An effective system to synthesize methanofullerenes: substrate–ionic liquid–ultrasonic irradiation

Sonochemical synthesis of novel C60 fullerene 1,4-oxathiane derivative through the intermediate fullerene radical anion

We have discovered a selective and efficient method for the synthesis of previously unknown 1,9-(1',4'-oxathiano)-1,9-dihydro-(C₆₀-I_h)[5,6]fullerene, a compound with the direct attachment of the sulfur atom to the fullerene core. The method is based on the reaction of C₆₀ with 1,2-hydroxythiols in the presence of inorganic bases in air under ultrasonication. The significance of ultrasound has been exemplified with the comparative conventional methods. The title compound has been identified with mass-(MALDI TOF/TOF), one- and two-dimensional NMR ¹H and ¹³C (COSY, HSQC, HMBS), IR, UV-Vis spectroscopic techniques. Using the direct EPR method, we have detected radical anion C₆₀^- (g = 2.0046 and ΔH = 2 G) as a key reaction intermediate of the sonochemical reaction. Based on the experimental results and quantum chemical calculations, we have proposed a mechanism for the conversion of C₆₀ and 2-mercaptoethanol to the C₆₀-1,4-oxathiane adduct.

A selective synthesis of the fullerene-fused dioxane adduct via heterogeneous reaction of C60 with α-diols and NaOH under ultrasonication

A novel ultrasonic-mediated approach to the synthesis of 1,9-dihydro[C₆₀-I_h][5,6](1,4-dioxano)fullerene based on the heterogeneous reaction of fullerene with α-diols and NaOH has been developed. It allows producing the fullerene derivatives with high yields and selectivity.

Functionalization of [60]fullerene through fullerene cation intermediates

Fullerene cations, namely [60]fullerene radical cation (C₆₀˙⁺) and organo[60]fullerenyl cation (RC₆₀⁺), open paths for the efficient derivatization of a great variety of fullerenes.

Structures and properties of Saturn-like complexes composed of oligothiophene macrocycle with methano[60]fullerene and [70]fullerene

π-Expanded oligothienylene macrocycle with a large inner cavity incorporates fullerenes such as methano[60]fullerene (C61H2) and [70]fullerene (C70) inside to form Saturn-like complexes. Although the oligothiophene macrocycle weakly interacts with fullerenes in solution, it forms stable Saturn-like fullerene complexes in the solid state. X-ray analysis of the Saturn-like complexes exhibited short contacts between the sulfur atoms of the oligothiophene macrocycle and fullerene carbons, which hinder the rotation of fullerenes. As a result, the non-covalent interaction between the oligothiophene macrocycle and fullerenes was employed in crystal structure determination of fullerenes. UV–vis–NIR spectra of the Saturn-like complexes showed weak donor–acceptor interaction between the oligothiophene macrocycle and fullerenes.

Ultrasound in Combination with Ionic Liquids: Studied Applications and Perspectives

Ionic liquids (ILs) as reaction media, and sonochemistry (US) as activation method, represent separately unconventional approaches to reaction chemistry that, in many cases, generate improvements in yield, rate and selectivity compared to traditional chemistry, or even induce a change in the mechanisms or expected products. Recently, these two technologies have been combined in a range of different applications, demonstrating very significant and occasionally surprising synergetic effects. In this book chapter, the advantages and limitations of the IL/US combination in different chemical applications are critically reviewed in order to understand how, and in which respects, it could become an essential tool of sustainable chemistry in the future. Fundamental aspects and practical considerations of the combination are discussed to better control and demonstrate the brought synergetic effects.

Synthesis and characterization of branched fullerene-terminated poly(ethylene glycol)s

Direct transesterification of phenyl-C₆₁-butyric acid methyl ester with polyethylene glycols produces a range of multiple fullerene species. The use of a monodispersed PEG core allows isolation of a pure fully substituted product.

Alkali-metal trichloroacetates for dichloromethylenation of fullerenes: nucleophilic addition-substitution route

The first experimental evidence that fullerenes react with alkali-metal trichloroacetates through a nucleophilic addition-substitution route, yielding dichloromethylenefullerenes as the final products, is reported. The intermediates, C60 (CCl3 )(-) and C70 (CCl3 )(-) anions, have been isolated in their protonated forms as ortho-C60 (CCl3 )H, as well as three ortho and one para isomer of C70 (CCl3 )H. The structures were unambiguously determined by means of (1) H, (13) C, and (1) H-(13) C HMBC NMR spectroscopy along with UV/Vis spectroscopy. The observed regiochemistry was analyzed with the aid of quantum chemical calculations. Conversion of the protonated compounds into the [6,6]-closed C60/70 (CCl2 ) cycloadducts under basic conditions can be effected only for the ortho isomers, whereas para-C70 (CCl3 )H decomposes back into pristine C70 .

Ionic liquids and ultrasound in combination: synergies and challenges

The advantages and the limits of the ionic liquid/ultrasound combination for different applications in chemistry are critically reviewed to understand how it could become an essential tool in future years.

Addition of dihydromethano group to fullerenes to improve the performance of bulk heterojunction organic solar cells

Adding a compact dihydromethano (CH2 ) group to a 58π-indene fullerene (C60 (Ind)) creates a 56π-electron dihydromethano/indene fullerene (C60 (CH2 )(Ind)) and raises the LUMO level with only a minimal increase in size. This class of compounds features reduced conjugation that raises the LUMO level, and a high electron mobility because of the small CH2 addend.

Electroreduction of N-methylphthalimide in room temperature ionic liquids under insonated and silent conditions

The selective electroreduction N-methylphthalimide to 3-hydroxy-2-methyl-isoindolin-1-one has been performed in ionic liquids using phenol as a proton donor under silent and ultrasonic conditions. A significant increase in the rate of electroreduction is shown using ultrasonic activation and in addition high current efficiencies were observed. Some decomposition of the ionic liquid was found to have occurred under exposure to ultrasound.

Facile and potent synthesis of carbon bridged fullerene dimers (HC60–CR2–C60H type)

Novel carbon bridged fullerene dimers (HC60-CR2-C60H type) are obtained in high yield by the reaction of aminomethylenebis(phosphonate) anions with [60]fullerene.