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Shortest Double‐Walled Carbon Nanotubes Composed of Cycloparaphenylenes
Author(s) -
Hashimoto Sigma,
Iwamoto Takahiro,
Kurachi Daisuke,
Kayahara Eiichi,
Yamago Shigeru
Publication year - 2017
Publication title -
chempluschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.801
H-Index - 61
ISSN - 2192-6506
DOI - 10.1002/cplu.201700097
Subject(s) - van der waals force , chemistry , ternary operation , carbon nanotube , exothermic reaction , titration , selectivity , mixing (physics) , configuration entropy , computational chemistry , molecule , thermodynamics , nanotechnology , materials science , organic chemistry , physics , computer science , programming language , catalysis , quantum mechanics
Abstract The host–guest chemistry of cycloparaphenylenes (CPPs) of different sizes is described. [ n ]CPPs ( n =5, 6, 7, 8, and 10) selectively interact with [ n +5]CPPs, forming complexes [ n +5]CPP⊃[ n ]CPP, which are the shortest double‐walled armchair carbon nanotubes. The size selectivity is dictated by the difference in diameters of the CPPs (that is, 0.34–0.35 nm), which maximizes attractive van der Waals interactions. Theoretical calculations suggest that the orbital energies of the CPPs become perturbed upon complex formation, and orbital mixing between the two CPPs is predicted for large CPP pairs. The association constants in 1,1,2,2‐[D 2 ]tetrachloroethane, estimated by 1 H NMR titration, are approximately 10 3 mol L −1 at 50 °C. Van't Hoff plot analysis reveals that complexation is driven mainly by entropy owing to desolvation of the CPPs. [13]CPP also forms a complex with [4]cyclo‐2,7‐pyrenylene ([4]CPY), which is a π‐extended [8]CPP. Theoretical calculations suggest that the formation of [13]CPP⊃[4]CPY is more exothermic than that of [13]CPP⊃[8]CPP. A ternary complex, [15]CPP⊃[10]CPP⊃C 60 , is also formed by mixing [15]CPP and [10]CPP⊃C 60 .