The crystal and molecular structure of syn-2,11-diselena[3,3]metacyclophane and comparison with the dithia-analogue

1982 ◽  
Vol 60 (3) ◽  
pp. 362-367 ◽  
Author(s):  
Gordon W. Bushnell ◽  
Reginald H. Mitchell
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Solid State ◽  
Crystal And Molecular Structure ◽  
State Structure ◽  
X Ray Diffraction ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Anti Conformer ◽  
R Value

The crystal structure of syn-2,11-diselena[3,3]metacyclophane, 1a, has been determined by single crystal X-ray diffraction and refined to an R-value of 0.039. The crystal structure is monoclinic with a = 1926(1), b = 801.4(3), c = 924(1) pm, β = 98.9(1)°, and is isomorphous with that of the analogous sulphur compound. The space group is P21/n with 4 molecules per cell, D(meas) = 1.733 g cm−3, D(calcd) = 1.726 g cm−3. The molecule has the syn-conformation with the largest possible Se—Se distance of 721.8 pm. The benzenoid rings form a dihedral angle of 19.1°. The distance between the internal aryl hydrogen atoms on rings 1 and 2 is 285.1 pm. The internal aryl C atoms are 314.6 pm apart. The 1Hmr solution spectra of 1a are consistent with the solid state structure, and can be explained without involving equilibration with an anti-conformer.

The crystal structure of C.I. Pigment Red 2, 1′-(2,5-dichlorophenyl)azo-2′hydroxy-3′-phenylamidonaphthalene

1977 ◽  
Vol 146 (4-6) ◽  
Author(s):  
A. Whitaker
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Crystal And Molecular Structure ◽  
X Ray Diffraction ◽  
Hydrogen Atoms ◽  
Monoclinic System ◽  
X Ray ◽  
Cell Parameters ◽  
Intramolecular Hydrogen

AbstractThe crystal and molecular structure of C.I. Pigment Red 2, l′-(2,5-dichlorophenyl)azo-2′-hydroxy-3′-phenylamidonaphthalene has been determined by x-ray diffraction techniques. It crystallizes in the monoclinic system with cell parametersThe hydrogen atoms have been found and included but not refined. The final residual is 15.3%. The molecule is probably in the form of the hydrazone tautomer. The intramolecular hydrogen bonds keep most of the molecule approximately planar while it appears that the remainder is held in the same plane due to steric hinderence between the molecules. The molecules are packed in columns with alternate molecules antiparallel and are linked by van der Waals forces.

Crystal structure – reactivity correlations in the solid state photochemistry of N-(tert-butyl)succinimide

1994 ◽  
Vol 72 (9) ◽  
pp. 1952-1960 ◽  
Author(s):  
Tai Y. Fu ◽  
John R. Scheffer ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Solid State ◽  
Crystalline State ◽  
Crystal And Molecular Structure ◽  
Carbonyl Oxygen ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Tert Butyl ◽  
Close Contacts

In order to provide experimental evidence on the stereoelectronic requirements for intramolecular hydrogen atom abstraction by carbonyl oxygen, N-(tert-butyl)succinimide, 1, was investigated by the crystal structure – reactivity correlation method. In this method, the success or failure of a given reaction in the crystalline state is correlated with the geometric parameters associated with the process as determined by X-ray crystallography. In the case of N-(tert-butyl)succinimide, the crystal and molecular structure shows that the molecule adopts a conformation in which there are very close contacts (d = 2.17–2.24 Å) between the carbonyl oxygen atoms and certain γ-hydrogen atoms on the tert-butyl group. In accord with these close contacts, ultraviolet irradiation of N-(tert-butyl)succinimide in the crystalline state leads to transfer of one of the γ-hydrogen atoms from carbon to oxygen. This produces a 1,4-biradical which closes to form a cyclobutanol, and the cyclobutanol undergoes ring opening to afford the final stable product, tetrahydro-1H-azepine-2,5-dione, 2. The crystal and molecular structure of photoproduct 2 is also reported. In contrast to many solid state transformations, there was no discernable melting of the crystals during reaction, and complete conversions of 1 into 2 could be achieved. The isolated chemical yield of photoproduct 2 from the solid state reaction (79%) is in fact considerably higher than that reported by Kanaoka and Hatanaka for the corresponding solution phase process (49%). This permitted the solid state reaction to be followed to 100% conversion by X-ray powder diffractometry, which showed that the process is a single crystal-to-polycrystalline transformation involving a regular and progressive conversion of 1 into 2 with no obvious diffraction peaks that might be attributable to the intermediate cyclobutanol.

