Department of Chemistry, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Nat Mater. 2012 Oct;11(10):877-81. doi: 10.1038/nmat3408. Epub 2012 Sep 16.
Fundamental understanding of how crystals of organic molecules nucleate on a surface remains limited because of the difficulty of probing rare events at the molecular scale. Here we show that single-molecule templates on the surface of carbon nanohorns can nucleate the crystallization of two organic compounds from a supersaturated solution by mediating the formation of disordered and mobile molecular nanoclusters on the templates. Single-molecule real-time transmission electron microscopy indicates that each nanocluster consists of a maximum of approximately 15 molecules, that there are fewer nanoclusters than crystals in solution, and that in the absence of templates physisorption, but not crystal formation, occurs. Our findings suggest that template-induced heterogeneous nucleation mechanistically resembles two-step homogeneous nucleation.
由于难以在分子尺度上探测稀有事件，因此对有机分子晶体在表面上成核的基本理解仍然有限。在这里，我们表明，通过在模板上介导无定形和可移动的分子纳米团簇的形成，碳纳米角表面上的单分子模板可以从过饱和溶液中引发两种有机化合物的结晶。单分子实时透射电子显微镜表明，每个纳米团簇最多由大约 15 个分子组成，溶液中的纳米团簇比晶体少，并且在没有模板的情况下发生物理吸附，但不发生晶体形成。我们的发现表明，模板诱导的异质成核在机制上类似于两步均相成核。
