C60-based composites in view of topochemical reactions

The current paper is aimed at the determination of barriers that govern the covalent coupling between partners of C-60-based composites consisting of two fullerenes C-60 (C-60 dimer), C-60 and single-walled carbon nanotubes ([C-60-(4,4)] carbon nanobuds), and C-60 and graphene ([C-60-(5,5)] and [C-60-(9,8)] graphene nanobuds). Barrier energies are determined as coupling ones E-cpl(tot) and are expanded over two contributions that present the total energy of deformation of the composites' components E-def(tot) and the energy of covalent coupling E-cov(tot). In view of these energetic parameters and in contrast to expectations, seemingly identical reactions that are responsible for the formation of intermolecular [2 + 2] cycloadditions in the studied composites result in different final products. This peculiarity is suggested to occur as a result of the topochemical character of the covalent coupling between the two members of the studied composites, once additionally complicated by the varied donor-acceptor contribution.