Physik Department E20, TU München, James-Franck Strasse, D-85748 Garching, Germany.
Nat Chem. 2010 Feb;2(2):131-7. doi: 10.1038/nchem.503. Epub 2010 Jan 10.
The bulk properties of glasses and amorphous materials have been studied widely, but the determination of their structural details at the molecular level is hindered by the lack of long-range order. Recently, two-dimensional, supramolecular random networks were assembled on surfaces, and the identification of elementary structural motifs and defects has provided insights into the intriguing nature of disordered materials. So far, however, such networks have been obtained with homomolecular hydrogen-bonded systems of limited stability. Here we explore robust, disordered coordination networks that incorporate transition-metal centres. Cobalt atoms were co-deposited on metal surfaces with a ditopic linker that is nonlinear, prochiral (deconvoluted in three stereoisomers on two-dimensional confinement) and bears terminal carbonitrile groups. In situ scanning tunnelling microscopy revealed the formation of a set of coordination nodes of similar energy that drives a divergent assembly scenario. The expressed string formation and bifurcation motifs result in a random reticulation of the entire surface.
玻璃和非晶态材料的体性质已经得到了广泛的研究，但由于缺乏长程有序，其分子水平的结构细节的确定受到阻碍。最近，二维超分子随机网络在表面上组装，基本结构基元和缺陷的识别为无序材料的诱人性质提供了深入的了解。然而，到目前为止，这些网络都是通过有限稳定性的同分子氢键系统获得的。在这里，我们探索了包含过渡金属中心的稳定无序配位网络。将具有非线性、前手性（在二维约束下展开为三个立体异构体）和末端氰基基团的双齿配体与钴原子一起共沉积在金属表面上。原位扫描隧道显微镜揭示了一组相似能量的配位节点的形成，这推动了一个发散的组装方案。表达的字符串形成和分支模式导致整个表面的随机网状结构。
