Photoinduced Reaction of [60]Fullerene with Tertiary Amines: Synthesis of [60]Fulleropyrrolidines

[60]Fulleropyrrolidine derivatives were prepared from the photoinduced reaction of [60]fullerene and tertiary amines.     

Synthesis of disubstituted [60]fullerene-fused lactones: ferric perchlorate-promoted reaction of [60]fullerene with malonate esters

The ferric perchlorate-mediated reaction of [60]fullerene with substituted malonate esters in the presence of acetic anhydride afforded the rare disubstituted [60]fullerene-fused lactones. A possible reaction mechanism is proposed.     

1,2,4,5-Tetra([5]trovacenyl)benzene: an organometallic tetraradical displaying pronounced electro- and magnetocommunication

The organometallic tetraradical 1,2,4,5-[(eta)7-C7H7)V(all eta]5-C5H4)]4C6H2 has been prepared and structurally characterized. The isotropic EPR spectrum displays 29 a(51V) hyperfine lines, the intensity distribution slightly deviating from binomial. Exchange coupling therefore approaches the strong exchange limit, J(ortho) not equal to J(meta) not equal to J(para) greater or approximately 50 a(51V) with a(51V)= 0.0067 cm(-1). According to magnetic susceptometry, the interaction is antiferromagnetic. While redox splittings deltaE(1/2) are resolved for the four reduction steps this is not the case for oxidation.     

On the thermal stability of [60]fullerene cycloadducts: retro-cycloaddition reaction of 2-pyrazolino[4,5:1,2][60]fullerenes

2-Pyrazolino[4,5:1,2][60]fullerenes undergo a thermally induced retro-cycloaddition process whose efficiency is influenced by the nature of the C-substituent. C-Aryl-N-Aryl-2-pyrazolino[60]fullerenes (2a-d) poorly undergo a thermal retro-cycloaddition reaction even in the presence of a strong dipolarophile or a metal Lewis acid which, in contrast to other fullerene derivatives, shows their remarkable thermal stability. C-Alkyl-N-Aryl-2-pyrazolino[60]fullerenes (2e-f) show a different behavior, being more vulnerable to the presence of copper triflate and leading to the retro-cycloaddition product (pristine C60) in good yield.     

[60]Fullerene-flavonoid dyads

A range of fullerene-chalcone, fullerene-flavone, and fullerene-chromone dyads, including a bis(flavonyl)-fullerene dyad, were prepared by 1,3-dipolar cycloaddition reactions of azomethine ylides to C₆₀ and by cyclopropanation of C₆₀ with flavonyl malonates. Synthetic and natural flavonoid derivatives were used as starting materials.     

富勒烯[60]的光化学反应研究

从光物理出发,综述了近几年富勒烯「６０」的光化学反应研究进展。Ｃ６０能发生诸多的光化学反应：（１）光氧化;（２）光氢化还原;（３）「２＋２」光环化加成;（４）与叔胺的光加成;（５）与氨基酸的光加成;（６）与金属有机化合物的光加成。     

Synthesis of [60]fullerene acetals and ketals: reaction of [60]fullerene with aldehydes/ketones and alkoxides

The reaction of C(60) with propionaldehyde (butyraldehyde or phenylacetaldehyde) and MeONa-MeOH or EtONa-EtOH in anhydrous chlorobenzene in the presence of air at room temperature unexpectedly gave rare fullerene acetals 2aa-cb, while the reaction of C(60) with acetone (acetophenone, cyclohexanone, or cyclopentanone) and MeONa-MeOH or EtONa-EtOH under the same conditions afforded the uncommon fullerene ketals 4aa-db. A possible reaction mechanism for the formation of the fullerene acetals and ketals is proposed based on further experimental results.     

Nucleophilic substitution of alkylchlorodihydro[60]fullerenes: thermodynamic stabilities of alkylated C60 cation intermediates

Thermodynamic stabilities of alkylated C60 cations (RC60+) were determined based on the activation free energies of SN1 solvolysis of the title compounds, indicating that these cations have stabilities comparable to that of the tert-butyl cation.     

