Crystal and molecular structure ofcis-dicarbonyltetraphosphinechromium(O), [(CO)2(PH3)4Cr]

The crystal and molecular structure ofcis-dicarbonyltetraphosphinechromium(O), [(CO)₂(PH₃)₄Cr] has been determined by X-ray diffraction methods. The compound crystallizes in the monoclinic system: space groupC2/c,a = 6·968(6),b = 11·98(1),c = 12·87(1) Å, = 99·80(8) °,V= 1059(3) ų,Z=4,D _m = 1·534(5),D _x = 1·531(5) gcm^–3, diffraction symmetry 2/m. The structure was solved by conventional methods, and refined by least-squares techniques to an agreement factorR = 0·078. The chromium atoms lie on rotation diads, and thus the molecules must have at least the symmetry 2(C ₂); they were found to have, within the limits of accuracy, the even higher symmetrymm2 (C _2v ). There are two distinct independent Cr-P distances in the molecule, the Cr-P bonds where phosphorus istrans to carbonyl [2·338(4) Å] being significantly longer than those where phosphorus istrans to phosphine [2·282(4) Å]. This difference may be attributed to a difference in the back-bonding capabilities of the two types of ligands.We wish to thank Professor Dr E. O. Fischer for his stimulating interest in this work. Our thanks are due also to the Leibniz Rechenzentrum der Bayerischen Akademie der Wissenschaften for use of their computing facilities. This work would not have been possible without a generous grant from the Deutsche Forschungsgemeinschaft which is gratefully acknowledged.     

Structural studies of molybdenum(VI) coordination chemistry: Crystal and molecular structure of Mo2O4(2,2-dimethylpropane-1,3-diolate)2.(H2O)2 containing a μ-dioxo bridge

Journal of Chemical Crystallography - The crystal structure of the compound Mo2 VI O4 (2,2-dimethylpropane-1,3-diolate)2 · (H2O)2 has been determined. Crystals are triclinic, space...     

Crystal and molecular structures of 4-N-morpholino-7-phenyl 1,3-isobenzofurandione

The crystal and molecular structures of 4-N-morpholino-7-phenyl-1,3-isobenzofurandione have been determined by X-ray diffraction analysis (Nicolet R3m automated diffractometer, MoK _α radiation, graphite monochromator, θ/2θ scan mode). It is found that the compound crystallizes in the orthorhombic system, space group Pbca. The unit cell parameters are as follows: a = 7.773(2) Å, b = 14.652(3) Å, c = 25.614(5) Å, and Z = 8. The structure is solved by the direct method and refined to R1 = 0.0504 [I > 2σ(I)]. The conformational and geometric characteristics of the studied compound and the molecular packing in the crystal are discussed.     

Crystal structures of two azo compounds, 2-methyl-2-(4-bromphenylazo)-1,3-indandione and 2-methyl-2-(4-ethoxyphenylazo)-1,3-indandione

In the two title compounds, the 2-methyl-1,3-dioxoindan-2-yl and 4-(brom; ethoxy) phenyl groups aretrans with respect to one another. The phenyl ring and the azo group are not coplanar in the two molecules. The five-membered rings of the two compounds adopt an envelope conformation. The crystallographic parameters are as follows: 2-Methyl-2-(4-bromphenylazo)-1,3-indandione (I): monoclinic, P2₁/a witha=8.098(2),b=14.442(2),c=12.554(1)Å, =100.55(2)^o, andD _calc=1.58 g cm^–3 forZ=4; 2-methyl-2-(4-ethoxyphenylazo)-1, 3-indandione (II): monoclinic, P2₁/a witha=8.258(2),b=14.449(1),c=13.559(2)Å, =101.19(1)^o, andD _calc=1.29 g cm^–3 forZ=4.     

