π-Extended Fullerenes with a Reactant Inside

Abstract

Fullerene–graphene hybrids potentially exhibit unprecedented properties owing to interactive communication between the two units through a linkage. However, most of their discrete molecular structures have been still undisclosed thus far. With the recent rise in the awareness of facile access to molecular nanocarbon hybrids, we showcase novel π-extended fullerenes with a fused pyrazine or imidazole. Owing to the effective planar–curved π-conjugation, their absorption coefficients significantly increased in the visible region. Curiously enough, during the formation of π-extended fullerenes, an in situ generated NH3 molecule was spontaneously encapsulated inside the fullerene cavity. The NH3 molecule then underwent a timed orifice-expansion triggered by its sustained release. This is the first demonstration that fullerene captures a reactant inside, suggesting their potential usage for a sustained dosing and/or material delivery toward postfunctionalization of fullerene–graphene hybrids.

Construction of a 21‐Membered‐Ring Orifice on [60]Fullerene

“…For the practical usage of open- [60]fullerenes in an effective molecular storage/delivery of reactants or short-lived chemicals, a huge orifice is thus highly demanded. [5] The significant contribution on the construction of a 20membered-ring orifice (A, Figure 1) was made by Iwamatsu and co-workers in 2004. [6] They used an open-[60]fullerene with a ring-atom count of 12 as a key precursor which was then found to generate a huge orifice by a reaction with aromatic diamines.…”

[60]Fullerene-Fused Cyclopentanes: Mechanosynthesis and Photovoltaic Application

“…Over the past 3 decades, functionalization of [60]­fullerene (C 60 ) has attracted extensive attention as a result of remarkable applications in materials science, biological sciences, and nanotechnology. , Various types of reactions have been developed to synthesize fullerene derivatives . Fullerene-fused carbocycles have been widely studied to explore their specific potential applications, especially their enormous potential in organic photovoltaics and perovskite solar cells .…”

π-Extended Open-[70]Fullerenes with a Fused Azaacene

“…The related π-extended [60]­fullerenes were, afterward, prepared through a conventional dehydration reaction with aromatic diamines at the iminocyclopentene dione or bis­(imino)­cyclopentenone moiety on open-[60]­fullerenes. Recently, we developed a synthetic method for producing π-extended [60]­fullerenes having a fused imidazole by a reaction using 1,2-diaminoarene with a weak aromaticity, in which characteristic absorption behavior is induced by the effective π-conjugation with the introduced planar π-system . At present, however, the synthesis of imidazole-fused open-[60]­fullerenes is less known.…”