Theoretical Determination of Interaction and Cohesive Energies of Weakly Bound Cycloparaphenylene Molecules

We investigate here, by applying dispersion-corrected theoretical methods, the energy stability of dimers formed by [n]­cycloparaphenylene molecules (n = 5, 6, 7, 8, 10, and 12 being the number of benzene rings strained to form the nanoring) when they self-assemble in crystalline samples. Their cyclic topology confers to these samples a rich variety of dimer orientations, i.e. tubular or herringbone-like, according to the nanoring size, with the final form of their crystal packing depending subtly on the energy difference and the number of symmetry-related repetitions between these two microstructures. We finally calculate the cohesive energies for the illustrative cases n = 6 and n = 12, through the interaction energies of the unique and symmetry-related supramolecular motifs found, to finally understand the driving forces between the emergence of nanochannel-like structures.