Crystal and molecular structure of 2-(1,3-benzothiazol-2-yl)-2-(4-tert-butylcyclohexylidene)ethanonitrile

The crystal and molecular structure of the title compound (C₁₉H₂₂N₂S) has been investigated by single crystal X-ray methods. The crystals are orthorhombic, space groupPbca, with cell dimensions:a=12.082(2)Å,b=11.460(2)Å,c=25.128(4)Å. The structure was solved by direct methods, and refined with 1225 independent reflections by a full-matrix, least-squares procedure, which converged toR=0.042. The benzene and thiazole planes are coplanar and the cyclohexane ring adopts a chair conformation.     

Crystal and molecular structures of two polymorphs of 4-methyl-2-nitroacetanilide (MNA)

Journal of Chemical Crystallography - The crystal and molecular structure of white (MNA-1) and yellow (MNA-3) forms of 4-methyl-2-nitroacetanilide have been determined by X-ray diffraction...     

Crystal structures of twoN-substituted 2-thioxo-1,3-dithiole-4-carboxamides

The two closely related compoundsN,N-dimethyl 5-(methylthio)-2-thioxo-1,3-dithiole-4-carboxamide1 andN-(p-methoxy-phenyl)-N-methyl 5-(methylthio)-2-thioxo-1,3-dithiole-4-carboxamide2 have been characterized by X-ray crystal structure determination. Crystal data for1: triclinic, ,a=6.767(1),b=12.594(2),c=6.648(1) Å, =101.38(1), =93.37(2), =79.62(1)°,V=546.2 ų,Z=2. Crystal data for2: monoclinic, Cc,a=19.836(4),b=6.057(1),c=15.860(3) Å, =127.61(3)°,V=1509.5ų,Z=4. The molecular structures of1 and2 show remarkable differences concerning the conformational behavior. These differences are related to the nature of the substituents at the nitrogen atom. The presence of an aromatic system in2 leads to an almost planar arrangement of the -oxoketene dithioacetal moiety. This effect is accompanied by a short intramolecular S...O contact of 2.648(2) Å. In the absence of an aromatic system, as is the case for compound1, neither a resonance effect along the -oxoketene dithioacetal fragment nor a short S...O distance is observed.     

Crystal and molecular structure of 0,0,0-propan-1,2,3-trithionobenzoate (3TBZ): Implication for thermally induced solid-state transformation of 3TBZ

The crystal and molecular structure of 0,0,0-propan-1,2,3-trithiobenzoate (3TBZ) has been determined by direct methods. Crystals are monoclinic,a=6.810(2),b=35.950(2),c=9.415(2) Å,=94.78(2)°, space group P2₁/c,Z=4. The structure was refined using full-matrix least-squares toR=0.078,R _w=0.064, 1957 reflections CuK radiation, =1.5418 Å. The molecule has one relatively short S---C (methylene) intramolecular distance, S(2)---C(38)=3.440(4)Å, approximately 1.5 Å less than the shortest S---C distance observed in related crystal structures. An hypothesis related to this short contact is proposed in order to account for the unusual pyrolitic behavior of this compound in the solid state.     

Crystal and molecular structure of 2,2′-diphenyl-4,4′-di(2-phenyl-2-propenyl)-4, 4′-bi-5(4H)thiazolone

Molecules of C₃₆H₂₈N₂O₂S₂ crystallize in the monoclinic space groupP2₁/c with cell dimensionsa = 8.9326(3),b = 20.0197(11),c = 17.0349(8) Å, and = 92.20(1) °,Z = 4,D _x = 1.276 g cm^–3, (CuK) = 18.16 cm^–1. The structure was solved by Patterson methods and refined by least-squares calculations to anR of 0.057 andR _w = 0.066 for all reflections. The main differences in the two halves of the dimer are due to the different torsion angles in the propenyl chain.     

Crystal and molecular structure of (2E,4S,10R)-4-hydroxy-2-undecen-10-olide (nor-patulolide C), C11H18O3

The stereogeometry and absolute configuration of the title compound has been proved by an X-ray diffraction analysis. Crystal data: monoclinic, P2₁,a=7.7976(2),b=7.8288(2),c=8.9791(4) Å, =90.331(4)^o, Z=2. The crystal structure has been solved by vector search methods and refined toR=0.042 for 1798 observed reflections.     

