Size-regulable vesicles based on anion-π interactions.
Taking tetraoxacalix[2]arene[2]triazine as a functionalization platform, a series of new amphiphilic molecules were synthesized in 18 to 53 % yields by using a fragment coupling protocol. These amphiphilic molecules self-assembled into stable vesicles in a mixture of THF and water, with the surface of the vesicles engineered by electron-deficient cavities. Various anions are able to selectively influence the size of self-assembled vesicles, following the order of F(-) < ClO4(-) < SCN(-) < BF4(-) < Br(-) < Cl(-) < NO3(-), as revealed by DLS measurements. Such a sequence was independent with the hydration cost and in agreement with the binding strength of anions with tetraoxacalix[2]arene[2]triazine host molecule, indicating that the anion-π interaction most probably competed over other possible weak interactions and accounted for this interesting selectivity. In addition, the chloride permeation process across the membrane of the vesicles was also preliminarily studied by means of fluorescent experiments. This study, in addition to providing the potentiality of heteracalixaromatics as new models to construct functional vesicles, opens a new avenue to study the anion-π interactions in aqueous and also potentially in living systems.
Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190 (P.R. China).
Qing
Q
He
Yuchun
Y
Han
Yilin
Y
Wang
Zhi-Tang
ZT
Huang
De-Xian
DX
Wang
anions; calixarenes; noncovalent interactions; self-assembly; vesicles