Molecular assembly with a figure-of-eight nanohoop as a strategy for the collection and stabilization of cyclo[18]carbon†
Abstract
The recently synthesized novel figure-of-eight nanohoop with two strained oligoparaphenylenes (OPPs) was theoretically designed to collect and stabilize new allotropic carbon cyclo[18]carbon (C18) through molecular assembly. The size adaptability and shape complementarity of C18 to OPP make it possible for them to combine into extraordinary ring-in-ring supramolecules. Thermodynamic analysis of 2C18@OPP showed that the host–guest complex should spontaneously form below 404 K. Molecular dynamics (MD) simulations demonstrated that the assembly of C18 and OPP into host–guest complexes of up to 1 : 2 can occur at ambient temperature. Various real-space function analyses revealed that the nature of the non-covalent interaction between C18 and OPP is the van der Waals (vdW) attraction characterized by π–π stacking. Photoexcitation makes the host–guest complexes less stable in their S1 state by causing the central linker to flatten.