Alkylated [6,6]-open difluoromethanofullerenes C60(CF2)R2: Facile synthesis, electrochemical behavior and photovoltaic applications

CF2‐Functionalized Trifluoromethylated Fullerene C70(CF3)8(CF2): Structure, Electronic Properties, and Spontaneous Oxidation at the Bridgehead Carbon Atoms

“…The major isomer C 70 (CF 3 )(CF 2 ) is identified as the previously reported C s -C 70 (CF 3 ) 8 (CF 2 ) [2] (herein-after C s -8CF 2 ) with its eight CF 3 groups and the CF 2 moiety attached to the equatorial belt of the carbon cage as shown in Figure 1. The CF 2 bridge is inserted into a [5,6]-bond of C s -C 70 (CF 3 ) 8 and opens it to 2.099(4) Å. [2] Single crystal X-ray diffraction analysis of the minor isomer of C 70 (CF 3 ) 8 [CF 2 ] (hereinafter C 1 -8CF 2 ) reveals non-symmetric addition of the CF 2 group at a [6,6]-bond at one of the poles of the C 70 cage (Figure 3b).…”

“…In addition, open configuration of the CF 2 -bridge is characterized by enhanced reactivity of the bridgehead atoms that are capable to selectively attach sterically undemanding moieties. [6,7] Such modifications can be used for directed tuning of the physicochemical properties of the fullerene-based functional materials.…”

“…Recently, we reported the synthesis and X-ray characterization of the [5,6]-open C s -C 70 (CF 3 ) 8 (CF 2 ). [2] Here we present a more detailed investigation of that reaction and isolation of another isomer, [6,6]-open C 1 -C 70 (CF 3 ) 8 (CF 2 ), as well as the products of rapid ambient oxidation and hydration of the [5,6]open C 70 (CF 3 ) 8 (CF 2 ). The whole set of available products is presented in Figure 1.…”

“…

Thermally-induced CF 2 addition to C s -C 70 (CF 3 ) 8 upon reaction with sodium chlorodifluoroacetate is found to proceed via the nucleophilic cyclopropanation pathway, possibly with a certain involvement of the alternative singlet carbene pathway. Of the two major isomers of C 70 (CF 3 ) 8 (CF 2 ) characterized by X-ray diffraction and spectroscopically, the less abundant one has a [6,6]-open structure whereas the more abundant product is a [5,6]-open isomer with highly reactive bridgehead sites. Under ambient conditions, its rapid oxidation and hydration produce C 70 (CF 3 ) 8 [CF 2 ](OH) 2 and C 70 (CF 3 ) 8 [CF 2 ](OH)H, respectively, in which the π-system is split in two disjoint caps and the HOMO-LUMO gap is considerably increased, as evidenced by the blue-shifted fluorescence.

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Tightly Bound Double‐Caged [60]Fullerene Derivatives with Enhanced Solubility: Structural Features and Application in Solar Cells

“…[5][6][7][8][9][10] However,e xcessive functionalization is knownt os uppress the electron mobility.F or example, OSCs based on fullerenet ris-adducts demonstrate at wofold drop in electron mobility and disappointingly low current density relative to mono-a nd bis-adducts. [11] An alternative approacht o optimization of fullerene-based acceptor phases consists of the replacement of traditional C 60 andC 70 with higher fullerenes, [12] endohedralf ullerenes, [13] heterofullerenes, [14] or homofullerenes, [15,16] but the resulting benefit of increased opticald ensity is largely outweighed by their higher cost and limited availability.…”