Synthesis, C-13 NMR, and X-ray crystal structure of N6,N9-octamethylenepurinecyclophane

1992 ◽  
Vol 70 (1) ◽  
pp. 186-196 ◽  
Author(s):  
R. A. Bell ◽  
R. Faggiani ◽  
H. N. Hunter ◽  
C. J. L. Lock
Keyword(s):  
Crystal Structure ◽  
Direct Methods ◽  
Chloride Ion ◽  
Nucleophilic Aromatic Substitution ◽  
Nucleophilic Attack ◽  
Aliphatic Chain ◽  
Aromatic Substitution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Small Distortion

The synthesis and structure determination of N6,N9-octamethylenepurine cyclophane by single crystal X-ray diffraction is reported. The cyclophane was prepared from 6-chloropurine and 8-aminooctanoic acid as starting materials. The aminooctyl fragment was first attached to N9 of 6-chloropurine by means of the Mitsunobu reaction and cyclization to the cyclophane effected by nucleophilic attack of the amino group at the C6 position and displacement of chloride ion. Reversing the reaction strategy did not result in formation of the cyclophane. Crystals of the cyclophane were monoclinic, P2/n, a = 9.620(3), b = 12.266(3), c = 11.994(2), Å, β = 111.25(2)°, Z = 4. Intensities were measured with a Nicolet P3 diffractometer and MoKα radiation at room temperature. The structure was solved by direct methods and refined to R = 0.0683, Rw = 0.0493 based on 1730 reflections. The molecule shows some strain, but bond lengths and angles are normal. Attempts to relieve the strain are made by a small distortion of the purine rings and bending of the N6 and C8′ atoms out of the planes to which they are attached (0.314(4), 0.459(5) Å). Further, the N6,H6,Cl′ group is twisted by 30° from the pyrimidine plane and the torsion angles in the aliphatic chain are distorted from the idealized 60, 120, 180° (average, 13.6°; range 5.1–24.9°). These distortions result in some weakening of the π-bonding in the adenine moiety. Keywords: purinophane synthesis, nucleophilic aromatic substitution, conformational analysis, crystal structure.

Crystal structure determination of the conformation of two bicyclo[3.3.1]nonan-ones

1985 ◽  
Vol 63 (6) ◽  
pp. 1166-1169 ◽  
Author(s):  
John F. Richardson ◽  
Ted S. Sorensen
Keyword(s):  
Crystal Structure ◽  
Direct Methods ◽  
Chair Conformation ◽  
Molecular Structures ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Final Agreement

The molecular structures of exo-7-methylbicyclo[3.3.1]nonan-3-one, 3, and the endo-7-methyl isomer, 4, have been determined using X-ray-diffraction techniques. Compound 3 crystallizes in the space group [Formula: see text] with a = 15.115(1), c = 7.677(2) Å, and Z = 8 while 4 crystallizes in the space group P21 with a = 6.446(1), b = 7.831(1), c = 8.414(2) Å, β = 94.42(2)°, and Z = 2. The structures were solved by direct methods and refined to final agreement factors of R = 0.041 and R = 0.034 for 3 and 4 respectively. Compound 3 exists in a chair–chair conformation and there is no significant flattening of the chair rings. However, in 4, the non-ketone ring is forced into a boat conformation. These results are significant in interpreting what conformations may be present in the related sp2-hybridized carbocations.

Nitroxide radicals appended to phthalonitriles: synthesis, structural characterization and photophysical properties

2021 ◽  
Vol 77 (3) ◽  
pp. 137-143
Author(s):  
Ismail Fidan ◽  
Emel Onal ◽  
Catherine Hirel
Keyword(s):  
Magnetic Measurements ◽  
Photophysical Properties ◽  
Nucleophilic Aromatic Substitution ◽  
Structural Studies ◽  
Aromatic Substitution ◽  
Nitronyl Nitroxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Assisted ◽  
Ft Ir

The syntheses of 4-[4-(4,4,5,5-tetramethyl-2-imidazoline-3-oxide-1-oxyl-2-yl)phenoxy]phthalonitrile (3, C21H19N4O3) and 4-[4-(4,4,5,5-tetramethyl-2-imidazoline-1-oxyl-2-yl)phenoxy]phthalonitrile (4) were carried out by microwave-assisted nucleophilic aromatic substitution of 4-nitrophthalonitrile (2) by the pre-formed 2-(4-hydroxyphenyl)-4,4,5,5-tetramethyl-2-imidazoline-3-oxide-1-oxyl (1). Compounds 3 and 4 were characterized unambiguously by a rich array of analyses, such as melting point, FT–IR, MALDI–TOF MS, elemental analysis, UV–Vis, CV, EPR, magnetic measurements and single-crystal X-ray diffraction. Structural studies demonstrate that the C—H...X and C—X...π (X = O and N) interactions in the radical nitronyl nitroxide groups play an important role in the assembly of the crystal structures. Moreover, cyclic voltammetry analyses show that the phthalonitrile substituent retains the redox properties of the Ullman radicals.

