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首页> 外文期刊>Chemistry: A European journal >Addition of carbenes to the sidewalls of single-walled carbon nanotubes
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Addition of carbenes to the sidewalls of single-walled carbon nanotubes

机译：在单壁碳纳米管的侧壁上添加卡宾

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The addition of carbenes CX2 (X=H, Cl) to single-walled carbon nanotubes (SWNTs) was investigated by density functional theory and finite, hydrogen-terminated nanotube clusters or periodic boundary conditions in conjunction with basis sets of up to polarized triple-quality. For armchair [(3,3) to (12,12)] and zigzag tubes [(3,0) to (18,0)], reaction of CH2 with the C-C bond oriented along the tube axis (A) is less exothermic than with those C-C bonds having circumferential (C) orientation. This preference decreases monotonically with increasing tube diameter for armchair, but not for zigzag tubes; here, tubes with small band gaps have a very low preference for circumferential addition. Axial addition results in cyclopropane products, while circumferential addition produces "open" structures for both armchair and zigzag tubes. ne barriers for addition of dichlorocarbene to a (5,5) SWNT, studied for a finite C90H20 cluster, are higher than that for addition to C-60, in spite of similar diameters of the carbon materials. Whereas addition of CCl2 to [60]fullerene proceeds in a concerted fashion, addition to a (5,5) armchair SWNT is predicted to occur stepwise and involve a diradicaloid intermediate according to B3LYP, PBE, and GVB-PP computations. Addition to C bonds of (5,5) armchair tubes resulting in the thermodynamically more stable insertion products is kinetically less favorable than that to A bonds yielding cyclopropane derivatives.
机译：通过密度泛函理论和有限的，氢封端的纳米管簇或周期边界条件，结合多达三极化的基团，研究了向单壁碳纳米管（SWNTs）中添加的卡宾CX2（X = H，Cl）。质量。对于扶手椅[（3,3）至（12,12）]和曲折管[（3,0）至（18,0）]，CH2与沿管轴（A）定向的CC键的反应放热较小与那些具有圆周（C）方向的CC键相比。对于扶手椅，这种偏好随着管子直径的增加而单调降低，但对于曲折管子则不然。在这里，带隙小的管子对圆周增加的选择非常低。轴向添加会生成环丙烷产品，而圆周添加会生成扶手椅和曲折管的“开放”结构。尽管碳材料的直径相似，但针对有限的C90H20团簇研究的将二氯卡宾添加到（5,5）SWNT中的障碍仍然高于添加C-60的障碍。尽管向[60]富勒烯中添加CCl2是一致的，但根据B3LYP，PBE和GVB-PP计算，预计向（5,5）扶手椅SWNT中的添加将逐步发生，并涉及双自由基类中间体。 （5，5）扶手椅管的C键加成导致热力学上更稳定的插入产物在动力学上不如产生环丙烷衍生物的A键加成。

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