109 research outputs found
9-(Dicyanomethylidene)fluorene–tetrathiafulvalene (1/1)
The title compound, C16H8N2·C6H4S4, crystallizes with the fluorene derivative placed in a general position and two half tetrathiafulvalene (TTF) molecules, each completed to a whole molecule through an inversion center. The fluorene ring system is virtually planar (r.m.s. deviation from the mean plane = 0.027 Å) and the dicyano group is twisted from the fluorene plane by only 3.85 (12)°. The TTF molecules are also planar, and their central C=C bond lengths [1.351 (8) and 1.324 (7) Å] compare well with the same bond length in neutral TTF (ca 1.35 Å). These features indicate that no charge transfer occurs between molecules in the crystal; the compound should thus be considered a cocrystal rather than an organic complex. This is confirmed by the crystal structure, in which no significant stacking interactions are observed between molecules
Chloridotris(pentafluorobenzenethiolato-κS)[tris(4-fluorophenyl)phosphine-κP]osmium(IV)
The title complex, [Os(C6F5S)3Cl(C18H12F3P)], displays a trigonal-bipyramidal OsIV coordination geometry with the S atoms of three thiolate ligands occupying the equatorial positions. The thiolate pentafluorophenyl substituents are all placed above the equatorial plane, forming a claw-like cavity which accommodates the chloride ligand with a normal Os—Cl bond length. The phosphine ligand trans to the chloride ligand reveals a short Os—P bond length compared to other chloride–phosphine OsIV complexes (average = 2.40 Å). This strong bonding indicates that the inductive effect of the F atoms in the phosphine does not affect significantly its basicity, compared to triphenylphosphine. This feature is also consistent with the known poor trans influence of Cl−. The crystal packing involves π–π contacts between inversion-related thiolate C6F5 rings, with a centroid–centroid separation of 3.659 (8) Å
Diallyl 5-[(4-hexyloxyphenyl)iminomethyl]-m-phenylene dicarbonate
The title molecule, C27H31NO7, an imine derivative bearing both carbonate and allyl functionalities, was synthesized in the hope of obtaining a mesogenic polymerizable material. The allylcarbonate arms are fully disordered over two sets of sites, reflecting a large degree of rotational freedom about σ bonds [occupancies: 0.665 (9)/0.335 (9) for one substituent, 0.564 (9)/0.436 (9) for the other]. In contrast, the hexyl chain is ordered, and presents the common all-trans extended conformation. The benzene rings connected via the imine group make a dihedral angle of 9.64 (11)°. In the crystal, the Y-shaped molecules are weakly associated into centrosymmetric dimers through pairs of C—H⋯O(hexyl) contacts. The resulting layers of dimers, approximately parallel to (25), are closely packed in the crystal, allowing π⋯π interactions between benzene rings of neighboring layers: the separation between the centroid of the benzene ring substituted by allylcarbonate and the centroid of the benzene ring bearing the hexyloxy group in the adjacent layer is 3.895 (1) Å
(S)-(+)-N-Benzylidene-1-(1-naphthyl)ethylamine
In the title chiral aldimine, C19H17N, the azomethine group is not fully conjugated with the phenyl substituent: the dihedral angle between phenyl and C*—N=C mean planes is ϕ3 = 23.0 (2)°. Compared with the earlier DFT-B3LYP/6–31 G(d) computations from the literature, the C=N—C*—C(naphthyl) torsion angle, found at ϕ2 = −118.0 (2)° in the X-ray structure, does not match the angle calculated for the potential minimum energy at ϕ2 = 0°. However, this angle is close to the second potential energy minimum at ϕ2 = −120° which is ca. 8.5 kJ mol−1 above the global energy minimum. Thus, the reported X-ray structure corresponds to the second most likely (according to DFT) conformer, allowing the existence of other polymorphs to be anticipated
2,2′-(Propane-1,3-diyl)bis(2H-indazole)
The title molecule, C17H16N4, is a bis-indazole crystallized in the rare 2H-tautomeric form. Indazole heterocycles are connected by a propane C3 chain, and the molecule is placed on a general position, in contrast to the analogous compound with a central C2 ethane bridge, which was previously found to be placed on an inversion center in the same space group. In the title molecule, indazole rings make a dihedral angle of 60.11 (7)°, and the bridging alkyl chain displays a trans conformation, resulting in a W-shaped molecule. In the crystal, molecules interact weakly through π–π contacts between inversion-related pyrazole rings, with a centroid–centroid separation of 3.746 (2) Å
