A carbon heptagon ring is a key unit responsible for structural defects in sp2-hybrized carbon allotropes including fullerenes, carbon nanotubes and graphenes, with consequential influences on their mechanical, electronic and magnetic properties. Previous evidence concerning the existence of heptagons in fullerenes has been obtained only in off-line halogenation experiments through top-down detachment of a C2 unit from a stable fullerene. Here we report a heptagon-incorporating fullerene C68, tentatively named as heptafullerene[68], which is captured as C68Cl6 from a carbon arc plasma in situ. The occurrence of heptagons in fullerenes is rationalized by heptagon-related strain relief and temperature-dependent stability. 13C-labelled experiments and mass/energy conservation equation simulations show that heptafullerene[68] grows together with other fullerenes in a bottom-up fashion in the arc zone. This work extends fullerene research into numerous topologically possible, heptagon-incorporating isomers and provides clues to an understanding of the heptagon-involved growth mechanism and heptagon-dependent properties of fullerenes.

Chemical manipulation of fullerenes has allowed the production of heptagon-containing fullerenes, but they have not been synthesised using bottom-up approaches. Here, a heptagon-containing fullerene[68] is obtained as C68Cl6 from a carbon arc plasma.

Reaction of AgNO3 and 2,2′-bipyridine (bipy) under ultrasonic treatment gave the title compound, [Ag(C10H8N2)(NH3)]NO3. The crystal structure consists of dimers formed by two symmetry-related AgI–bipy monomers connected through intra-dimer π–π stacking and ligand-unsupported Ag⋯Ag inter­actions. A crystallographic C2 axis passes through the mid-point of and is perpendicular to the Ag⋯Agi(−x + 1, y, −z + ) axis. In addition, each AgI cation is coordinated by one chelating bipy ligand and one ammine ligand, giving a trigonal coordination environment capped by the symmetry-equivalent Ag atom. Mol­ecules are assembled by Ag⋯Ag, π–π, hydrogen-bond (N—H⋯O and C—H⋯O) and weak Ag⋯π inter­actions into a three-dimensional framework. Comparing the products synthesized under different mechanical treatments, we found that reaction conditions have a significant influence on the resulting structures. The luminescence properties of the title compound are also discussed.

In the title compound, C12H9NOS, the sulfoxide O atom is disordered over two sites with occupancies of 0.907 (4) and 0.093 (4). The dihedral angle betweeen the two aromatic rings is 18.40 (14)°. Different types of supramolecular interactions including inter­molecular N—H⋯O hydrogen bonds and π–π contacts [centroid–centroid distances = 3.9096 (16) and 4.1423 (16) Å] between the aromatic rings of symmetry-related mol­ecules are observed in the crystal structure.

In the title compound, {[Zn(C8H3NO6)(C10H8N2)(H2O)]·H2O}n, the ZnII ion is square-pyramidally coordinated, and bridged by 2-nitro-terephthalate ligands, forming a chain running along [10]. Intra­molecular hydrogen bonds are formed between the coordinated water mol­ecules and the nitro O atoms. Adjacent chains are linked by hydrogen bonds between the coordinated water mol­ecules and the O atoms of the monodentate carboxyl groups.

In the title compound, [Ag(NH3)2]2(C8H3NO6)·H2O, the cations have an almost linear coordination geometry with two ammine ligands and inter­act with the water mol­ecules [Ag⋯Owater = 2.725 (4) and 2.985 (4) Å]. In the crystal, N—H⋯O and O—H⋯O hydrogen bonds, combined with weak (lone pair)⋯π [O⋯centroid distance = 3.401 (4) Å] and π–π stacking [centroid–centroid distance = 3.975 (3) Å] inter­actions, stabilize the three-dimensional supra­molecular network.

