3,5-Di-bromo-4-carbamoyl-benzoic acid 2-propanol monosolvate.

In the title solvated crystal, C8H5Br2NO3·C3H8O, the acid mol-ecules form inversion dimers by pairwise N-H⋯O hydrogen bonds between carbamoyl groups and the carboxyl and carbamoyl groups link to form head-to-tail inversion dimers. The 2-propanol hydroxyl group inter-poses between adjacent head-tail pairs, resulting in C 3 3(10) chains of hydrogen bonds propagating along [100]. The mol-ecules of 2-propanol are disordered over two sets of sites in a 0.598 (8):0.402 (8) ratio. The best-fit planes of the carbamoyl group and benzene ring are inclined by 88.26 (11)°. This is a greater inclination than was previously reported with CH3, Cl, F or H in place of the Br atoms, although those analogues did not have a para carboxyl group.

Crystal structure of 2,3,5,6-tetra-bromo-tereph-thalo--nitrile.

The title crystal (systematic name: 2,3,5,6-tetra-bromo-benzene-1,4-dicarbonitrile), C8Br4N2, is the first bromo analog in a study of cyano-halo (C≡N⋯X) non-bonded contacts in crystals of halogenated di-cyano-benzenes. The complete mol-ecule is generated by a crystallographic center of symmetry. In the extended structure, each Br atom accepts one C≡N⋯Br inter-action, and each N atom is bis-ected by two. This contact network forms a nearly planar sheet structure propagating in the (01) plane, similar to that reported in hexa-methyl-benzene co-crystals of the tetra-chloro analog.

Crystal structures of 2,4,6-tri-iodo-benzo-nitrile and 2,4,6-tri-iodo-phenyl isocyanide.

The title crystals, C7H2I3N, are isomorphous. Both mol-ecules lie across two crystallographic mirror planes and a twofold axis. The principal supra-molecular inter-action is centric R22(10) CN/NC⋯I short contacts involving both ortho I atoms, with two contacts bis-ecting each cyano and iso-cyano group. These form ribbons along [010] and give rise to a planar sheet structure parallel to (100). All pairs of adjacent sheets have centric stacking, a mode not previously reported for sheets of this type. This study completes the series of homo-2,4,6-trihalobenzo-nitriles, in which I atoms give the strongest CN⋯X and NC⋯X inter-actions (X = F, Cl, Br, I).

Crystal structures of methyl 3,5-di-bromo-4-cyano-benzoate and methyl 3,5-di-bromo-4-iso-cyano-benzoate.

The title crystals, C9H5Br2NO2, are the first reported 2,6-dihalophenyl cyanide-isocyanide pair that have neither three- nor two-dimensional isomorphism. Both crystals contain contacts between the carbonyl O atom and a Br atom. In the crystal of the cyanide, R22(10) inversion dimers form based on C≡N⋯Br contacts, a common packing feature in this series of crystals. In the isocyanide, the corresponding N≡C⋯Br contacts are not observed. Instead, the iso-cyano C atom forms contacts with the meth-oxy C atom. RNC was refined as a two-component pseudo-merohedral twin.

Crystal structures of 2,6-di-bromo-4-methyl-benzo-nitrile and 2,6-di-bromo-4-methyl-phenyl isocyanide.

In the title crystals, C8H5Br2N, which are isomorphous, the steric bulk of the methyl group causes neighboring mol-ecules to become mutually inclined. This prevents the formation of planar or nearly planar sheets, which were observed in the tri-chloro and tri-bromo analogs. Instead of CN/NC⋯Br contacts, tetra-meric Br⋯Br contacts are observed. These contacts form tetra-gonally puckered sheets parallel to (001). The CN/NC and methyl groups are grouped at the peaks and troughs. Both mol-ecules lie across crystallographic mirror planes; thus, the methyl H atoms are disordered over two sets of sites with equal occupancy. The title nitrile is a redetermination. The refinement converged at R[F2 > 2σ(F2)] = 0.020, whereas the original determination [Gleason & Britton, (1976 ▸). Cryst. Struct. Commun.5, 229-232] had R = 0.112.

A 2:1 co-crystal of 3,5-di-bromo-4-cyano-benzoic acid and anthracene.

The title co-crystal, C8H3Br2NO2·0.5C14H10, was self-assembled from a 2:1 mixture of the components in slowly evaporating di-chloro-methane. The mol-ecules adopt a sheet structure parallel to (1-12) in which carb-oxy hydrogen-bonded dimers and anthracene mol-ecules stagger in both dimensions. Within the sheets, six individual cyano acid mol-ecules surround each anthracene mol-ecule. Cyano acid mol-ecules form one of the two possible R22(10) rings between neighboring cyano and bromo groups. Compared to the di-chloro analog [Britton (2012 ▸). J. Chem. Crystallogr.42, 851-855], the dihedral angle between the best-fit planes of acid and anthracene mol-ecules has decreased from 7.1 to 0.9 (2)°.

