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首页> 外文期刊>Chemistry: A European journal >Shape-Controlled Bridged Silsesquinoxanes: Hollow Tubes and Spheres
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Shape-Controlled Bridged Silsesquinoxanes: Hollow Tubes and Spheres

机译：形状控制桥倍半硅氧烷：空心管和球体

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摘要

A new approach for the morphological control of bridged silses-quioxanes has been achieved by the hydrolysis of silylted organic molecules bearing urea groups. The urea groups are responsible for the auto-association of the molecules through intermolecular hydrogen-bonding interactions. The self-assembly leads to supramolecular architectures that have the ability to direct the organization of hybrid silicas under controlled hydrolysis. The hydrolysis of the chiral diureido derivatives of trans-(1,20_diaminocyclohexane 1 under basic conditions has been examined. The solid-state NMR spectra (~(29)Si and ~(13)C) showed the hybrid nature of these materials with wholly preserved Si-C covalent bonds throughout the silicate network. Hybrid silicas with hollow tubular morphologies were obtained by the hydrolysis of the enantiomerically pure compounds, (R,R)-1 or (S,S)-1, whereas the corresponding racemic mixture, rac-1, led to a hybrid with ball-like structures. The tubular shape is likely to result from a combination of two phenomena: the auto-association abilities and a self-tem plating structuration of the hybrid materials by the organic crystalline precursor. Electronic microscopy techniques (SEM and TEM) gave evidence for the self-tem plating pathway. The formation of the ball-like structures occurs through a usual nucleation growth phenomenon owing to a higher solubility of the corresponding crystals in the same medium.
机译：通过水解带有脲基的甲硅烷基化的有机分子，已经获得了一种新的形态学控制桥连的硅酸酯-喹喔啉的方法。脲基通过分子间氢键相互作用负责分子的自缔合。自组装导致超分子结构具有在受控水解下指导杂化二氧化硅组织的能力。研究了反式-（1,20_二氨基环己烷1的手性二脲基衍生物在碱性条件下的水解，固态NMR光谱（〜（29）Si和〜（13）C）显示了这些材料与全部通过水解对映体纯的化合物（R，R）-1或（S，S）-1，得到相应的外消旋混合物，从而在整个硅酸盐网络中保持Si-C共价键。 rac-1导致了具有球形结构的杂化体，管状形状可能是由以下两种现象共同产生的：有机晶体前体对杂化材料的自缔合能力和自热镀结构。电子显微镜技术（SEM和TEM）为自热镀过程提供了证据，由于相同晶体在相同介质中的溶解度较高，因此通过通常的成核生长现象形成了球形结构。 。

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