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A novel nonclassical fullerene dihept-C70H6, captured from low-pressure combustion, is considered to be vital evidence for the further study of heptafullerenes.

A double-heptagon-containing C

Herein, a hetero(S,N)-quintuple [9]helicene (SNQ9H) molecule with an azacorannulene core was synthesized, currently representing the highest hetero-helicene reported in the field of multiple [n]helicenes. X-ray crystallography indicated that SNQ9H includes not only a propeller-shaped conformer SNQ9H-1, but also an unforeseen quasi-propeller-shaped conformer SNQ9H-2. Different conformers were observed for the first time in multiple [n≥9]helicenes, likely owing to the doping of heteroatomic sulfurs in the helical skeletons. Remarkably, the ratio of SNQ9H-1 to SNQ9H-2 can be regulated in situ by the reaction temperature. Experimental studies on the photophysical and redox properties of SNQ9H and theoretical calculations clearly demonstrated that the electronic structures of SNQ9H depend on their molecular conformations. The strategy of introducing heteroatomic sulfurs into the helical skeleton may be useful in constructing various conformers of higher multiple [n]helicenes in the future.

All previously reported C70 isomers have positive curvature and contain 12 pentagons in addition to hexagons. Herein, we report a new C70 species with two negatively curved heptagon moieties and 14 pentagons. This unconventional heptafullerene[70] containing two symmetric heptagons, referred to as dihept-C70 , grows in the carbon arc by a theoretically supported pathway in which the carbon cluster of a previously reported C66 species undergoes successive C2 insertion via a known heptafullerene[68] intermediate with low energy barriers. As identified by X-ray crystallography, the occurrence of heptagons facilitates a reduction in the angle of the π-orbital axis vector in the fused pentagons to stabilize dihept-C70 . Chlorination at the intersection of a heptagon and two adjacent pentagons can greatly enlarge the HOMO-LUMO gap, which makes dihept-C70 Cl6 isolable by chromatography. The synthesis of dihept-C70 Cl6 offers precious clues with respect to the fullerene formation mechanism in the carbon-clustering process.

A general one-step synthesis of symmetrical or unsymmetrical 1,4-di(organo)fullerenes from organo(hydro)fullerenes (RC60H) is realized by direct oxidative arylation. The new combination of catalytic trifluoromethanesulfonic acid (TfOH) and stoichiometric o-chloranil is the first to be used to directly generate an R-C60+ intermediate from common RC60H. Unexpectedly, the in situ generated R-C60+ intermediate is shown to be quite stable in whole 13C NMR spectroscopy characterization in the absence of cation quenching reagents. Because the direct oxidation of common RC60H to form the corresponding R-C60+ has never been realized, the present combination of TfOH and o-chloranil solves the challenges associated with the formation of stable RC60+ cations from common RC60H without any coordination of an R group.

The combustion has long been applied for industrial synthesis of carbon materials such as fullerenes as well as carbon particles (known as carbon black), but the components and structures of the carbon soot are far from being clarified. Herein, we retrieve an unprecedented hydrofullerene C66H4 from a soot of a low-pressure combustion of benzene-acetylene-oxygen. Unambiguously characterized by single-crystal X-ray diffraction, the C66H4 renders a nonclassical geometry incorporating two heptagons and two pairs of fused pentagons in a C2 v symmetry. The common vertexes of the fused pentagons are bonded with four hydrogen atoms to convert the hydrogen-linking carbon atoms from sp2 to sp3 hybridization, which together with the adjacent heptagons essentially releases the sp2-bond strains on the abutting-pentagon sites of the diheptagonal fused pentagon C66 (dihept-C66). DFT computations suggest the possibility for an in situ hydrogenation process leading to stabilization of the dihept-C66. In addition, the experiments have been carried out to study heptagon-dependent properties of dihept-C66H4, indicating the key responsibility of the heptagon for changing hydrocarbon activity and electronic properties. The present work with the unprecedented double-heptagon-containing hydrofullerene successfully isolated and identified as one of the low-pressure combustion products shows that the heptagon is a new building block for constructing fullerene products in addition to pentagons and hexagons in low-pressure combustion systems.

