The crystal and electron structure of N-(2,2,2-trichloro-1-morpholino-ethyl) formamide

1985 ◽  
Vol 50 (8) ◽  
pp. 1619-1628 ◽  
Author(s):  
Viktor Vrábel ◽  
František Pavelčík ◽  
Eleonóra Kellö ◽  
Stanislav Miertuš ◽  
Václav Konečný ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Least Squares Method ◽  
Direct Methods ◽  
Molecular Fragment ◽  
Structure Calculation ◽  
Electron Structure ◽  
Dihedral Angles ◽  
Stable Form ◽  
Anisotropic Temperature ◽  
Diagonal Approximation

The crystal structure was solved by direct methods and refined by the least squares method in a 9 x 9 block diagonal approximation using the anisotropic temperature parameters. The R-factor was decreased to a final value of 5.6% for 970 observed reflextions. The crystals are monoclinic with a space group of P21/c and lattice parameters of a = 1.1056(11), b = 0.8913(11), c = 1.2023(16) nm, β = 96.32°, and Z = 4. The crystal structure consists of discrete molecules between which hydrogen interactions of the N-H...O and C-H...O type were observed. The lengths of the N1-C3 (0.1432 nm) and C3-O1 (0.1203 nm) bonds and valence angles, C3-N1-C1 (119.9°), N1-C3-O1 (126.5°), indicate considerable delocalization of the π-electrons and participation of the lone electrone pair on N1 nitrogen in the conjugation in the N1-C3-O1 molecular fragment. The CNDO/2 quantum chemical method was used to calculate the electron structure. Calculation for partial optimization of the dihedral angles, φ and ω, indicated that the most stable form is obtained for the values φ = 0°, ψ = 120-150°, 240-270° and ω = 150-210°, 330-30°.

The crystal and electron structure of O-(2-chloroethyl)-O-isobutyl-O-(2-phenyl-4-methylthio-3-oxo-2H-pyridazine-5-yl) thiophosphate

1987 ◽  
Vol 52 (3) ◽  
pp. 696-706 ◽  
Author(s):  
Viktor Vrábel ◽  
František Pavelčík ◽  
Eleonóra Kellö ◽  
Stanislav Miertuš ◽  
Václav Konečný ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Structure Refinement ◽  
Bond Distance ◽  
Direct Methods ◽  
Electron Structure ◽  
Anisotropic Temperature ◽  
Wiberg Index ◽  
Trigonal Pyramid ◽  
Net Charges ◽  
Temperature Factors

The crystal structure of the title fungicide was solved by direct methods, using Σ2 relationship and tangent formula. The structure refinement was made by full-matrix least-squares with anisotropic temperature factors to the final R = 0.096 for 1 486 significant reflexions. The compound crystallizes in the orthorhombic system, the space group Pccn. The lattice parameters are a = 1.8719(9), b = 3.0426(33), c = 0.7616(2) nm and Z = 8. The intermolecular interactions of types C-H···Cl and C-H···O are observed between the centrosymmetrically related molecules in the crystal structure. The coordination polyhedron around phosphorus is between trigonal pyramid and tetrahedron. The planes of the phenyl and pyridazine rings are rotated through 70° each other. The electron structure was calculated by semiempirical CNDO/2 method. The calculations revealed the most negative net charges on S(2) and O(1). The value of Wiberg index Iw = 1.08 and the bond distance 0.149 nm show that the bond N(1)-C(5) is simple and is not involved in the conjugation.

The halotrichite group: the crystal structure of apjohnite

1976 ◽  
Vol 40 (314) ◽  
pp. 599-608 ◽  
Author(s):  
S. Menchetti ◽  
C. Sabelli
Keyword(s):  
Crystal Structure ◽  
Least Squares Method ◽  
Direct Methods ◽  
Water Molecules ◽  
Monoclinic Space Group ◽  
Direct Connection ◽  
Asymmetric Unit ◽  
X Ray ◽  
Bonding System ◽  
Hydrogen Bonding System

SummaryApjohnite, MnAl2(SO4)4·22H2O, is monoclinic, space group P21/c, a 6·198 (2), b 24·347 (4), c 21·266 (4) Å, β 100·28 (3)° and Z = 4. The crystal structure was determined by means of direct methods applied to X-ray data collected with a single-crystal diffractometer. At the end of the refinement, performed with least-squares method, the R index was 0·039.The SO4 tetrahedra, Al(H2O)5 octahedra, and MnO(H2O)5 octahedra are connected by a hydrogen bonding system; the only direct connection between polyhedra is by sharing of an oxygen between S(4) and Mn. In the asymmetric unit there are twenty-two water molecules, five of which lie in channels of the structure and are not linked to the cations but only to ligand water oxygens by means of hydrogen bonds.Powder data indicate a close structural relationship between apjohnite, halotrichite, and pickeringite.

