Metal Ion Mediation of Interfacial Chiral Supramolecular Formation of Amphiphilic Schiff Bases Studied by In Situ Second Harmonic Generation
Metal Ion Mediation of Interfacial Chiral Supramolecular Formation of Amphiphilic Schiff Bases Studied by In Situ Second Harmonic Generation
复制标题
原位二次谐波产生研究金属离子介导两亲希夫碱界面手性超分子形成
DOI：
10.1021/acs.jpcb.0c05545
复制
发表时间：
2020
影响因子：
3.3
通讯作者：
Zhang Zhen
中科院分区：
文献类型：
--
作者：
Xue Man;Zhang Li;Liu Minghua;Bai Yu;Guo Yuan;Zhang Zhen
手性席夫碱与金属离子之间的配位效应为制备手性超分子自组装体提供了一种有效的策略。研究了两亲性席夫碱对映体2-羟基-1-萘甲氨基-N，N′-双的超分子自组装利用原位二次谐波发生线性二色性（SHG-LD）技术结合紫外-可见光谱和原子力显微镜，研究了十八烷基-l/d-谷氨酸二酰胺（l/dGJ）在空气/水界面上的相互作用，发现lGJ和dGJ单分子膜在不同的界面上可以形成彼此的镜像结构，其可由金属离子介导。当Mg ~（2+）和Zn ~（2+）离子加入到亚相中时，thel/dGJ单分子膜自组装成纳米纤维状结构，并表现出与纯水界面相似的手性。当Cu ~（2+）离子加入到亚相中时，由于Cu ~（2+）的配位作用，破坏了thel/dGJ单分子膜的手性。随着亚相中Cu ~（2+）浓度的增加，手性过剩度（DCE）值减小。随着表面压力的增加，配合物的DCE值逐渐增大，表明配合物通过侧向分子堆积形成了手性超分子结构。
The coordination effects between chiral Schiff bases and metal ions can provide an effective strategy for fabricating chiral supramolecular self-assemblies. We studied the supramolecular self-assembly of the amphiphilic Schiff base enantiomer, 2-hydroxy-1-naphthylmethylamino-N,N′-bis(octadecyl)-l/d-glutamic diamide (l/dGJ), at the air/water interfaces by using in situ second harmonic generation linear dichroism (SHG-LD) technique combined with UV–vis spectroscopy and atom force microscopy.lGJ anddGJ monolayers can form mirror-image structures of each other at different interfaces, which can be mediated by metal ions. When Mg2+and Zn2+ions were added into the subphases, thel/dGJ monolayers self-assembled into a nanofiber-like structure and showed significant chirality similar to that at the pure water interface. However, when Cu2+ions were added into the subphase, the chirality of thel/dGJ monolayer was destroyed because of the Cu2+coordination effect. The degree of the chirality excess (DCE) value decreased with the increment of the concentration of Cu2+in the subphase. Furthermore, when the surface pressure increased, the DCE value of Cu2+–l/dGJ complexes increased gradually, which indicated that the Cu2+–l/dGJ complex aggregated into a chiral supramolecular structure through lateral molecular packing.