A cloth that adapts to the heat Textiles trap infrared radiation, which helps keep us warm in cold weather. Of course, in hot weather, this is less desirable. Zhang et al. constructed an infrared-adaptive textile composed of polymer fibers coated with carbon nanotubes. The yarn itself expanded and collapsed based on heat and humidity, which changed the spacing of the fibers. Wider fiber spacing allowed the textile to breathe but also altered the infrared emissivity of the textile. This allowed for better heat exchange under hot and wet conditions. The self-adjusting emissivity of the textile could help toward wearable thermal-management attire. Science , this issue p. 619

The combustion has long been applied for industrial synthesis of carbon materials such as fullerenes as well as carbon particles (known as carbon black), but the components and structures of the carbon soot are far from being clarified. Herein, we retrieve an unprecedented hydrofullerene C

The assembly of spherical fullerenes, or buckyballs, into single crystals for crystallographic identification often suffers from disordered arrangement. Here we show a chiral configuration of decapyrrylcorannulene that has a concave ‘palm’ of corannulene and ten flexible electron-rich pyrryl group ‘fingers’ to mimic the smart molecular ‘hands’ for self-adaptably cradling various buckyballs in a (+)hand-ball-hand(−) mode. As exemplified by crystallographic identification of 15 buckyball structures representing pristine, exohedral, endohedral, dimeric and hetero-derivatization, the pyrryl groups twist with varying dihedral angles to adjust the interaction between decapyrrylcorannulene and fullerene. The self-adaptable electron-rich pyrryl groups, susceptible to methylation, are theoretically revealed to contribute more than the bowl-shaped palm of the corannulene in holding buckyball structures. The generality of the present decapyrrylcorannulene host with flexible pyrryl groups facilitates the visualization of numerous unknown/unsolved fullerenes by crystallography and the assembly of the otherwise close-packed spherical fullerenes into two-dimensional layered structures by intercalation., The structures of fullerenes, or buckyballs, are often very difficult to resolve. Here, the authors describe a decapyrrylcorannulene host with ten flexible pyrryl groups that can efficiently co-crystallize with diverse fullerene derivatives in a ‘hand-ball-hand’ fashion, allowing crystallographic identification of commonly known types of fullerenes.

Heptagon-containing fullerenes (heptafullerenes) exhibit negative curvature. Herein, we report the first double negatively curved C70 isomer containing two symmetric heptagons moieties. The compound was captured in situ as dihept-C70Cl6 from a chlorine-involving carbon arc. As demonstrated by X-ray crystallography, the dihept-C70Cl6 isomer with two negatively curved heptagon moieties contained 14 pentagons and 21 hexagons, in which four of the 14 pentagons are fused. The unfavorable local tensile of the adjacent pentagons was dramatically decreased by the binding of chlorine atoms. The two pairs of adjacent pentagons are exactly fused to two concave heptagons, resulting in the negative curvature with a symmetric plane. The occurrence of heptagon moieties provides an additional stabilizing effect on the heptafullerene. Theoretical studies suggest that captured dihept-C70Cl6 can be rationally regarded as a product of C66 via successive C2 insertions. This present study provides insight into the mechanism responsible for heptafullerene formation in a carbon arc. Figure 1

A carboncone[1,2] molecule was rationally synthesized, pushing the study on all-carbon allotropes into a new dimension., Carboncones, a special family of all-carbon allotropes, are predicted to have unique properties that distinguish them from fullerenes, carbon nanotubes, and graphenes. Owing to the absence of methods to synthesize atomically well-defined carboncones, however, experimental insight into the nature of pure carboncones has been inaccessible. Herein, we describe a facile synthesis of an atomically well-defined carboncone[1,2] (C70H20) and its soluble penta-mesityl derivative. Identified by x-ray crystallography, the carbon skeleton is a carboncone with the largest possible apex angle. Much of the structural strain is overcome in the final step of converting the bowl-shaped precursor into the rigid carboncone under mild reaction conditions. This work provides a research opportunity for investigations of atomically precise single-layered carboncones having even higher cone walls and/or smaller apex angles.