Inter-digitation approach to encapsulation of C60: [C60 [symbol: see text] (p-phenylcalix[5]arene)2

p-Phenylcalix[5]arene shows a strong and selective binding of C60 in toluene resulting in crystallisation of a hemispherically inter-digitated 2:1 complex; the receptor itself crystallizes from toluene with self assembly through phenyl group inclusion.     

Preparation and structures of [6,6]-open difluoromethylene[60]fullerenes: C60(CF2) and C60(CF2)2

Difluoromethylenation of C60 with thermally decomposed CF2ClCO2Na provides novel C60(CF2) and C60(CF2)2 compounds with unique [6,6]-open structures. A theoretical survey of CF2 derivatives of C60 demonstrates that carbon cage opening can be controlled via charging of the molecule and that the thermodynamically preferable structures combine the trend to form open isomers with the compactness of the addition motifs, which results in the formation of windows in the fullerene cage.     

Highly regioselective transformation of out/out-equatorial bis(formylmethano)[60]fullerenes: construction of dissymmetric [60]fullerene-centered triads

Three kinds of out/out-equatorial bis(formylmethano)[60]fullerenes (1b-d) were obtained by the tether-directed bifunctionalization of [60]fullerene with bis(alpha-formylsulfonium ylide)s. The condensation of aromatic amines with 1b-d proceeded with an unexpectedly high regioselectivity to give one of two possible regioisomers of mono-imines as the main products (the ratio of the regioisomers, up to 97:3). By the transformation of the remaining formyl group in the mono-imines thus obtained, the corresponding dissymmetric bis-imines were efficiently synthesized.     

Azadibenzophospholes: functional building blocks with pronounced electron-acceptor character

A series of azadibenzophospholes with varying location of the nitrogen center has been synthesized and comprehensively characterized. In the context of the study, suitably brominated phenylpyridine precursors were accessed via Suzuki-Miyaura cross-coupling for the first time. Despite being nonfluorescent, X-ray crystallographic studies of two azadibenzophosphole oxides revealed planar conjugated scaffolds with high degree of π-conjugation. The P-oxidized species were found to show desirable reversible reduction features that support promising electron-accepting properties of the materials. The presence of the nitrogen as well as phosphorus centers within the scaffold allowed for further functionalization with transition metals, as well as methyl groups that result in altered absorption and redox features for the materials. Subsequent bromination of the scaffold selectively occurred at the exocyclic P-phenyl group, as confirmed via X-ray crystallography. This halogenation allowed for further modification of the system via catalytic cross-coupling with pyridine.     

Liquid-crystalline bisadducts of [60]fullerene

A second-generation cyanobiphenyl-based dendrimer was used as a liquid-crystalline promoter to synthesize mesomorphic bisadducts of [60]fullerene. Liquid-crystalline trans-2, trans-3, and equatorial bisadducts were obtained by condensation of the liquid-crystalline promoter, which carries a carboxylic acid function, with the corresponding bisaminofullerene derivatives. A monoadduct of fullerene was also prepared for comparative purposes. All the compounds gave rise to smectic A phases. An additional mesophase, which could not be identified, was observed for the trans-2 derivative. The supramolecular organization of the monoadduct derivative is governed by steric constraints. Indeed, for efficient space filling, adequacy between the cross-sectional areas of fullerene (approximately 100 A(2)) and of the mesogenic groups (approximately 22-25 A(2) per mesogenic group) is required. As a consequence, the monoadduct forms a bilayered smectic A phase. The supramolecular organization of the bisadducts is essentially governed by the nature and structure of the mesogenic groups and dendritic core. Therefore, the bisadducts form monolayered smectic A phases. The title compounds are promising supramolecular materials as they combine the self-organizing behavior of liquid crystals with the properties of fullerene.     

Synthesis of [60]fullerene-coumarin polyads

New polyads were obtained by covalently linking a coumarin dye to a fullerene (C₆₀) following two different strategies: 1,3-dipolar cycloaddition reaction of azomethine ylides or by cyclopropanation reaction. The new polyads are spectroscopically characterized and their fluorescence properties, including the observation of efficient singlet-singlet energy transfer, reported.     

