Ineffective OH Pinning of the Flipping Dynamics of a Spherical Guest within a Tight‐Fitting Tube

Abstract

A supramolecular/synthetic method has been devised to affix a sterically hindered substituent onto a fullerene guest encapsulated in a tubular host. A two‐wheeled complex of (C59N)‐(C59N) with a tubular host was oxidatively bisected to afford a C59N+ cation captured in the tube. The C59N+ cation in the tube was then trapped by ethanol or water, which led to an oxy substituent pinned on the guest. The guest motions within the tube were modulated by the pinned substituent, and up‐and‐down flipping motions were halted by an ethoxy substituent. A hydroxy substituent, however, was ineffective in halting the flipping motions, despite the tight‐fitting relationship between the tubular host and the spherical guest. Theoretical calculations of the dynamics revealed that the flipping motions were assisted by OH‐π hydrogen bonds between the guest and the carbon‐rich wall and that sliding motions of the OH group were also facilitated by deformations of the tube.

Target-oriented design of helical nanotube molecules for rolled incommensurate bilayers

“…The present system should also be interesting subjects to be investigated by state-of-the-art theoretical and physical investigations, because of the presence of rapid dynamic rotational motions (Supplementary Fig. 9 ) on top of due considerations of appropriate theoretical models 26 , 27 . The ΔG difference between these complexes was largely ascribed to the entropy (– T Δ S ).…”

Akaike's Information Criterion for Stoichiometry Inference of Supramolecular Complexes

“…[18] ([4]CC + C 120 ), [19] ([4]CA + C 120 ) and [20] The antemortem data are taken from preceding papers. [18,19,20] The postmortem analyses by AIC showed that 2 : 1 is the best model for these systems. See Table 1.…”

“…A series of 2 : 1 host-guest complexes was concluded via antemortem analyses with the Job plot in previous studies, [18,19] and a similar dumbbell-shaped guest of C 118 N 2 was likewise concluded to be a 2 : 1 complex with the [4]CC host by antemortem methods. [20] However, considering the unique structural divergency of the host and guest, [15] we noticed that the 1 : 1, 1 : 2 and 2 : 1 models should be examined for postmortem analyses of dumbbell-and-cylinder complexes. These systems should provide an interesting problem to choose the best model from three fitting equations.…”

“…[18,19,20] For the postmortem analyses in the present study, we noticed that ITC data were superior for global fitting analyses of complexation processes that potentially involved two-stage associations, [3,22,23] and fitting analyses were performed with the ITC data of three dumbbell-and-cylinder systems ([4]CC + C 120 , [4]CA + C 120 and [4]CC + C 118 N 2 ) that were originally investigated for the antemortem analyses. [18,19,20] After fitting with three models (1 : 1, 1 : 2 and 2 : 1), GOF was first evaluated with R 2 and χ 2 values (Table 1). We found that the R 2 values were intuitively superior to determine the GOF level, and most models for the three dumbbell-and-cylinder systems showed a sufficient level of GOF (> 0.9).…”

First Synthesis of the Inherently Chiral Trans‐4′ Bisadduct of C59N Azafullerene by Using Cyclo‐[2]‐dodecylmalonate as a Tether

“…radical by [10]CPP nanobelts has been also demonstrated [5] . Furthermore, the C 59 N + cation was isolated by supramolecular complexation with ( P )‐(12,8)‐[4]cyclo‐2,8‐chrysenylene, stabilized by SbCl 6− as the counter anion [6] . These azafullerene reactive intermediates, that is, C 59 N .…”