Synthesis And Gel Properties Of Low Molecular Weight Organogels Based On Tetrathiofulvalene

Low molecular weight organogels are supramolecular soft materials self-assembled by small organic molecules through intermolecular hydrogen bonds,π-πstacking,vander Waals forces,hydrophobic and dipole dipole interactions.Because the driving force during the formation of the gel is a weak interaction,which endows it with sensitive properties to external environmental stimuli.In recent years,studies on the use of low molecular weight organogels for drug delivery and sustained release,chemical sensing,and treatment of toxic dyes in water have received extensive attention.In this paper,combined with the previous research work of our research group,three series of low molecular weight organogelators containing tetrathiafulvalene（TTF）units were synthesized,and their gel systems were studied in response to stimuli and treatment of pollutants in water applications in other fields.The main research contents are as follows:1.A series of low molecular weight organogelators containing phenylalanine and pyridazine with anthraquinone-extended tetrathiafulvalene（ex-TTF）were synthesized.Their structures were characterized by NMR,FT-IR and MS,respectively.The properties and self-assembly behavior of the gel were studied by FE-SEM,FT-IR and variable concentration ¹H NMR.It was found that this series of gelling factors formed opaque gels in aromatic hydrocarbon solvents and DMF solvents.During the self-assembly process,the quadruple hydrogen bonds between amide units are the main driving force.The change of the length of the flexible chain in the molecule and the presence of C₆₀guest also have a certain effect on the assembly structure and morphology.2.A series of thiocrown ether cyclized tetrathiafulvalene（TTF）low molecular weight organogels were synthesized.After characterization of the molecular structure,the gel properties of the series of gel factors were tested.The gel factor was cooled by ultrasound to form opaque gel after heating in DMSO solvent.SEM shows that the xerogel is a flower like structure of micron size.The stimulus response of gel factor was tested,including anionic,TCNQ redox,Na⁺and other stimuli response tests,and the mutual conversion of gel to sol was realized.Due to the complexation of crown ether holes with Na⁺,the gel system was destroyed,and then the gel system was restored by adding EDTA.3.A series of low molecular weight organogels of thiocrown ether cyclized tetrathiafulvalene（TTF）containing cholesterol were synthesized.After characterization of the molecular structure,The gel tests were carried out and it was found that the parity of the flexible chain of the target compound had an effect on the gel behavior.Only when the flexible chain was even 21b（n=4）and 21d（n=6）,the target compound was gelatinous and only gel in cyclohexane,hexane,cyclohexanol and n-butanol specific solvents.The morphology of xerogels changes with the change of the length of the flexible chains.Moreover,the morphology of xerogels formed by different solvents varies greatly under low multiple.The adsorption capacity of gel factor 21a to Rhodamine B solution and methylene green solution in cyclohexane was studied by UV-vis spectroscopy.The result showed that gel factor 21a in cyclohexane had a stronger adsorption capacity to Rhodamine B solution than to methylene green solution.