Crystal and molecular structure of unsubstituted and p-methoxy-substituted acetylbenzoylmethanatoboron difluoride

1997 ◽  
Vol 212 (5) ◽  
Author(s):  
Y. Dromzée ◽  
J. Kossanyi ◽  
V. Wintgens ◽  
P. Valat ◽  
H. Hartmann ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Least Squares ◽  
Crystal Structures ◽  
Structure Analysis ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Crystal Structure Analysis ◽  
Full Matrix

AbstractThe crystal structures of two borines were solved by direct methods and refined by full-matrix least-squares procedure. 6-methyl-4-phenyl-1,3,2-(2The crystal structure analysis of compound

Crystal and molecular structure of 2,6-dimethyl-3,5-di[N-methyl]carbamoyl-4-[3,4-methoxy]phenyl-l,4-dihydropyridine hemihydrate and 2,6-dimethyl-3,5-di[N-methyl]carbamoyl-4-[furan]1,4-dihydropyridine

1999 ◽  
Vol 214 (12) ◽  
Author(s):  
M. Bidya Sagar ◽  
K. Ravikumar ◽  
Y. S. Sadanandam
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Crystal Structures ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Asymmetric Unit ◽  
Full Matrix

AbstractThe crystal structures of two dihydropyridines were solved by direct methods and refined by full-matrix least-squares procedure. 2,6-Dimethyl-3,5-di[N-methyl]-carbamoyl-4-[3,4-methoxy]phenyl-1,4-dihydropyridine hemihydrate, CBoth compounds crystallize with two molecules in the asymmetric unit. In compound

Reaction of N,N′-dihydroxy-.N,N′-dimethylmethanediamine with phenylboronic acid and the crystal and molecular structure of N,N′-dihydroxy-N,N′-dimethylmethanediamine

1989 ◽  
Vol 67 (11) ◽  
pp. 1959-1963 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Phenylboronic Acid ◽  
Direct Methods ◽  
Exact Formula ◽  
Full Matrix ◽  
Space Group ◽  
Hydrogen Bonded

The reaction of N,N′-dihydroxy-N,N′-dimethylmethanediamine with phenylboronic acid leads to the product 1,7-dimethyl-3,5-diphenyl-2,4,6-trioxa-7-aza-1-azonia-3-bora-5-boratabicyclo[3.3.0]octane rather than the expected product 1,5-dimethyl-3-phenyl-1,5-diaza-2,4-dioxa-3-boracyclohexane. The structure of N,N′-dihydroxy-N,N′-dimethylmethanediamine has been determined and is discussed in terms of its reaction with PhB(OH)2. Crystals of N,N′-dihydroxy-N,N′-dimethylmethanediamine are tetragonal, a = 8.5346(3), c = 8.4178(7) Å, Z = 4, space group P421c. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.036 and Rw of 0.038 for 333 reflections with I ≥ 3σ(I). The structure consists of hydrogen-bonded dimers having exact [Formula: see text] symmetry. Keywords: N,N′-dihydroxy-N,N′-dimethylmethanediamine, crystal structure.

Crystal and molecular structure of L-prolinatodiphenylboron

1977 ◽  
Vol 55 (6) ◽  
pp. 958-965 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Conformational Disorder ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths

Crystals of L-prolinatodiphenylboron are monoclinic, a = 5.9427(5), b = 14.4633(7), c = 8.9654(4) Å, β = 98.423(8)°, Z = 2, space group P21. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.037 and Rw of 0.053 for 1477 reflections with I ≥ 3σ(I). The proline ring exhibits conformational disorder. The crystal structure consists of discrete molecules linked by N—H … O hydrogen bonds (N … O = 2.893(3) Å) along the short a axis. Intramolecular N—B coordination occurs to form a system of two fused five-membered rings. Bond lengths (corrected for libration) are: N—B, 1.630(3), O—B, 1.529(3), O—C, 1.219(3) and 1.300(3), N—C, 1.506(3) and 1.507(3), C(sp3)–C(sp3), 1.525(4), C(sp2)—C(sp3), 1.517(3), and mean C—C(phenyl), 1.394 Å.

Crystal and Molecular Structure of B-Phenyl-diptychboroxazolidine,

1975 ◽  
Vol 53 (10) ◽  
pp. 1393-1401 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Thermal Motion ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths

Crystals of B-phenyl-dictychboroxazolidine are monoclinic, a = 8.4977(4), b = 9.0617(5), c = 7.0105(3) Å, β = 111.627(3)°, Z = 2, space group P21. The structure was solved by direct methods and was refined by full-matrix least squares procedures to a final R of 0.040 for 967 reflections with I ≥ 3σ(I). The bond lengths involving nonhydrogen atoms have been corrected for thermal motion. Bond lengths are: B—O, 1.460(3) and 1.474(3), B—N, 1.666(3), B—C, 1.613(3), C—O, 1.411(3) and 1.419(3), C—N, 1.485(3) and 1.486(3), C(sp3)—C(sp3), 1.514(4) and 1.524(4), C—C(ar), 1.384–1.400(4–6), mean C—H, 0.98(4), and N—H, 0.87(5) Å. The crystal structure consists of discrete molecules of B-phenyl-diptychboroxazolidine each linked to two others by N—H … O hydrogen bonds (O … N = 2.914(3) Å) to form continuous spirals along b.