Crystal and molecular structure of pyridinium di-μ-oxo-bis(oxodichloroaquomolybdate(V)) monohydrate, (pyh)2[Mo2O4Cl4(H2O)2] · H2O

The crystal and molecular structure of pyridinium di--oxo-bis(oxodichloroaquomolybdate(V)) monohydrate has been determined from MoK diffractometer data. The compound crystallizes in the monoclinic space groupP2 ₁/m witha = 7.544(1),b= 17.046(3),c = 7.894(1) Å, = 106.00(1) ° andZ = 2. The structure was solved by the heavy-atom technique and refined by full-matrix least-squares method toR = 0.046, using 1800 reflections for whichF> 4(F). Molybdenum atoms are linked by the double oxygen bridge with an Mo—O distance of 1.943(4) Å and an Mo—O—Mo angle of 83.4(2) °. The Mo—Mo distance is 2.584(1) Å, indicating direct Mo—Mo bonding. The pyridinium and [Mo₂O₄C1₄(H₂O)₂]^2- ions are hydrogen bonded through N—H ... O bonds. The N ... O contact is 2.656(8) Å.     

Crystal structures of 4-amino-1,2,4-triazolidine-3,5-dione (urazine) (C2H4N4O2) and dichlorobis (4-amino-1,2,4-triazolidine-3,5-dione-N,O) copper (II) (C4H8Cl2CuN8O4)

Crystal structure analyses of urazine and of its adduct with CuCl₂ show that this ligand can exchange interactions of stacking that cannot be defined as simple - interactions. The copper atoms are octahedrally coordinated by two oxygen atoms and two aminic nitrogen from chelating uraxines and two chlorine atoms. The crystals of urazine are monoclinicP2₁ c:a=6.741(1),b=5.815(1),c=11.141(2) Å,/gb=92.13(1)°,V _c=436.4(1) ų,Z=4,R=0.0402 for 714 independent observed reflections; the crystals of [CuCl₂(urazine)₂] are triclinicP¯1:a=5.236(1),b=6.662(1),c=8.411(1) Å,=93.00(1),=104.87(1), =105.69(1)°,V _c=270.66(8) ų,Z=1,R=0.0380 for 875 independent observed reflections.     

Crystal and molecular structure of chloro(2,2′,2″-terpyridine)palladium(II)chloride dihydrate,C15H15Cl2N3O2Pd

The crystal and molecular structure of chloro(2,2,2-terpyridine)palladium(II)-chloride dihydrate, C₁₅H₁₅Cl₂N₃O₂Pd, has been determined by single crystal X-ray diffraction techniques. The crystals are orthorhombic: space groupPna2₁,a = 17·217(9),b = 14·026(8),c = 6·801(5) Å,Z = 4. Least-squares refinement of 2064 non-zero manually gathered diffractometer reflexions was carried out to a conventional unweightedR of 0·069. The molecule consists of a basically planar 4-coordinate [Pd(terpy)Cl]⁺ cation and a Cl^– anion. The molecules are packed in a layer structure in which the average separation is about 3·4 Å, the closest approach being 3·13 Å between a palladium atom and one of the nitrogen atoms of a neighboring molecule. Bond distances are within acceptable limits of predicted values. Deviations from planarity in the coordinated terpyridine ligand are presumably due to its steric limitations and are similar to those found in other terpyridine complexes.This work was supported in part by the National Science Foundation under grants GP-7510 and GP-11776.     

