碳纳米管内P-Ylide反应的理论研究

Theoretical study of the P-Ylide reaction in the carbon nanotube

碳纳米管空腔不仅可以改变填充到其内部分子的性质,而且对其内部的SN2取代反应有促进或抑制作用,因而被视为一种新型的'固体溶剂'.本文通过密度泛函理论研究了CH2O和PH3CH2在气相、苯溶液和碳纳米管空腔内的[2+2]加成反应.结果表明,与气相相比,碳纳米管空腔对于[2+2]环加成反应影响不大,这是因为所研究的[2+2]环加成反应中,反应物并不是轴对称的,不同于SN2取代反应的一维线性排列,所以具有较大轴向极化率的碳纳米管对[2+2]环加成反应影响较小.

Recent studies have shown that the inner phase of carbon nanotubes （CNTs） can not only change the properties of molecules inside the tube, but also enhance or restrain the SN2 reactions. Thus, the CNTs can be considered a form of solid solvent. In this paper, we study the [2＋2] cycloaddition reaction between CH2O and PH3CH2 in the gas phase, benzene solution and inner phase of CNT using the density functional theory （DFT）. The results indicate that the inner phase of CNT has little effect on the [2＋2] cycloaddition reaction. This can be explained as that while taking the linear arrangement for SN2 reaction, the reactants do not possess the axial symmetry for the studied [2＋2] cycloaddition reaction. Therefore, although the CNT has large axial polarizability, it can exert little influence on the [2＋2] cycloaddition reaction. Our studies will be helpful for further understanding of the inner phase chemistry of CNTs.