Base-promoted reaction of C60Cl6 with thioamides: an access to [60]fullereno[1,9-d] thiazoles

Regioselective reaction of C₆₀Cl₆ with thioamides via a radical annulation to form fullereno thiazole derivatives is reported. The reaction is promoted by K₂CO₃, which might deprotonate thioamide to initiate a single electron transfer from thioamide anion to C₆₀Cl₆. The experiments with various thioamides establish the proposed base-promoted reaction as a facile route for synthesis of fullereno fused thiazole derivatives starting from C₆₀Cl₆, a prevalent synthon in fullerene chemistry. In addition, the tunable electrochemical properties of the fullereno thiazole products have been investigated for their potential photovoltaic application.     

Reaction of [60]fullerene with CF3COOHal affords an unusual 1,3-dioxolano-[60]fullerene

Reaction of C₆₀ with acyl hypohalogenites CF₃COOBr or CF₃COOI in the presence of water affords an orthoester-type 1,3-dioxolanofullerene in 40-50% yield. This method cannot be applied for the synthesis of 1,3-dioxolanofullerenes bearing aryl- or alkyl-groups since they undergo non-selective halogenation under the reaction conditions.     

Self-inclusion properties of C60-linked calix[5]arene

C₆₀-linked calix[5]arenes were synthesized and their intramolecular binding properties were investigated. The self-inclusion ratio of the C₆₀ moiety was determined by using UV-vis spectroscopy, and the ratio depends on chain length, temperature, and solvent. Influence of temperature and solvent was explained by the thermodynamic data of the intramolecular complex formation process.     

Sulfur-containing dihydro-pyrrolo [60]fullerene derivatives via 1,3-dipolar cycloadditions of glycine imine esters to C60

C₆₀ reacts thermally with 1,3-dipoles, formed in situ, from sulfide-bearing imines of glycine esters, and affords dihydro-pyrrolo [60]fullerene derivatives containing a vinylic sulfide group, which were isolated in good yields, and characterized with ¹H and ¹³C NMR, FTIR, UV-vis spectroscopies, and with FAB, ESI mass spectrometries. The new derivatives contain a sulfide, an imine, and an ester functionality for further chemical transformations. Mechanistic considerations with regard to the loss of a mercaptan molecule in the course of the cycloaddition are deployed.     

Das Reaktionsverhalten von Cp2NbCl2 gegenüber WF6—Struktur von [Cp2NbCl2]4[WF6]2[WCl6]

The oxidation of Cp₂NbCl₂ with pure WF₆ in SO₂ solution yielded the cationic metallocene species [Cp₂NbCl₂]⁺[WF₆]⁻ essentially in quantitative yield. The same reaction carried out in the presence of either equimolar amounts or a two-fold excess of HCN led to the preparation of the new niobocenium salt [Cp₂NbCl₂]₄⁺[WF₆]²⁻ which was studied by single crystal X-ray diffraction. This compound represents the first example of a structurally characterized metallocene-WF₆⁻ complex, and crystallizes in the tetragonal system: space group, P4₁2₁2(No. 92), a = 11.083(8) Å, c = 48.285 (9) Å; Z = 8; R = 0.0759, R_W = 0.0841. ab]Die Oxidation von Cp₂NbCl₂ mit reinem WF₆ führt in SO₂-Lösung zur Synthese von [Cp₂NbCl₂ ]⁺[WF₆]⁻ in nahezu quantitativer Ausbeute. Die analoge Reaktion führt unter Anwesenheit der äquimolaren Menge oder eines zweifachen Überschusses an HCN zur Ausbildung des Niobocenium-Komplexsalzes [Cp₂NbCl₂]₄⁺ [WF₆]₂⁻[WCl₆]²⁻, von dem eine Röntgenstrukturanalyse angefertigt wurde. Diese Verbindung repräsentiert den ersten structurell charakterisierten Vertreter eines Metallocen-WF₆⁻-Komplexes und kristallisiert im tetragonalen System: Raumgruppe P4₁2₁2 (Nr. 92), a = 11.083(8) Å, c = 48.285(9) Å; Z = 8; R = 0.0759, R_W = 0.0841. kw]Niobium; X-ray diffraction; Oxidation; Metallocenes     

Selective formation of C60F18(g) and C60F36(g) by reaction of [60]fullerene with molecular fluorine