(–)-(S)-N,N′-Bis[1-(1-naphthyl)ethyl]oxalamide
The title molecule, C26H24N2O2, displays C
2 symmetry, with the molecule located on a twofold axis perpendicular to the plane of the oxalamide unit –NH—CO—CO—NH–. The oxalamide core deviates from planarity, as reflected by the O=C—C=O and N—C—C—N torsion angles of 164.3 (5) and 163.2 (5)°, respectively. The naphthyl groups are oriented toward the same face of the oxalamide mean plane and make a dihedral angle of 43.76 (8)°. This conformation is suitable for the formation of intermolecular N—H⋯O hydrogen bonds, giving noncentrosymmetric dimers incorporating R
2
2(10) ring motifs. These nonbonding interactions propagate along the 61 screw axis normal to the molecular twofold axis, resulting in a single-stranded right-handed helix parallel to [001]. In the crystal, Δ helices are arranged side-by-side and interact through π–π contacts between naphthyl groups. The shortest centroid–centroid separation between interacting benzene rings is 3.623 (4) Å
Synthesis and Characterization of bis[(2-ethyl-5-methyl-imidazo-4-yl)methyl]Sulfide and Its Coordination Behavior toward Cu(II) as a Possible Approach of a Copper Site Type I
The synthesis and characterization of a novel ligand, bis[(2-ethyl-5-methyl-imidazo-4-yl)methyl]sulfide (bemims), as well as a bemims-containing copper(II) coordination complex are described. In this complex, [Cu(bemims)X2] with X = NO3−, bemims acts as a tridentate ligand and two monodentate nitrate ions complete the coordination sphere. Both imidazole N atoms and the thioether S atom of bemims participate in coordination. The Cu(II) ion is five-coordinated with a slightly distorted square-pyramidal geometry (τ = .09). Electrochemical studies and spectroscopic data for this complex are compared with some blue copper proteins in order to assess its ability to mimic the copper center of type I copper proteins
Allyl 4-hydroxyphenyl carbonate
The title molecule, C10H10O4, is a functionalized carbonate used in the synthetic route to organic glasses. The central CH fragment of the allyl group is disordered over two positions, with occupancies in a 0.758 (10):0.242 (10)ratio. This disorder reflects the torsional flexibility of the oxygen–allyl group, although both disordered parts present the expected anticlinal conformation, with O—CH2—CH=CH2 torsion angles of −111 (2) and 119.1 (4)°. The crystal structure is based on chains parallel to [010], formed by O⋯H—O hydrogen bonds involving hydroxyl and carbonyl groups as donors and acceptors, respectively. The molecular packing is further stabilized by two weak C—H⋯π contacts from the benzene ring of the asymmetric unit with two benzene rings of neighboring molecules
Trimesic acid dimethyl sulfoxide solvate: space group revision
The structure of the title solvate, C9H6O6·C2H6OS, was determined 30 years ago [Herbstein, Kapon & Wasserman (1978 ▶). Acta Cryst. B34, 1613–1617], with data collected at room temperature, and refined in the space group P21. The present redetermination, based on high-resolution diffraction data, shows that the actual space group is more likely to be P21/m. The crystal structure contains layers of trimesic acid molecules lying on mirror planes. A mirror plane also passes through the S and O atoms of the solvent molecule. The molecules in each layer are interconnected through strong O—H⋯O hydrogen bonds, forming a two-dimensional supramolecular network within each layer. The donor groups are the hydroxyls of the trimesic acid molecules, while the acceptors are the carbonyl or the sulfoxide O atoms
1,3-Bis{(+)-(S)-[1-(1-naphthyl)ethyl]iminomethyl}benzene dichloromethane solvate
In the title compound, C32H28N2·CH2Cl2, the complete Schiff base and solvent molecules are both generated by crystallographic twofold axes, with the two C atoms of the former and the C atom of the latter lying on the rotation axis. The central benzene ring is substituted with two chiral groups including imine functionalities, with the common E configuration. The dihedral angle between the central benzene ring and the terminal naphthalene ring is 45.42 (9)° and that between the two naphthalene rings is 89.16 (8)°. The conformation of the Schiff base allows solvent molecules to fill the voids in the crystal, affording a stable 1:1 solvate, but the solvent interacts poorly with the Schiff base, as reflected by its rather high displacement parameters
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