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 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 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.

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

1978 ◽  
Vol 56 (12) ◽  
pp. 1705-1709 ◽  
Author(s):  
Aris Terzis ◽  
J. Brian Faught ◽  
T. Bruce Grindley
Keyword(s):  
Crystal And Molecular Structure ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Stable Conformation ◽  
Relative Configuration ◽  
X Ray ◽  
Ring Compounds ◽  
Methylene Groups ◽  
R Value ◽  
Medium Ring

The crystal structure of cis-anti-cis-4,5:9,10-biscyclohexano-1,3,6,8-tetraoxecane (2) has been determined by X-ray diffraction. The crystals are monoclinic, a = 11.120(1), b = 8.127(1), c = 7.990(1) Å, β = 110.01(1)°, P21/c, with Z = 2. The structure was solved by the application of symbolic addition procedures and refined to a final R value of 0.031 (Rw 0.040) for 989 reflections with I > 2.0σ(I).This structural determination confirms a previous tentative assignment of the relative configuration of 2. In the crystal, the two cis-substituted cyclohexane rings adopt chair conformations in which the equatorial oxygens on different rings are linked through methylene groups to axial oxygens on the other rings. The central 10-membered tetraoxecane ring adopts the boat–chair–boat conformation, the most stable conformation for cyclodecane.

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.

scholarly journals Biological Activity, Structural Characterization and Crystal Packing of Chromane-Carboxylate Derivatives

2018 ◽  
Vol 11 (1) ◽  
pp. 1-5
Author(s):  
Viktor Vrábel ◽  
Július Sivýb ◽  
Jan Světlíkc ◽  
Štefan Marchalínd ◽  
Šafař Peterd
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Biological Activity ◽  
Crystal And Molecular Structure ◽  
Crystal Packing ◽  
Chair Conformation ◽  
Heterocyclic Ring ◽  
X Ray Diffraction ◽  
Compound I ◽  
X Ray

Abstract We report here the crystal and molecular structure of a new chromane-derivative, namely isopropyl( 2R*,3S*,4S*)-4-(benzo[d]thiazol-2-ylamino)-2-hydroxy-2-ethylchromane-3-carboxylate (I), C21H22N2O4S, which crystallizes as racemate in the space group C2/c. Its structure has been solved using X-ray diffraction data obtained at low temperature (100(2) K). In this compound, the chromane moiety consists of a benzene ring fused with a six-membered heterocyclic ring which adopts a distorted half-chair conformation. The molecules are linked by a combination of O-H∙∙∙N and N-H∙∙∙O hydrogen bonds, resulting in a twodimensional network which helps stabilizing the crystal structure of the compound (I). Dihedral angle between the chromane and benzothiazol rings is 80.6(1)0.

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.

The crystal and molecular structure of 1,4-diphenyl-2,2′,3,3′,5,5′,6,6′-octamethylcyclo-1,4-diphospha-2,3,5,6-tetrasilahexane, a phosphorus–silicon heterocycle

1979 ◽  
Vol 57 (2) ◽  
pp. 174-179 ◽  
Author(s):  
A. Wallace Cordes ◽  
Paul F. Schubert ◽  
Richard T. Oakley
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Chair Conformation ◽  
Monoclinic Space Group ◽  
Single Bond ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray ◽  
Bond Lengths

The crystal structure of 1,4-diphenyl-2,2′,3,3′,5,5′,6,6′-octamethylcyclo-1,4-diphospha-2,3,5,6-tetrasilahexane, (PhPSi2Me4)2, has been determined by single crystal X-ray diffraction. The crystals are monoclinic, space group P21/c, with a = 9.866(1), b = 11.921(1), and c = 11.324(2) Å, β = 104.31(1)°, Z = 2, and ρcalcd = 1.15 g/cm3. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.060 and Rw of 0.078, for 1173 reflections with intensities greater than 3σ. The (PhPSi2Me4)2 molecule lies on a crystallographic centre of symmetry, and the six-membered P2Si4 ring has a chair conformation with equatorial phenyl groups. The endocyclic angles at P (104.4(1)°) and Si (104.9(2)°) are intermediate between those found in cyclic hexaphosphine and hexasilane molecules, and the Si—Si and P—Si distances of 2.345(3) and 2.252(4) Å, respectively, correspond to single bond lengths, with no appreciable evidence for secondary pπ → dπ bonding between phosphorus and silicon. The Si—C (1.867(8) Å) and P—C (1.828(7) Å) bond lengths are also normal. The variations in the Si—P—C (101.6(2)°, 108.6(2)°), P—Si—C (range 106.2(3)–120.0(3)°), and Si—Si—C (range 105.8(3)–113.7(3)°) angles indicate that the positions of the exocyclic methyl and phenyl groups are influenced by both intra- and intermolecular steric forces.