Fluorination of C₆₀(s), C₆₀(s)-MnF₂(s), C₆₀(s)-NiF₂(s) and C₆₀(s)-MnF₃(s) mixtures has been studied by Knudsen cell mass spectrometry with admission of molecular fluorine. The fluorination is selective when fullerene reacts with the fluorine chemisorbed on the MnF₂ surface. When the MnF₂ content in the initial mixture is at least 90 mol% both C₆₀F₁₈ and C₆₀F₃₆ are selectively formed. Under certain conditions, mixtures predominantly containing one of three compounds C₆₀F₃₈, C₆₀F₄₀, and C₆₀F₄₂ can be obtained. A consecutive change of the main fluorination products (C₆₀F₁₈ and C₆₀F₃₆) takes place at constant temperature (720 K) and on fluorine admission. A quantitative explanation of this fact is given. Selective fluorination of C₆₀(s) by molecular fluorine is compared with solid-phase fluorination using MnF₃(s) as a fluorinating agent.     

Pentamethylated derivatives of [60]fullerene: X-ray structure of the C60Me5H and ESR spectroscopy evidence for the stable radical C60Me5

Single-crystal X-ray study of 6,9,12,15,18-pentamethyl-1,6,9,12,15,18-hexahydro(C₆₀-I_h)[5,6]fullerene (C₆₀Me₅H) has been reported. In crystal packing, the stacking self-organization of molecules is realized. It is concluded that the formation of such polar columns is a general rule for crystals of C₆₀R₅H independent of the nature of the R group. An ESR spectrum of the stable fullerenyl radical of the cyclopentadienyl-type, C₆₀Me₅, was observed in a sample of the pentamethylated[60]fullerene. Rotation of methyl groups around C-C bonds is restricted on the ESR scale time and therefore protons within each methyl group are non-equivalent.     

A [2+3] fragment coupling approach to N,O-bridged calix[1]arene[4]pyridines and their complexation with C60

Functionalized N,O-bridged calix[1]arene[4]pyridines, first examples of the odd-numbered heterocalixaromatics containing mixed heteroatom bridges and mixed aromatic units, have been synthesized from the Pd₂(dba)₃/dppp-catalyzed 2+3 macrocyclic fragment coupling reaction between readily available staring materials. These novel macrocyclic compounds, which adopted distorted 1,3-alternate conformation in solid state, were powerful host molecules able to form 1:1 complex with fullerene C₆₀ in solution, giving binding constant up to 49,494 M⁻¹.     

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 and structure of [Ph3MeP]3[Sb3I12]·Me2C=O, [Ph3MeP]3[Sb2I9], [Ph3MeP]2[SbI5], and [Ph3MeP]3[Sb3I12] antimony complexes

Complexes [Ph₃MeP]₃[Sb₃I₁₂]Me₂C=O (I), [Ph₃MeP]₃[Sb₂I₉] (II), and [Ph₃MeP]₂[SbI₅] (III) were obtained via the reaction of triphenylphosphonium iodide with antimony triiodide in acetone in 1:1, 3:2 and 2:1 molar ratios. Reaction of the complex III with antimony triiodide (1:1) affords [Ph₃MeP]₃[Sb₃I₁₂] (IV). The structure of the obtained complexes was confirmed by X-ray analysis.     

Two new metal derivates of the alumosiloxane [Ph2SiO]8[AlO(OH)]4: [Ph2SiO]8[AlO2(Na)]4 · 5(THF) and [Ph2SiO]8[AlO(OH)]2[AlO2]2[Zn(OH)]2 · 2(OEt2)

When the polycyclic alumosiloxane [Ph₂SiO]₈[AlO(OH)]₄ is allowed to react with either cyclopentadienyl sodium in tetrahydrofuran or with dimethyl zinc in diethyl ether the organic ligands on the metal elements are eliminated as cyclopentadiene or methane and the metals are bonded to oxygen atoms in the alumosiloxane forming [Ph₂SiO]₈[AlO₂(Na)]₄ · 5(THF) or [Ph₂SiO]₈[AlO(OH)]₂[AlO₂]₂[Zn(OH)]₂ · 2(OEt₂), respectively. X-ray structure determinations reveal that in the sodium derivative the original polycycle rests almost unchanged while in the zinc derivative the inner skeleton is rearranged.     

A ready access to unprecedented N-anilinopyrazolino[60]fullerenes

A simple and efficient method for the preparation of new synthons based on versatile amino-functionalize pyrazoline[60]fullerene is described. These intermediates are useful in the preparation of new derivatives for applications in materials science. Finally, electrochemical studies of the newly prepared compounds have been performed in solvents with different polarities.     

