Evidence for the Perchlorate Anion Coordination in the Structure of Uranyl Cation Complex with N,O-Donor Ligands in a Solution: RMC-EXAFS Study

Crystallography Reports - Complexing of organic ligands with actinides plays a key role in the processes of spent nuclear fuel reprocessing in the final stages of the nuclear fuel cycle. N,O-Donor...     

Molecular Structure and Supramolecular Architecture of Brivanib: (R)-1-(4-(4-Fluoro-2-methyl-1H-indol-5-yloxy)-5-methylpyrrolo[2,1-f] [1,2,4]triazin-6-yloxy)propan-2-ol

Crystallography Reports - Crystal structure of brivanib ((R)-1-(4-(4-fluoro-2-methyl-1H-indol-5-yloxy)-5-methylpyrrolo[2,1-f][1,2,4]triazin-6-yloxy)propan-2-ol) is reported for the first time....     

The structure of 1-(p-fluorophenylmethyl)-2-(4-methyl-1-piperazinyl)-1H-benzimidazole hydrogen fumarate

The crystal and molecular structure of the title compound has been determined by X-ray analysis. The 1-(p-fluorophenylmethyl)-2-(4-methyl-1-piperazinyl)-1H-benzimidazole ion cocrystallizes with fumaric acid, (C₁₉H₂₂N₄F⁺·C₄H₃O ₄ ^– ), in space group P-1 with cell dimensions a = 9.938(1), b = 10.131(1), c = 12.712(1) Å, = 86.57(1), = 69.41(2), and = 67.22(2)°. The piperazine N4 atom is protonated and contacts the deprotonated O atom of the fumarate anion through a hydrogen bond. The benzimidazole ring is nearly planar and makes a dihedral angle of 111.25(12)° with the fluorophenyl ring. The piperazine ring adopts a chair conformation.     

Crystal structure and conformation of Linomide [N-methyl-N-phenyl-1,2-dihydro-4-hydroxy-1-methyl-2-oxo-quinoline-3-carboxamide]: A novel immunomodulator

Linomide [N-methyl-N-phenyl-1,2-dihydro-4-hydroxy-1-methyl-2-oxo-quinoline-3-carboxamide] is a new immunomodulator from Phamacia Laboratories, Helsingborg, Sweden. Linomide (LS-2616) has delayed hypersensitivity in rat skin, potentiates mouse natural killer cell activity, and stimulates polyclonal T-cell activation. It has been shown that LS-2616 abolishes the effects of continuous cyclosporine treatment in experimental models. Crystal structure of LS-2616 has been undertaken as a first step in the establishment of a possible structure–function relationship for the drug. Crystals of LS-2616 (C₁₈H₁₆N₂O₃) obtained from methylene chloride are monoclinic, of space group P2₁/a with the following crystallographic parameters: a = 8.793(1) Å, b = 22.349(3) Å, c = 7.808(1) Å, = 92.96(1)°, V = 1532.3(6) ų, _obs = 1.34 Mg/m³, _calc = 1.337 Mg/m³, and Z = 4. The structure was solved with CAD-4 data using MULTAN programs and refined to a final R value of 0.041. The N-methyl carboxamide is in the cis configuration and is turned away from the quinoline ring by 87°. FK506 is a novel 23-membered macrolide lactone which is currently used for bone marrow and organ transplantations. The crystal structure of FK506 has been published. The absolute configuration of FK506 was established as a cis-amide which contains a L-pipecolic acid moiety. Preliminary modeling studies of FK506 with LS-2616 revealed that this cis conformation for the N-methyl carboxamide leads to a lower binding energy than the corresponding trans conformation. The plane of the phenyl group is inclined by 95° to the carboxamide plane. The molecule has the familiar herring-bone type of packing, characteristic of the polyphenyl molecules, stabilized by O–H O and C–H O hydrogen bonds involving the hydroxyl group and the ketone substituents on the quinoline ring and the N-methyl group of the carboxamide.     

Transport and Magnetotransport in the New Quasi-Two-Dimensional Organic Metal (BETS)2ZnBr4(C6H4Cl2) with Different Electron Structure of Neighboring Cation Layers

Intralayer and interlayer transports and Shubnikov – de Haas oscillations are investigated in the new dual-layered organic metal (BETS)₄ZnBr₄(C₆H₄Cl₂). It is shown that: a) the interlayer resistance behavior corresponds to incoherent transport; b) the behavior of quantum oscillations is well described by the model of a coherent network of magnetic breakdown orbits. Both the interlayer transport and quantum oscillations are in a good agreement with the theoretical calculation of the zone structure.     