High quality graphene materials that readily disperse in water or organic solvents are needed to achieve some of the most ambitious applications. However, current synthetic approaches are typically limited by irreversible structural damages, little solubility, or low scalability. Here, we describe a fundamental study of graphene chemistry and covalent functionalization patterns on sp2 carbon lattices, from which a facile, scalable synthesis of high quality graphene sheets was developed. Graphite materials were efficiently exfoliated by reductive, propagative alkylation. The exfoliated, propagatively alkylated graphene sheets (PAGenes) not only exhibited high solubility in common solvents such as chloroform, water, and N-methyl-pyrrolidone, but also showed electrical conductivity as high as 4.1 × 103 S/m, which is 5 orders of magnitude greater than those of graphene oxides. Bright blue photoluminescence, unattainable in graphene, was also observed. We attribute the rise of blue photoluminescence in PAGenes...

We demonstrate the separation of chirality-enriched single-walled carbon nanotubes (SWCNTs) by degree of surface functionalization using high-performance CE. Controlled amounts of negatively charged and positively charged functional groups were attached to the sidewall of chirality-enriched SWCNTs through covalent functionalization using 4-carboxybenzenediazonium tetrafluoroborate or 4-diazo-N,N-diethylaniline tetrafluoroborate, respectively. Surfactant- and pH-dependent studies confirmed that under conditions that minimized ionic screening effects, separation of these functionalized SWCNTs was strongly dependent on the surface charge density introduced through covalent surface chemistry. For both heterogeneous mixtures and single-chirality-enriched samples, covalently functionalized SWCNTs showed substantially increased peak width in electropherogram spectra compared to nonfunctionalized SWCNTs, which can be attributed to a distribution of surface charges along the functionalized nanotubes. Successful separation of functionalized single-chirality SWCNTs by functional density was confirmed with UV-Vis-NIR absorption and Raman scattering spectroscopies of fraction collected samples. These results suggest a high degree of structural heterogeneity in covalently functionalized SWCNTs, even for chirality-enriched samples, and show the feasibility of applying CE for high-performance separation of nanomaterials based on differences in surface functional density.

Although tremendous advances in fullerene sciences have been achieved since the first discovery of fullerene in the middle of 1980’, the formation of these all-carbon cages still remains a mystery. Based on available experimental and computational evidences, some interpretations responsible for fullerene formation have been suggested in literatures. Most of them can be classified as bottom-up, top-down or size-up/size-down models. Suffering from limitation of powerful evidences, however, most of them still require validation. Herein we review the most important hypothetic fullerene formation models that have been proposed to date.

Although derivatives of fullerenes are prevalent in the fullerene-producing flame, chemistry of these derivatives has rarely been discussed in previous literatures. Here we show a series of nascent intermediates that are on-line produced in the flame of acetylene-benzene-oxygen and in situ captured by C60 for clarifying the growth of carbon clusters. Based on MS, NMR, IR, UV/Vis analyses as well as single-crystal diffraction, in combination with DFT calculations, the intermediates captured by C60 are identified. The present work exemplifies the capture of possible intermediates by C60 from the flame, and thus provides insight into the mechanism responsible for the formation of fullerene.

The National Natural Science Foundation of China (Grant 20525103, 20721001, and 20531050) and the 973 Program (Grant 2007CB815301).

