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As a promising hydrogen-storage material, graphene is expected to have a theoretical capacity of 7.7 wt%, which means a carbon-hydrogen atomic ratio of 1:1. However, it hasn’t been demonstrated yet by experiment, and the aim of the U.S. Department of Energy is to achieve 5.5 wt% in 2025. We designed a spatially-confined electrochemical system and found the storage capacity of hydrogen adatoms on single layer graphene (SLG) is as high as 7.3 wt%, which indicates a carbon-hydrogen atomic ratio of 1:1 by considering the sp3 defects of SLG. First, SLG was deposited on a large-area polycrystalline platinum (Pt) foil by chemical vapor deposition (CVD); then, a micropipette with reference electrode, counter electrode and electrolyte solution inside was impacted on the SLG/Pt foil (the working electrode) to construct spatially-confined electrochemical system. The SLG-uncovered Pt atoms act as the catalytic sites to convert protons (H+) to hydrogen adatoms (Had), which then spill over and are chemically adsorbed on SLG through surface diffusion during the cathodic scan. Because the electrode processes are reversible, the Had amount can be measured by the anodic stripping charge. This is the first experimental evidence for the theoretically expected hydrogen-storage capacity on graphene at ambient environment, especially by using H+ rather than hydrogen gas (H2) as hydrogen source, which is of significance for the practical utilization of hydrogen energy.

As a fundamental chemical property, aromaticity guides the synthesis of novel structures and materials. Replacing the carbon moieties of aromatic hydrocarbons with transition metal fragments is a promising strategy to synthesize intriguing organometallic counterparts with a similar aromaticity to their organic parents. However, since antiaromaticity will endow compound instability, it is a great challenge to obtain an antiaromatic organometallic counterpart based on such transition metal replacement in aromatic hydrocarbons. Here, we report an efficient aromaticity transformation on aromatic naphthalene through the bridgehead replacement of an osmium fragment, leading to the unprecedented synthesis of metal-bridgehead naphthalene featuring a highly twisted structure as confirmed by X-ray crystallography characterization. Such a twisted conformation works together with its phosphonium substituents to release the antiaromaticity in the planar conformation of the metal-bridgehead naphthalene. Our findings prove the bridgehead involvement of transition metals in unexpected aromaticity modifications and open an avenue for novel metal-bridgehead complexes.

Carbon nanohoop, a class of constrained molecular architecture consisting of linked arene units, has attracted considerable interest from both experimental and theoretical chemists due to its synthetic challenge and aesthetic architectures. Another fascinating and synthetically challenging species, the Mobius-type molecule, has been attracting the scientific community with its elegant structure and aromaticity. Thus, combining two things together, synthesizing a carbon nanohoop with Mobius topology remains more challenging to date. Here we report a cyclophenylene featuring Mobius strip characterized by X-ray crystallography. Theoretical calculations reveal that such type of nanohoop is fully conjugated systems with electrons delocalized both in π sextets and the bridging carbon-carbon bonds. This work highlights that the manipulation of phenylene connection in a carbon nanohoop can help obtain more delicate and aesthetic molecular architectures.

Here, we report a facile method to synthesize a series of macrocycles with different conformations. The planar macrocycle dimer (1), twisted macrocycle trimer (2) and "figure-eight" tetramer (3) are clearly elucidated by X-ray single-crystal analysis, in which the electron-rich phenanthrene units offer the possibility of supramolecular assembly. As expected, in the solid state, 1 and 3 assemble into a columnar stack and an interlocking dimer, respectively, via π-π interactions between the phenanthrene units. Compared to the rigid conformation of dimer 1, the structure of tetramer 3 is more flexible due to its enlarged ring size. 3 can deform from a figure-eight into a boat-shaped geometry to host a planar electron-deficient guest using its electron-rich phenanthrene units. When assembled with spherical electron-deficient C60 , interestingly, 3 further undergoes a conformational transformation from a figure-eight to a belt shape in order to host C60 . These supramolecular assembly behaviors of 3 demonstrate that it is an adaptable macrocyclic host for both planar molecules and fullerenes.