The crystal structure of gatehouseite

2011 ◽  
Vol 75 (6) ◽  
pp. 2823-2832
Author(s):  
P. Elliott ◽  
A. Pring
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Three Dimensional ◽  
Direct Methods ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Manganese Phosphate ◽  
Phosphate Mineral ◽  
Unit Formula

AbstractThe crystal structure of the manganese phosphate mineral gatehouseite, ideally Mn52+(PO4)2(OH)4, space group P212121, a = 17.9733(18), b = 5.6916(11), c = 9.130(4) Å, V= 933.9(4) Å3, Z = 4, has been solved by direct methods and refined from single-crystal X-ray diffraction data (T = 293 K) to an R index of 3.76%. Gatehouseite is isostructural with arsenoclasite and with synthetic Mn52+(PO4)2(OH)4. The structure contains five octahedrally coordinated Mn sites, occupied by Mn plus very minor Mg with observed <Mn—O> distances from 2.163 to 2.239 Å. Two tetrahedrally coordinated P sites, occupied by P, Si and As, have <P—O> distances of 1.559 and 1.558 Å. The structure comprises two types of building unit. A strip of edge-sharing Mn(O,OH)6 octahedra, alternately one and two octahedra wide, extends along [010]. Chains of edge- and corner-shared Mn(O,OH)6 octahedra coupled by PO4 tetrahedra extend along [010]. By sharing octahedron and tetrahedron corners, these two units form a dense three-dimensional framework, which is further strengthened by weak hydrogen bonding. Chemical analyses by electron microprobe gave a unit formula of (Mn4.99Mg0.02)Σ5.01(P1.76Si0.07(As0.07)Σ2.03O8(OH)3.97.

Crystal structure of cis-Tetracarbonylbis(chloromercury)iron

1976 ◽  
Vol 29 (9) ◽  
pp. 1905 ◽  
Author(s):  
CL Raston ◽  
AH White ◽  
SB Wild
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Diffraction Data ◽  
Title Compound ◽  
Direct Methods ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Independent Molecules

The crystal structure of the title compound has been determined by direct methods from X-ray diffraction data and refined by least squares to a residual of 0.071 for 2647 'observed' reflections. Crystals are monoclinic, C2/c, a = 36.81(1), b = 11.181(2), c = 20.369(5) �, β = 95.28(3)�, Z = 32. There are four independent molecules in the asymmetric unit, all with the cis disposition of ligands (<Fe-Hg), 2.498 �; <Hg-Fe-Hg), 80.9�); in one of the molecules one of the carbonyl sites is occupied by a more substantial moiety, possibly a result of partial occupancy of HgCl as a result of disorder or decomposition.

scholarly journals The reaction of 3,5-diphenyl-1,2-dithiolium-4-olate with aniline: the crystal structure of 1-phenylimino-2-phenylamino-3-phenylindene

1987 ◽  
Vol 65 (12) ◽  
pp. 2830-2833 ◽  
Author(s):  
David M. McKinnon ◽  
Peter D. Clark ◽  
Robert O. Martin ◽  
Louis T. J. Delbaere ◽  
J. Wilson Quail
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Direct Methods ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

3,5-Diphenyl-1,2-dithiolium-4-olate (1) reacts with aniline to form 1-phenylimino-2-phenylamino-3-phenylindene (3a). Under suitable conditions, 6-phenylbenzo[b]indeno[1,2-e]-1,2-thiazine is also formed. These structures are confirmed by alternative syntheses. The molecular structure of 3a has been determined by single crystal X-ray diffraction. Compound 3a crystallizes in the monoclinic space group C2/c with unit cell dimensions a = 20.777(3) Å, b = 6.130(3) Å, c = 31.327(3) Å, 3 = 99.59(1)°, and Z = 8. The structure was solved by direct methods and refined by least squares to a final R = 0.055. The molecular structure of 3a shows the three phenyl containing substituents to have the planes of their ring systems tilted between 40° and 60° from the plane of the indene system due to steric repulsions.

