The title compound, C26H18, consists of a benzene ring with meta-substituted 1-naphthalene substituents, which are essentially planar (r.m.s. deviation = 0.039 and 0.027 Å). The conformation is mixed syn/anti, with equivalent torsion angles about the benzene–naphthalene bonds of 121.46 (11) and 51.58 (14)°.

The title compound, C26H18, consists of a benzene ring with meta-substituted 2-naphthalene substituents, which are essentially planar [r.m.s. deviations = 0.022 (1) and 0.003 (1) Å]. The conformation is syn, with equivalent torsion angles about the benzene–naphthalene bonds of −36.04 (13) and +34.14 (13)°. The mol­ecule has quasi-C s mol­ecular symmetry.

The title compound, C32H40N2O4, is a 1,10-diaza-18-crown-6 cryptand with an o-terphenyl bridge. In the polyether ring, two adjacent –CH2– groups are disordered with very nearly equal populations of two conformers. The ordered bond lengths are normal, with average C—C = 1.511 (3) Å, C—O = 1.421 (3) Å, and C—N = 1.466 (4) Å. The r.m.s. deviations of the three rings of the terphenyl bridge vary from 0.007 to 0.009 Å and the two rings ortho to one another are twisted by 50.75 (5) and 47.76 (4)° with respect to the third ring. The N⋯N distance is 5.408 (1) Å.

The dirhodium complex, [Rh2(C18H15P)4(CO)2]·2(CH3)2CO, has crystallographic twofold symmetry and the Rh—Rh distance is 2.6266 (8) Å. The four atoms proximate to each Rh atom [Rh—P = 2.3222 (7) and 2.3283 (8) Å, and Rh—C = 1.961 (3) and 2.045 (3) Å] form a distorted tetra­hedron with large deviations from the putative tetra­hedral angles [r.m.s. deviation = 23 (1)°]. The six angles more closely approximate those of a trigonal bipyramid [r.m.s. deviation = 14 (1)°] with one missing equatorial ligand. The two bridging carbonyl ligands are much more linearly coordinated to one Rh [Rh—C O = 151.0 (2)°] than to the other [127.0 (2)°], and the two Rh2CO planes form a dihedral angle of 45.43 (5)°. The two acetone solvent mol­ecules are disordered, and their estimated scattering contribution was subtracted from the observed diffraction data using the SQUEEZE routine in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148–155].

The title compound, C34H30N4O2, lies on an inversion center and consists of two 3-substituted-1H-indole units linked by a 1,2-dimethyl­enehydrazine bridge. It is one of numerous examples in which two aromatic ring systems are joined by this 4-atom bridge. The geometry of the centrosymmetric bridge is: C(arom)—C = 1.444 (3), C=N = 1.284 (3), N—N = 1.414 (4) Å, C(arom)—C=N = 122.6 (2) and C=N—N = 111.9 (2)°. The nine non-H atoms of the indole unit lie in a plane (δr.m.s. = 0.0089 Å) which is twisted 6.0 (2)° with respect to the hydrazine bridge plane. The benzyl­oxymethyl substituents do not lie in the plane of the rest of the mol­ecule and are in a folded rather than an extended conformation. This is described by the three torsion angles in the middle of the C=N—C—O—CBz group, viz. 98.5 (3), −62.1 (3), and −66.3 (2)°.

The title compound, C12H14O3, is a natural product derived from the medium-sized hawthorn Crataegus persimilis (’prunifolia’). The mean plane of the butene moiety is twisted by 13.27 (7)° with respect to the that of the dioxobenzaldehyde moiety. There is an intra­molecular hydrogen bond between the hydroxyl group and the carbonyl O atom.

In the title complex, [Cu(C15H19N2)2] or [Cu(L 2)] (HL is 3,3′,4,4′,5,5′-hexa­methyl­pyrromethene), the CuII atom is coordinated by four N atoms [Cu—N 1.939 (2)–1.976 (2) Å] from two L ligands in a distorted tetra­hedral geometry. The mean planes of the CuN2C3 metallocyclic rings form a dihedral angle of 72.73 (6)°. In the L ligands, the pyrrole rings are inclined to each other at dihedral angles of 3.03 (7) and 9.83 (7)°. The crystal packing exhibits weak inter­molecular C—H⋯π inter­actions, which form chains in [100].

In the title solvate, [Rh2(C22H18N2O2)(C8H12)2]·CH2Cl2, each organometallic mol­ecule is composed of two RhI cations, the tetra­dentate dianion α,α′-bis­(salicylaldiminato)-m-xylene and two 1,5-cyclo­octa­diene (COD) ligands. Each RhI atom is coordinated by one O atom [Rh—O = 2.044 (2) and 2.026 (2) Å], one N atom [Rh—N = 2.083 (2) and 2.090 (2) Å], and one COD ligand via two η2-bonds, each directed toward the mid-point of a C=C bond (Cg): Rh—Cg = 2.007 (2), 2.013 (2), 2.000 (2) and 2.021 (2) Å. Each RhI atom has a quasi-square-planar coordination geometry, with average r.m.s. deviations of 0.159 (1) and 0.204 (1) Å from the mean planes defined by Rh and the termini of its four coordinating bonds. The two COD ligands have quasi-C 2 symmetry, twisted from ideal C 2v symmetry by 30.0 (3) and −33.1 (3)°, and are quasi-enanti­omers of one another. The intra­molecular Rh⋯Rh distance of 5.9432 (3) Å suggests that there is no direct metal–metal inter­action.