The utility of 4-aminobenzoic acid in promotion of hydrogen bonding in crystallization processes: the structures of the cocrystals with halo and nitro subsituted aromatic compounds, and the crystal structures of the adducts with 4-nitroaniline (1:1), 4-(4-nitrobenzyl)pyridine (1:2), and (4-nitrophenyl)acetic acid (1:1)

A number of molecular adducts of 4-aminobenzoic acid (4-ABA) have been prepared and characterized using infrared spectroscopy and in three cases by X-ray diffration methods. These three compounds are with 4-nitroaniline [(4-ABA) (C₆H₆N₂O₂)], 4-(4-nitrobenzyl) pyridine, [(4-ABA)₂(C₁₂H₁₀N₂O₂)₄], and (4-nitrophenyl)acetic acid, [(4-ABA) (C₈H₇NO₄)]. Other compounds described are with 4-chlorobenzoic acid, [(4-ABA) (C₇H₅ClO₂)], 4-bromobenzoic acid, [(4-ABA) (C₇H₅BrO₂)], 4-cyanobenzoic acid, [(4-ABA) (C₇H₆N₂)], 2-nitrobenzoic acid, [(4-ABA) (C₇H₅NO₄)], and 3-nitrobenzoic acid, [(4-ABA) (C₇H₅NO₄)]. All compounds have 1:1 stoichiometry except that with 4-(4-nitrobenzyl)pyridine (1:2) which is unique in being retro-stoichiometric. A review of the systematics of the 4-aminobenzoic acid adducts is also made, particularly with respect to the infrared characterization of the cocrystalline materials and prediction of their NLO potential.     

Molecular and crystal structures of 1-methyl-2-Oxo-3-acetoxy-4-hydroxy-4-(Phenyl)piperidine, 1-ethyl-2-oxo-3,4-dihydroxy-4-(Pyridyl)piperidine, and 1-benzyl-2-oxo-3,4-dihydroxy-4-(Pyridyl)piperidine and the role of hydrogen bonds in molecular packing in crystals

The molecular and crystal structures of 1-methyl-2-oxo-3-acetoxy-4-hydroxy-4-(phenyl)hydropyridine, 1-ethyl-2-oxo-3,4-dihydroxy-4-(pyridyl)piperidine, and 1-benzyl-2-oxo-3,4-dihydroxy-4-(pyridyl)piperidine are determined by X-ray diffraction analysis. These three hydroxy derivatives of hydropyridine are the convenient model compounds in studies of the influence of intramolecular and intermolecular hydrogen bonds on the conformation and packing of molecules in crystals. The molecules of hydroxy derivatives possess a considerable conformational flexibility and can form an extended network of intramolecular and intermolecular hydrogen bonds. It is shown that these compounds more often than others form noncentrosymmetric and polysystem crystals. The role of the molecular association and the type of hydrogen-bonded associates (syntons) in crystal packing are discussed.     

Pseudo-Merohedral Twinning in the Structure of the Hydrated 1:1 Proton-Transfer Compound of 5-Sulfosalicylic Acid with 4-Aminopyridine

Abstract  

The structure of the pseudo-merohedrally twinned crystal of the 1:1 proton-transfer compound of 5-sulfosalicylic acid (3-carboxy-4-hydroxybenzenesulfonic acid) with 4-aminopyridine: 4-aminopyridinium 3-carboxy-4-hydroxybenzenesulfonate sesquihydrate has been determined at 180 K and the hydrogen-bonding pattern is described. Crystals of the compound are monoclinic with space group P2₁/c, with unit cell dimensions a = 35.2589(8), b = 7.1948(1), c = 24.5851(5) ?, β = 110.373(2)°, and Z = 16. The monoclinic asymmetric unit comprises four cation–anion pairs and six water molecules of solvation with only the pyridinium cations having pseudo-symmetry as a result of inter-cation aromatic ring π–π stacking effects. Extensive hydrogen bonding gives a three-dimensional framework structure.     

Crystal structure of the molecular inclusion complex tetra-p-nitro-tetra-O-butyl calix[4]arene with acetone (1:2)

The crystal structure of the inclusion complex of tetra-p-nitro-tetra-O-butyl calix[4]arene 1 with acetone, [(C₄₄H₅₂N₄O₁₂)·2CH₃COCH₃], was measured by X-ray crystallographic analysis with an imaging plate method. It belongs to the space group C2/c, with a = 13.131(3),b = 21.480(4), c = 19.645(4)Å, = 105.69(3)°, and D_cale = 1.177 mg/m³ for Z = 4. Crystal data indicate that the host molecule 1 exist in a pinched-cone conformation, and the action of one molecule of host upon two molecules of acetone forms a channel type intermolecular inclusion complex.     

