Crystal structure of dimethyl N,N'-[(ethyne-1,2-di-yl)bis-(1,4-phenyl-enecarbon-yl)]bis-(l-alaninate).

The di-phenyl-ethyne unit of the title mol-ecule, C24H24N2O6, deviates slightly from planarity. The l-alanine moieties adopt distorted helical conformations of opposite winding direction. Infinite ribbons of N-H⋯O=C-connected mol-ecules represent the basic supra-molecular entities of the crystal structure. These aggregates are linked by C-H⋯O hydrogen bonds involving the oxygen atoms of the methyl carboxyl-ate units. The crystal studied was refined as an inversion twin.

Crystal structure of (N,N'-ethyl-enebis{3-[2-(3-nitro-phen-yl)hydrazin-1-yl-idene]-4-oxo-pentan-2-iminato})copper(II)-3-[2-(3-nitro-phen-yl)hydrazin-1-yl-idene]pentane-2,4-dione (1/1).

In the title 1:1 co-crystal, [Cu(C24H24N8O6)]·C11H11N3O4, each of the crystal components forms undulating layers which stack alternately along the b-axis direction. Mol-ecules of the CuII complex are connected via C-H⋯O hydrogen bonds involving the nitro and keto oxygen atoms, thus forming supra-molecular networks. Mol-ecules of the aryl-hydrazone component are linked by C-H⋯O inter-actions into zigzag strands showing no inter-strand association.

Crystal structures of dimethyl 5-iodo-iso-phthal-ate and dimethyl 5-ethynyl-iso-phthal-ate.

In dimethyl 5-iodo-isophthalate, C10H9IO4, (I), the planes through the methyl carboxyl-ate moieties are tilted with respect to the benzene ring, whereas the mol-ecular framework of dimethyl 5-ethynylisophthalate, C12H10O4, (II), is perfectly planar. The crystal structure of (I) is stabilized by a three-dimensional supra-molecular network comprising C-H⋯O=C hydrogen bonds, as well as I⋯O=C inter-actions. In the crystal of (II), the mol-ecules are connected via C-Hethyn-yl⋯O=C hydrogen bonds to infinite strands. Moreover, π-π arene stacking inter-actions connect the mol-ecular chains into two-dimensional supra-molecular aggregates.

Crystal structure of a new polymorph of di(thio-phen-3-yl) ketone.

The crystal structure of the title compound, C9H6OS2, represents a new polymorph. The crystal structure was solved in the ortho-rhom-bic space group Pbcn with one half of the mol-ecule in the asymmetric unit. The thio-phene rings are perfectly planar and twisted with respect to each other, showing the mol-ecule to be in an S,O-trans/S,O-trans conformation. In the crystal, C-H⋯O hydrogen bonds connect the mol-ecules into layers extending parallel to the ab plane. The crystal structure also features π-π inter-actions.

Crystal structure of 2-chloro-5-(3-hy-droxy-3-methyl-but-1-yn-1-yl)pyrimidine.

In the title compound, C9H9ClN2O, the ethynyl-pyrimidine moiety displays an almost planar geometry. In the crystal, mol-ecules are linked by O-H⋯N and C-Hpyrimidine⋯O hydrogen bonds, forming a three-dimensional supra-molecular architecture.

Crystal structures of 2-acetyl-4-ethynylphenol and 2-acetyl-4-(3-hy-droxy-3-methylbut-1-yn-1-yl)phenol.

In the title compounds, C10H8O2, (I), and C13H14O3, (II), the 2-acetyl-4-ethynylphenol unit displays a planar geometry, which is stabilized by an intra-molecular O-H⋯O hydrogen bond. The crystal structure of (I) is constructed of infinite strands, along [101], of C-H⋯O=C hydrogen-bonded mol-ecules, which in turn are linked by C-H⋯π inter-actions. In the crystal of (II), which crystallized with three independent mol-ecules per asymmetric unit, the non-polar parts of the mol-ecules form hydro-phobic layered domains, parallel to (10-1), which are separated by the polar groups. While the 2-acetyl-phenol part of the mol-ecules are involved in O-H⋯O=C hydrogen bonding, the ternary OH groups creates a cyclic pattern of O-H⋯O hydrogen bonds.

Crystal structures of functional building blocks derived from bis(benzo[b]thiophen-2-yl)methane.

