Multiple cation insertion into a polyaromatic hydrocarbon guided by data and computation

We report the synthesis, structural characterization and magnetic properties of K3coronene. Coronene is identified as a suitable polycyclic aromatic hydrocarbon (PAH) candidate for intercalation because of its electronic structure similarity with C60 and similarity in void space and crystal structure to other PAH previously demonstrated by structure determination to intercalate K+ ions. Convex hull calculations with energies from crystal structure prediction based on ion insertion into the identified void space suggest that the x = 3 composition in Kxcoronene is stable at 0 K. Exploration of reaction conditions and compositions revealed that the mild reducing agent KH allows formation of K3coronene. The structure of K3coronene solved from synchrotron powder X-ray diffraction features extensive reorientation and associated disorder of coronene molecules driven by K+ intercalation and occupation of sites both within and between the coronene stacks that are partially retained from the parent structure. This disruption of the host structure is greater when three cations are inserted per coronene than in known structures where the maximum ratio of potassium to PAH is 2. Superconductivity is not observed, contrary to previous reports on Kxcoronene. The expected localised moment response is suppressed, which may be associated with the combination of extensive disorder and close coronene3- - coronene3- contacts.