Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan.
J Am Chem Soc. 2012 Sep 26;134(38):15887-96. doi: 10.1021/ja305769v. Epub 2012 Sep 14.
Catalyst-free, chirality-controlled growth of chiral and zigzag single-walled carbon nanotubes (SWCNTs) from organic precursors is demonstrated using quantum chemical simulations. Growth of (4,3), (6,5), (6,1), (10,1) and (8,0) SWCNTs was induced by ethynyl radical (C(2)H) addition to organic precursors. These simulations show a strong dependence of the SWCNT growth rate on the chiral angle, θ. The SWCNT diameter however does not influence the SWCNT growth rate under these conditions. This agreement with a previously proposed screw-dislocation-like model of transition metal-catalyzed SWCNT growth rates [Ding, F.; Proc. Natl. Acad. Sci. 2009, 106, 2506] indicates that the SWCNT growth rate is an intrinsic property of the SWCNT edge itself. Conversely, we predict that the rate of SWCNT growth via Diels-Alder cycloaddition of C(2)H(2) is strongly influenced by the diameter of the SWCNT. We therefore predict the existence of a maximum growth rate for an optimum diameter/chirality combination at a given C(2)H/C(2)H(2) ratio. We also find that the ability of a SWCNT to avoid defect formation during growth is an intrinsic quality of the SWCNT edge.
使用量子化学模拟，从有机前体中无催化剂、手性控制地生长手性和锯齿形单壁碳纳米管 (SWCNT)。通过乙炔基自由基 (C(2)H) 加成到有机前体来诱导 (4,3)、(6,5)、(6,1)、(10,1) 和 (8,0) SWCNT 的生长。这些模拟表明 SWCNT 生长速率强烈依赖于手性角θ。然而，在这些条件下，SWCNT 直径不会影响 SWCNT 生长速率。这与先前提出的过渡金属催化的 SWCNT 生长速率的螺旋位错模型一致[Ding, F.; Proc. Natl. Acad. Sci. 2009, 106, 2506]，表明 SWCNT 生长速率是 SWCNT 边缘本身的固有特性。相反，我们预测 C(2)H(2) 的 Diels-Alder 环加成通过 C(2)H 生长 SWCNT 的速率强烈受到 SWCNT 直径的影响。因此，我们预测在给定的 C(2)H/C(2)H(2) 比下，对于给定的直径/手性组合存在最大生长速率。我们还发现，SWCNT 在生长过程中避免形成缺陷的能力是 SWCNT 边缘的固有质量。
