Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States.
Materials Research Institute, Pennsylvania State University , University Park, Pennsylvania 16802, United States.
J Am Chem Soc. 2017 Nov 15;139(45):16343-16349. doi: 10.1021/jacs.7b09311. Epub 2017 Nov 1.
Synthesis of well-ordered reduced dimensional carbon solids with extended bonding remains a challenge. For example, few single-crystal organic monomers react under topochemical control to produce single-crystal extended solids. We report a mechanochemical synthesis in which slow compression at room temperature under uniaxial stress can convert polycrystalline or single-crystal benzene monomer into single-crystalline packings of carbon nanothreads, a one-dimensional sp carbon nanomaterial. The long-range order over hundreds of microns of these crystals allows them to readily exfoliate into fibers. The mechanochemical reaction produces macroscopic single crystals despite large dimensional changes caused by the formation of multiple strong, covalent C-C bonds to each monomer and a lack of reactant single-crystal order. Therefore, it appears not to follow a topochemical pathway, but rather one guided by uniaxial stress, to which the nanothreads consistently align. Slow-compression room-temperature synthesis may allow diverse molecular monomers to form single-crystalline packings of polymers, threads, and higher dimensional carbon networks.
具有扩展键合的有序低维碳固体的合成仍然是一个挑战。例如，很少有单晶有机单体在拓扑化学控制下反应生成单晶扩展固体。我们报告了一种机械化学合成方法，其中在室温下单向应力下的缓慢压缩可以将多晶或单晶苯单体转化为碳纳米线的单晶堆积，一维 sp 碳纳米材料。这些晶体数百微米的长程有序性使得它们很容易剥落成纤维。尽管由于每个单体形成多个强共价 C-C 键以及反应物单晶有序性的缺乏而导致尺寸发生较大变化，但机械化学反应仍会产生宏观单晶。因此，它似乎没有遵循拓扑化学途径，而是由单轴应力引导，纳米线始终与之对齐。低温常压合成可能允许多种分子单体形成聚合物、纤维和更高维碳网络的单晶堆积。