The syntheses of three bis(benzo[b]thiophen-2-yl)methane derivatives, namely bis(benzo[b]thiophen-2-yl)methanone, C17H10OS2, (I), 1,1-bis(benzo[b]thiophen-2-yl)-3-(trimethylsilyl)prop-2-yn-1-ol, C22H20OS2Si, (II), and 1,1-bis(benzo[b]thiophen-2-yl)prop-2-yn-1-ol, C19H12OS2, (III), are described and their crystal structures discussed comparatively. The conformation of ketone (I) and the respective analogues are rather similar for most of the compounds compared. This is true for the interplanar angles, the Caryl-Cbridge-Caryl angles and the dihedral angles. The best resemblance is found for a bioisotere of (I), viz. 2,2'-dinaphthyl ketone, (VII). By way of interest, the crystal packings also reveal similarities between (I) and (VII). In (I), the edge-to-face interactions seen between two napthyl residues in (VII) are substituted by S...π contacts between the benzo[b]thiophen-2-yl units in (I). In the structures of the bis(benzo[b]thiophen-2-yl)methanols, i.e. (II) and (III), the interplanar angles are also quite similar compared with analogues and related active pharmaceutical ingredients (APIs) containing the dithiophen-2-ylmethane scaffold, though the dihedral angles show a larger variability and produce unsymmetrical molecules.

Two terphenyl-based diol hosts and corresponding solvent inclusions with dimethylformamide and acetonitrile.

Having reference to an elongated structural modification of 2,2'-bis(hydroxydiphenylmethyl)biphenyl, (I), the two 1,1':4',1''-terphenyl-based diol hosts 2,2''-bis(hydroxydiphenylmethyl)-1,1':4',1''-terphenyl, C44H34O2, (II), and 2,2''-bis[hydroxybis(4-methylphenyl)methyl]-1,1':4',1''-terphenyl, C48H42O2, (III), have been synthesized and studied with regard to their crystal structures involving different inclusions, i.e. (II) with dimethylformamide (DMF), C44H34O2·C2H6NO, denoted (IIa), (III) with DMF, C48H42O2·C2H6NO, denoted (IIIa), and (III) with acetonitrile, C48H42O2·CH3CN, denoted (IIIb). In the solvent-free crystals of (II) and (III), the hydroxy H atoms are involved in intramolecular O-H···π hydrogen bonding, with the central arene ring of the terphenyl unit acting as an acceptor. The corresponding crystal structures are stabilized by intermolecular C-H···π contacts. Due to the distinctive acceptor character of the included DMF solvent species in the crystal structures of (IIa) and (IIIa), the guest molecule is coordinated to the host via O-H···O=C hydrogen bonding. In both crystal structures, infinite strands composed of alternating host and guest molecules represent the basic supramolecular aggregates. Within a given strand, the O atom of the solvent molecule acts as a bifurcated acceptor. Similar to the solvent-free cases, the hydroxy H atoms in inclusion structure (IIIb) are involved in intramolecular hydrogen bonding, and there is thus a lack of host-guest interaction. As a result, the solvent molecules are accommodated as C-H···N hydrogen-bonded inversion-symmetric dimers in the channel-like voids of the host lattice.

Crystal structure of 1-iodo-3-{[4-(tert-butyl-sulfan-yl)phen-yl]ethyn-yl}azulene.

The title compound, C20H19IS, features a 1,3-disubstituted azulene involving an ethynylene elongated 4-(tert-butyl-sulfanyl)-phenyl sidearm and an iodine atom as the substituents. The azulene ring system is almost planar (r.m.s. deviation = 0.012 Å) and subtends a dihedral angle of 35.7 (1)° with the benzene ring. As a result of the inherent dipole character of the azulene core, a supra-molecular π-π dimer [separation between the centroids of the five- and seven-membered rings = 3.7632 (10) Å] with anti-parallel orientated mol-ecules can be observed in the crystal. The packing is consolidated by an unusual I⋯π(acetyl-ene) contact [I⋯Cg = 3.34 Å, C-I⋯Cg = 173.3°], and a very weak C-H⋯π inter-action is also found in the structure, with the azulene five-membered ring as the acceptor.

Crystal structure of 4'-bromo-2,3,5,6-tetra-fluoro-biphenyl-4-carbo-nitrile.