X-ray mapping in heterocyclic design: III. Diffractometric study of the crystal structure of 1-methyl-2-oxo-2,3-dihydroimidazo[1,2-a]pyridinium bromide

The crystal structure of 1-methyl-2-oxo-2,3-dihydroimidazo[1,2-a]pyridinium bromide C₈H₉BrN₂O is determined by X-ray diffraction. The structure is solved by the direct method and refined by the least-squares procedure to R = 0.0599. The geometry of the pyridinium fragment observed in the molecule corresponds to the limited number of centers at which the positive charge can be delocalized. Apparently, this delocalization predominantly occurs in the NCN fragment of the imidazole ring and only slightly affects the pyridine moiety of the molecule.     

Crystal and molecular structure of: 5-(1-oxoethyl)-1-methyl-2-(5-bromo-6-methoxy-2-naphthyl)-6-oxabicyclo[3.2.1]octan-7-one and 5-(1-oxoethyl)-1-methyl-2-(5-bromo-6-methoxy-2-naphthyl)-6-oxabicyclo[3.2.1]octane

X-ray crystallographic studies of the two title compounds have shown that the molecules crystallize in the same triclinic space group, , with very similar cell dimensions. For C₂₁H₂₁BrO₄,a=12.056(5),b=13.206(5),c=7.595(3)Å, =90.38(3), =106.07(3) and =124.42(3)° and for C₂₁H₂₃BrO₃,a=12.076(6),b=13.090(5),c=7.490(3)Å, =92.65(5), =104.90(5) and =124.55(5)°. Both compounds possess the oxabicyclo[3.2.1]octane bridged ring system and differ only at the carbon to the ring oxygen where the Csp³ in the ether is replaced by Csp²=O in the lactone. Both cyclohexane rings adopt distorted chair conformations and the lactone and ether rings approximate closely to the envelope conformation. The bromine substituent at C(4) results in distortion of the naphthalene ring. Both molecules pack with the naphthalene rings parallel to each other with interplanar spacings of 3.71 Å in the ether and 3.66Å in the lactone.     

Crystal and Molecular Structure of the 1:2 Salt Formed Between 1,2-(4-Pyridyl)Ethane and 2-(4-Hydroxyphenylazo)Benzoic Acid

Abstract  Proton transfer occurred during co-crystallization of 1,2-(4-pyridyl)ethane with 2-(4-hydroxyphenylazo)benzoic acid to yield a salt comprising a 1:2 ratio of 1,2-bis(4-pyridinium)ethane dications and 2-(4-hydroxyphenylazo)benzoate anions. Centrosymmetrically related anions associate by charge-assisted O–H···O hydrogen bonds to form 24-membered {···OC₃N₂C₄OH}₂ synthons. These are connected into a supramolecular polymer via charge-assisted N–H···O hydrogen bonds involving the 1,2-bis(4-pyridinium)ethane dications. The compound crystallizes in the triclinic space group P−1 with a = 8.517(4) ?, b = 9.110(5) ?, c = 10.477(5) ?, α = 96.850(13)°, β = 94.446(12)°, γ = 104.946(10)° and Z = 1 {two anions and a dication}. Index Abstract  Supramolecular chains mediated by charge-assisted O–H···O and N–H···O hydrogen bonding are found in the salt containing a 1:2 ratio of 1,2-bis(4-pyridinium)ethane dications and 2-(4-hydroxyphenylazo)benzoate anions.      

Very strong hydrogen bonds in hydrated 1:1 adducts of an olefinic double betaine with perchloric and nitric acids: L·HClO4·H2O and L·HNO3·H2O [L=cis-(p-Me2N+C5H4N)2C2(COO−)2]

The hydrated 1:1 adducts of an olefinic double betaine with perchloric and nitric acids, L·HClO₄·H₂O I and L·HNO₃·N₂O2 [L=cis-(p-Me₂N⁺C₅H₄N)₂C₂(COO^–)₂], have been shown to be nearly isostructural by X-ray crystallography and infrared spectroscopy. The common cationic unit HL⁺ of both compounds exhibits significant semi-quinonoid character and possesses symmetrym, ist two coplanar carboxylate groups being linked by a very strong, nearly linear intramolecular O–H–O hydrogen bond [O...O 2.397(9)Å and O–H–O 167.1° for1; 2.388(7)Å and 167.4° for2]. The HL⁺ units are further connected by intermolecular O–H...O hydrogen bonds between the exocyclic carboxyl oxygen atoms and the water molecules to generate polymeric zigzag chains running parallel to thec axis, and the disordered ClO₄ or NO ₃ ^– anions occupy channels running parallel to thea axis in the resulting host lattice.     

