Study Of Self-Assembly Behavior Of Lipotripeptide Controlled By Center Amino Acid And Lipotetrapeptide Determined By Dipole Moment

In recent years,the self-assembly behavior and appliaction of pepeide derivatives have been deeply studied.Functional peptide molecules show advantages in enantioseparation,asymmetric catalysis and drug delivery.It is of great theoretical significance to understand the mechanism of chiral control and chiral transfer in the process of supermolecular self-assemble.In this paper,the lioptripeptides and lipotetrapeptides were synthesized and the effect of chiral center on nanostructure and molecular packing were studied by introducing achiral glycine and changing the sequence of amino acids which helps to understand the process of chirality transforred from the molecular level to the supramolecular level.First,for Gly-Ala-Ala tripeptides,the chirality of the middle amino acid controlled the handedness of the nanobelts and the stacking of molecular.Compared with"C-terminal determination" rule,the achiral amino acid had a profound effect on the self-assemble of lipotripeptides.Molecules packed parallelly in the self-assemblies of lipotripeptides.For AGA and AAG,the homochiral tripeptides formed white sediment in the mixture of CH3OH/H2O,which self-assembled into nanobelts.Second,for the lipotetrapeptides which had only one alanine chiral center,the alanine moved from the alkyl chain to the C-terminal.In the mixture of CH3OH/H2O,the handedness of the nanostructure was changed accordingly.However,when alanine was linked to the alkyl chain,the molecule formed white precipitates.A continuous alignment of glycine made it easier to crystallize.The results also indicated that the movement of alanine on the alkyl chain led to the change of dipole moment and the steric hindrance of the methyl group on its side group,which have a great effect of the handness of the nanostructures.Third,1,4-phenylene-bridged-polybissilsesquioxane nanobelts were prepared using the tripeptides through a supramolecular templating approach.The material containing mesoporous structures was used to selectively adsorb and separate chiral small molecules.