Synthesis and properties of L(AS)₃-type low-molecular-mass organic gelators based on citryl aromatic amino acid cholesteryl ester

Three types of L(AS)(3) gelators have been synthesized by the reaction of phenylalanine, tyrosine and tryptophan , whose amino were protected and reacted with cholesterol under the condition of citric acid as a linker, respectively. The synthetic gelators performed strong gelation ability in cyclohexane and isopropanol. The structure, thermal stability and mechanical properties of the gels were observed; the gel formation mechanism was analyzed with XRD and SEM and the results showed that the hydrogen bonding and the pi-pi interaction force remarkably increased due to the existence of a great deal of amide bonds, ester bonds and aromatic rings in gelators. The gels are packed in a layered structure and are stable against temperature change. Among three gelators, citric acid tyrosine cholesterol ester displays a good gel-solution conversion under trifluomacetic acid-triethylamine simulation in isopropanol. The study is expected to have application in the detection of organic amines in the field of sensing.