Polycyclic aromatic hydrocarbons (PAHs) generally refer to aromatic compounds containing two or more fused benzene rings. PAHs have excellent optical, electronic and self-assembly properties, and have important applications in organic light-emitting diodes (OLED), organic field effect transistors (OFET), organic solar photovoltaic cells (OPVC) and other fields. The introduction of heteroatoms to PAHs can adjust the electronic structure, dipole moment, and the self-assembly behavior. Among them, sulfur-doped PAHs have been widely studied. Due to the proper energy level and bonding mode of sulfur atom, the sulfur-doped PAHs have stronger dipole-dipole interactions, electron donating ability, and weakened aromaticity. Sulfur-doped PAHs usually exhibit unique redox characteristics and better hole transporting, so they are widely used as p-type organic semiconductor and electronic donor in photoelectric conversion, and donation unit in donor-acceptor conjugated molecules. Doping PAHs with sulfur is mainly through two ways: post-modification and fusing the sulfur-containing heterocyclic unit. On the other hand, regarding the regulation of geometric structure of carbon skeleton, non-hexagonal ring is introduced to transform the molecular structure from planar to curved structure. The structural distortion can be achieved by the peripherial stereo-hindrance. For example, the PAHs containing helicene units have a highly distorted structure, thus showing a unique optical, electric and assembly properties. In order to construct novel PAHs, this article combines heteroatom doping and geometric control of carbon skeleton. A twisted tri-sulfur-doped PAH C36S3H10(C9H11)6 (molecule 1 ) was synthesized by oxidative cyclodehydrogenation of an oligophenylene precursor, which contains three thiophene rings. X-ray single crystal diffraction exactly characterized the structure of molecule 1 . Because the ring is not completely fused, molecule 1 contains two [5]helicene units, which leads to a twisted molecular structure. In crystalline state, molecule 1 forms dimers through C−H···π and weak π-π interactions, which further packs into one-dimensional columnar stacking through the weak interactions of C−H···π and C−H···S. Different from the planar PAHs, the twisted molecule 1 is not easy to aggregate in solution. Molecule 1 exhibits a yellow photoluminescence, but its quantum yield is low. Combined with the study of transient fluorescence spectroscopy, it is speculated that its twisted molecular structure may be the reason for its low quantum yield. The synthesis of molecule 1 enriches the family of sulfur-doped PAHs, and the derivatives with alkyl chains of molecule 1 can be synthesized in the future and be used as organic semiconductors or electron donors in solar cells and organic electronic devices, etc.

The radial conjugated π-system of cycloparaphenylenes (CPPs) makes them intriguing fluorophores and unique supramolecular hosts. However, the bright photoluminescence (PL) of CPPs was limited to the blue light and the supramolecular assembly behavior of large CPPs was rarely investigated. Here we present the synthesis of tetra-benzothiadiazole-based [12]cycloparaphenylene (TB[12]CPP), which exhibits a lime to orange PL with an excellent quantum yield up to 82 % in solution. The PL quantum yield of TB[12]CPP can be further improved to 98 % in polymer matrix. Benefiting from its enlarged size, TB[12]CPP can accommodate a fullerene derivative or concave-convex complexes of fullerene and buckybowl through the combined π-π and C-H⋅⋅⋅π interactions. The latter demonstrates the first case of a ternary supramolecule of CPPs.

The metal-carbon triple bonds and carbon-carbon triple bonds are both highly unsaturated bonds. As a result, their reactions tend to afford cycloaddition intermediates or products. Herein, we report a reaction of M≡C and C≡C bonds that affords acyclic addition products. These newly discovered reactions are highly efficient, regio- and stereospecific, with good functional group tolerance, and are robust under air at room temperature. The isotope labeling NMR experiments and theoretical calculations reveal the reaction mechanism. Employing these reactions, functionalized dπ-pπ conjugated systems can be easily constructed and modified. The resulting dπ-pπ conjugated systems were found to be good electron transport layer materials in organic solar cells, with power conversion efficiency up to 16.28% based on the PM6: Y6 non-fullerene system. This work provides a facile, efficient methodology for the preparation of dπ-pπ conjugated systems for use in functional materials.

Generally, the conjugated homo-macrocycles (CHMs) are synthesized by covalently linking the repeating subunits. However, large subunits are often difficult to conjugate together due to severe stereo-hindrance. Meanwhile, large polyaromatic blocks can not only incorporate its appealing electronic and optical properties into CHMs but also distort the CHMs from planar to three-dimensional (3D) molecular structure. Here we synthesized the 3D CHM composed of large polyaromatic units by post-π-extension. Specifically, cyclo-m-phenylenes, as the cyclic precursor, were π-extended by C-C coupling and then subjected to dehydrocyclization, affording cyclo-1,3-dibenzo[e,1]pyrenylenes (CMDP). The structures of CMDPs were unambiguously characterized by single crystal X-ray diffraction, showing a congested and strained 3D conformation, which was also confirmed by theoretical calculations. Compared with the monomer, CMDPs showed redshifted absorption and emission, as well as a tenfold enhancement in photoluminescence quantum yield, which could be attributed to their 3D conformation.

All-inorganic and earth-abundant bi-/trimetallic hydr(oxy)oxides are widely used as oxygen evolution electrocatalysts owing to their remarkable performance. However, their atomically precise struct ...

Carbon-rich two-dimensional (2D) materials show significant potential in energy storage and conversion applications. A conjugated 2D covalent organic polymer (COP) with embedded triphenylene (TP) units was synthesized by Glaser–Hay cross-coupling and validated by Raman, IR, XPS and NMR spectroscopy. TP-COP exhibited a uniform pore size of 5.4 A and laminar structure with an interlayer spacing of 3.8 A, which could be mechanically exfoliated to yield few-layered nanosheets. Interfacial polymerization produced the continuous TP-COP films from quasi-monolayer to multilayer. As the anode materials of lithium batteries, TP-COP delivered large reversible capacity up to 1624 mA h g−1, high charge rate, and good recycling ability. These properties are likely due to the presence of lithium ions in both the interspace of the expanded sp2 moieties and the in-plane nanopores of TP-COP.

