Adduct removal from methanofullerenes via reductive electrochemistry

Beulen, Marcel W. J.; Echegoyen, Luís; Rivera, José A.; Herranz, M. Ángeles; Martín‐Domenech, Ángel; Martı́n, Nazario

doi:10.1039/b001428l

Cited by 26 publications

(18 citation statements)

References 14 publications

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“…These experimental results are fully in agreement with those previously obtained in our group using other solvents 3. From the analysis of these results, it is possible to have an idea of the difference between the rate constants for the homogenous reactions occurring after peaks II and III.…”

Section: Resultssupporting

confidence: 90%

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Mechanisms of Electrochemically‐Induced Retro‐Cyclopropanation Reactions of Fullerene Derivatives Using Digital Simulations

Carano

Echegoyen

2003

Chemistry A European J

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Three C(60) derivatives, 1, 2 and 3, have been studied by cyclic voltammetry (CV) under high vacuum in anhydrous tetrahydrofuran (THF). The CV behavior was essentially similar to that already observed for other cyclopropanated fullerene derivatives. After the second reduction processes all compounds undergo a chemical reaction that generates another electroactive species. This "new" chemical species is likely to be the compound with the cyclopropane ring open. Differences in CV behavior were observed for the different addends. Electrochemical data obtained at different scan rates for a given potential window, were fit with the BAS digital simulation program, DigiSim. The purpose of this study was to probe the proposed mechanisms and to obtain reliable estimations of the kinetic constants for the homogeneous chemical reactions taking place during the CV experiments. Calculations at the PM3 level lend additional support to the conclusions derived from digital simulations. The proposed mechanism is similar for all the compounds and involves two main chemical reactions in a reversible square scheme.

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Section: Resultssupporting

confidence: 90%

“…Some spiromethanofullerenes were also found to be unstable after multiple reduction processes,3 and CPE experiments have led to the isolation of C 60 in high yields. Thus the electrochemical removal of methano‐adducts is not limited to the malonate derivatives of fullerenes (Bingel adducts).…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of Electrochemically‐Induced Retro‐Cyclopropanation Reactions of Fullerene Derivatives Using Digital Simulations

Carano

Echegoyen

2003

Chemistry A European J

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“…The indandione derivative 28 yielded 58% and the anthraquinone compound 30 65% of recovered C 60 after 3.7 and 2.3e Ϫ CPE, respectively, followed by reoxidation. [39,40] These observations clearly showed that the retro-Bingel reaction was more general than originally believed and was redefined as a retro-cyclopropanation reaction.…”

Section: The Scope Of the Retro-cyclopropanation Reactionmentioning

confidence: 91%

Electrochemically Induced Retro‐Cyclopropanation Reactions

2004

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The efficient removal of methano addends from fullerenes using reductive electrochemistry is a versatile and useful reaction, which was initially called the retro-Bingel reaction since it was observed for the first time on bis(alkoxycarbonyl)methano adducts, commonly known as Bingel adducts. Since its initial discovery, this reaction has been successfully employed in the separation of enantiomers and constitutional isomers of fullerenes, which in some cases were otherwise not accessible. Even more interesting than the retro-Bingel reaction was the electrochemically induced isomerization that bis-methano adducts of C 60 exhibit, and which was referred to as the ''shuffle''. The combination of both reactions gave interesting results during the electrolysis of tetrakis-, pentakis-, and hexakis-Bingel adducts of C 60 . The selective removal of Bingeltype addends, while leaving other addends undisturbed, was also investigated. More recently, it was observed that in addition to bis(alkoxycarbonyl)methano adducts, electrochemical Spain in 1972. She received her B.Sc., M.Sc., and PhD degrees in 1995 MICROREVIEWS: This feature introduces the readers to the authors' research through a concise overview of the selected topic. Reference to important work from others in the field is included. reduction of other methano adducts, such as spiromethanofullerenes, could also result in removal of the methano addends, thus the reaction was more generally denoted as retro-cyclopropanation. In some of the spiromethanofullerenes investigated, and depending on the solvent used, an electrochemically induced intermolecular addend transfer was observed, which provided a regioisomeric distribution that differed significantly from that obtained by a synthetic route. We have recently shown that singly bonded dimers are formed as intermediates during retro-cyclopropanation reactions. In this microreview, we describe the general observations that led to the initiation of these exciting electrochemical investigations, review the differences between the chemical and electrochemical methodologies in retro-cyclopropanation reactions and explore the mechanisms involved during addend removal.