The title compound was prepared from the reaction of perchloroacenaphthylene with an excess of sodium salt of 4-methyloxythiophenol in toluene/ethanol (1:1) solvent and structurally characterized by single-crystal X-ray diffraction. The compound crystallizes in the Monoclinic space group P2(1) with the parameters: a = 10.351(1) A, b = 20.453(3) A, c = 12.1837(16) A, β = 105.584(3)°, V = 2484.5(6) A3, with Z = 2 formula units. The title compound 4,7-dichloro-1,2,3,5,6,8-hexakis-(4-methoxy-phenylsulfanyl)-acenaphthylene was synthesized from perchloroacenaphthylene C 12 Cl 8 with an excess of 4-methoxybenzene thiolate in toluene/ethanol (1:1) .

The title host molecule exhibits remarkable conformational flexibility in its crystalline inclusion clathrates. The alternation in molecular packing modes of this flexible host molecule, between the cyclohexane and benzene clathrates, corresponds to the sizes and shapes of the guests and the weak molecular forces between the host and the guest. The crystals of cyclohexane clathrate are triclinic, space group P 1 ¯ with a = 10.3996(10), b = 11.1750(11), c = 21.694(2) A, α = 103.628(2)°, β = 94.885(2)°, γ = 92.910(2)°, V = 2434.8(4) A3 and Z = 2. The crystals of benzene clathrate are monoclinic, space group P2(1)/c, a = 10.774(3), b = 10.845(3), c = 41.063(11) A, β = 96.497(5)°, V = 4768(2) A3 and Z = 4.

1,6-Bis(4-methoxyphenylsulfanyl) perchlorofluoranthene, a molecule with a dramatic orientation effect due to intramolecular aromatic π–π interactions (APPI), was synthesized and characterized using X-ray diffraction, DFT calculations, UV–vis absorption spectra, and excitation spectra. The crystals are monoclinic, space group P2(1)/ n with a = 7.9707(10), b = 18.349(2), c = 20.649(3) A, β = 95.259(3)°, V = 3007.3(7) A 3 and Z = 4. The flexibility of the five-membered ring in the molecule was shown to facilitate the intramolecular APPI formation.

We report a simple strategy to construct a multiple gadolinium complex decorated fullerene (CGDn) as an enhanced T1 contrast agent. The CGDn exhibits much higher T1 relaxivity (∼49.7 mM(-1) s(-1)) than individual Gd-DOTA, and shows excellent T1 contrast enhancement ability both in vitro and in vivo.

Crystal structure analysis shows the 2,4,5,7,9,10-hexachloro-1,3,6,8-tetrakis-(4-methoxyphenylthio) pyrene host and its cyclohexane guest in the Pnma crystal lattice. The crystal data and refinement parameter for the title compound are: a = 15.864(3), b = 30.455(6), c = 9.231(5) A, V = 4459.2 (14) A3. For Z = 4 and M w = 1045.76, the calculate density Dcal = 1.558 g/cm3. The C–H···π interaction and C–H Cl interaction stabilized the inclusion of cyclohexane molecules. The S···Cl weak interaction assembled the host molecules into a two-dimensional layer structure, and a three-dimensional structure was obtained by connecting the layers with C–H···O hydrogen bonding.

通讯作者地址: Zheng, LS (通讯作者), Xiamen Univ, Dept Chem, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, Dept Chem, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China

This study demonstrates the simultaneous exfoliation and modification of graphitic carbon nitride (g-C3N4) via reductive alkylation. Our results reveal that the method is feasible and highly efficient in producing 2D g-C3N4 nanosheets which greatly overcome the drawbacks of bulk g-C3N4 photocatalyst. The reduced band gap caused by the covalent functionalization of alkyl chains on g-C3N4 lattice improves the photoresponse and the visible-light harvesting ability, indicating more charge carriers will generate under visible-light irradiation. In addition, the significantly enlarged surface area and the nanosheet structural benefits are favorable for the separation of photogenerated charge carriers. The photocatalytic activity of AGCNNs under visible-light irradiation is highly enhanced because of the synergistic effects of these favorable factors. The RhB photodegradation rate and the photocatalytic H2 evolution rate of AGCNNs are 3.9 and 1.9 times as fast as that of g-C3N4, respectively. The photocatalytic activity of AGCNNs is further improved when combined with a minority of graphene sheets which are employed as electron acceptors promoting the separation of photogenerated charge carriers. The RhB photodegradation rate and the photocatalytic H2 evolution rate of AGCNNs are further improved to 9.1 and 3.3 times as fast as that of g-C3N4, respectively.