Preparation, properties, and X-ray crystal structure of a 1:1 complex of tetrathiafulvalene and p-dinitrobenzene

1982 ◽  
Vol 60 (16) ◽  
pp. 2057-2061 ◽  
Author(s):  
Martin R. Bryce ◽  
Anthony S. Secco ◽  
James Trotter ◽  
Larry Weiler
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
Direct Methods ◽  
X Ray Diffraction ◽  
Crystalline Complex ◽  
X Ray ◽  
Triclinic System ◽  
Donor Acceptor ◽  
Bulk Magnetic Susceptibility ◽  
R Value

A crystalline complex of tetrathiafulvalene and p-dinitrobenzene has been prepared and characterised by esr and ir spectroscopy, bulk magnetic susceptibility, dc conductivity, and an X-ray diffraction analysis. It is a neutral 1:1 complex which is an insulator at room temperature, σRT = 2.5 × 10−7 ohm−7 cm−1. The complex crystallizes in the triclinic system, space group [Formula: see text] with cell constants a = 6.915(1), b = 7.615(1), c = 8.149(1) Å, α = 79.39(1), β = 69.55(1), γ = 70.81(1)°, Z = 1. Data were collected on an Enraf-Nonius CAD-4 diffractometer. The structure was solved by direct methods and refined to an R-value of 0.028 for 1222 observed reflections. The structure consists of molecules stacked in an alternating donor–acceptor fashion along the c-axis. Mixed sheets parallel to [Formula: see text] are comprised of tetrathiafulvalene and p-dinitrobenzene molecules arranged end-on in the [021] direction.

Molecular conformation of di-o-anisylcarbinol: an X-ray diffraction study

1983 ◽  
Vol 61 (9) ◽  
pp. 2001-2005 ◽  
Author(s):  
C. Faerman ◽  
H. Negri ◽  
G. Punte ◽  
A. A. Vitale ◽  
N. S. Nudelman
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Diffraction Study ◽  
Molecular Conformation ◽  
Direct Methods ◽  
X Ray Diffraction ◽  
X Ray ◽  
Triclinic System ◽  
Phenyl Rings ◽  
R Factors

Di-o-anisylcarbinol crystallizes in the triclinic system, space group [Formula: see text] with a = 7.50 (4), b = 10.89 (4), c = 7.98 (3) Å, α = 101.9 (1), β = 94.1 (1), γ = 94.6 (1)°, Z = 2, V = 633.11 Å3, Dc = 1.28 mg m−3, Dm = 1.26 (1) mg m−3, CuKα radiation, λ = 1.54178 Å, μ(CuKα) = 0.633 mm−1, F(000) = 260. The structure has been determined by direct methods using single crystal X-ray data and refined by least-squares to the final R factors R = 5.89% and Rw = 5.35%. The molecule has a twist-skewed conformation with the phenyl rings on nearly orthogonal planes. The crystal structure shows a hydrogen-bonded dimer and a peculiar arrangement of the methoxy and phenyl groups.

Odigitriaite, CsNa5Ca5[Si14B2O38]F2, a new caesium borosilicate mineral from the Darai-Pioz alkaline massif, Tajikistan: Description and crystal structure

2017 ◽  
Vol 81 (1) ◽  
pp. 113-122 ◽  
Author(s):  
Atali A. Agakhanov ◽  
Leonid A. Pautov ◽  
Elena Sokolova ◽  
Frank C. Hawthorne ◽  
Vladimir Yu Karpenko ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Double Layer ◽  
Direct Methods ◽  
Double Layers ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Calculated Density ◽  
X Ray ◽  
Mohs Hardness ◽  
Alkaline Massif