Quintulene, a non-graphitic cycloarene with fivefold symmetry, has remained synthetically elusive due to its high molecular strain originating from its curved structure. Here we report the construction of extended quintulene, which was unambiguously characterized by mass and NMR spectroscopy. The extended quintulene represents a naturally curved nanocarbon based on its conical molecular geometry. It undergoes dimerization in solution via π−π stacking to form a metastable, but isolable bilayer complex. Thermodynamic and kinetic characterization reveals the dimerization process as entropy-driven and following second-order kinetics with a high activation energy. These findings provide a deeper understanding of the assembly of conical nanocarbons. Comparison of optical properties of monomer and dimer points toward a H-type interlayer coupling in the dimer., Quintulene, a quintuple non-graphitic cycloarene, is challenging to synthesize. Here, the authors synthesize and characterize the cone-shaped extended quintulene and its bilayer dimer, and disclose its dimerization as an entropy-driven, second-order reaction with a substantial activation energy.

Molecular cutout of defect-containing bilayer graphene was achieved by bottom-up synthesis and showed defect-enhanced luminesce., The electronic structure of bilayer graphene can be altered by creating defects in its carbon skeleton. However, the natural defects are generally heterogeneous. On the other hand, rational bottom-up synthesis offers the possibility of building well-defined molecular cutout of defect-containing bilayer graphene, which allows defect-induced modulation with atomic precision. Here, we report the construction of a molecular defect-containing bilayer graphene (MDBG) with an inner cavity by organic synthesis. Single-crystal x-ray diffraction, mass spectrometry, and nuclear magnetic resonance spectroscopy unambiguously characterize the structure of MDBG. Compared with its same-sized, defect-free counterpart, the MDBG exhibits a notable blue shift of optical absorption and emission, as well as a 9.6-fold brightening of its photoluminescence, which demonstrates that a single defect can markedly alter the optical properties of bilayer graphene.

Tumor microenvironment-induced ultrasmall nanodrug generation (TMIUSNG) is an unprecedented approach to overcome the drug penetration barriers across complex biological systems, poor circulation stability and limited drug loading efficiency (DLE). Herein, a novel strategy was designed to synthesize metal-organic nanodrug complexes (MONCs) through supramolecular coassembly of photosensitizer sinoporphyrin sodium, chemotherapeutic drug doxorubicin and ferric ions. Compared with the free photosensitizer, MONCs produced 3-fold more reactive oxygen species (ROS) through the energy transfer-mediated fluorescence quenching. Remarkably, the self-delivering supramolecular MONCs with high DLE acted as a potent ultrasmall-nanodrug generator in response to the mild acidic tumor microenvironment to release ultrasmall nanodrugs (5-10 nm in diameter) from larger parental nanoparticles (140 nm in diameter), which in turn enhanced the intratumor permeability and therapeutic efficacy. The key mechanism of MONC synthesis was proposed, and we, for the first time, validated the generation of supramolecular scaffold intermediates between MONCs' assembly/disassembly states, as well as their involvement in multidrug ligands interactions. This proof-of-concept TMIUSNG strategy provides a foundation for the rational design of analogous carrier-free nanotheranostics through the combination of multiple therapeutic agents and metal ions with imaging functions.

Arc-discharge of graphite is the most prevalent technique for synthesis of novel fullerenes, but the extreme conditions of the carbon arc prevent any currently available instrument from detecting the reaction species inside. To detour the difficulties for probing the derivatization mechanism in the drastic arc-discharge conditions, C78Cl6(C5Cl6) with prototypical C2v(2)-C78 cage has been isolated and characterized in the products of the chlorine-involving carbon arc. The structure of C2v(2)-C78Cl6(C5Cl6), featuring with fullerene C2v(2)-C78 doubly functionalized by chlorine atoms and perchlorinated cyclopentadiene, has been identified by X-ray crystallography. Confirmed by standard Density Functional Theory (DFT) calculations and Car-Parrinello simulations as well as mass spectrometry, the fullerene core has been revealed to form firstly followed then by reaction with chlorine atoms and afterwards with perchlorinated cyclopentadiene, with implication about stepwise reaction temperatures and sequences for the formation of fullerenes and their derivatives in the otherwise inaccessible extreme conditions of the carbon arc.