Crystal structures of medium ring compounds. Part III. The crystal and molecular structure of trans-anti-trans-4,5:9,10-biscyclohexano-1,3,6,8-tetraoxecane

1979 ◽  
Vol 57 (16) ◽  
pp. 2154-2158 ◽  
Author(s):  
Aris Terzis ◽  
T. Bruce Grindley
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Crystal And Molecular Structure ◽  
Chair Conformation ◽  
Membered Ring ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ring Compounds ◽  
R Value ◽  
Medium Ring

The crystal structure of trans-anti-trans-4,5:9,10-biscyclohexano-1,3,6,8-tetraoxecane (3) has been determined by X-ray diffraction. The crystals are monoclinic, a = 11.919(3), b = 17.330(7), c = 7.019(2) Å, β = 98.91(1)°, P21/c, with Z = 4. The structure was solved by application of the tangent formula and refined by large block least squares to a final R value of 0.060 (Rw = 0.058).The ten-membered ring is present in the crystal in a twist-chair-boat-chair conformation — one which has been calculated to be relatively unstable for cyclodecane. Possible reasons why 3 adopts this conformation are discussed.

The conformation of a ten-membered ring: the crystal and molecular structure of trans-syn-trans-4,5:9,10-biscyclohexano-1,3,6,8-tetraoxecane

1977 ◽  
Vol 55 (14) ◽  
pp. 2692-2699 ◽  
Author(s):  
Aris Terzis ◽  
T. Bruce Grindley ◽  
J. Brian Faught
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Crystal And Molecular Structure ◽  
Membered Ring ◽  
Thermal Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
R Value

The crystal structure of trans-sys-trans-4,5:9,10-biscyclohexano-1,3,6,8-tetraoxecane (1) has been determined by X-ray diffraction. The crystals are monoclinic, a = 10.995(2), b = 5.291(1), c = 12.241(2) Å, β = 114.68(1)°, P21/c, with Z = 2. The structure was solved by the application of symbolic addition procedures and refined with anisotropic thermal parameters for all atoms to a final R value of 0.039 (Rw 0.062) for 1135 independent reflections.The ten-membered tetraoxecane ring is present in the crystal in a boat-chair-boat (BCB) conformation, which is somewhat different in geometry than the BCB conformations observed for cyclodecane derivatives. The causes of these differences are discussed. Intramolecular non-bonded interactions cause one CH2 group to be significantly distorted from local C2v symmetry.

The crystal and molecular structure of syn-[4.4.3]propella-2,4,12-trien-11-ol 3,5-dinitrobenzoate

1985 ◽  
Vol 63 (4) ◽  
pp. 862-865 ◽  
Author(s):  
Judith C. Gallucci ◽  
Katsuo Ohkata ◽  
Leo A. Paquette
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Crystal And Molecular Structure ◽  
Molecular Geometry ◽  
Chair Conformation ◽  
Membered Ring ◽  
Aqueous Acetone ◽  
X Ray Diffraction ◽  
X Ray ◽  
R Value

The crystal structure of syn-[4.4.3]propella-2,4,12-trien-11-ol 3,5-dinitrobenzoate, 2, has been determined by single crystal X-ray diffraction and refined to an R value of 0.051. The crystal structure is triclinic with a = 10.208(2), b = 13.355(2), c = 7.068(1) Å, α = 99.35(1)°, β = 100.63(1)°, γ = 100.79(1)°, and the space group is [Formula: see text] with two molecules per cell, D(calcd) = 1.39 g cm−3. The unsaturated five-membered ring resides in an envelope conformation with C6—C11—C12—C13 lying essentially in a plane. The fifth atom, C1, is positioned 0.47 Å out of this plane on the side opposite O1. The latter is situated 1.38 Å away and projects the 3,5-dinitrobenzoate group above the central portion of the cyclohexadiene unit. Four contiguous carbon atoms in the latter ring are mutually coplanar and the fused cyclohexane ring adopts a chair conformation. The overall molecular geometry is reconcilable with its solvolytic behavior in aqueous acetone.

The crystal structure of dibutyl-bis(pentamethylenedithiocarbamato)tin(IV)

1986 ◽  
Vol 51 (11) ◽  
pp. 2521-2527 ◽  
Author(s):  
Jan Lokaj ◽  
Eleonóra Kellö ◽  
Viktor Kettmann ◽  
Viktor Vrábel ◽  
Vladimír Rattay
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Least Squares ◽  
Coordination Polyhedron ◽  
Crystal And Molecular Structure ◽  
Distorted Octahedron ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray

The crystal and molecular structure of SnBu2(pmdtc)2 has been solved by X-ray diffraction methods and refined by a block-diagonal least-squares procedure to R = 0.083 for 895 observed reflections. Monoclinic, space group C2, a = 19.893(6), b = 7.773(8), c = 12.947(8) . 10-10 m, β = 129.07(5)°, Z = 2, C20H38N2S4Sn. Measured and calculated densities are Dm = 1.38(2), Dc = 1.36 Mg m-3. Sn atom, placed on the twofold axes, is coordinated with four S atoms in the distances Sn-S 2.966(6) and 2.476(3) . 10-10 m. Coordination polyhedron is a strongly distorted octahedron. Ligand S2CN is planar.

