Selective Preparation of Oxygen-Rich [60]Fullerene Derivatives by Stepwise Addition of tert-Butylperoxy Radical and Further Functionalization of the Fullerene Mixed Peroxides

• Published in: Journal of organic chemistry 2004-04, Vol.69 (7), p.2442-2453
• Main Authors: Huang, Shaohua, Xiao, Zuo, Wang, Fudong, Gan, Liangbing, Zhang, Xiang, Hu, Xiangqing, Zhang, Shiwei, Lu, Mujian, Pan, Qinqi, Xu, Li
• Format: Article
• Language: English
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; Materials science; Physics; Specific materials
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo049974q

tert-Butylperoxy radicals add to C60 selectively to form multi-adducts C60(O) m (OOtBu) n (m = 0, n = 2, 4, 6; m = 1, n = 0, 2, 4, 6) in moderate yields under various conditions. Visible light irradiation favors epoxide formation. High concentration of tert-butylperoxy radicals mainly produces the hexa-homoadduct C60(OOtBu)6 6; low concentration and long reaction time favor the epoxy-containing C60(O)(OOtBu)4 7. The reaction can be stopped at the bis-adducts with limited TBHP. A stepwise addition mechanism is discussed involving mono-, allyl-, and cyclopentadienyl C60 radical intermediates. m-CPBA reacts with the 1,4-bis-adduct to form C60(O)(OOtBu)2 and C60(O)3(OOtBu)2. The C−O bond of the epoxy ring in 7 can be cleaved with HNO3 and CF3COOH. Nucleophilic addition of NaOMe to 7 follows the SN1 and extended SN2‘ mechanism, from which four products are isolated with the general formula C60(O) a (OH) b (OMe) c (OOtBu) d . Visible light irradiation of the hexa-adduct 6 results in partial cleavage of both the C−O and O−O bonds of peroxide moieties and formation of the cage-opened compound C60(O)(O)2(OOtBu)4. All the fullerene derivatives are characterized by spectroscopic data. A single-crystal structure has been obtained for an isomer of C60(O)(OH)2(OMe)4(OOtBu)2.