基于葫芦脲[8]包结增强供体-受体作用构筑“刚-柔”型超分子共聚物

设计合成了一种缺电性的刚性棒状超分子单体,在葫芦脲(CB[8])存在下,它与富电性的柔性单体受CB[8]包结增强的供体-受体作用驱动在水中共组装形成"刚-柔"(rod-coil)型超分子共聚物.运用核磁共振滴定实验、紫外-可见光谱、二维扩散排序核磁共振谱(DOSY)、动态光散射(DLS)以及透射电子显微镜(TEM)等对超分子聚合物的形成及其结构进行了证实和表征,并发现该超分子共聚物在低浓度下采取伸展的线形构象,当浓度增加到一定程度后其线形骨架发生卷曲,转变为颗粒状团聚结构.     

Dielectric layer-dependent surface plasmon effect of metallic nanoparticles on silicon substrate

The electromagnetic interaction between Ag nanoparticles on the top of the Si substrate and the incident light has been studied by numerical simulations. It is found that the presence of dielectric layers with different thicknesses leads to the varied resonance wavelength and scattering cross section and consequently the shifted photocurrent response for all wavelengths. These different behaviours are determined by whether the dielectric layer is beyond the domain where the elcetric field of metallic plasmons takes effect, combined with the effect of geometrical optics. It is revealed that for particles of a certain size, an appropriate dielectric thickness is desirable to achieve the best absorption. For a certain thickness of spacer, an appropriate granular size is also desirable. These observations have substantial applications for the optimization of surface plasmon enhanced silicon solar cells.     

两个手性胶囊分子的氢键介质的动态共价键合成

从手性环己-1,2-二胺衍生的手性双头基前体出发合成了两个手性的双层结构的胶囊化合物。设计前体带有氨基和醛基,它们被连接到两个分子内氢键诱导的折叠体片段上。分子内氢键通过促进三个亚胺键的形成促进两个大环板块的选择性形成。