High quality graphene sheets are prepared via exfoliation of graphite by repeated (8 cycles) reductive, propagative alkylation in Li and naphthalene containing THF to which 1-bromododecane (6-bromohexanoic acid, 11-bromoundecanoic acid, or methyl-6-bromohexanoate) is slowly added (reaction time of 12 h).

Simultaneous separation and identification of perchlorinated polycyclic aromatic hydrocarbons (PCPAHs) and fullerenes is of practical interest due to the growth mechanism of fullerenes involved with PCPAHs. Non-aqueous reversed-phase high-performance liquid chromatography (HPLC), with an ODS column and a gradient mobile phase of methanol-ethanol-cyclohexane mixtures, was combined with both rapid-scan ultraviolet spectrometry (UV) and atmospheric pressure chemical ionization mass spectrometry (APCI-MS) for the separation and identification of over 80 PCPAHs as well as fullerenes C60 and C70, that were synthesized in the discharge reaction of chloroform. PCPAH retention was found to depend on the number of aromatic rings and the degree of non-planarity of PCPAH structure. Based on the isotopic pattern of molecular ion or/and quasi-molecular ion peaks in corresponding mass spectra, molecular compositions of the PCPAH products were unambiguously determined. The results obtained from the HPLC-UV-MS analysis not only are helpful for the understanding of the fullerenes formation mechanism, but also contribute to the analytical technique capable of separating and identifying the complicated mixture of PCPAHs and fullerenes.

In addition to I h symmetry buckminsterfullerene, four other isomers of C 60 were generated in a microwave plasma of chloroform. The newly observed isomers, separated and identified by a high performance liquid chromatography coupled with mass spectrometry (HPLC–MS), were found to be stable at room temperature but transform to buckminsterfullerene when heated. With regards to the generation of various fully chlorinated carbon clusters as well as the C 60 isomers, which may be attributed to the rapidly cooling of the synthetic reaction, a modified Pentagon Road scheme is suggested for fullerene formation.

通讯作者地址: Zheng, LS (通讯作者), Xiamen Univ, Dept Chem, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, Dept Chem, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China

Covalent chemistry typically occurs randomly on the graphene lattice of a carbon nanotube because electrons are delocalized over thousands of atomic sites, and rapidly destroys the electrical and optical properties of the nanotube. Here we show that the Billups-Birch reductive alkylation, a variant of the nearly century-old Birch reduction, occurs on single-walled carbon nanotubes by defect activation and propagates exclusively from sp(3) defect sites, with an estimated probability more than 1,300 times higher than otherwise random bonding to the 'π-electron sea'. This mechanism quickly leads to confinement of the reaction fronts in the tubular direction. The confinement gives rise to a series of interesting phenomena, including clustered distributions of the functional groups and a constant propagation rate of 18 ± 6 nm per reaction cycle that allows straightforward control of the spatial pattern of functional groups on the nanometre length scale.

We demonstrate diameter-dependent, progressive alkylcarboxylation of single-walled carbon nanotubes by recycling a modified Billups–Birch reaction. The strong diameter dependence was confirmed by Raman spectroscopy. Alkylcarboxylation made SWNTs soluble in water, allowing the more readily functionalized, smaller diameter nanotubes to be enriched by water extraction.