AbstractOdigitriaite, a new Cs, Na, Ca borosilicate mineral, was discovered in moraine adjacent to the Darai-Pioz alkaline massif in the upper reaches of the Darai-Pioz river at the intersection of the Turkestansky, Zeravshansky and Alaisky mountain ridges, Tajikistan. It occurs as irregular thin flakes associated with quartz, pectolite, baratovite, fluorite, pekovite, polylithionite, aegirine, leucosphenite, pyrochlore, neptunite, reedmergnerite, mendeleevite-(Ce), zeravshanite and sokolovaite. It is colourless with a white streak, is translucent and has a vitreous lustre; it does not fluoresce under ultraviolet light. Odigitriaite is brittle with an uneven fracture and a Mohs hardness of 5. The calculated density is 2.80(2) g/cm3. The indices of refraction are α = 1.502, β = 1.564, γ = 1.576; 2Vobs = 46(2)°, dispersion is weak r > v, and there is no pleochroism. The chemical composition is as follows (electron microprobe, H2O calculated from structure): SiO2 55.30, Al2O3 0.09, Y2O3 0.44, MnO 0.94, FeO 0.10, PbO 0.21, K2O 0.01 Cs2O 8.36, B2O3 4.75, H2O 0.37, F 1.74, O = F2 –0.74, total 99.43 wt.%. The empirical formula of odigitriaite is Cs0.90Na5.12Ca4.68Mn0.20Y0.06Fe0.02Pb0.01[Si13.92Al0.03B2.06O38]F1.39(OH)0.62. The end-member formula is CsNa5Ca5[Si14B2O38]F2. The strong reflections in the powder X-ray diffraction pattern are: [(d, Å), (I, %), (hkl)]: 5.45 (25) (1 1 3), 4.66 (33) (3 1 1), 4.40 (26) (0 2 2), 4.10 (36) (3 1 3), 3.95 (25) (3̄ 1 3), 2.85 (31) (2 2 2), 2.68 (40) (0 0 6), 3.62 (45) (0 2 4), 3.35 (100) (2̄ 2 4), 3.31 (30) (3̄ 1 5), 3.25 (35) (4 0 4), 3.04 (60) (4̄ 2 2), 2.925 (22) (4̄ 2 3), 1.813 (23) (9 1 0). Odigitriaite is monoclinic, space group C2/c, a = 16.652(5), b = 9.598 (3), c = 22.120(7) Å, β= 92.875(14)°, V = 3530.9(1.9) Å3, Z = 4. The crystal structure of odigitriaite was solved by direct methods and refined to an R1 value of 2.75% based on single-crystal X-ray data. It is a double-layer sheet-borosilicate mineral; Cs and Na are intercalated within the double-layer sheet, and the double layers are linked by interstitial Ca and Na atoms.

X-ray Diffraction Study of the Crystal Structure of the Tl Ternary Chalcogenides Tl2x In2(1−x)Se2, x = 0.2, 0.3,...0.9

1998 ◽  
Vol 54 (4) ◽  
pp. 358-364 ◽  
Author(s):  
K. G. Hatzisymeon ◽  
S. C. Kokkou ◽  
A. N. Anagnostopoulos ◽  
P. I. Rentzeperis
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Rietveld Method ◽  
Direct Methods ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
Volume Decrease

A series of thallium ternary chalcogenides with the composition Tl2x In2(1−x)Se2, x = 0.2, 0.3,...0.9, have been studied by X-ray powder and, for some of them, single-crystal diffraction. They are tetragonal, space group I4/mcm, Z = 4, and isostructural with the binary semiconductor TlSe. Their crystal structures have been solved by direct methods and refined by the Rietveld method to a precision which is satisfactorily comparable to single-crystal results. As x is changed from x = 0.2 to x = 0.9 the unit-cell parameters and volume decrease or increase following Kurnakov's law, which is valid for solid solutions. Refined positional parameters of Se, In—Se and Tl—Se bond lengths vary with x also according to the same law. The distribution of In and Tl cations in 4(a) and 4(b) sites depends on the stoichiometry x and the crystals are composed of [In3+Se2]_{\infty}^- chains along the c axis in which InSe4 tetrahedra share edges; the chains are interconnected with Tl+(In+) ions.

Ring contraction of 4-substituted 2,6-dichlorophenols. The crystal structure of 2,2,4α,5α-Tetrachloro-1α,3α-dihydroxycyclopentane-1,4-carbolactone

1977 ◽  
Vol 30 (10) ◽  
pp. 2195 ◽  
Author(s):  
RM Christie ◽  
RW Rickards ◽  
KJ Schmalzl ◽  
D Taylor
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Direct Methods ◽  
Major Product ◽  
X Ray Diffraction ◽  
Ring Contraction ◽  
Full Matrix ◽  
Space Group ◽  
X Ray ◽  
Counter Data

Alkaline chlorination of the 4-alkyl-2,6-dichlorophenols (2b) and (2c) proceeds through ring contraction and halolactonization to form the 4α- alkyl-2,2,5α-trichloro-1α,3α-dihydroxycyclopentane-1,4-carbolactones (4b) and (4c). Under similar conditions, 2,4,6-trichlorophenol affords the analogous 2,2,4α,5α-tetrachloro-1α,3α-dihydroxycyclopentane-1,4- carbolactone (4a) in low yield, in addition to the Hantzsch acid (3a) as the major product. The acid (3a) upon further treatment undergoes chloro-lactonization to give the lactone (4a). The structures of the lactones (4b) and (4c) follow from spectroscopic comparison with (4a), the structure of which has been established by X-ray diffraction (C6H4Cl4O4 orthorhombic a 13.485(1), b 12.348(1), c 11.371(1) Ǻ, space group Pccn, Z 8, solved by direct methods and refined by block-diagonal and full-matrix least squares to R 0.031, Rw 0.043 for 1313 unique counter data with I/σ(I) ≥ 3.0).

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