Synthesis of 4-aziridino[C60]fullerene-1,8-naphthalimide (C60-NI dyads) and their photophysical properties

A series of 4-aziridino[C₆₀]fullerene-1,8-naphthalimide (C₆₀-NI) dyads 4 ([6,6]-closed ring) were synthesized as the only addition product from the reaction of C₆₀ with the corresponding azide compounds 3 under microwave irradiation in good yield. A quenching of fluorescence was shown in dyads 4, and this decay was evidenced to be an intramolecular process.     

Sr2InF7-Sr2[InF7] oder Sr2F[InF6]? [1]

The new compound Sr₂InF₇ single crystals has been prepared from a melt using single crystals, the strucutre of Sr₂InF₇ is isotypic with K₂NbF₇ [2]. Details of the structure are discussed, using the Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN.     

Formation of [C60C5H5] adduct cations and theoretical study of the isomers

We study here the reactions between C₆₀ and planar C₅H₅⁺ cations that lead to the formation of [C₆₀C₅H₅]⁺ adduct cations in the chemical ionization source of the mass spectrometer. The structures, stabilities and charge locations of some possible isomers of [C₆₀C₅H₅]⁺: σ-adduct, π-complex, [1,4]- and [l,2]-addition cations, are studied by AM1 semiempirical molecular orbital calculations. We find that the most stable is the σ-addition cation. Another interesting and stable structure is the π-complex cation which is bonded by the electrostatic interaction at the inter-ring distance of 1.589 Å with the C_5v symmetry. The C₅H₅⁺ cyclopentadienium cation seems to be an “inverted umbrella” sitting on a five-membered ring of the C₆₀ cage.     

Cycloaddition of diazothioates to [60]fullerene

The cycloaddition of diazothioates to fullerene C₆₀ has been investigated under thermal and catalytic conditions. The reaction between C₆₀ and α-non-substituted diazothioates affords individual pyrazolino[60]fullerenes in contrast to 2-substituted diazothioates which give rise to [2+1] cycloadducts, exclusively.     

Direct benzyne-C60 addition does not generate a [5,6] open fulleroid

Recent reports describe the different products resulting from the reaction of C₆₀ with benzyne generated from anthranilic acid derivatives and isoamyl nitrate in the presence and absence of triethylamine. Reinvestigation here via ¹H, ¹³C, HMBC NMR and Mass spectroscopy elucidates that these products are the [6,6] closed C₆₀-fused δ lactones, and not the [5,6] open fulleroids which would result from benzyne addition. Furthermore, theoretical calculations show that the open isomer [5,6] benzyne addition is less stable than the [5,6] closed isomer as an isolable product.     

Solvothermal synthesis and characterisation of new one-dimensional indium and gallium sulphides: [C10N4H26]0.5[InS2] and [C10N4H26]0.5[GaS2]

Two new main group metal sulphides, [C₁₀N₄H₂₆]_0.5[InS₂] (1) and [C₁₀N₄H₂₆]_0.5[GaS₂] (2) have been prepared solvothermally in the presence of 1,4-bis(3-aminopropyl)piperazine and their crystal structures determined by single-crystal X-ray diffraction. Both compounds are isostructural and crystallise in the monoclinic space group P2₁/n (Z=4), with a=6.5628(5), b=11.2008(9), c=12.6611(9) Å and β=94.410(4)° (wR=0.035) for compound (1) and a=6.1094(5), b=11.2469(9), c=12.7064(10) Å and β=94.313(4)° (wR=0.021) for compound (2). The structure of [C₁₀N₄H₂₆]_0.5[MS₂] (M=In,Ga) consists of one-dimensional [MS₂]⁻ chains which run parallel to the crystallographic a axis and are separated by diprotonated amine molecules. These materials represent the first example of solvothermally prepared one-dimensional gallium and indium sulphides.     

Formation of [Cp2TiSbMe2]2, [Cp2TiSb(SiMe3)2]2 and [Cp2TiCl]2·2Mes4Sb2

Reactions of [Cp₂Ti(btmsa)] (btmsa = bis(trimethylsilyl)acetylene) with R₄Sb₂ (R = Me, Me₃Si) give [Cp₂TiSbMe₂]₂ (1) or [Cp₂TiSb(SiMe₃)₂]₂ (2) respectively. [Cp₂TiCl]₂·2Mes₄Sb₂ (3) is serendipitously formed from [Cp₂Ti(btmsa)] and Mes₂SbH containing NH₄Cl traces.     

[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.