Crystal and molecular structure of catena-μ-acetatomonobromodiamminecopper(II), C2H9BrCuN2O2

The crystal structure of catena-μ-acetatomonobromodiamminecopper([I]), C₂H₉BrCuN₂O₂, has been determined by three-dimensional Patterson and Fourier methods, and refined by least-squares procedures to R=4·7%. The orthorhombicPnma unit cell of dimensions a=9·01(1), b=7·60(1), c=10·38(1) Å contains 4 formula-entities. Two oxygen atoms from different acetate groups (Cu-O=2·001(6) and 1·995(5) Å) and two ammonia molecules (Cu-N=1·984(6) Å) coordinate to the copper atom in atrans square-planar arrangement. This is extended to square-pyramidal by a long contact with the bromine atom (Cu-Br=2·865(3) Å). One more long contact with the other oxygen atom of the carboxyl group (Cu-O(1ⁱ)=2·942(7) Å) realizes a distorted octahedral coordination. The acetate groups lie in mirror planes, and bridge the coordination polyhedra in zig-zag chains parallel to [100].     

Crystal and molecular structure of 3-chloro-3,6-dinitro-2,2-dimethyl-4-chromanone, C11H9N2O6Cl

3-Chloro-3,6-dinitro-2,2-dimethyl-4-chromanone is the first 3-chloro-3-nitro-4-chromanone to be synthesized by nitrating its corresponding 4-chromanone at the 3 position and then chlorinating the nitration product. Its structure was determined by IR, NMR, MS and x-ray crystallography. It crystallizes as a pair of enantiomers with 2 molecules in the primitive triclinic space group P (#2) with a = 9.476(2), b = 10.906(3), c = 6.578(5) Å, and = 101.08(3), = 90.13(3), = 73.23(1)°, V = 637.7500 ų, and Z = 2. The nitro group at the 6 position conjugates with the benzene ring. The pyranone ring has a half-chair conformation; the chloro group occupies the pseudoequatorial position, and the nitro group occupies the pseudoaxial position. The 2 and 3 positions are essentially antiperiplanar, minimizing steric interaction.     

Crystal and molecular structure of tris (2,2,6,6-tetramethyl-3,5-heptanedionato) aquodysprosium(III), Dy(thd)3H2O

The crystal structure of Dy(thd)₃H₂O has been solved by three-dimensional X-ray methods at room temperature. The space group isP¯1 and the cell dimensions area = 14·21(1),b = 14·88(2),c = 11·60(2) Å, = 99·76(3), = 109·91(1), = 114·08(1) °.Z = 2,D _m = l·24 andD _x = 1·238 gcm^–3, respectively. Full-matrix least-squares refinement of atomic and individual isotropic thermal parameters, using 3015 intensities obtained by counter methods, terminated with a conventionalR of 0·058. The oxygen polyhedron around dysprosium has pure seven-coordination geometry, the seventh ligand being the water molecule. The water is hydrogen bonded to two oxygen atoms of a centre of symmetry related formula unit so that two formula units are in fact held together by hydrogen bonds in a dimer.Supported by National Institute for Metallurgy, Johannesburg.     

Crystal structures of 1,1-di(p-substituted phenyl)-2,2-dinitroethylenes

The X-ray crystal structures of 1,1-di(p-methylphenyl)-2,2-dinitroethylene (2), 1,1-di(p-methoxylphenyl)-2,2-dinitroethylene (3), 1,1-di(p-fluorophenyl)-2,2- dinitroethylene (4), 1,1-di(p-chlorophenyl)-2,2-dinitroethylene (5), and 1-phenyl-1- (p-nitrophenyl)-2,2-dinitroethylene (6) are reported and compared with that of 1,1-diphenyl-2,2-dinitroethylene (1). Owing to steric repulsion between the aryl rings, the single bond lengths between C(1) and the two ring carbons atoms are longer than the normal sp²–sp² bond distance of 1.46 Å. For 4–6 in which the aryl rings contain electron-withdrawing substituents (F, Cl, NO₂), the double bonds between C(1) and C(2) are shorter than those in 2 and 3, whose aryl rings containing electron-donating substituents. Furthermore, the steric repulsion between the aryl rings and C NO₂ fragments results in an appreciable twist about the central double bond. The two aryl rings of compounds 1–6 make dihedral angles of 77.7, 66.6, 62.8, 80.9, 82.0, and 71.2°, and the two C NO₂ fragments make dihedral angles of 68.5, 67.8, 65.9, 76.9, 73.0, and 71.9°, respectively.