Probing the spatial requirements for [60]fullerene-[60]fullerene π-stacking and the syn addition of [60]fullerenes across acenes

The reaction between 2 equiv of [60]fullerene and 6,8,15,17-tetraphenylheptacene-7,16-quinone leads to both cis and trans-bis[60]fullerene adducts. This result contrasts sharply with the highly diastereoselective syn additions of [60]fullerenes across 6,13-diphenylpentacene and 6,8,15,17-tetraphenylheptacene. The importance of spatially dependent [60]fullerene-[60]fullerene π-stacking interactions in promoting a syn addition of [60]fullerenes is discussed.     

Synthesis of [60]fullerene-functionalized rotaxanes

Synthesis of [60]fullerene (C₆₀)-functionalized rotaxanes via Diels-Alder reactions with C₆₀ is described. Diels-Alder reaction of C₆₀ and sulfolene moiety as masked diene attached on the wheels of rotaxanes results in high yields of C₆₀ incorporation. Rotaxanes are prepared by tin-catalyzed urethane-forming end-capping reaction with isocyanate of pseudorotaxane having the wheel carrying C₆₀ functionality as introduced by the Diels-Alder reaction. The Diels-Alder reaction was accomplished as end-capping reaction between C₆₀ and pseudorotaxane bearing sultine moiety as masked diene on the axle terminal. A variety of C₆₀-containing [2]rotaxanes was prepared in moderate to good yields by these Diels-Alder protocols.     

Gas-phase methylation of [60]fullerene

Direct methylation of [60]fullerene via a gas-phase reaction in a CH4/H2 atmosphere was performed using a modified hot filament chemical vapor deposition method. Pressures were varied from 10 to 60 mbar and the substrate was maintained at 690 degrees C. High-resolution matrix-assisted laser desorption ionization (MALDI) mass spectrometry analysis showed signals corresponding to C60H18-2n(H,CH3)n. Collision-induced dissociation experiments confirmed a maximum of 18 ligands possible to the [60]fullerene cage.     

[60]富勒烯的超分子自组装研究进展

超分子自组装是发展超分子电子学的重要途径。随着纳米科学和技术的迅速发展,自组装技术已成功地应用于纳米尺度物质的维数、形貌和功能等的调控。作为构筑分子水平上一维、二维、三维有序功能结构和高有序分子聚集态结构的关键技术,超分子自组装技术有力地推动了具有优良光、电、磁性能的分子材料和纳米功能材料更深层次的研究。本文综述了超分子自组装在富勒烯科学领域的基础研究和应用,特别是对有利于自组织和自组装功能的富勒烯基衍生物的设计与合成、超分子作用力引导的具有特定结构的分子体系的可控自组装、以及富勒烯分子聚集态结构材料的光物理过程、超分子中电子转移和能量转移现象进行了描述;并对卟啉、四硫富瓦烯、碗烯和杯芳烃等一系列富π电子化合物和大环主体分子等包含[60]富勒烯的主体化合物的超分子作用和超分自组装体以及通过氢键、π-π作用、静电力和范德华力和金属配位作用形成的[60]富勒烯超分子自组装体进行了总结,对未来发展进行了展望。     

Liquid-crystalline [60]fullerene-TTF dyads

[structure: see text] [60]Fullerene was functionalized with a TTF derivative and a bis-mesogenic fragment. The synthetic methodology was based on the addition of a malonate derivative to C60 (Bingel-type reaction). Both the malonate and dyad showed smectic B and A phases. The supramolecular organization within the smectic layers was of the monolayer type for the malonate and of the bilayer type for the fullerene derivative. In the latter case, the supramolecular organization was governed by the C60 unit.     

60]- and [70]Fullerenes are trifluoromethylated across 5:6-bonds

Trifluoromethylation of [60]- and [70]fullerenes occurs across both 6:6- and 5:6-bonds giving unsymmetrical tetramethyl adducts having four contiguous CF3 groups; both fullerenes give bis adducts which do not involve 6:6-addition, and unsymmetrical hexa-adducts (with contiguous CF3 groups) are also obtained from [60]fullerene.