Crystal and Molecular Structure of 3-Iodo-2-propynyl-N-butylcarbamate

1997 ◽  
Vol 52 (2) ◽  
pp. 256-258 ◽  
Author(s):  
Evgeni V. Avtomonov ◽  
Rainer Grüning ◽  
Jörg Lorberth
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Title Compound ◽  
Crystal And Molecular Structure ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dimensional Network ◽  
Carbamate Group ◽  
Oxygen Atoms

Abstract The crystal structure of the title compound has been determined by X-ray diffraction methods. Due to the Lewis acidic character of the iodine substituent a “zig-zag” chain is formed via intermolecular interactions (2.933(4) A) between iodine and oxygen atoms of theocarbamate moiety. A three-dimensional network is formed through hydrogen-bridging (2.04 A) between NH-groups and the oxygen atoms of the neighbouring carbamate group of the next molecule.

Molecular and Crystal Structure of Two Cyclobuten-3,4-dione Derivatives: The Dithallium Salt of 1,2-Dicyanimino-(TI2CMCB) and the 1,2-Diiodocyclobuten-3,4-dione (I2CB)

1989 ◽  
Vol 44 (2) ◽  
pp. 169-174 ◽  
Author(s):  
Bruno Lunelli ◽  
Magda Monari
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Crystal And Molecular Structure ◽  
Molecular And Crystal Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calorimetric Measurements ◽  
Ft Ir

Abstract The crystal and molecular structure of the dithallium salt of the 1,2-dicyanim inocyclobuten-3,4-dione dianion and of 1,2-diiodocyclobuten-3,4-dione, determined by X-ray diffraction, are reported and discussed. Results of FT-IR and calorimetric measurements are also presented.

Synthesis of Triferrocenylbenzenes by Tantalum(V)-Catalyzed Cyclotrimerization of Ethynylferrocene. The Crystal Structure of 1,3,5-Triferrocenylbenzene

1997 ◽  
Vol 62 (10) ◽  
pp. 1577-1584 ◽  
Author(s):  
Petr Štěpnička ◽  
Ivana Císařová ◽  
Jan Sedláček ◽  
Jiří Vohlídal ◽  
Miroslav Polášek
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Single Crystal ◽  
High Yield ◽  
Isomer Mixture ◽  
State Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Yield Formation

Exclusive, high-yield formation of the cyclotrimers of ethynylferrocene (1) was observed when TaCl5 in benzene was employed as catalyst. Analysis of the resulting isomer mixture by means of HPLC and 1H NMR revealed the presence of 1,3,5-triferrocenylbenzene (sym-2) and 1,2,4-triferrocenylbenzene (asym-2) in the ratio of 4 : 6. A small amount of pure sym-2 isomer was isolated, and its solid-state structure was established by single-crystal X-ray diffraction. The molecules of sym-2 possess a distorted up-up-down arrangement of the ferrocenyl groups attached to the benzene ring.

Synthesis and Crystal and Molecular Structure of trans-Dichloro(ethanedial dioximato(1—)-N,N')(ethanedial dioxime-N,N')rhodium(III)

1989 ◽  
Vol 44 (1) ◽  
pp. 5-8
Author(s):  
Michel Mégnamisi-Bélombé
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Room Temperature ◽  
Crystal And Molecular Structure ◽  
Crystallographic Direction ◽  
Monoclinic Space Group ◽  
Coordination Geometry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cl Atoms

Abstract trans-Dichloro(ethanedial-dioximato)(ethanediaI-dioxime)rhodium (III), RhCl2(GH)(GH2), has been synthesized and its structure determined by single crystal X-ray diffraction at room temperature. C4H7Cl2N4O4Rh, Mr = 348.94. monoclinic space group P21/ɑ; a = 10.543(3), b = 8.363(2), c = 11.512(3)Å ; β = 92.79(2)°; V = 1024Å3; Z = 4; Dc = 2.26 Mg m-3. Final Rw = 0.075 for 2035 reflections and 139 parameters. The coordination geometry around Rh is a dis­torted (4+2) octahedron, with four chelating N atoms lying in the equatorial plane and the two Cl atoms in the apical positions. The H atoms of the oxime groups are involved in relatively weak intramolecular O-H-O bridgings, as well as in very strong intermolecular bridgings which extend throughout the crystal structure and propagate nearly parallel to the [101] crystallographic direction.

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