The asymmetric unit of the title solvate, C21H22N2O2·CH3OH, contains one methanol solvent mol-ecule and one mol-ecule of the heterocycle that is built up by the fusion of four six-membered rings A, C, D, E and one five-membered ring B. The indole moiety (rings A and B) is essentially planar, with an r.m.s. deviation of 0.013 Å, whereas rings C and D adopt a twisted conformation with a trans-rin...

The title compound, C(21)H(30)O(6), a natural ent-kaurane diterpenoid, was obtained from the medicinal plant Isodon serra. The five rings in the mol-ecule exhibit the expected cis and trans junctions. The three six-membered rings adopt chair, twist-boat and boat conformations, while two five-membered rings adopt envelope conformations. There are two mol-ecules in the asymmetric unit, related by...

The title compound, C(23)H(20)N(2)O(7), consists of three fused six-membered rings (A, B and C) and one five-membered ring (D), linked to two ethyl acetate groups. The four fused rings are slightly folded around the O=C⋯C=O direction of the anthraquinone system, with a dihedral angle of 3.07 (8)° between the fused five- and six-membered rings (C and D) and the terminal ring (A). The planes thro...

The distorted octa-hedral geometry about the Sn(IV) atom in the title compound, [Sn(C(6)H(5))(2)(C(14)H(19)N(4)S)Cl], is defined by the N,N,S-tridentate Schiff base ligand, two mutually trans ipso-C atoms of the Sn-bound phenyl groups, and the Cl atom which is trans to the azo N atom. The two five-membered chelate rings and pyridyl ring are almost coplanar with the dihedral angle between the ou...

The equilibrium molecular structure of the decasilsesquioxane, Si(10)O(15)H(10), in the gas phase has been determined by gas electron diffraction. Molecular dynamics calculations were used to give amplitudes of vibration and differences between interatomic distances in the equilibrium structure and the vibrationally averaged distances that are given directly by the diffraction data. The molecul...

Polycyclic aromatic hydrocarbons (PAHs) in which five-membered rings have been interspersed among the six-membered rings generally display curved p systems that can be either fully closed (fullerenes) or partially open (bowl-shaped fullerene fragments), depending on the number of five-membered rings. Both classes of compounds belong to the larger family we call ‘GEODESIC POLYARENES.’ Herein, we...

In the title compound, C(18)H(26)O(3)S(8), the two five-membered rings exhibit envelope conformations. The two S atoms in the 17-membered macrocycle deviate from the plane of the fused five-membered ring by 1.429 (3) and -1.434 (3) Å in opposite directions.

In the title mol-ecule, C(20)H(26)O(3), a clerodane diterpenoid isolated from Dodonaea viscosa-, the trans-fused six-membered rings of the deca-line system display chair conformations. The five-membered lactone ring adopts an envelope conformation and the five-membered furan ring is essentially planar with a maximum deviation of 0.0052 (12) Å.

The mol-ecular structure of the title compound, C(28)H(20)N(4)O(6), consists of three fused six-membered rings (A,B,C) and one five-membered ring (D). The latter is linked to an isoxazole ring (E) via a methyl-ene unit. A 4-nitro-phenyl substituent (F) is attached to the isoxazole. The fused five and six-membered rings (C,D) are almost coplanar with an r.m.s. deviation of 0.0345 Å and make a di...

We suggest four new benzene dimers, (C(6)H(6))(2), all featuring one or more cyclohexadiene rings trans-fused to 4- or 6-membered rings. These hypothetical dimers are 50-99 kcal/mol less stable than two benzenes, but have computed activation energies to fragmentation ≥27 kcal/mol. A thorough search of potential escape routes was undertaken, through cyclobutane ring cleavage to 12-annulenes, sig...