The crystal structure of 4-iodoacetophenone azine

4-Iodoacetophenone azine crystallizes in the space group Pbcn with cell parametersa = 34.5187(19), b = 7.2638(4), and c = 6.3736(3) Å. The azine shows a gauche conformation with regard to the N—N bond and the phenyl rings are twisted in a way that leads to the largest possible twist between the benzene rings of each azine. This azine conformation allows for intermolecular arene–arene T-contacts between pairs of benzene rings and these double-T contacts involve only molecules within the same layer. All azines are perfectly colinear within each layer and this results in a quadrilateral kite-shaped arrangement of iodine atoms at the interface of each layer. The iodine-iodine distances within each layer are 4.5 and 5.1 Å, and the three unique angles of the kite-shaped quadrilaterals are 97.1, 76.9, and 88.8°. The iodine atoms in adjacent layers pack such that atoms of one layer fill the square interstices of the next layer. The distances between iodine atoms in adjacent layers are 4.5 and 4.1 Å. The C—I bonds are not orthogonal to the I-planes and the direction of the molecules in adjacent layers causes a deviation of about 40° from colinearity     

Synthesis of 1,2-dimethoxy-1,2-di(pyridin-2-yl)-1,2-ethanediol: Crystal and molecular structure determination

The compound, 2-hydroxy-[1,2-di(pyridin-2-yl)]ethane-1-one, 1, was isolated from the reaction of 2-pyridinecarboxaldehyde and 2-pyridinemethanol at 140°C without catalyst or solvent and characterized by¹H-NMR and IR spectral data. The compound 1 was treated with ethyl acetate to produce the 1,2-di(pyridin-2-yl)ethane-1,2-dione, 2. When 2 was dissolved in an excess of CH₃OH, crystals of 1,2-dimethoxy-1,2-di(pyridin-2-yl)-1,2-ethanediol, 3, were obtained. The molecular and crystal structure of 3 was determined by single crystal X-ray diffraction. The compound crystallizes in the monoclinic system belonging to the P2₁/n space group with a = 6.867(2) ?, b=9.546(4) ?, c=10.522(5) ?, α=90°, β=98.48(4)°, γ=90°. The asymmetric unit comprises two molecules of 3. Although the di-hemiketal was obtained in crystal form, it was found to be unstable, because its IR spectrum changed after a short time, indicating that it had been converted back to the original diketone, 2. The IR showed signals at 1713, and 1690 due to νC =O assigned to di-ketone group.     

Crystal structure of a butyllithium 1,2-dipiperidinoethane dimer complex

The crystal structure of butyllithium solvated by 1,2-dipiperidinoethane, BuLi·DPE-6, which has been used as an initiator for a number of important commercial anionic polymerization reactions, is reported. The complex crystallizes from pentane as a centrosymmetric dimer in the monoclinic space group P2₁/n with a = 9.8619(12), b = 17.963(2), c = 10.3655(12) ?, β = 114.090(2)° and Z = 2. The dimer is located on a crystallographic inversion center. The crystal under investigation was found to be non-merohedrally twinned. In contrast to the two other dimeric BuLi complexes previously structurally characterized in the solid state, BuLi·DPE-6 has a planar central Li₂C₂ core. Semi-empirical (PM3) calculations were used to determine the lowest energy conformations of the dimer and also identified three structural motifs that affect Li₂C₂ dimer ring planarity.     

Crystal and molecular structure of 6-t-butyl-1,2-naphthoquinone-1-oxime

The structure of 6-t-butyl-1,2-naphthoquinone-1-oxime was determined by direct methods by the use of MoK diffractometer data and was refined toR = 0.12. The crystals are monoclinic:a = 8.32(1),b = 6.70(1),c = 11.14(1) Å, = 101(1) °,Z = 2,P2₁/m. The molecule is crystallographically flat and lies in a mirror plane. Pronounced diffuse scattering on [010] oscillation photographs is caused by disorder in the orientation of thet-butyl group. The compound occurs in the oxime form, and not as a 1,2-nitroso naphthol.     

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.     