The title compound, C13H4BrF4N, synthesized from 1,4'-bromo-iodo-benzene and 4-bromo-2,3,5,6-tetra-fluoro-benzo-nitrile in a coupling reaction was found to crystallize in the ortho-rhom-bic space group P212121. The two phenyl rings are rotated with respect to each other by 40.6 (6)°. The mol-ecules inter-act via aryl-perfluoroaryl stacking [3.796 (2) and 3.773 (2) Å], resulting in inter-molecular chains along the a-axis direction. C-H⋯F contacts of about 2.45 Šconnect these chains. In contrast to the structure of the parent compound 4'-bromo-biphenyl-4-carbo-nitrile, CN⋯Br contacts that could have given rise to a linear arrangement of the biphenyl mol-ecules desirable for non-linear optical (NLO) materials are not observed in the packing. Instead, several Br⋯F [3.2405 (17) and 3.2777 (18) Å] and F⋯F [2.894 (2) Å] contacts of side-on type II form an inter-molecular network of zigzag chains. The crystal studied was refined as an inversion twin.

Crystal structure of diethyl 2-amino-6-[(thio-phen-3-yl)ethyn-yl]azulene-1,3-di-carboxyl-ate.

The title compound, C22H19NO4S, has an almost planar geometry supported by intra-molecular N-H⋯O and C-H⋯O hydrogen bonds. The thio-phene ring is inclined to the azulene ring by 4.85 (16)°, while the eth-oxy-carbonyl groups are inclined to the azulene ring by 7.0 (2) and 5.7 (2)°. In the crystal, mol-ecules are linked by pairs of N-H⋯O hydrogen bonds, forming inversion dimers with an R 2 (2)(12) ring motif. The dimers are linked via C-H⋯π inter-actions, forming sheets parallel to (10-1).

Separation of xylenes by enclathration.

The isomers of xylene have been separated by enclathration using three host compounds: 9,9'-bianthryl (H1), 9,9'-spirobifluorene (H2) and trans-2,3-dibenzoylspiro[cyclopropane-1,9-fluorene] (H3). The structures of each host with a single xylene isomer have been elucidated and, for H1, the relative lattice energies of the clathrates with ortho- and para-xylene have been evaluated.

Crystal structure of 4,4'-(ethane-1,2-di-yl)bis-(2,6-di-bromo-aniline).

In the title compound, C14H12Br4N2, the mol-ecule lies across an inversion center and hence the benzene rings are strictly coplanar. In the crystal, mol-ecules are linked by N-H⋯N and weak N-H⋯Br hydrogen bonds, forming a two-dimensional network parallel to (101). In addition, type II Br⋯Br inter-actions [3.625 (4) Å] complete a three-dimensional supra-molecular network.

Flexible low-voltage organic complementary circuits: finding the optimum combination of semiconductors and monolayer gate dielectrics.

Low-voltage p-channel and n-channel organic transistors with channel lengths down to 0.5 µm using four small-molecule semiconductors and ultra-thin dielectrics based on two different phosphonic acid monolayers are fabricated on plastic substrates and studied in terms of effective mobility, intrinsic mobility and contact resistance. For the optimum materials combination, flexible complementary circuits have signal delays of 3.1 µs at 5 V.

Crystal structure of 2,2''-bis-(2,7-di-chloro-9-hy-droxy-9H-fluoren-9-yl)-1,1':4',1''-terphenyl tri-ethyl-amine trisolvate.

In the title solvate, C44H26Cl4O2·3C6H15N, the asymmetric part of the unit cell comprises two halves of the diol mol-ecules, 2,2''-bis-(2,7-di-chloro-9-hy-droxy-9H-fluoren-9-yl)-1,1':4',1''-terphenyl, and three mol-ecules of tri-ethyl-amine, i. e. the diol mol-ecules are located on crystallographic symmetry centres. Two of the solvent mol-ecules are disordered over two positions [occupancy ratios of 0.567 (3):0.433 (3) and 0.503 (3):0.497 (3)]. In the diol mol-ecules, the outer rings of the 1,1':4',1''-terphenyl elements are twisted with reference to their central arene ring and the mean planes of the fluorenyl moieties are inclined with respect to the terphenyl ring to which they are connected, the latter making dihedral angles of 82.05 (8) and 82.28 (8)°. The presence of two 9-fluoren-9-ol units attached at positions 2 and 2'' of the terphenyl moiety induces a 'folded' geometry which is stabilized by intra-molecular C-H⋯O hydrogen bonds and π-π stacking inter-actions, the latter formed between the fluorenyl units and the central ring of the terphenyl unit [centroid-centroid distances = 3.559 (1) and 3.562 (1) Å]. The crystal is composed of 1:2 complex units, in which the solvent mol-ecules are associated with the diol mol-ecules via O-H⋯N hydrogen bonds, while the remaining solvent mol-ecule is linked to the host by a C-H⋯N hydrogen bond. The given pattern of inter-molecular inter-actions results in formation of chain structures extending along [010].