Die Kristallstruktur des Trichlorphons C4H8O4PCl3

1969 ◽  
Vol 24 (9) ◽  
pp. 1071-1074 ◽  
Author(s):  
E. Höhne ◽  
Kh. Lohs
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Least Squares Method ◽  
Unit Cell ◽  
Fourier Methods ◽  
Space Group ◽  
R Factor ◽  
Anisotropic Temperature ◽  
Temperature Factors ◽  
Atomic Coordinates

The crystal structure of trichlorphon [O,O-Dimethyl- (1-hydroxy-2,2,2-trichlor-äthyl) -phosphonat] has been determined by PATTERSON and FOURIER methods. Space group P212121 with 4 molecules in a unit cell of dimensions α = 8,96 ± 0,03 A, b= 18,60 ± 0,05 Å, c = 5,80 ± 0,02 A were determined. Atomic coordinates and anisotropic temperature factors have been refined by the least squares method. The final R-factor is R (hkl) =0,102.

The molecular and crystal structure of 4,4-dimethyl-6,6-diphenyl-tetrahydro-2H-pyran-2-one

1989 ◽  
Vol 54 (6) ◽  
pp. 1661-1665
Author(s):  
Jiří Novotný ◽  
Jan Ondráček ◽  
Marián Schwarz ◽  
Bohumil Kratochvíl
Keyword(s):  
Crystal Structure ◽  
Nmr Spectroscopy ◽  
Least Squares ◽  
Heterocyclic Compound ◽  
Least Squares Method ◽  
Lactone Ring ◽  
Direct Methods ◽  
Molecular And Crystal Structure ◽  
Boat Conformation ◽  
C Nmr

The molecular and crystal structure of 4,4-dimethyl-6,6-diphenyl-tetrahydro-2H-pyran-2-one was solved by direct methods and anisotropically refined by the least squares method. The final R-factor value was 0.065 for 2 181 observed reflections (I > 1.96σ (I)) and 272 refined parameters. The symmetry of the structure corresponds to the P21/c space group with lattice parameters a = 11.207(2), b = 8.168(1), c = 16.896(3) Å, β = 90.05(1)°. The unit cell contains four formula units. A lactone structure was found for this geminally substituted heterocyclic compound and was also demonstrated by 1H and 13C NMR spectroscopy. The lactone ring assumes the boat conformation.

Crystal structure of praseodymium sulphate octahydrate

1981 ◽  
Vol 155 (3-4) ◽  
Author(s):  
I. S. Ahmed Farag ◽  
M. A. El-Kordy ◽  
N. A. Ahmed
Keyword(s):  
Crystal Structure ◽  
Least Squares Method ◽  
Three Dimensional ◽  
The Other ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Bridging Ligand ◽  
Dimensional Network ◽  
Anisotropic Temperature ◽  
Temperature Factors

AbstractThe crystals of PrThe crystal structure has been determined from three-dimensional single-crystal X-ray diffraction data and refined by the least-squares method, using anisotropic temperature factors, to a discrepancy index ofThe molecules are arranged in layers forming a three-dimensional network. Each Pr atom is coordinated with eight oxygen atoms, four of which are related to sulphate groups, the other four are to water molecules. The sulphate ion, located at the twofold axis, behaves as a bidentate bridging ligand connecting two Pr atoms. The other sulphate ion acts as a threefold bridging ligand between three neighbouring Pr atoms.

Crystal Structure of N-Acetylkynurenine

1979 ◽  
Vol 32 (4) ◽  
pp. 911 ◽  
Author(s):  
CHL Kennard ◽  
Y Matsuura ◽  
N Tanaka ◽  
M Kakudo
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Least Squares ◽  
Direct Methods ◽  
Dihedral Angles ◽  
Asymmetric Unit ◽  
Amino Groups ◽  
Torsion Angles ◽  
Bonding System ◽  
Hydrogen Bonding System

The crystal structure of N-acetylkynurenine [o-NH2C6H4COCH2CH(COOH)NHCOCH3] was determined by direct methods. The crystals are monoclinic, a 11.200(2), b 9.708(1), c 11.451(1) �,β 90.16(2)�, space group P21, with Z 4. The structure was refined by least squares to R 0.033 with 1909 unique reflections, collected on an automated four-circle diffractometer. The structure is similar to the related L-trytophan hydrochloride. The two molecules in the asymmetric unit (A,B) are generally similar structurally but differ slightly in the conformation of the N-acetyl chain which has dihedral angles with the plane of the benzene ring of 78.0� (A) and 81.5� (B). Torsion angles about the C(α)-C(β) bond between C(γ) and both the carboxyl and the amino groups make them mutually gauche. There is an extensive hydrogen-bonding system between the two distinct molecules and between similar molecules either to form a dimer or a linear polymer.