By artificial mimic of the natural [FeFe]-hydrogenases, a series of polyoxometalate-based high-nuclear Ni clusters containing a varying number of {Ni 4 O 4 } cubane cores, K 1.5 Na 26.5 [{Ni 4 (OH) 3 (PO 4 )} 4 ( A- PW 9 O 34 ) 4 ]·62H 2 O ( 1 ), Na 28 [{Ni 4 (OH) 3 (PO 4 )} 4 ( A- PW 9 O 34 ) 2 ( B- PW 9 O 34 ) 2 ]·102H 2 O ( 2 ), and Na 28 [{Ni 4 (OH) 3 (VO 4 )} 4 ( B- PW 9 O 34 ) 4 ]·74H 2 O ( 3 ), were synthesized and systematically characterized. Compounds 1 − 3 contain {Ni 16 (XO 4 ) 4 (OH) 12 } (X = P, V) core encapsulated by the trivacant A- / B- {PW 9 O 34 } ligands. Compounds 1 − 3 as homogeneous catalysts for visible-light-driven H 2 evolution indicate that they not only show high photocatalytic performance (High TON of 578.8, 679.1, and 931.1 for 1 − 3 were achieved, respectively), but also their catalytic performance was improved with the increasing number of {Ni 4 O 4 } cubanes. Multiple stability experiments confirm that compounds 1 − 3 maintain their structure intact under the photocatalytic conditions. The above research provides a platform for mimicking the structures of natural hydrogenases to further explore more efficient and inexpensive H 2 evolution catalysts.

Defect engineering has been regarded as a promising strategy for tuning the chemical modification on graphene surfaces in order to achieve novel physicochemical properties. However, there have been very few studies that have quantitatively evaluated the activating effect of defects on chemical reactivity. Here we showed the controllable chemical functionalization of single-layer graphene (SLG) by defect engineering and quantitatively evaluated the activating effects of defects on their surrounding areas on graphene by a simplified geometric model. The tunable density of the grafted aryl group on SLGs by defect engineering was demonstrated to be able to direct sequential supramolecular assembly and spatial patterning was achieved.

Full-carbon electronics at the scale of several angstroms is an expeimental challenge, which could be overcome by exploiting the versatility of carbon allotropes. Here, we investigate charge transport through graphene/single-fullerene/graphene hybrid junctions using a single-molecule manipulation technique. Such sub-nanoscale electronic junctions can be tuned by band gap engineering as exemplified by various pristine fullerenes such as C60, C70, C76 and C90. In addition, we demonstrate further control of charge transport by breaking the conjugation of their π systems which lowers their conductance, and via heteroatom doping of fullerene, which introduces transport resonances and increase their conductance. Supported by our combined density functional theory (DFT) calculations, a promising future of tunable full-carbon electronics based on numerous sub-nanoscale fullerenes in the large family of carbon allotropes is anticipated., All-carbon electronics holds promise beyond the conventional silicon-based electronics, but it remains challenging to manufacture them with well-defined structures thus tunability. Tan et al. control charge transport in single-molecule junctions using different fullerenes between graphene electrodes.

The oxygen evolution reaction is a crucial step in water electrolysis to develop clean and renewable energy. Although noble metal-based catalysts have demonstrated high activity for the oxygen evolution reaction, their application is limited by their high cost and low availability. Here we report the use of a molecule-to-cluster strategy for preparing ultrasmall trimetallic clusters by using the polyoxometalate molecule as a precursor. Ultrafine (0.8 nm) transition-metal clusters with controllable chemical composition are obtained. The transition-metal clusters enable highly efficient oxygen evolution through water electrolysis in alkaline media, manifested by an overpotential of 192 mV at 10 mA cm–2, a low Tafel slope of 36 mV dec–1, and long-term stability for 30 h of electrolysis. We note, however, that besides the excellent performance as an oxygen evolution catalyst, our molecule-to-cluster strategy provides a means to achieve well-defined transition-metal clusters in the subnanometer regime, which p...

Buckybowls are fascinating components of supramolecular assemblies owing to their unique bowl-shaped π-surfaces. Herein we present a protocol for the functionalization of a sulfur-doped buckybowl, trithiasumanene, via a brominated intermediate, from which thiolated trithiasumanenes were derived. The curved surface and electron-donating properties of thiolated trithiasumanenes promote their ready assembly with fullerenes to form concave-convex complexes. The supramolecular assembly behavior in solution was investigated by NMR analysis. The structures of supramolecular complexes were unambiguously characterized by crystallography. The crystals of the concave-convex complexes showed high thermal stability and photoconductivity.

Filiació URV: SI As a bridge to connect medium-sized fullerenes, fused-pentagon C74 is still missing heretofore. Of 14-246 possible isomers, the first fused-pentagon C74 with the Fowler-Manolopoulos code of 14-049 was stabilized as C74Cl10 in the chlorine-involving carbon arc. The structure of C74Cl10 was identified by X-ray crystallography. The stabilization of pristine fused-pentagon C74 by stepwise chlorination was clarified in both theoretical simulation with density functional theory calculations and experimental fragmentation with multistage mass spectrometry.

Porous N-doped carbon coated Co3O4 fish-scale structures were successfully fabricated via chemical transformation of a well-designed N-rich Co-MOF at 500 °C in a nitrogen atmosphere. Due to the synergistic effect between the assembled porous Co3O4 nanoparticles and the N doped C coating, the sample exhibited excellent electrochemical properties as an anode material for lithium-ion batteries. The specific capacity can remain at a stable value of about 612 mA h g−1 at a current of 1000 mA g−1 within 500 cycles.