Crystal structure of 3H-1,2-benzodithiol-3-one 1-oxide

The compound 3H-1,2-benzodithiol-3-one 1-oxide (2) has proven useful in modeling the reactivity of the novel antitumor antibiotic leinamycin (1). The crystal structure of this unusual sulfur heterocycle is reported here. The molecule crystallizes in the P-1 space group with cell parameters a = 7.168(4), b = 7.670(3), c = 7.922(3)Å, = 68.34(4), = 83.86(3), = 65.50(3),° and U = 367.8 ų.     

Crystal and molecular structure of bis-tetraphenylarsonium-tris-(cis-1,2-dicyano-1,2-ethylenedithiolato)Fe(IV)

The crystal structure of bis-tetraphenylarsonium-tris-(cis-1,2-dicyano-1,2-ethylenedithiolato)Fe(IV), [(C₆H₅)₃As]₂Fe[S₂C₂(CN)₂]₃, has been determined using 3154 independent, non-zero reflexions collected by counter techniques. The substance crystallizes in the monoclinic system: space groupI2/a,a = 20·153(8),b = 13·411(5),c = 21·497(8) Å and = 95·28(8) °;D _m = 1·41(2),D _c = 1·43 g cm^–3 andZ = 4. The structure consists of Ph₄As⁺ cations in general positions and tris-(cis-1,2-dicyano-1,2-ethylenediothiolato)Fe(IV) anions on two-fold axes. Although the coordination around the arsenic atom is tetrahedral, the overall symmetry of the cation is 1 (C ₁), probably because the phenyl rings are rotated to accommodate the requirements of packing. The coordination of the six sulphur atoms about the iron atom is trigonal antiprismatic, approximating closely to an octahedron: for any pair oftrans sulphur atoms, the S-Fe-S angle is about 171 °.     

Crystal structure of monomethylammonium tribromocadmate(II)

CH₃NH₃CdBr₃ crystallizes in the space group Ccm2₁, a = 13.693(1) Å, b = 7.906(1) Å, c = 6.886(1) Å, V = 745.46(15) ų, Z = 4, D _x = 3.42 Mg m^–3. The structure of the title compound is one-dimensional consisting of infinite chains made of face sharing CdBr₆ octahedra. The methylammonium groups are situated in the space between chains. The cations and anions are joined by hydrogen bonding.     

Crystal and molecular structure of augustamine

The crystal and molecular structure of augustamine (1), C₁₇H₁₉NO₄ an amaryllidaceae alkaloid of the tazettine group has been determined by direct methods from single crystal x-ray diffractometer data and refined by full-matrix least squares. The alkaloid (1) crystallizes in the space group P2₁2₁2₁, with cell parameters: a = 7.833(8) b = 11.08(2) å, c = 16.69(6) Å, Z = 4, D_c = 1.381 g/cm^–3, R = 7.6% for 1115 observed reflections. The molecule, having a hexacyclic ring system, is very rigid with the ring B in a chair conformation. Molecular mechanics calculations have been made using MM3(2000) force field.     

Crystal and molecular structure of cyclotriveratrylene

Slow evaporation of a solution made from rigorously dried toluene and cyclotriveratrylene (CTV) has led to crystals of the guest-free CTV. These belong to the monoclinic space groupP2₁/n witha=12.582(3),b=9.575(5),c=19.738(5) Å,=95.15(2)°;D _c =1.26 g cm^–3 forZ=4. Refinement based on 1708 observed reflections led toR=0.045. The nine-membered ring of the CTV has the expected crown conformation.     

Crystal and molecular structure of pisatin

(+)-Pisatin, C₁₇H₁₄O₆, a lipophilic substance with antifungal activity, has been isolated fromPisum sativum L. following fungal inoculation. Orthorhombic crystals of the monohydrate belong to the space groupP2₁2₁2₁ witha = 6.910(3),b = 9.006(2),c = 24.253(4) Å, andZ = 4. The structure was solved by direct methods from diffractometer data measured with CuK radiation. Refinement with anisotropic temperature factors given to the non-hydrogen atoms converged atR = 0.058 for the 1255 observed terms. The molecular conformation is similar to the conformation recently reported for phaseollin, a related phytoalexin. Hydrogen bonds involving the water and pisatin molecules link the latter into infinite spirals extending alongb.     