Crystal structure of the molecular adduct of 5-mono[(4-nitrophenyl)azo]-25,26,27,28-tetrahydroxycalix[4]arene with chloroform (1:1)

The crystal structure of the molecular adduct of 5-mono[(4-nitrophenyl)azo]-25,26,27,28-tetrahydroxycalix[4]arene (2) with chloroform (C₃₄H₂₇N₃O₆ CHCl₃) was determined by X-ray crystallographic analysis. It was found to possess a monoclinic space group P2(1)/n, with a = 15.9306(13) Å, b = 10.6293(9) Å, c = 20.3194(17) Å, = 110.480(2)° and D_calc = 1.428 Mg/m³ for _Z = 4. Crystal data indicated that the calix[4]arene moiety of 2 exists in a distorted-cone conformation with intramolecular hydrogen bonds.     

Crystal structure of the molecular complex of 3-[1-(4-nitrophenyl)-3-oxobutyl]-4-hydroxychromen-2-one with ethanol

The crystal structure of 2,3H-2-methyl-4-(4-nitrophenyl)-5-oxobenzopyrano[3,4-e]dihydropyran-2-ol is investigated using X-ray diffraction. The unit cell contains an ethanol molecule that forms hydrogen bonds with O-H and C-O groups of two molecules of the main compound and acts as a proton donor and a proton acceptor in these hydrogen bonds. Owing to these interactions, infinite chains are formed in the crystal. The crystallographic data for the structure of C₁₉H₁₅NO₆·C₂H₅OH (M = 399.39) are as follows: the crystals are triclinic, space group P1, a = 5.5340(3) Å, b = 8.0109(4) Å, c = 11.0112(5) Å, α = 88.773(2)°, β = 84.788(2)°, γ = 79.958(2)°, and Z = 1.     

Ultrafine Co1−xZnxFe2O4 particles synthesized by hydrolysis: Effect of thermal treatment and its relationship with magnetic properties

Co_1−xZn_xFe₂O₄ (x = 0, 0.2 and 0.4) fine powders with particles size of 3 nm were prepared by hydrolysis method. The powders were annealed at 500 °C for 3 h. With heat treatment, the average particles size increased to 12 nm with corresponding increase in blocking temperature, saturation magnetization and reduced remanence. A significant increase in coercive field was found only for the pure CoFe₂O₄.     

X-ray mapping in heterocyclic design: 16. X-ray diffraction study of 1-(4-chlorophenacyl)-4-methyl-1,5,6,7-tetrahydro-2<Emphasis Type="Italic">H</Emphasis>-cyclopenta[<Emphasis Type="Italic">b</Emphasis>]pyridin-2-one

The structure of 1-(4-chlorophenacyl)-4-methyl-1,5,6,7-tetrahydro-2H-cyclopenta[b]pyridin-2-one is studied using single-crystal X-ray diffraction. The structure (a = 37.006(8) Å, b = 8.967(3) Å, c = 27.911(3) Å, β = 96.52(2)°, Z = 24, space group P2₁/c) is solved by direct methods and refined to R₁ = 0.0608 and wR₂ = 0.1170. Six crystallographically independent molecules differ in the dihedral angle between the phenyl and heterocycle planes. The formation of Cl?Cl aggregates is discussed.     

Separation of 4-aminobenzoic acid by cocrystallization: Crystal structure of the complex of 4-aminobenzoic acid with (2R,3R)-tartaric acid

4-Aminobenzoic acid (PABA) has been successfully separated from a mixture containing 2-aminobenzoic acid and (2R,3R)-tartaric acid. X-ray structure analysis confirms the separating result. The molecular complex formed by PABA and tartaric acid in 1:1 molar ratio crystallizes in the orthorhombic space group P2₁2₁2₁ with cell dimensions of a = 7.329(1) Å, b = 12.095(2) Å, c = 15.231(3) Å, V = 1350.1(4) ų, Z = 4. The crystal structure comprises protonated PABA, monoanion of tartaric acid, and crystalline water. The extensive H-bonding network exists in the crystal structure. H bonding between tartaric acid and both terminal groups on para position of PABA is considered as a possible reason for the successful separation.