Broken-hearted carbon bowl via electron shuttle reaction: energetics and electron coupling

Unprecedented one-step C=C bond cleavage leading to opening of the buckybowl (pi-bowl), that could provide access to carbon-rich structures with previously inaccessible topologies, is reported; highlighting the possibility to implement drastically different synthetic routes to pi-bowls in contrast to conventional ones applied for polycyclic aromatic hydrocarbons. Through theoretical modeling, we evaluated the mechanistic pathways feasible for pi-bowl planarization and factors that could affect such a transformation including strain and released energies. Through employment of Marcus theory, optical spectroscopy, and crystallographic analysis, we estimated the possibility of charge transfer and electron coupling between open corannulene and a strong electron acceptor such as 7,7,8,8-tetracyanoquinodimethane. Alternative to a one-pot solid-state corannulene unzipping route, we reported a nine-step solution-based approach for preparation of novel planar open corannulene-based derivatives in which electronic structures and photophysical profiles were estimated through the energies and isosurfaces of the frontier natural transition orbitals.

Automated summary

The research reveals an unprecedented one-step C=C bond cleavage opening the buckybowl, offering access to previously inaccessible carbon-rich structures and demonstrating the potential for drastically different synthetic routes compared to traditional methods for polycyclic aromatic hydrocarbons. Through theoretical modeling and experimental analysis, the study evaluates mechanistic pathways for planarizing the buckybowl, factors influencing this transformation, and the possibility of charge transfer between open buckybowl and electron acceptors. Additionally, a nine-step solution-based approach is presented for preparing novel derivatives with estimated electronic structures and photophysical properties.