The outer walls of double-walled carbon nanotubes (DWNTs) were selectively oxidized using a combination of oleum and nitric acid. Intercalation of oleum between bundled DWNTs enabled a homogeneous reaction by equally exposing all outer wall surfaces to the oxidants. At optimized reaction conditions, this double-wall chemistry enabled high water solubility through carboxylic acid functional groups introduced to the outer wall, while leaving the inner tube intact, as shown by Raman scattering and high resolution TEM. These outer wall selectively oxidized DWNTs retained electrical conductivity up to 65% better than thin films of similarly functionalized single-walled carbon nanotubes, which can be attributed to enhanced electrical percolation via the nonoxidized inner tubes.

A superparamagnetic reduced graphene oxide-Fe(3)O(4) hybrid composite (rGO-Fe(3)O(4)) was prepared via a facile and straightforward method through the solvothermal reaction of iron (III) acetylacetonate (Fe(acac)(3)) and graphene oxide (GO) in ethylenediamine (EDA) and water. By this method, chemical reduction of GO as well as the formation of Fe(3)O(4) nanoparticles (NPs) can be achieved in one step. The Fe(3)O(4) NPs are firmly deposited on the surfaces of rGO, avoiding their reassembly to graphite. The rGO sheets prevent the agglomeration of Fe(3)O(4) NPs and enable a uniform dispersion of these metal oxide particles. The size distribution and coverage density of Fe(3)O(4) NPs deposited on rGO can be controlled by varying the initial mass ratio of GO and iron precursor, Fe(acac)(3). With an initial mass ratio of GO and Fe(acac)(3) of 5:5, the surfaces of rGO sheets are densely covered by spherical Fe(3)O(4) NPs with an average size of 19.9 nm. The magnetic-functionalized rGO hybrid exhibits a good magnetic property and the specific saturation magnetization (M(s)) is 13.2 emu g(-1). The adsorption test of methylene blue from aqueous solution demonstrates the potential application of this rGO-Fe(3)O(4) hybrid composite in removing organic dyes from polluted water.

通讯作者地址: Zheng, LS (通讯作者), Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 2. Univ Malaya, Dept Chem, Kuala Lumpur 50603, Malaysia

Boron nitride nanotubes (BNNTs) are inappropriate for further chemical derivatization because of their chemical inertness. We demonstrate covalent activation of chemically inert BNNTs by isophorone diisocyanate (IPDI) to form isocyanate group (NCO)-terminated BNNT precursors with an 'NCO anchor' ready for further functionalization. As identified by Fourier transform infrared spectroscopy, a number of molecules or polymers with -COOH, -OH or -NH₂ groups are readily attached to the activated IPDI-BNNTs. The IPDI-BNNT-involving polymer composites have shown mechanical properties are considerably improved due to the good dispersibility of IPDI-BNNTs in the polymer matrix and the strong interfacial interactions between BNNTs and polymers. The methodology reported here provides a promising method to promote the chemical reactivity of BNNTs and covalently modify polymer nanocomposites with improved mechanical performance.

Double-walled carbon nanotubes were enriched from their single- and few-walled counterparts as well as other carbonaceous byproducts coexisting in as-synthesized materials using Billups–Birch reductive alkylcarboxylation chemistry. The enrichment was made possible due to high selectivity of the reaction towards smaller diameter, single-walled carbon nanotubes and more defective carbonaceous structures. Raman resonant scattering studies suggest that alkylcarboxylation selectively occurred on the outerwalls while the inner-tubes remained unaffected. The separated double-walled carbon nanotubes were water soluble due to outerwall alkylcarboxylation, but the Raman modes and part of the optical properties of the inner-tubes were preserved.

地址: 1. Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 2. Xiamen Univ, Dept Chem, Xiamen 361005, Peoples R China 3. Chinese Acad Sci, Inst Chem, Beijing 100080, Peoples R China 4. Chinese Acad Sci, Wuhan Inst Phys & Math, State Key Lab Magnet Resonance & Mol Phys, Wuhan 430071, Peoples R China 电子邮件地址: syxie@jingxian.xmu.edu.cn