydrazine were synthesized and could form stable gels in bulk organic solvents and self-assemble into various microstructures in organogel phases. It is found that hydrogen bonding and van der Waals interactions play an important role on the formation of organogels. In different solvents, the organogelators can self-assemble into various architectures, such as the benzene gel (compound 2) gives a cotton-like morphology, while in cyclohexane compound 2 formed lamellar nanostructure in gel phase. However, in the same solvent, homologues organogelators self-assemble into similar nanostructure.