Crystal and Molecular Structure of (±)-7,7-(2′,2′-Dimethyl)pentamethylene-1-methyl-norbornane-2-oxime

1975 ◽  
Vol 53 (5) ◽  
pp. 765-776 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Full Matrix ◽  
Space Group ◽  
Centrosymmetric Dimers

Crystals of (±)-7,7-(2′,2′-dimethyl)pentamethylene-1-methyl-norbornane-2-oxime are monoclinic, a = 9.202(2), b = 12.852(3), c = 12.698(3) Å, β = 110.83(2)°, Z = 4, space group P21/c. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.048 for 1538 reflections with I ≥ 3σ(I). The crystal structure consists of pairs of molecules linked by N … H—O hydrogen bonds (N … O = 2.821(3) Å ) to form centrosymmetric dimers. Bond distances are as follows: C—N = 1.266(3), N—O = 1.426(3), mean C(sp3)—C(sp3) = 1.540, and mean C(sp3)—C(sp3) = 1.511 Å.

The crystal structure and stereochemistry of 2-acetyl-3,5,6-trihydroxy-5,6-dimethyl-2-cyclohexenones

1988 ◽  
Vol 66 (2) ◽  
pp. 246-248 ◽  
Author(s):  
Giorgio Adembri ◽  
Mirella Scotton ◽  
Alessandro Sega
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Structure Analysis ◽  
Direct Methods ◽  
Crystal Structure Analysis ◽  
Full Matrix ◽  
Space Group ◽  
X Ray ◽  
Bicyclic System ◽  
Centrosymmetric Dimers

The stereochemistry of 3a, one of the 2-acetyl-3,5,6-trihydroxy-5,6-dimethylcyclohexenones, obtained by rearrangement of 2,3-diacetyl-4-hydroxy-4-methylcyclopentenone, 2a, under basic conditions, was determined by an X-ray crystal structure analysis. An ORTEP plot shows the configuration of (5RS,6RS)-2-acetyl-3,5,6-trihydroxy-5,6-dimethylcyclohexenone and the presence of a conjugated chelated system involving the H-bonding between O(3)… H(31) and H(31)… O(2).Crystals of 3a are triclinic, a = 10.979(4), b = 7.766(3), c = 6.382(3) Å, α = 86.23(2), β = 72.86(1), γ = 88.23(2)°, Z = 2, space group [Formula: see text]. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.036 and Rw = 0.039 for 1324 reflections with I > 3σ(I).The structure of 3a consists of centrosymmetric dimers which contain a nearly planar bicyclic system of a cyclohexenone moiety and a chelated system (Scheme 2).The pathway of the reaction allows one to put forward some hypothesis on the stereochemistry of some analogues of the cyclohexenones 3a and 3b.Faisant appel à la diffraction des rayons-X, on a déterminé la stéréochimie du composé 3a, une des acétyl-2 trihydroxy-3,5,6 diméthyl-5,6 cyclohexénones obtenues par une transposition de la diacétyl-2,3 hydroxy-4 méthyl-4 cyclopenténone, 2a, en milieu alcalin. Une courbe ORTEP démontre que la configuration est (5RS,6RS) pour l'acétyl-2 trihydroxy-3,5,6 diméthyl-5,6 cyclohexénone et qu'il existe un système de chélation conjugué impliquant des liaisons hydrogènes entre O(3)… H(31) et H(31)… O(2).

Crystal and molecular structure of [dimethyl(3,5-dimethyl-1-pyrazolyl)(ethanol-amino)gallato (N(2),O,N(3))](η3-cycloheptatrienyl)dicarbonylmolybdenum

1981 ◽  
Vol 59 (11) ◽  
pp. 1665-1670 ◽  
Author(s):  
Kenneth S. Chong ◽  
Steven J. Rettig ◽  
Alan Storr ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Amino Nitrogen ◽  
Full Matrix ◽  
Octahedral Environment ◽  
Distorted Octahedral ◽  
Unusual Type

