Formation process and electron-beam incident energy dependence of one-dimensional uneven peanut-shaped C₆₀ polymer studied using in situ high-resolution infrared spectroscopy and density-functional calculations

Abstract

A 3 kV electron-beam irradiation of a C60 film gives rise to formation of one-dimensional (1D) uneven peanut-shaped C60 polymer with a cross-linked structure close to that of the P08 C120 stable isomer obtained from the general Stone–Wales rearrangement. In this study, we examined the evolution of infrared (IR) spectra of C60 films with respect to electron beam (EB) irradiation time, using in situ high-resolution IR spectroscopy and first-principles density-functional calculations, and found semi-quantitatively that the 1D uneven peanut-shaped C60 polymer is formed via intermediate polymers with a cross-linkage close to that of P04 and P06 C120 isomers obtained from GWS rearrangement. In addition, we examined the dependence of EB-induced C60 polymerization on an incident energy of EB in the range 3–7 kV. IR spectra obtained for 5 and 7 kV EB irradiation of C60films showed the same product as for 3 kV EB irradiation. However, when 5 and 7 kV EBs continued to irradiate C60 films for a long time after the polymer formation, the 1D peanut-shaped polymer did not proceed to become 1D polymers with a more coalesced linkage than that of the P08 one but was destroyed to become amorphous carbons.

Synthesis, Properties, and Packing Structures of Corannulene‐Based π‐Systems Containing Heptagons

“…We proposed that compound 1 is formed from 2 through intermediate 3 (pentaphenanthreno[9,10-a;9',10'-d;9'',10''-g;9''',10'''-j;9'''',10''''-m]corannulene) by the formation of five hexagons, because the formation of an all-sp 2 heptagon by the Scholl reaction was thought to be difficult. [11,18] In fact, we independently confirmed that [6]helicene, ap artial structure of 3,d oes not convert into hexa [7]circulene under the same Scholl reactionc onditions (Scheme 1b). [13] Herein we report new,u nexpected findings discovered during our studyt oi dentify the reaction pathway generating warpedn anographene 1.A sp ossible intermediates for 1,w e have successfully synthesized and characterized two new corannulene-based p-systems containing heptagons (4 and 5), which are different from the originally proposed 3.M oreover, this serendipitous discoveryo fn ew PAHs containingn egative Gaussianc urvatures enabledu st oc ompare the photophysical properties and packing structures of as eries of corannulenebased p-systems containing heptagons.…”

“…[5] Examples of heptagon-containing exotic nanocarbonsa re shown in Figure 1a. [6][7][8] The bottom-up organic synthesis of molecular nanocarbons is useful for the construction of various types of nanocarbon materials. Heptagon-containingn onplanar polycyclic aromatic hydrocarbons (PAHs) [9][10][11][12][13] are much less commont han pentagon-containing nonplanar PAHs such as corannulene and its derivatives [4a, 14] (Figure 1b).…”

High-resolution transmission electron microscopic and electron diffraction studies of C60 single crystal films before and after electron-beam irradiation

“…100 keV and more), C 60 are elastically interacted with incident electrons and thus destroyed to form amorphous carbon [4]. On the other hand, in the case of EB with a low kinetic energy (less than 10 keV), C 60 are inelastically interacted with incident electrons and thus sometimes damaged and sometimes polymerized with each other [5,6]. Besides EB incident energy, the interactions with substrates should be considered for a few C 60 layers [7].…”

“…In our previous work [6], we examined the evolution of infrared (IR) spectra of C 60 films with respect to EB irradiation time, using in situ high-resolution IR spectroscopy and firstprinciples density-functional calculations, and found semihttp://dx.doi.org/10.1016/j.carbon.2014.09.049 0008-6223/Ó 2014 Elsevier Ltd. All rights reserved.…”

“…IR spectra obtained for 5 and 7 kV EB irradiation of C 60 films showed the same product as for 3 kV EB irradiation. However, when 5 and 7 kV EBs were continued to irradiate C 60 films for a long time after the 1D polymer formation, the 1D peanut-shaped polymer was proceeded not to be 1D polymers with a more coalesced linkage than that of the P08 C 120 but to be amorphous carbons [6].…”