Crystal and molecular structure of geiparvarin

The structure of the antitumor agent geiparvarin was determined by direct methods from CuK diffractometer data. The crystals of synthetic geiparvarin have the space groupP2₁/c witha = 8.305(1),b = 11.077(1),c = 18.287(1) Å, = 98.79(1) °, andZ = 4. The structure was refined toR = 0.047. The chemically determined structure was confirmed. Bond distances and angles are normal and there are no unusual C-H O intermolecular contacts.IUPAC name: 7-[3-(4,5-dihydro-5,5-dimethy1-4-oxo-2-furanyl)-2-butenyi]-oxy-(2H-1-benzopyran-2-one).Camille and Henry Dreyfus Teacher-Scholar, 1978–1983; National Institutes of Health Career Development Award, 1980–1985.     

Crystal and molecular structure of pentachloromonoisopropylaminocyclotriphosphazatriene

Crystals of N₃P₃C1₅ (NHC₃H₇) are monoclinic:a=15.059(7),b=14.815(5),c=6.501(6) Å, =95.03(6)°, space groupP2₁/n, and Z=4. The atomic positions were determined by direct methods and refined by least-squares refinement from diffractometer X-ray intensity data toR=0.063 for 1530 reflections. In the structure, pairs of molecules mutually related by a center of symmetry are linked by N-H N hydrogen bonds. The endocyclic P-N bonds range in length from 1.556 to 1.603 Å depending on the location of the bond relative to the isopropylamino group, and the exocyclic P-N bond is only a little longer (1.617 Å). The nongeminal P-Cl bond is significantly longer (2.036 Å) than the remaining P-Cl bonds (1.988–2.013 Å). The phosphazene ring shows only a very small departure from planarity. The isopropylamino group has a symmetrical conformation, with a Cl-P-N-C torsion angle of 90.5°.     

Crystal and molecular structure of chloramphenicol

Chloramphenicol, C₁₁H₁₂Cl₂N₂O₅, is orthorhombic, space groupC222₁,a = 17.495(3),b = 7.321(2),c = 22.130(4) Å, andZ = 8. The structure was solved by direct methods and refined to a finalR value of 0.068 for 1186 counter-reflections. Estimated standard deviations for bond lengths and bond angles involving nonhydrogen atoms average 0.009 Å and 0.6 °, respectively. All the hydrogen atoms that are bonded to O or N and are available for hydrogen-bond formation take part in the hydrogen-bonding network. The crystals become brown in color on prolonged exposure to X-rays and -rays. Our structural investigation with colored crystal does not indicate any structural change.     

Crystal and molecular structure of benzylidenemalononitrile

Benzylidenemalononitrile, C₁₀H₆N₂ crystallizes in the monoclinic space group,P2₁/c;a = 9·385,b = 3·976,c = 22·152 Å, = 93·53 °,V _c = 825·03 ų,D _m = 1·231,D _c = 1·242 g cm^–3,Z= 4. The structure was solved by fitting cojointly an assumed molecular shape to both the near-origin peaks of the sharpened vector map and the distribution in the Harker (U,1/2,W) section, followed by trial-and-error establishment of the coordinates. The structure was then refined by full-matrix least squares, reducingR to 0·090 for data comprising 1412 reflexions (0·086, omitting 373 unobserved) from room temperature CuK Weissenberg photographs. Steric hindrance of the malononitrile group and a hydrogen atom in theortho position of the phenyl ring causes simultaneous expansion of the bond angles between the malononitrile group and the benzylidene group and rotations of these groups relative to each other. These constraints cause the two groups to be non-planar, the dihedral angle between their least-squares planes being 11·0 °.     

Crystal and molecular structure of delsoline

The crystal and molecular structure of the diterpenoid alkaloid delsoline (1) C₂₅H₄₁NO₇, M_r 467.61, has been determined by an X-ray analysis. The X-ray crystal structure which could not be solved earlier withMultan, has now been solved using the SIR 88 analysis program. The compound crystallizes in the space groupP2₁2₁2₁ with cell parameters:a=12.529(2),b=13.118(1),c=14.231(6)Å,V=2339(1)ų,Z=4,D _calc=1.33 g/cm^–3, (CuK)=1.54184 Å,(CuK )=7.4 cm^–1,R/R _w =0.068/0.040 for 2539 reflections. The A ring of delsoline exists in the boat conformation stabilized by an intramolecular N---H-O hydrogen bond. Ring D also is in a boat form. Unambiguous proton and carbon-13 nmr assignments have been made by a detailed analysis of the DEPT, COSY, NOESY, and HETCOR nmr spectra.     