So far the entrapped metals for the isolated endohedral metallofullerenes (EMFs) are primarily limited to rare earth metals, whereas except group-IVB metals, whether it is possible to entrap other d-block transition metals remains unclear. Herein we report the successful entrapment of the group-VB transition metal vanadium(V) into fullerene cage, affording the heretofore unknown V-containing EMFs. Two novel V-containing EMFs--V(x)Sc(3-x)N@C80 (x = 1, 2)--were isolated, and their molecular structures were unambiguously determined by X-ray crystallography to be I(h)(7)-C80 cage entrapping the planar VSc2N/V2ScN clusters. V(x)Sc(3-x)N@I(h)(7)-C80 (x = 1, 2) were further characterized by UV-vis-NIR and ESR spectroscopies and electrochemistry, revealing that the electronic and magnetic properties of V(x)Sc(3-x)N@I(h)(7)-C80 (x = 1, 2) are tunable upon varying the number of entrapped V atoms (i.e., x value). The molecular structures and electronic properties of V(x)Sc(3-x)N@I(h)(7)-C80 (x = 1, 2) were further compared with those of the reported analogous EMFs based on lanthanide metals and the adjacent group-IVB transition metal Ti, revealing the peculiarity of the group-VB transition metal V-based EMFs.

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.

Alzheimer’s disease (AD) is a neurodegenerative disease that affects cognition and behavior. The neuroinflammatory response in the brain is an important pathological characteristic in AD. In this study, we investigated the neuroprotective effects of 1-Methylnicotinamide (MNA), known as the main metabolite of nicotinamide, on reducing lipopolysaccharide (LPS)-induced cognitive deficits via targeting neuroinflammation and neuronal apoptosis. We found that the mice treated with LPS exhibited cognitive deficits in the novel object recognition, Morris water maze and Y-maze avoidance tests. However, intragastric administration of MNA (100 or 200 mg/kg) for 3 weeks significantly attenuated LPS-induced cognitive deficits in mice. Importantly, MNA treatment suppressed the protein expression of nuclear factor-kappa B p65 (NF-κB p65), pro-inflammatory cytokines (TNF-α, IL-6) and decreased the activation of microglia and astrocytes in the hippocampus and frontal cortex of LPS-induced mice. In addition, MNA treatment suppressed neuronal apoptosis by reducing the number of TUNEL-positive cells, caspase-3 activation and increasing the level of Bcl-2/Bax ratio in the hippocampus and frontal cortex. These findings indicate that MNA could be a potential neuroprotective drug in neurodegenerative diseases such as AD.

The chemical nature of the edge periphery essentially determines the physical properties of graphene. As a molecular-level model system, large polycyclic aromatic hydrocarbons, that is, so-called nanographenes, can be chemically modified through either edge functionalization or doping with heteroatoms. Although the synthetic methods for edge substitution are well-developed, incorporation with heteroatoms by the bay annulation of large PAHs remains an enormous challenge. In this study, we present a feasible peripheral sulfur annulation of hexa-peri-hexabenzocoronene (HBC) by thiolation of perchlorinated HBC. The tri-sulfur-annulated HBC and di-sulfur-annulated HBC decorated with phenylthio groups were obtained and characterized by X-ray diffraction, revealing their distinct sulfur-annulated peripheral structure. Associated with theoretical calculations, we propose that the regioselective sulfur annulation results from the minimization of strain in the aromatic backbone. We further demonstrate the structure-correlated property modulation by sulfur annulation, manifested by a decrease in band gap and tunable redox activity.

The spontaneous formation of discrete spherical nanosized molecules is prevalent in nature, but the authentic structural mimicry of such highly symmetric polyhedra from edge sharing of regular polygons has remained elusive. Here we present a novel ball-shaped {(HNEt3)[Ag37S4(SC6H4(t)Bu)24(CF3COO)6(H2O)12]} cluster () that is assembled via a one-pot process from polymeric {(HNEt3)2[Ag10(SC6H4(t)Bu)12]}n and CF3COOAg. Single crystal X-ray analysis confirmed that is a Td symmetric spherical molecule with a [Ag36(SC6H4(t)Bu)24] anion shell enwrapping a AgS4 tetrahedron. The shell topology of belongs to one of 13 Archimedean solids, a truncated tetrahedron with four edge-shared hexagons and trigons, which are supported by a AgS4 Platonic solid in the core. Interestingly, the cluster emits green luminescence centered at 515 nm at room temperature. Our investigations have provided a promising synthetic protocol for a high-nuclearity silver cluster based on underlying geometrical principles.