Conformation Dependent Cyclizations of 1,3,3,5-Tetraphenylpentane-1,5-dione

1992 ◽  
Vol 57 (11) ◽  
pp. 2383-2399 ◽  
Author(s):  
Pavel Šebek ◽  
Jiří Novotný ◽  
Bohumil Kratochvíl ◽  
Marián Schwarz ◽  
Josef Kuthan
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Least Squares Method ◽  
Direct Methods ◽  
Lattice Parameters ◽  
Molecular And Crystal Structure ◽  
Complex Hydrides ◽  
Pyran Derivative ◽  
Phenylmagnesium Bromide

The molecular and crystal structure of 1,3,3,5-tetraphenylpentane-1,5-dione (I) obtained from direct methods and anisotropically refined by the least-squares method shows that the two 3,3-phenyl groups force the molecule into a conformation suitable for formation of cyclic products and intermediates. Compound I crystallizes in P1 group with lattice parameters a = 8.444(1), b = 10.195(2), c = 14.618(2) Å, α = 75.52(2)°, β = 73.22(1)°, γ = 65.47(1)°. Photochemically and thermally found was the system I ↔ II. The reaction of 1,5-dione I with phenylmagnesium bromide gives the 2,3-dihydropyran derivative III, whereas complex hydrides give a mixture of IV and VI. On treatment with magnesium, the diketone I gives diol VIII. Chlorine (Cl2) reacts with compound I to give the mono-, di-, and tetrachloro derivatives XII, XIII, and XIV, respectively. Bromine (Br2) produces 3,5-dibromo-4H-pyran derivative XVIII, whereas I2 only catalyzes the formation of 4H-pyran V. The formylation of dione I with dimethylformamide and POCl3 gives the 4H-pyran-3-carbaldehyde XX. Probable mechanisms of the reactions investigated and the stereochemistry of compounds VI, VIII, XIII, and XIV are discussed.

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.

scholarly journals Crystal structure of 2-nitro-N-(5-nitro-1,3-thiazol-2-yl)benzamide

2014 ◽  
Vol 70 (12) ◽  
pp. o1252-o1252 ◽  
Author(s):  
Rodolfo Moreno-Fuquen ◽  
Diego F. Sánchez ◽  
Javier Ellena
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Dihedral Angles ◽  
Two Dimensional ◽  
Compound C ◽  
Dimensional Network ◽  
Benzene Rings ◽  
The Mean ◽  
Amide Fragment

In the title compound, C10H6N4O5S, the mean plane of the non-H atoms of the central amide fragment C—N—C(=O)—C [r.m.s. deviation = 0.0294 Å] forms dihedral angles of 12.48 (7) and 46.66 (9)° with the planes of the thiazole and benzene rings, respectively. In the crystal, molecules are linked by N—H...O hydrogen bonds, forming chains along [001]. In addition, weak C—H...O hydrogen bonds link these chains, forming a two-dimensional network, containingR44(28) ring motifs parallel to (100).

scholarly journals The crystal structure of szenicsite, Cu3MoO4(OH)4

1998 ◽  
Vol 62 (04) ◽  
pp. 461-469 ◽  
Author(s):  
Peter C. Burns
Keyword(s):  
Crystal Structure ◽  
Goodness Of Fit ◽  
Direct Methods ◽  
Ligand Field ◽  
Area Detector ◽  
Vertex Sharing ◽  
Distorted Octahedral ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Least Squares Techniques

Abstract The crystal structure of szenicsite, Cu3MoO4(OH)4, orthorhombic, a = 8.5201(8), b = 12.545(1), c = 6.0794(6) Å, V = 649.8(2) Å3, space group Pnnm, Z = 4, has been solved by direct methods and refined by least-squares techniques to an agreement index (R) of 3.34% and a goodness-of-fit (S) of 1.11 for 686 unique observed [|F| ⩾ 4σF] reflections collected using graphite-monochromated Mo-Kα X-radiation and a CCD area detector. The structure contains three unique Cu2+ positions that are each coordinated by six anions in distorted octahedral arrangements; the distortions of the octahedra are due to the Jahn-Teller effect associated with a d 9 metal in an octahedral ligand-field. The single unique Mo6+ position is tetrahedrally coordinated by four O2− anions. The Cu2+ϕ6 (ϕ: unspecified ligand) octahedra share trans edges to form rutile-like chains, three of which join by the sharing of octahedral edges to form triple chains that are parallel to [001]. The MoO4 tetrahedra are linked to either side of the triple chain of Cu2+ϕ6 octahedra by the sharing of two vertices per tetrahedron, and the resulting chains are cross-linked through tetrahedral-octahedral vertex sharing to form a framework structure. The structure of szenicsite is closely related to that of antlerite, Cu3SO4(OH)4, which contains similar triple chains of edge-sharing Cu2+ϕ6 octahedra.

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