Crystal and molecular structure of piperidinium-acet-p-Cl-anilide-bromide

The crystal structure of piperidinium-acet-p-Cl-anilide-bromide is monoclinic, space group P 2₁/n with 8 formula units C₁₃H₁₈N₂OBrCl in the unit cell. The lattice constants are a = 7.337(2), b = 17.865(4), c = 22.822(5) Å, and β = 94.66(1)°. The title compound is not isomorphous to the corresponding chloride. Br ions are linked to the molecules by hydrogen bonds forming chains in the crystal structure.     

Crystal structures of complexes of tri-, tetra-, or nonaethyleneglycol dimethyl ether with dichloropicric acid and water

The 1:2:2 triglyme/dichloropicric acid/water adduct is triclinic, space group P ; at 172(2) K, a = 4.9210(10), b = 13.424(3), c = 14.068(3) Å, = 115.04(3), = 90.93(3), = 92.24(3)°, D _x = 1.600(5) g cm^–3, V = 840.8(3) ų, and Z = 1. Each water molecule is hydrogen bonded to a terminal OCH₃ group of one polyether and to an oxygen adjacent to an OCH₃ of a neighboring polyether, resulting in two-dimensional ribbons. These ribbons, in turn, are assembled into a three-dimensional structure held together by chains of dichloropicric acid molecules connected to each other through chlorine–nitro group oxygen intermolecular interactions. The picric acid chains are attached to the water–polyether ribbons by hydrogen bonds from the picric acid to the water. The 1:2:2 tetraglyme/dichloropicric acid/water adduct is monoclinic, space group C2/c; at 172(2) K, a = 30.529(6), b = 5.4210(11), c = 25.413(5) Å, = 122.33(3)°, D _x = 1.597(3) g cm^–3, V = 3553.7(12) ų, and Z = 4. The hydrogen bonding pattern resembles that of the analogous 1:2:2 pentaglyme complex reported previously, with the exception that both of the lone pairs of the central oxygen atom participate in hydrogen bonding to protons of water molecules. The second water proton is hydrogen bonded to a terminal OCH₃ group. In this complex the dichloropicric acid molecules form a two-dimensional layer through chlorine–nitro group oxygen intermolecular interactions. The water molecules bond each isolated polyether molecule to adjacent dichloropicric acid layers. The 1:4:4 nonaglyme/dichloropicric acid/water complex is triclinic, space group P ; at 172(2) K, a = 8.0830(16), b = 13.570(3), c = 16.751(3) Å, = 102.01(3), = 102.39(3), = 96.43(3), D _x = 1.637(6) g cm^–3, V = 1731.5(6), and Z = 1. The hydrogen bonding pattern is similar to that in the pentaglyme complex, except that four dichloropicric acid molecules and four water molecules are coordinated to a single polyether, and the polyether chain is appreciably disordered. In this case there are again chains of dichloropicric acid molecules held together by intermolecular chlorine–oxygen interactions. The chains are packed into two-dimensional layers held together through hydrogen bonds to water. Each isolated polyether is connected to four water molecules, two attached to dichloropicric acid molecules in one layer and the other two connected to the adjacent layer.     

Crystal and molecular structure of L-N-acetylhistidinamide

The title compound crystallizes in the monoclinic space group P 2₁ with 2 formula units C₈H₁₂N₄O₂ in the unit cell. The lattice parameters are a = 8.529, b = 11.735, c = 4.925 Å, and β = 94.61°. The crystal structure has been determined by direct methods and refined by full-matrix least squares calculations to the discrepancy factor R = 0.033.     

Crystal and molecular structure of dichlorofluoroacetamide

The crystal structure of dichlorofluoroacetamide has been determined from three-dimensional counter data, and refined by full-matrix least-squares techniques. The crystals belong to the monoclinic space groupP2₁ /c and have the unit-cell parametersa = 10.207(4),b = 5.729(2),c = 9.971(4) Å, = 105.21(8) °, andD _x = 1.72 g cm^-3. The structural refinement gave a finalR factor of 0.067 from 440 observed reflections. The compound has nearly equal disorder of the -Cl₂F moiety about the C-C bond axis with occupancy factors of the two fragments being 0.48 and 0.52.