Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz (Germany); Graduate School Materials Science in Mainz, Staudinger Weg 9, 55128 Mainz (Germany).
Angew Chem Int Ed Engl. 2014 Feb 3;53(6):1525-8. doi: 10.1002/anie.201309104. Epub 2014 Jan 22.
The synthesis of structurally well-defined, monodisperse carbon nanotube (CNT) sidewall segments poses a challenge in materials science. The synthesis of polyphenylene cylinders that comprise typical benzene connectivity to resemble precursors of [9,9] and [15,15] CNTs is now reported, and the products were characterized by X-ray crystallography. To investigate the oxidative cyclodehydrogenation of ring-strained molecules as a final step towards a bottom-up synthesis of CNT sidewall segments, phenylene-extended cyclic p-hexaphenylbenzene trimers ([3]CHPB) were prepared, and NMR studies revealed a strain-induced 1,2-phenyl shift. It was further shown that an increase in ring size leads to selectively dehydrogenated macrocycles. Larger homologues are envisioned to give smooth condensation reactions toward graphenic sidewalls and should be used in the future as seeds for CNT formation.
结构明确、单分散的碳纳米管（CNT）侧壁片段的合成在材料科学中是一个挑战。现在已经报道了合成包含典型苯连接的聚苯撑圆柱体，这些圆柱体类似于[9,9]和[15,15]CNT 的前体，并且通过 X 射线晶体学对产物进行了表征。为了研究作为 CNT 侧壁片段的自下而上合成的最后一步的环应变分子的氧化环脱氢反应，合成了苯并扩环的环状 p-六苯基苯三聚体([3]CHPB)，并且 NMR 研究表明存在应变诱导的 1,2-苯位移。进一步表明，环尺寸的增加导致选择性脱氢的大环。更大的同系物预计会朝着石墨状侧壁进行平滑的缩合反应，并且将来应该用作 CNT 形成的种子。
