d⁸ rhodium and iridium complexes of corannulene

Abstract

[(COE)2M]+ fragments (M = Rh, Ir; COE = cyclooctene) react with corannulene to give η6-bound complexes [(COE)2Rh(η6-C20H10)]PF6 and [(COE)2Ir(η6-C20H10)]PF6. Both compounds were characterized by X-ray diffraction studies, and binding in the solid state is compared with that of their aromatic analogues [(COE)2M(η6-arene)]PF6 (aryl = benzene and phenanthrene). Solution NMR studies show that the [(COE)2Rh]+ fragment walks over the curved aromatic surface of corannulene, whereas the Ir analogue is not fluxional. Experimental as well as computational studies suggest that inter-ring movement of the Rh complex follows a hub migration mechanism. Initial reactivity studies indicate that the [(COE)2M]+ fragments can undergo chemical transformations, such as transfer dehydrogenation and substitution reactions, while still bound to corannulene. Copyright © 2006 American Chemical Society.