The asymmetric unit of the title polymeric compound, [Zn3(C10H8O4)3(C5H5N)2]n or [Zn3(dmbdc)3(py)2]n (dmbdc = 2,5-dimethyl­benzene­dicarboxyl­ate; py = pyridine) contains two Zn(II) ions, one of which is located on an inversion centre, one and a half 2,5-dimethyl­benzene­dicarboxyl­ate ligands and one pyridine ligand. Each ZnO6 octa­hedron is sandwiched between two ZnO4N square-pyramids, forming a trinuclear zinc secondary building unit (SBU); each SBU is further linked by six 2,5-dimethyl­benzene­dicarboxyl­ate ligands with six adjacent trinuclear zinc SBU’s, forming a two-dimensional layer structure with a (3,6) net. One of the three zinc ions is octa­hedrally coordinated and the other two are square-pyramidally coordinated. The coordination modes for 2,5-dimethyl­benzene­dicarboxyl­ates are bis­(bidentate) or bidentate-tridentate.

The title compound, C13H9BrO, has been synthesized by the intra­molecular Friedel–Crafts reaction of 1-(1-bromo-4-naphth­yl)-3-chloro­propan-1-one. There are two approximately planar [maximum deviations of 0.8 (2) and 0.4 (2) Å in the two mol­ecules] molecules in the asymmetric unit. The dihedral angle between their mean planes is 19.72 (8)°. Weak inter­molecular C—H⋯O hydrogen bonding is present in the crystal structure.

The asymmetric unit of the title compound, [Zn5(C12H12O4)4(OH)2(C10H8N2)]n, consists of three ZnII ions (one of which is located on a twofold rotation axis), two 5-tert-butyl­isophthalate ligands, one 4,4′-bipyridine ligand and one hydroxide group. The five ZnII ions form a penta­nuclear zinc cluster, which is further bridged by ten organic ligands, forming two-dimensional sheets. The central zinc ion of the cluster has site symmetry 2 and is octahedrally coordinated in a N2O4 donor set, whereas the other four zinc atoms are tetrahedrally coordinated by four O atoms. The coordination modes for the 5-tert-butyl­isophthalates are bis­(bidentate) or bidentate-monodentate. Hydrogen bonds are formed between adjacent sheets through the hydroxide groups and the O atoms of the monodentate carboxyl­ate groups. The two tert-butyl groups are disordered over two positions with ratios of 0.64 (2):0.36 (2) and 0.85 (3):0.15 (3).

In the title compound, C15H8O, the asymmetric unit contains four independent mol­ecules and crystallizes with aromatic π–π stacking inter­actions[centroid–centroid distances = 3.5326 (18) Å].

In the title compound, C4H3ClO3, mol­ecules are linked via O—H⋯O hydrogen bonds into an infinite chain with graph-set motif C(6) along the c axis.

The mol­ecule of the title compound, C17H10O, is nearly planar, the largest deviation from the mean plane being 0.06 Å. The crystal structure is governed by π–π inter­actions, with centroid–centroid distances ranging from .559 to 3.730 Å.

The asymmetric unit of the title compound [Zn8(C16H12N2O4)4(H2O)4]·6C3H7NO, consists of eight ZnII cations, four tetra­valent anionic ligands, L 4− (L 4− = 3,3′-(1E,1′E)-(ethane-1,2-diylbis(azan-1-yl-1-yl­idene))bis­(methan-1-yl-1-yl­idene)dibenzene-1,2-bis­(olate), four coordinated water mol­ecules and six N,N-dimethyl­formamide solvate mol­ecules. The coordination complex comprises an octa­nuclear ZnII unit with its ZnII centers coordinated in two discrete distorted square-pyramidal geometries. Four ZnII atoms each coordinate to two nitro­gen atoms and two phenolate oxygen atoms from an individual L 4− ligand and one coordinated water mol­ecule. The other four ZnII atoms each bind to five phenolate oxygen atoms from three different L 4− ligands. In the crystal structure, the ZnII complex unit, coordinated water mol­ecules and dimethyl­formamide solvate mol­ecules are linked via O—H⋯O and C—H⋯O hydrogen bonds. Mol­ecules are connected by additional inter­molecular O—H⋯O and C—H⋯O hydrogen bonds, forming an extensive three dimensional framework.