A Versatile Route to Substituted 1,4-Diazine-Fused [60]Fullerenes

An alternative route to [5,6]fullereno-C(60)-I(h)()-[1,9-d]-2'-hydroxycyclohexanone (4a) is presented based on the [4 + 2] cycloaddition of 2,3-bis(trimethylsiloxy)butadiene (3) and [60]fullerene. The oxidation of the primary monoadduct with bromine yield the new [5,6]fullereno-C(60)-I(h)()-[1,9-d]-1',2'-cyclohexanedione (5) which can be isolated as the dimethoxime derivative (9). The diketone 5 constitutes a versatile reactant for the synthesis of different substituted [5,6]fullereno-C(60)-I(h)()-[1,9-b]-1',2',3',4'-tetrahydrophenazines (6a-d). The isolation, characterization, controlled-temperature (1)H NMR measurements as well as UV-vis and fluorescence studies of these new heterocycles are presented.