Synthesis of Metal Fullerene Complexes by the Use of Fullerene Halides

K(C60R5) (1, R = Me, Ph) was generated by deprotonation of C60R5H (2) and allowed to react with N-fluoropyridinium triflate and N-chloro- and N-bromosuccinimide in benzene at 25 °C for 10 min to obtain halogenated fullerenes C60R5X (3a: R = Me, X = F; 3b: R = Me, X = Cl; 3c: R = Me, X = Br; 4a: R = Ph, X = F; 4b: R = Ph, X = Cl, 4c: R = Ph, X = Br) in good yield. The pentamethyl[60]fullerene halides are useful for the synthesis of a variety of η5-fullerene metal complexes. The reaction of the fullerene bromide 3c with the low-valent transition metal complexes Na[Re(CO)4], Fe(CO)5, Ru3(CO)12, and Na[Co(CO)4] gave Re(η5-C60Me5)(CO)3 (5), Fe(η5-C60Me5)Br(CO)2 (6), Ru(η5-C60Me5)Br(CO)2 (7), and Co(η5-C60Me5)(CO)2 (8), respectively. The structures of halide 3c and rhenium complex 5 were determined by X-ray crystallography. Electrochemical measurements on 3b and 3c were also performed. The iron complex 6 was converted into Fe(η5-C60Me5)Cp (9), Fe(η5-C60Me5)Me(CO)2 (10), Fe(η5-C60Me5)(CO)2(CCH) (11), and Fe(η5-C60Me5)(CO)2(CCPh) (12), by ligand exchange reactions.