Two new polytypes of 2,4,6-tri-bromo-benzo-nitrile.

Three polymorphs of 2,4,6-tri-bromo-benzo-nitrile (RCN), C7H2Br3N, two of which are novel and one of which is a redetermination of the original structure first determined by Carter & Britton [(1972). Acta Cryst. B28, 945-950] are found to be polytypic. Each has a layer structure which differs only in the stacking of the layers. Each layer is composed of mol-ecules associated through C N⋯Br contacts which form R (2) 2(10) rings. Two such rings are associated with each N atom; one with each ortho-Br atom. No new polytypes of 1,3,5-tri-bromo-2-iso-cyano-benzene (RNC) were found but a re-determination of the original structure by Carter et al. [(1977). Cryst. Struct. Commun. 6, 543-548] is presented. RNC was found to be isostructural with one of the novel polytypes of RCN. Unit cells were determined for 23 RCN samples and 11 RNC samples. Polytypes could not be distinguished based on crystal habits. In all four structures, each mol-ecule of the asymmetric unit lies across a mirror plane.

Crystal structure of rac-3-[2,3-bis-(phenyl-sulfan-yl)-3H-indol-3-yl]propanoic acid.

The title compound, C23H19NO2S2, was obtained as an unexpected regioisomer from an attempted synthesis of an inter-mediate for a substituent-effect study on ergot alkaloids. This is the first report of a 1H-indole mono-thio-ating at the 2- and 3-positions to give a 3H-indole. In the crystal, the acid H atom is twisted roughly 180° from the typical carb-oxy conformation and forms centrosymmetric O-H⋯N hydrogen-bonded dimers with the indole N atom of an inversion-related mol-ecule. Together with a weak C-H⋯O hydrogen bond involving the carbonyl O atom, chains are formed along [100].

Crystal structure of rac-(3a'R,9a'R)-3a'-(indol-3-yl)-1',2',3',3a',4',9a'-hexa-hydro-spiro-[cyclo-pentane-1,9'-penta-leno[1,2-b]indole] p-xylene hemisolvate.

The title compound, C26H26N2·0.5C8H10, is the first reported characterized 2:2 product from acid-catalyzed condensation of indole with cyclo-penta-none and no other 2:2 products were observed. Recrystallization from p-xylene gave the title hemisolvate with the p-xylene mol-ecule located about an inversion center. The terminal penta-lene ring is envelope-flap disordered at the C atom farthest from the skeletal indole unit, with a refined occupancy ratio of 0.819 (4):0.181 (4). The major component has this C atom bent away from the spiro-fused cyclo-pentane ring. In the crystal, mol-ecules are connected by N-H⋯π inter-actions, forming chains along [100], and N-H⋯π and C-H⋯π inter-actions, forming chains along [001], which results in the formation of slabs parallel to (010).

Crystal structure of (±)-(3aR,5R,8bR)-5-hydroper-oxy-2-phenyl-6-tosyl-4,5,6,8b-tetra-hydro-pyrrolo-[3,4-e]indole-1,3(2H,3aH)-dione.

The title compound, C23H20N2O6S, crystallizes as a racemate in the space group P-1, with an overall L- or J-shape to each mol-ecule. Centrosymmetric pairs of mol-ecules are tandem hydrogen bonded between the hydro-per-oxy H atom and carbonyl O atom. A different centrosymmetric pairing has stacked S-tolyl rings, and a third pairing is L,J-inter-locked by the short leg. Except for stacked tolyl pairs, neighboring π-systems are much closer to orthogonal than coaxial. The title compound is the first example of a hydro-peroxide obtained from the autoxidation of a Diels-Alder adduct of a 2-vinyl-pyrrole.

Crystal structure of (1S,2R,6R,7R,8S,12S)-4,10,17-triphenyl-15-thia-4,10-diaza-penta-cyclo[5.5.5.0(1,16).0(2,6).0(8,12)]hepta-deca-13,16-diene-3,5,9,11-tetrone p-xylene hemisolvate.

The title tetrone compound, C32H22N2O4S· 0.5C8H10, is the major product (50% yield) of an attempted Diels-Alder reaction of 2-(α-styr-yl)thio-phene with N-phenyl-male-imide (2 equivalents) in toluene. Recrystallization of the resulting powder from p-xylene gave the title hemisolvate; the p-xylene mol-ecule is located about an inversion center. In the crystal, the primary tetrone contacts are between a carbonyl O atom and the four flagpole H atoms of the bi-cyclo-[2.2.2]octene core, forming chains along [001].