Open-Cage Fullerene as a Macrocyclic Ligand for Na, Pt, and Rh Metal Complexes

An open-cage [60]fullerene derivative was prepared throughMalapradeoxidation of a vicinal triol moiety as the key step. Above the 17-memberedorifice, there is one carboxyl group. Three ketone carbonyl groupsand one lactone carbonyl group are located on the rim of the orifice.The carboxylic and carbonyl oxygen atoms around the orifice act asstrong polydentate ligands for a sodium ion. These oxygen atoms alsoreact with [Rh(CO)(2)Cl](2) to form various isomericrhodium complexes with comparable stability. The fullerene C UCbond on the rim of the orifice forms a stable platinum complex whentreated with Pt(PPh3)(4). Single crystal X-raydiffraction data reveal that one of the carboxylic oxygen atoms abovethe orifice forms a H-bond with the water molecule trapped in thecage.