Synthesis of Fullerene Oxides Containing Both 6,6-Closed Epoxide and 5,6-Open Ether Moieties through Thermolysis of Fullerene Peroxides
摘要:
Thermolysis of the fullerene hexaadduct C-60(OO'Bu)(6) results in cleavage of two O-O bonds and elimination of two tert-butoxy groups to form two isomeric products with the formula C-60(O)(2)(OO'Bu)(4) in comparable yields. The two oxygen atoms exist as two epoxy groups in one isomer 3, and as an epoxy and an ether group in the other isomer 2. Addition of hydroxylamine to 2 opens both the epoxy and the ether moieties to give a cage-opened keto-ketoxime derivative.
Selective Preparation of Oxygen-Rich [60]Fullerene Derivatives by Stepwise Addition of tert-Butylperoxy Radical and Further Functionalization of the Fullerene Mixed Peroxides
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).
Punching a Carbon Atom of C
<sub>60</sub>
into its Own Cavity to Form an Endohedral Complex CO@C
<sub>59</sub>
O
<sub>6</sub>
under Mild Conditions
作者:Lijun Shi、Dazhi Yang、Francesca Colombo、Yuming Yu、Wen‐Xiong Zhang、Liangbing Gan
DOI:10.1002/chem.201303501
日期:2013.12.2
Punching the ball: By using multistep chemical reactions as a “can opener”, a half circle opening is cut around a pentagon in C60 to form an open‐cage fullerene with an 18‐membered orifice. During the process, one carbonatom in the fullerene skeleton is eliminated into the cavity as carbon monoxide to form a stable endohedralcomplexCO@C59O6 (see figure). The single‐crystal X‐ray structure shows
冲球:通过使用多步化学反应作为“开罐器”,在C 60中的五边形处切一个半圆的开口,形成带有18元孔的开笼式富勒烯。在此过程中,富勒烯骨架中的一个碳原子作为一氧化碳被排入空腔,形成了稳定的内六面体复合物CO @ C 59 O 6(见图)。X射线单晶结构表明,被捕的一氧化碳与笼子之间具有很强的偶极-偶极相互作用。
Lewis Acid Promoted Preparation of Isomerically Pure Fullerenols from Fullerene Peroxides C<sub>60</sub>(OO<i>t</i>-Bu)<sub>6</sub> and C<sub>60</sub>(O)(OO<i>t</i>-Bu)<sub>6</sub>
Fullerene mixed peroxides C-60(t-BuOO)(6) and C-60(O)(t-BuOO)(6) react with Lewis acids to form various fullerenols through the partial fragmentation of t-BuOO groups. Two monohydroxyl fullerenols with the general formula C-60(OH)(t-BuOO)(5) and six monohydroxyl fullerenols with the general formula C-60(O)(OH)(t-BuOO)(5) were prepared, which are essentially the same except the location of the OH group. An additional reaction of the monohydroxyl fullerenols gave bis- and trishydroxyl fullerenols. Single-crystal X-ray structures have been obtained for the two monohydroxyl fullerenols. Other compounds are characterized by chemical correlation and their spectroscopic data. Cuprous bromide could protect the most reactive t-BuOO group from being attacked by stronger Lewis acids. The proposed mechanism mainly involves Lewis acid induced heterolysis of the peroxo O-O bond.