Crystal structure of 1,3-bis-{[4-(acetyl-sulfanyl)phenyl]ethynyl}azulene.

In the title compound, C30H20O2S2, the dihedral angles between the central azulene ring system (r.m.s. deviation = 0.039 Å) and the pendant benzene rings are 28.96 (7) and 55.15 (7)°. The dihedral angles between the benzene rings and their attached acetyl-sulfanyl groups are 59.60 (10) and 84.79 (10)°. The expected π-π stacking inter-actions are not observed in the crystal structure; instead, the packing features C-H⋯O hydrogen bonds, which link the mol-ecules into C(12) [010] chains, which are supported by weak C-H⋯π contacts.

Redetermination of 2-methyl-4-nitro-pyridine N-oxide.

An improved crystal structure of the title compound, C6H6N2O3, is reported. The structure, previously solved [Li et al. (1987 ▶). Jiegou Huaxue (Chin. J. Struct. Chem.), 6, 20-24] in the ortho-rhom-bic space group Pca21 and refined to R = 0.067, has been solved in the ortho-rhom-bic space group Pbcm with data of enhanced quality, giving an improved structure (R = 0.0485). The mol-ecule adopts a planar conformation with all atoms lying on a mirror plane. The crystal structure is composed of mol-ecular sheets extending parallel to the ab plane and connected via C-H⋯O contacts involving ring H atoms and O atoms of the N-oxide and nitro groups, while van der Waals forces consolidate the stacking of the layers.

Photochemical dimerization of a fluorinated dibenzylideneacetone in chloroform solution.

(1E,4E)-1,5-Bis(2,6-difluorophenyl)penta-1,4-dien-3-one, C17H10F4O, (I), dimerizes under sunlight in chloroform solution to form the corresponding cyclobutane derivative, (2E,2'E)-1,1'-[2,4-bis(2,6-difluorophenyl)cyclobutane-1,3-diyl]bis[3-(2,6-difluorophenyl)prop-2-en-1-one], C34H20F8O2, (II). The crystal structure of (I) explains why no topochemical dimerization can occur in the solid state. In the solid, molecules of dimer (II) show the `truxillic acid'-type arrangement of crystallographic centres of inversion, with half a molecule per asymmetric unit and cell dimensions closely related to those of the monomer. Intermolecular interactions in both solids are dominated by C-H···O and C-H···F contacts and also comprise interactions with aromatic systems (C-H···π and π-π).

3,3''-Bis(9-hy-droxy-fluoren-9-yl)-1,1':3',1''-terphen-yl.

The asymmetric unit of the title compound, C44H30O2, contains two independent mol-ecules in which the terminal rings of the terphenyl element are inclined at angles of 36.3 (1) and 22.5 (1)° with respect to the central ring and the dihedral angles between the fluorenyl units are 72.3 (1) and 62.8 (1)°. In the crystal, pairs of O-H⋯O hydrogen bonds link the mol-ecules into inversion dimers. The hy-droxy H atoms not involved in these hydrogen bonds form O-H⋯π inter-actions in which the central terphenyl rings act as acceptors. Weak C-H⋯O contacts and π-π [centroid-centroid distance = 4.088 (2) Å] stacking inter-actions also occur. Taking into account directed non-covalent bonding between the molecules, the crystal is constructed of supramolecular strands extending along the a-axis direction.

5,5'-(Ethyne-1,2-di-yl)diisophthalic acid dimethyl sulfoxide tetra-solvate.

In the title compound, C18H10O8·4C2H6OS, the mid-point of the triple bond of the main mol-ecule is located on a special position, i.e. about an inversion center. The carboxyl groups are twisted slightly out of the planes of the aromatic rings to which they are attached, making dihedral angles of 24.89 (1) and 7.40 (2)°. The cystal packing features strong O-H⋯O hydrogen bonds, weaker C-H⋯O inter-actions and O⋯S contacts [3.0981 (11) Å] and displays channel-like voids extending along the a-axis direction which contain the dimethyl sulfoxide solvent mol-ecules.