Buckminsterfullerene (C60) represents a perfect combination of geometry and molecular structural chemistry. It has inspired many creative ideas for building fullerene-like nanopolyhedra. These include other fullerenes, virus capsids, polyhedra based on DNA, and synthetic polynuclear metal clusters and cages. Indeed, the regular organization of large numbers of metal atoms into one highly complex structure remains one of the foremost challenges in supramolecular chemistry. Here we describe the design, synthesis, and characterization of a Ag180 nanocage with 180 Ag atoms as 4-valent vertices (V), 360 edges (E), and 182 faces (F)––sixty 3-gons, ninety 4-gons, twelve 5-gons, and twenty 6-gons––in agreement with Euler’s rule V − E + F = 2. If each 3-gon (or silver Trigon) were replaced with a carbon atom linked by edges along the 4-gons, the result would be like C60, topologically a truncated icosahedron, an Archimedean solid with icosahedral (Ih) point-group symmetry. If C60 can be described mathematically as a curling up of a 6.6.6 Platonic tiling, the Ag180 cage can be described as a curling up of a 3.4.6.4 Archimedean tiling. High-resolution electrospray ionization mass spectrometry reveals that {Ag3}n subunits coexist with the Ag180 species in the assembly system before the final crystallization of Ag180, suggesting that the silver Trigon is the smallest building block in assembly of the final cage. Thus, we assign the underlying growth mechanism of Ag180 to the Silver-Trigon Assembly Road (STAR), an assembly path that might be further employed to fabricate larger, elegant silver cages.

We report a facile synthesis of novel angularly fused bistetracene derivatives where two tetracene skeletons are cata-annulated at three benzene rings. Compared with previously described examples, our bistetracenes exhibit a narrower HOMO–LUMO gap but still exhibit high stability. Attempted synthesis of di-substituted bistetracene (BT-2TIPS) also led to unexpected triple (BT-3TIPS) and four-fold (BT-4TIPS) alkylsilylethynyl substitution. The photophysical, electrochemical and optical properties as well as the solid-state structure of these three bistetracene analogues are investigated. A charge carrier mobility up to 0.42 cm2 V−1 s−1 was determined based on field effect transistors.

In search of functional molecular materials and the study of their formation mechanism, we report the elucidation of a hierarchical step-by-step formation from monomer (Mn) to heptamer (Mn7) to nonadecamer (Mn19) satisfying the relation 1 + Σn6n, where n is the ring number of the Brucite structure using high-resolution electrospray ionization mass spectrometry (HRESI-MS). Three intermediate clusters, Mn10, Mn12, and Mn14, were identified. Furthermore, the Mn19 disc remains intact when dissolved in acetonitrile with a well-resolved general formula of [Mn19(L)x(OH)y(N3)36-x-y](2+) (x = 18, 17, 16; y = 8, 7, 6; HL = 1-(hydroxymethyl)-3,5-dimethylpyrazole) indicating progressive exchange of N3(-) for OH(-). The high symmetry (R-3) Mn19 crystal structure consists of a well-ordered discotic motif where the peripheral organic ligands form a double calix housing the anions and solvent molecules. From the formula and valence bond sums, the charge state is mixed-valent, [Mn(II)15Mn(III)4]. Its magnetic properties and electrochemistry have been studied. It behaves as a ferrimagnet below 40 K and has a coercive field of 2.7 kOe at 1.8 K, which can be possible by either weak exchange between clusters through the anions and solvents or through dipolar interaction through space as confirmed by the lack of ordering in frozen CH3CN. The moment of nearly 50 NμB suggests Mn(II)-Mn(II) and Mn(III)-Mn(III) are ferromagnetically coupled while Mn(II)-Mn(III) is antiferromagnetic which is likely if the Mn(III) are centrally placed in the cluster. This compound displays the rare occurrence of magnetic ordering from nonconnected high-spin molecules.

Two monoxides of typical smaller chlorofullerenes, (#271)C50Cl10O and (#913)C56Cl10O, featured with double-fused-pentagons, were synthesized to demonstrate further regioselective functionalization of non-IPR (IPR = isolated pentagon rule) chlorofullerenes. Both non-IPR chlorofullerene oxides exhibit an epoxy structure at the ortho-site of fused pentagons. In terms of the geometrical analysis and theoretical calculations, the principles for regioselective epoxy oxidation of non-IPR chlorofullerenes are revealed to follow both "fused-pentagon ortho-site" and "olefinic bond" rules, which are valuable for prediction of oxidation of non-IPR chlorofullerenes.

The catalytic performances of bifunctional vanadium oxide supported on Hβ zeolite with redox and acid properties were investigated for dimethyl ether (DME) direct oxidation to polyoxymethylene dimethyl ethers (DMMx) (x=1-2). The best catalytic performance was obtained over 15%V2O5/Hβ. The catalysts were characterized by XRD, BET, NH3-TPD, H2-TPR, XPS and FT-IR in order to provide the further insight in the relationship of structure and activity. When the loading content of vanadium oxide was 15%, the presence of oxide species was dominantly the polymeric vanadia. The addition of vanadium oxide to the H-beta zeolite not only provided redox sites, but also changed the acid strength and distribution of H-beta zeolite as confirmed by NH3-TPD measurement, and the positive correlation was found between the DMMx selectivity and the ratio of weak and strong acid sites. The introduction of vanadium oxide with appropriate amount to the H-beta zeolite promoted the balance between the acid sites and redox sites, which was very vital for obtaining high DMMx selectivity.

