Nanofibers of Fullerene C₆₀ through Interplay of Ball‐and‐Socket Supermolecules

Abstract

Mixing solutions of p-tBu-calix[5]arene and C(60) in toluene results in a 1:1 complex (C(60)) intersection(p-tBu-calix[5]arene), which precipitates as nanofibers. The principle structural unit is based on a host-guest ball-and-socket nanostructure of the two components, with an extended structure comprising zigzag/helical arrays of fullerenes (powder X-ray diffraction data coupled with molecular modeling). Under argon at temperatures above 309 degrees C, the fibers undergo selective volatilization of the calixarenes to afford C(60)-core nanostructures encapsulated in a graphitic material sheath, which exhibits a dramatic increase in surface area. Above 650 degrees C the material exhibits an ohmic conductance response, due to the encapsulation process.

Unravelling the structure of the C60 and p-But-calix[8]arene complex

“…1,2 Macrocycles with electron-rich aromatic rings such as calix[n]arenes, 3-8 cyclotriveratrylenes 9,10 and related molecules [11][12][13] can bind fullerenes, and have featured in gaining access to novel architectures. One of the earliest complexes of calixarenes with fullerenes is based on the readily available p-Bu tcalix [8]arene ( Figure 1a) which binds fullerene C 60 in toluene, forming a discrete 1:1 complex with some selectivity over other fullerenes. 14,15 Indeed this complexation is effective in separating and purifying fullerene C 60 from carbon soot.…”

“…Within the C 60 /p-Bu t -calix [8]arene complex the phenolic hydroxyl groups of the calixarene are expected to retain at least part of the cyclic hydrogen bonded array on binding fullerene C 60 , with some reorganisation of the aromatic groups in providing hydrophobic pockets with complementarity of curvature with that of the surface of C 60 , in optimizing π-π interactions. 5,16 The complex is only sparingly soluble in toluene, but spontaneously decomposes in the presence of chlorinated solvents.…”

“…16 With advances in transmission electron microscopy (TEM) and associated electron diffraction, scanning electron microscopy (SEM), Raman spectroscopy and atomic force microscopy (AFM), advanced molecular simulation coupled with the availability of greater computer power, we have reinvestigated this complex in an attempt to gain further insight into the nature of interplay of the components, with the results from the integrated approach consistent with an unprecedented layered tetragonal array of fullerenes. [8]arene. (b) The colour change in a toluene solution of C60 induced by the addition of p-Bu tcalix [8]arene.…”

“…[8]arene. (b) The colour change in a toluene solution of C60 induced by the addition of p-Bu tcalix [8]arene. (1: before the addition of p-Bu t -calix [8]arene; 2: mixing for 5 min; 3: mixing for 30 min; 4: mixing for 1 day) (c-f).…”

“…(b) The colour change in a toluene solution of C60 induced by the addition of p-Bu tcalix [8]arene. (1: before the addition of p-Bu t -calix [8]arene; 2: mixing for 5 min; 3: mixing for 30 min; 4: mixing for 1 day) (c-f). SEM images of the C 60 /p-Bu t -calix [8]arene complex, showing square crystals ~5-30 µm in size.…”