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“…29a, 30 The third redox wave is new compared with the spectrum of C 60 , which is associated with the change of electronic structure in butyl‐OF‐C 60 upon conjugation 27b. 29, 31 It has been reported that a bond in the cyclopropane ring of methanofullerene derivatives may break upon the second reduction, which has been referred to as the retro‐Bingel reaction 29b. 31, 32 The fourth and fifth redox waves are also shifted to more‐negative values compared to those of C 60 .…”

Section: Resultsmentioning

confidence: 99%

“…29, 31 It has been reported that a bond in the cyclopropane ring of methanofullerene derivatives may break upon the second reduction, which has been referred to as the retro‐Bingel reaction 29b. 31, 32 The fourth and fifth redox waves are also shifted to more‐negative values compared to those of C 60 . All of the five reduction peaks are due to the fullerene core, so the energy‐level profiles of C 60 and OF remain essentially unchanged.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, Crystal Structures, and Optical/Electronic Properties of Sphere–Rod Shape Amphiphiles Based on a [60]FullereneOligofluorene Conjugate

Teng

Cao

et al. 2013

Chemistry An Asian Journal

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A series of sphere-rod shape amphiphiles, in which a [60]fullerene (C60) sphere was connected to the center of an oligofluorene (OF) rod through a rigid linkage (OF-C60), were designed and synthesized. Alkyl chains of various lengths were attached onto the OFs on both sides of the C60 spheres. These compounds, denoted as alkyl-OF-C60, were fully characterized by (1)H NMR, (13)C NMR, and FTIR spectroscopy and by MALDI-TOF mass spectrometry. The morphologies and structures of their crystals were elucidated by wide-angle X-ray diffraction (WAXD) and by electron diffraction in transmission electron microscopy (TEM). Butyl-OF-C60 forms a monoclinic unit cell (a=1.86, b=3.96, c=2.24 nm; α=γ=90°, β=68°; space group P2), octyl-OF-C60 also forms a monoclinic unit cell (a=2.21, b=4.06, c=1.81 nm; α=γ=90°, β=75.5°; space group C2m), and dodecanyl-OF-C60 forms a triclinic structure (a=1.82, b=4.35, c=2.26 nm; α=93.1°, β=94.5°, γ=92.7°; space group P1). The inequivalent spheres and rods were found to pack into an alternating layered structure of C60 and OF in the crystals, thus resembling a "double-cable" structure. UV/Vis absorption spectroscopy revealed an electron perturbation between the two individual chromophores (C60 and OF) in their ground states. Fluorescence spectroscopy exhibited complete fluorescence quenching of their solutions in toluene, thus suggesting an effective energy transfer from OF to C60. Cyclic voltammetry indicated that the energy-level profiles of C60 and OF remained essentially unchanged. This work has broad implications in terms of understanding the self-assembly and molecular packing of conjugated materials in crystals and has potential applications in organic field-effect transistors and bulk heterojunction solar cells.

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Adduct removal from methanofullerenes via reductive electrochemistry

Abstract: Electrochemical reduction of different spiromethanofullerenes leads to adduct removal, opening the way to new protecting-deprotecting groups in fullerene chemistry.

Cited by 26 publications

References 14 publications

Mechanisms of Electrochemically‐Induced Retro‐Cyclopropanation Reactions of Fullerene Derivatives Using Digital Simulations

Mechanisms of Electrochemically‐Induced Retro‐Cyclopropanation Reactions of Fullerene Derivatives Using Digital Simulations

Electrochemically Induced Retro‐Cyclopropanation Reactions

Synthesis, Crystal Structures, and Optical/Electronic Properties of Sphere–Rod Shape Amphiphiles Based on a [60]FullereneOligofluorene Conjugate

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