Synthesis, Mediation Andapplication Of Chiral Gel Based On Dipeptide

The organic gels constructed by small molecule gelators have attracted greatinterests in recent years. Since chirality serves as one of the most important featuresin the nature, how to mediate the conformation and the function of the chiralbiomolecules is a hot direction. Therefore, the synthesis of chiral small molecularorganic gel and the control of their microstructure application will become the focusof this research field.Firstly, the thesis reported a series of C2-symmetric organic small molecule gelobtained by condensation reaction using different series of dipeptides as the basic unit.The gelators was characterized by FT-IR, UV,1H-NMR,13C-NMR, massspectrometry and many other test methods.Secondly, one of the gelators, namely G1(L, L-Asp-Phe) was picked as theresearch object. The microstructure of G1in chloroform under different concentrationwas observed. With the increase of concentration, the gel microstructure changedfrom linear wrapped to a mesh structure, and then the dynamic self-assembly processof which was controlled by chiral drugs (e. g., quinine, quinidine). Interestingly, wefound that quinidine has inhibitory effect on the process of the self-assembly, andquinine exhibits an obvious promoting effect. The chiral amplification of the gelduring gel-formation by ultrasound in ethanol and the quinine’s impact during theprocession was analyzed subsequently. Besides, the gelating behavior of G1inethanol is strongly influenced by quinine and quinidine, but their tendency is oppositeto that in chloroform. This phenomenon indicates an interesting conclusion, that is,solvent induced interaction reversion.Then, the binding constants of the gelators with quinidine and quinine in ethanoland chloroform were analyzed, respectively. The results shows that in the ethanolphase, L, L gel’s constant with quinidine is smaller than quinine, while in thechloroform phase, and L, L gel’s constant with quinidine is larger than with quinine,D, D type gel have an opposite result. These data provide solid evidence that enables a better understanding of the solvent driven reversion of the chiral interaction.Finally, in order to study the application of gel, a layer of gel film was formedon the surface of the dialysis membrane, in which ultraviolet method was used tocalculate the release speed and analyze the chiral separation function of the gel. Theseresults indicate excellent chirality-selective permeation behavior of the membrane,where by the selectivity can be controlled and reversed by the application of aparticular solvent. In conclusion, we have described herein an interesting effect ofsolvent triggered chiral interaction reversion, which directly determines organogeland microstructure formation processes. It may thus provide important insight intothe design of chiral gels and relevant applications, such as enantiomeric separation.