The title compound, C15H17NO2S, exhibits intra­molecular hydrogen bonding between the amine H atom and a sulfonyl O atom. The conformation of the mol­ecule is described by the four PhCH2—NH—CH2—CH2—SO2Ph torsion angles of 79.6 (2), −166.21 (14), −70.29 (17) and −58.93 (13)°.

The title compound, C24H26O2Si2, has C 2 crystallographic symmetry. The dihedral angle between the aromatic rings is 84.5 (2)°. The acetyl­ene group is slightly non-linear, with angles at the acetyl­ene C atoms of 175.7 (2) and 177.0 (2)°. In the crystal structure, only van de Waals interactions occur.

The title compound, C18H14O, is polymorphic at 123 K. The ortho­rhom­bic form reported herein has two independent mol­ecules in the asymmetric unit, with mol­ecular volume 313.5 Å3. The previously reported triclinic (P-1) form [Raston & Scott (2000 ▶). Green Chem., 2, 49–52] has mol­ecular volume 309.6 Å3 at the same temperature. All three mol­ecules deviate significantly and systematically from the putative Cs symmetry (δr.m.s. = 0.0265, 0.0256, 0.0497 Å). Comparison of the two molecules in the orthorhombic polymorph shows that 16 of the 19 equivalent pairs of framework atoms have a mirror-image pattern of deviations (above/below plane), suggesting that the two are quasi-enanti­omorphs. The pattern of deviations in the triclinic form is nearly the same (13 of 19 atom pairs) as the ortho­rhom­bic form.

The title compound C20H20O4S, is polymorphic. In the tetra­gonal form, the mol­ecule lies on a crystallographic twofold axis, while the monoclinic form has only approximate C 2 mol­ecular symmetry. The greatest excursion from C 2 symmetry is in the orientation of the two phenyl rings; at 100 K, one of the rings is rotated −37.2 (3)° and the other by 46.9 (3)° from their symmetric (tetra­gonal) positions. There are only minor differences in the three-ring nucleus; the best mol­ecular fit of the tetra­gonal and monoclinic forms, both at 100 K and excluding phenyl rings and H atoms, shows an r.m.s. deviation of 0.066 Å. Both forms have the same absolute configuration.

The title mol­ecule, C20H24O2, is a chalconoid derivative in which the keto–enone group is slightly distorted from planarity; the O=C—C=C torsion angle is 12.24 (13)°.

In the title HBr salt of (S)-homoserine lactone, C4H8NO2 +·Br−, the five-membered ring has an envelope conformation, with the –CH2– C atom adjacent to the N-substituted C atom at the flap position. The four-atom mean plane (r.m.s. deviation = 0.005 Å) of the envelope forms a dihedral angle of 32.12 (9)° with the three-atom flap plane. The distorted square-pyramidal coordination about the anion involves five surrounding cations, with the square base defined by three N—H⋯Br hydrogen bonds [Br⋯N = 3.3046 (10), 3.3407 (12) and 3.3644 (13) Å] and near-contact with an H atom attached to C [Br⋯C = 3.739 (1) Å]. Another Br⋯C contact of 3.427 (1) Å defines the apex. There is also an N—H⋯O hydrogen bond present linking the cations.

The title compound, C30H18Cl6O3·0.82CH2Cl2, consists of a slightly cup-shaped seven-ring truxene nucleus with hy­droxy and dichloro­methyl substituents at stereocenters 5R/S, 10R/S and 15R/S. C—Cl distances are in the range 1.759 (4)–1.783 (3) Å. Solvent channels parallel to the b axis appear to be partially occupied by highly disordered dichloro­methane solvent mol­ecules, the contribution of which were removed from the refinement with the SQUEEZE procedure in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148–155]. Only one of the OH groups forms a hydrogen bond, which is inter­molecular to another OH group, forming centrosymmetric dimers in the crystal.

The title compound, C11H23NO5P+·I−, consists of an eight-membered cationic heterocyclic ring in a boat–chair conformation. The ring features a tetra­alkyl­ammonium N and a methyl­phospho­nate P atom. A –CH2(CO)OC2H5 ester side chain at the C adjacent to oxygen produces two chiral centers at that substituted C atom and the P atom, both of which were determined to have absolute R,R configurations. A previously determined racemic bromide analog has exactly the same ring but with a –C15H31 side chain. In that structure, both chiral centers show the same relative R/S,R/S configurations, but the ring in the bromide analog is in a boat conformation.