Here we report hexathienocoronenes (HTCs), fully thiophene-annelated coronenes in which six double bonds in the periphery are thieno-fused. The derivatives tetrasubstituted with hexyl and dodecyl chains show a phase formation that strongly depends on the chain length. HTCs are remarkably stronger donors than the known thiophene-annelated coronenes but do not readily assemble into well-ordered films when deposited from the vapor phase. Thus, thin-film transistors fabricated by vacuum deposition have only modest field-effect mobilities of 0.002 cm(2) V(-1) s(-1).

The triple sequentially fused pentagons (TSFP) motif is one of the basic subunits that could be used for constructing fullerenes, but it violates the isolated pentagon rule (IPR) and has not been found in carbon cages to date. The properties of TSFP-incorporating fullerenes are thus poorly explored both theoretically and experimentally. Reported herein are four chlorinated derivatives of three different fullerene cages, all with the TSFP motif. X-ray crystallographic analyses indicate that the molecular strain inherent to the pentagon adjacency of a TSFP is significantly relieved upon exohedral chlorination, leaving one of the four pentagon fusion sites unsaturated and rendering the present derivatives chiral. This unique reactivity, in stark contrast to that of previously reported non-IPR fullerenes containing double fused pentagons or triple directly fused pentagons, can be rationalized by density functional theory calculations, and are expected to stimulate further studies of these new members of the fullerene family, both theoretically and experimentally.

Pure non-IPR (isolated-pentagon-rule) C 60 isomer has rarely been investigated experimentally. The recently reported availability of #1809 C 60 Cl 8 opens an avenue for experimental investigation of #1809 C 60 , a C 2v -symmetric C 60 isomer having two pairs of fused pentagons. Herein, the experiments on #1809 C 60 were performed on the basis of thermal dechlorination of #1809 C 60 Cl 8 in the solid state and gas phase. #1812 C 60 Cl 6 was employed for comparative study. As determined by Raman and other methods, #1809 C 60 from thermal decomposition of #1809 C 60 Cl 8 crystals readily coalesces to form carbon solid with a collapsed crystal lattice. In contrast, dechlorination via thermal spray of #1809 C 60 Cl 8 in the gas phase is feasible for investigation of monodispersed all-carbon C 60 isomer, because the existence of #1809 C 60 in the gas phase has been confirmed by experimental evidence from mass spectrometry and high-performance-liquid-chromatography.

The most stable fullerenes obey the isolated-pentagon rule (IPR): hexagons of carbon atoms entirely surround pentagons to minimize strain. Recently, some examples of fused-pentagon fullerenes have been reported and this Review summarizes current work to stabilize non-IPR fullerenes. The isolated pentagon rule (IPR) is now widely accepted as a general rule for determining the stability of all-carbon fullerene cages composed of hexagons and pentagons. Fullerenes that violate this rule have been deemed too reactive to be synthesized. The stabilization of non-IPR endohedral fullerenes depends on charge transfer from the encapsulated metal clusters (endoclusters) to fullerene cages, the electronic properties of empty all-carbon cages, the matching size and geometries of fullerene and endocluster, as well as the strong coordination of the metal ions to fused pentagons. The stability of non-IPR exohedral fullerenes can be rationalized primarily by both the 'strain-relief' and 'local-aromaticity' principles. This Review focuses on recent work on stabilization of non-IPR fullerenes, including theoretical and empirical principles, experimental methods, and molecular structures of fused-pentagon fullerenes characterized so far. The special chemical properties of non-IPR fullerenes that distinguish them from IPR-satisfying ones are also emphasized.

One abiding surprise in fullerene science is that I(h)-symmetric buckminsterfullerene C(60) (ref. 1) (I(h)-C(60) or (#1,812)C(60), the nomenclature specified by symmetry or by Fowler's spiral algorithm) remains the sole C(60) species experimentally available. Setting it apart from the other 1,811 topological isomers (isobuckminsterfullerenes) is its exclusive conformity with the isolated-pentagon rule, which states that stable fullerenes have isolated pentagons. Although gas-phase existence of isobuckminsterfullerenes has long been suspected, synthetic efforts have yet to yield successful results. Here, we report the realization of two isobuckminsterfullerenes by means of chlorination of the respective C(2v)- and C(s)-symmetric C(60) cages. These chlorinated species, (#1,809)C(60)Cl(8)(1) and (#1,804)C(60)Cl(12)(2), were isolated in experimentally useful yields. Structural characterization by crystallography unambiguously established the unique pentagon-pentagon ring fusions. These distinct structural features are directly responsible for the regioselectivity observed in subsequent substitution of chlorines, and also render these unprecedented derivatives of C(60) isomers important for resolving the long-standing puzzle of fullerene formation by the Stone-Wales transformation scheme.

