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

Abstract

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 π-π 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 trifluoroacetic acid-triethylamine simulation in isopropanol. The study is expected to have application in the detection of organic amines in the field of sensing.