The title compound, C48H40, is a tetra­isopropyl-substituted polyannulenoenyne. The unsubstituted polyannulenoenyne, C36H16 (CSD: RICVEE; CAS: 186494-87-1), has quasi-D 2 (222) symmetry, as determined by least-squares fit (excluding H atoms) to a model optimized in D 2 symmetry by mol­ecular mechanics (r.m.s. deviation = 0.239 Å). The least-squares fits of 36 common C atoms of the title compound (at 90 K) to the parent (at 295 K) and to the optimized model show r.m.s. deviations of 0.419 and 0.426 Å, respectively.

The title mol­ecule, C30H24, was prepared as a possible precursor to buckminsterfullerene cages. The two enanti­omers adopt the anti configuration, with one S/R and two R/S methyl groups, one anti to the other two. The truxene framework is slightly non-planar: with respect to the central six-ring mean plane, the three methyl C atoms are 1.377 (3), −1.475 (3) and 1.515 (3) Å distant, whereas the respective proximate peripheral six-ring mean planes make dihedral angles of 6.27 (6), 3.45 (7) and −7.37 (7)°.

In the title compound, C26H24, the central cyclo­octa­tetra­ene ring has a boat conformation, and the mol­ecule is saddle shaped. The seat is defined by the mean plane of the four-atom attachment points (r.m.s. deviation = 0.014 Å) of the two bicyclo­heptane substituents. These substituents comprise the pommel and cantle, with each mean plane defined by four atoms proximate to the seat (r.m.s. deviations = 0.001 and 0.000 Å). Relative to the seat, the pommel and cantle bend up 33.36 (5) and 34.22 (4)°, while the benzo units (flaps, r.m.s. deviations = 0.008 and 0.013 Å) bend down 33.48 (4) and 36.58 (4)°.

The title compound, C24H42N2O7, is a chiral lactam-constrained amino acid with a six-membered ring backbone and isopropyl and tert-butyl ester side chains. The conformation of the six-membered ring can be described as a half chair, with two CH2 C atoms lying 0.443 (1) and −0.310 (1) Å out of the best plane of the other four atoms (mean deviation = 0.042 Å). Both N atoms are sp 2 hybridized, lying 0.0413 (9) and 0.067 (1) Å out of the planes defined by the three C atoms bonded to them. The absolute configuration was determined, based on resonant scattering of light atoms in Cu Kα radiation.

In the title compound, C13H18O3SSi, the SO3 group displays a partial rotational (ca 50°) disorder about the C—S bond, with relative proportions 0.7744 (13):0.2256 (13). This disorder also forces the propynyl CH2 group to be disordered.

The crystal structure of the title compound, C12H11NS, features parallel chains of alternating N—H⋯S hydrogen-bonded mirror-image conformers along [10]. The mol­ecular conformation is that of an envelope, with all of the framework atoms except one close to a mean plane (rms deviation 0.054 Å); one C atom of the cyclo­hexene­thione ring forms the envelope flap, which makes a dihedral angle of 48.6 (1)° with the rest of the mol­ecule. There is a π–π* inter­action between pairs of enanti­omers in adjacent chains; the distance between parallel planes is 3.466 (1) Å.

The title compound, C33H24O6·0.17H2O, which is commonly known as (SR,SR,SR)-trimethyl 1,10,19-truxentricarboxyl­ate, crystallizes as a hydrate with the water mol­ecule encapsulated between three ester groups by O—H⋯O hydrogen bonding to two of them. The water mol­ecule site is not fully occupied in the crystal studied, with a refined site occupancy of 0.167 (5). The 27-atom ring system is approximately planar, with a maximum deviation of 0.148 (1) Å, and the three ester substituents are all on the same side of this plane.

The title compound, C19H24O6, is a sesquiterpene lactone isolated from the Kenyan plant Warburgia ugandensis. Ring A adopts a chair conformation, ring B is in a C 2 twist conformation and the lactone ring is nearly planar with maximum deviation 0.007 (1) Å. The reported absolute configuration is based on that of the similar compound bromo-parasiticolide A and is supported by analysis of Bijvoet differences from light atoms in Mo Kα radiation.

The previously reported room-temperature crystal structure [Jaud Baldy, Negrel, Poite & Chanon (1993 ▶). Z. Kristallogr. 204, 289–291] of the title compound, C20H8Cl12, is monoclinic with Z′ = 1, whereas the 90 K structure reported herein is triclinic with Z′ = 2 and shows a 2% volume contraction. The crystallographically independent unit chosen consists of both enanti­omers (Λ and Δ) of this propeller-like mol­ecule. Both enanti­omers display quasi-twofold symmetry, with average bond-length/bond-angle deviations of 0.0018 (4) Å and 0.41 (2)° for Λ, and 0.0026 (4) Å and 0.50 (2)° for Δ.