A general class of C3 -symmetric Ag9 clusters, [Ag9 S(tBuC6 H4 S)6 (dpph)3 (CF3 SO3 )] (1), [Ag9 (tBuC6 H4 S)6 (dpph)3 (CF3 SO3 )2 ]⋅CF3 SO3 (2), [Ag9 (tBuC6 H4 S)6 (dpph)3 (NO3 )2 ] ⋅NO3 (3), and [Ag9 (tBuC6 H4 S)7 (dpph)3 (Mo2 O7 )0.5 ]2 ⋅2 CF3 COO (4) (dpph=1,6-bis(diphenylphosphino)hexane), with a twisted trigonal-prism geometry was isolated by the reaction of polymeric {(HNEt3 )2 [Ag10 (tBuC6 H4 S)12 ]}n , 1,6-bis(diphenylphosphino)hexane, and various silver salts under solvothermal conditions. The structures consist of discrete clusters constructed from a girdling Ag9 twisted trigonal prism with the top and bottom trigonal faces capped by diverse anions (i.e., S(2-) and CF3 SO3 (-) for compound 1, 2×CF3 SO3 (-) for compound 2, 2×NO3 (-) for compound 3, and tBuC6 H4 S(-) and Mo2 O7 (2-) for compound 4). This trigonal prism is bisected by another shrunken Ag3 trigon at its waist position. Interestingly, two inversion-related Ag9 trigonal-prismatic clusters are dimerized by the Mo2 O7 (2-) ion in compound 4. The twist is amplified by the bulkier thiolate, which also introduces high steric-hindrance for the capping ligand, that is, the longer dpph ligand. Four more silver-sulfur clusters (namely, compounds 5-8) with their nuclearity ranging from 6-10 were solely characterized by single-crystal X-ray diffraction to verify the above-described synergetic effect of mixed ligands in the construction of Ag9 twisted trigonal prisms. Surprisingly, only cluster 1 emits yellow luminescence at λ=584 nm at room temperature, which may be attributed to a charge transfer from the S 3p orbital to the Ag 5s orbital, or mixed with metal-centered (MC) d(10) →d(9) s(1) transitions. Upon cooling from 300 to 80 K, the emission intensity was enhanced along with a hypsochromic shift. The good linear relationship between the maximum emission intensity and the temperature for compound 1 in the range of 180-300 K indicates that this is a promising molecular luminescent thermometer. Furthermore, cyclic voltammetric studies indicated that the diffusion- and surface-controlled redox processes were determined for compounds 1 and 3 as well as compound 4, respectively.

Atomically precise polyoxometalate-Ag2 S core-shell nanoparticles were generated in a top-down approach under solvothermal conditions and structurally confirmed by X-ray single-crystal diffraction as an interesting core-shell structure comprising an in situ generated Mo6 O22 (8-) polyoxometalate core and a mango-like Ag58 S38 shell. This result demonstrates the possibility to integrate polyoxometalate and Ag2 S nanoparticles into a core-shell heteronanostructure with precisely controlled atomical compositions of both core and shell.

The long-sought small-bandgap endohedral fullerene Sc3N@C82 with low kinetic stability has been successfully synthesized and isolated for the first time, for which the molecular structure has been unambiguously determined as Sc3N@C82-C2v(39718) by single crystal X-ray diffraction. The C82-C2v(39718) (or labeled as C82-C2v(9) according to the conventional numbering of the isolated pentagon rule (IPR) isomers based on the Fowler-Monolopoulos spiral algorithm) isomeric cage of Sc3N@C82 agrees well with its most stable isomer previously predicted by DFT computations and is dramatically different to those of the reported counterparts M3N@C82-Cs(39663) (M = Gd, Y) based on a non-IPR C82 isomer, revealing the strong dependence of the cage isomeric structure on the size of the encaged metal for C82-based metal nitride clusterfullerenes (NCFs).

Graphene nanoribbons (GNRs), defined as nanometer-wide strips of graphene, have attracted increasing attention as promising candidates for next-generation semiconductors. Here, we demonstrate a bottom-up strategy toward novel low band gap GNRs (E-g = 1.70 eV) with a well-defined cove-type periphery both in solution and on a solid substrate surface with chrysene as the key monomer. Corresponding cyclized chrysene-based oligornerS consisting of the dimer and tetramer are obtained via an Ullmann Coupling followed by oxidative intramolecular cyclodehydrogenation in solution, and much higher GNR homologues via on-surface synthesis. These oligomers adopt nonplanar structures due to the isteric repulsion between the two C-H bonds at the inner cove position. Characterizations by single crystal X-ray analysis, UV-vis absorption spectroscopy, NMR spectroscopy, and scanning tunneling microscopy (STM) are described. The interpretation is assisted by density functional theory (DFT) calculations.

National Basic Research 973 Program of China [2011CB935901]; National Nature Science Foundation of China [21031004, 21021061]; NFFTBS [J1030415]

通讯作者地址: Xie, SY (通讯作者),Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 2. Xiamen Univ, Dept Chem, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 电子邮件地址: syxie@xmu.edu.cn