摘要:
tert-Butylperoxy radicals add to C-60 selectively to form multi-adducts C-60(O)(m)((OOBu)-Bu-t), (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 C-60((OOBu)-Bu-t)(6) 6; low concentration and long reaction time favor the epoxy-containing C-60(O)((OOBu)-Bu-t)(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 C-60 radical intermediates. m-CPBA reacts with the 1,4-bis-adduct to form C-60(O)((OOBu)-Bu-t)(2) and C-60(O)(3)((OOBu)-Bu-t)(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 S(N)1 and extended S(N)2' mechanism, from which four products are isolated with the general formula C-60(O)(a)(OH)(b)(OMe)(c)((OOBu)-Bu-t)(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 C-60(O)(O)(2)((OOBu)-Bu-t)(4). All the fullerene derivatives are characterized by spectroscopic data. A single-crystal structure has been obtained for an isomer Of C-60(O)(OH)(2)(OMe)(4)((OOBu)-Bu-t)(2).