Preparation of Thieno[3,2-e][1,2]oxazepine, Thieno and [1]Benzothieno-[3,2-g][1,4]oxazonine, and 5H-Thieno and 1H-[1]Benzothieno-[3,2-h][1,5]oxazecine Derivatives by Ring Expansion Methods. X-Ray Crystal Structure of 1-Phenyl-1,3,4,5,6,7-hexahydro[1]benzothieno-[3,2-g][1,4]oxazonine-5-carbonitrile

1988 ◽  
Vol 41 (12) ◽  
pp. 1815 ◽  
Author(s):  
JB Bremner ◽  
EJ Browne ◽  
LM Engelhardt ◽  
CS Greenwood ◽  
AH White
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Tertiary Amine ◽  
Cyanogen Bromide ◽  
Crystal And Molecular Structure ◽  
Ring Expansion ◽  
Standard Methods ◽  
X Ray ◽  
Medium Ring

10-Phenyl-4,5,6,7,8,10-hexahydrothieno[3,2-g][1,4]oxazonine-6-carbonitrile (6a) and 11-phenyl-4,6,7,8,9,11-hexahydro-5H-thieno[3,2-h][1,5]oxazecine-6-carbonitrile (7a) were prepared in moderate yields by cyanogen bromide-induced ring expansion of tetrahydrothieno [2,3- c] pyridinylalkanol precursors (4a) and (5a), respectively. 1-Phenyl-1,3,4,5,6,7-hexahydro[1]- benzothieno [3,2-g][1,4]oxazonine-5-carbonitrile (6b) and 1-phenyl-3,4,5,6,7,8-hexahydro-1H- [1] benzothieno [3,2-h][1,5]oxazecine-6-carbonitrie (7b) were similarly prepared from the [1] benzothieno [2,3-c] pyridinylalkanol precursors (4b) and (5b). The medium-ring cyanamides (6b) and (7b) were converted by standard methods into their N-methyl analogues (8b) and (9b). 6-Methyl-8-phenyl-4,5,6,8-tetrahydrothieno[3,2-e][1,2] oxazepine (13) was prepared by thermal Meisenheimer rearrangement of the corresponding tertiary amine N-oxide (12). The compounds (6a, b), (7a, b) and (13) are each the first reported examples of new heterocyclic systems. The crystal and molecular structure of (6b) has been determined by X-ray crystallographic methods.

Synthese und Molekülgeometrie von Dichloro[η2-bis(di-r-butylphosphino)methan]pIatin(II), Pt(dtbpm)Cl2. Die Elektronenstruktur von 1,3-Diphosphaplatinacyclobutan-Fragmenten / Synthesis and Molecular Structure of Dichloro[η2-bis(di-t-butylphosphino)methane]platinum(II), Pt(dtbpm)Cl2. The Electronic Structure of 1,3-Diphosphaplatinacyclobutane Fragments

1987 ◽  
Vol 42 (4) ◽  
pp. 395-409 ◽  
Author(s):  
Peter Hofmann ◽  
Helmut Heiß ◽  
Gerhard Müller
Keyword(s):  
Molecular Structure ◽  
Electronic Structure ◽  
Crystal And Molecular Structure ◽  
Cone Angle ◽  
Membered Ring ◽  
Experimental Investigations ◽  
Molecular Orbital Calculations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Potential Precursor

Based upon the experimentally known but yet unexplained very different reactivities of the two isoelectronic and isolobal intermediates Pt(PMe3)2 and Pt(PEt3)2, the electronic structure and bonding capability of such 14 electron fragments as a function of their geometry (P-Pt-P angle α, determined by the phosphane cone angle) are investigated using molecular orbital calculations. A decrease of the P-Pt -P angle leads to an exceptionally pronounced energy ascent of the b2-HOMO of Pt(PR3)2 species, which, as a consequence, might lead to unusual reactivity patterns and bonding capabilities of 1,3-diphosphaplatinacyclobutane fragments, for which an extreme electronic situation is enforced by steric constraints. Dichloro[η2-bis(di-r-butylphosphino) methane]platinum(II), Pt(dtbpm)Cl2, is synthesized as a potential precursor of Pt(dtbpm), in order to allow experimental investigations of this taylor made four-membered ring chelate complex of Pt(0). The crystal and molecular structure of Pt(dtbpm)Cl2 · 2 CHCl3 has been determined by X-ray diffraction.

Sign in / Sign up

Export Citation Format

Share Document