Crystals of [dimethyl(3,5-dimethyl-l-pyrazolyl)(ethanolamino)gallato(N(2),O,N(3))](η3-cycloheptatrienyl)dicarbonylmolybdenum are monoclinic, a = 10.511(1), b = 8.335(1), c = 24.138(3) Å, β = 102.22(1)°, Z = 4, space group P21/c. The structure was solved by Patterson and Fourier syntheses and was reflned by full-matrix least-squares procedures to R = 0.028 and Rw = 0.046 for 3708 reflections with I ≥ 3σ(I). The crystal structure consists of discrete molecules linked by N—H … O hydrogen bonds (N … O = 2.929(5) Å). The Mo atom is in a distorted octahedral environment with the η3-C7H7 ligand occupying one coordination site, trans to the amino nitrogen, as a π-donating ligand. Important bond distances (corrected for libration) are: Mo—O, 2.245(2), Mo—N(amino), 2.249(3), Mo—N(pyrazolyl), 2.270(3), Mo—C(O), 1.950(4) and 1.947(4), Mo—C(C7H7), 2.176(4), 2.364(4), and 2.380(4), Ga—O, 1.919(3), Ga—N, 1.984(3), and Ga—C, 1.982(5) and 1.983(5) Å. An unusual type of disorder is present in which a second image of the molecule, approximately mirrored by the plane y = 1/4, is in evidence at low occupancy.

Crystal and molecular structure of difluoroboron N-methylacethydroxamate (2,2-difluoro-4,5-dimethyl-1,3-dioxa-4-azonia-2-boranatacyclopent-4-ene)

1977 ◽  
Vol 55 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter ◽  
W. Kliegel ◽  
D. Nanninga
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths

Crystals of difluoroboron N-methylacethydroxamate are monoclinic, a = 5.097(1), b = 10.653(2), c = 11.520(2) Å, β = 103.57(2)°, Z = 4, space group P21/c. The structure was solved by direct methods and was refined by full-matrix least squares procedures to a final R of 0.056 and Rw of 0.077 for 988 reflections with I ≥ 3σ(I). The structure features a planar five-membered BO2CN ring. Bond lengths (corrected for libration) are: B—F, 1.374(3) and 1.381(3), O—B, 1.496(3) and 1.497(3), O—N, 1.349(2), O—C, 1.346(2), C—N, 1.298(3) and 1.458(3), and C—C, 1.468(3) Å.

Crystal and Molecular Structure of 2,5-Bis(2′-hydroxyethylamino)-1,4-benzoquinone

1975 ◽  
Vol 53 (5) ◽  
pp. 777-783 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonds ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Full Matrix ◽  
Space Group ◽  
Compound C ◽  
Related Compounds ◽  
Centrosymmetric Molecule

Crystals of 2,5-bis(2′-hydroxyethylamino)-1,4-benzoquinone are monoclinic, a = 5.020(1), b = 19.238(3), c = 5.214(1) Å, β = 96.15(3)°, Z = 2, space group P21/n. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.045 for 646 reflections with I ≥ 3σ(I). The benzoquinone ring in the centrosymmetric molecule is slightly, but significantly, nonplanar. Bond distances in the compound (C—C, 1.247 (2) and 1.410 (3), C—N, 1.332 (3) and 1.457 (3), C—C, 1.384–1.514 (3), N—H, 0.89 (3), O—H, 1.07 (5), and C—H, 0.95–1.09 (3) Å) are similar to those in related compounds. The structure features an extensive network of N—H … O (N … O = 2.639 (3) and 3.033 (2) Å) and O—H … O(O … O = 2.757 (3) Å ) hydrogen bonds.

Structural studies of organoboron compounds. XXII. Preparation and crystal and molecular structure of tetramethylammonium-2,4,6,6-tetraphenyl-1,3,5-trioxa-2,4- dibora-6-boratacyclohexane

1985 ◽  
Vol 63 (12) ◽  
pp. 3516-3520 ◽  
Author(s):  
W. Kliegel ◽  
H.-W. Motzkus ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Physical Properties ◽  
Crystal And Molecular Structure ◽  
Structural Parameters ◽  
Direct Methods ◽  
Maximum Deviation ◽  
Structural Studies ◽  
Full Matrix ◽  
The Mean

Details of the preparation and physical properties of (Me4N)+ (Ph4B3O3)− are given. Crystals of tetramethylammonium 2,4,6,6-tetraphenyl-1,3,5-trioxa-2,4-dibora-6-boratacyclohexane are orthorhombic, a = 18.130(2), b = 11.9745(7), c = 12.5187(5) Å, Z = 4, space group Pna21. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.056 and Rw = 0.064 for 1460 reflections with I ≥ 2σ(I). The crystal structure consists of discrete tetramethylammonium cations and tetraphenylboroxinate anions, the first such anion to be structurally characterized. The six-membered B3O3 ring is significantly non-planar, having a flattened O(1)-envelope conformation (maximum deviation from the mean plane = 0.074(4) Å for O(1)). The boroxine ring in the anion shows significant deviations from the D3h symmetry observed for neutral boroxines. Important mean structural parameters: B(sp3)—O = 1.494(2), B(sp2)—O[B(sp3)] = 1.320(9), B(sp2)—O[B(sp2)] = 1.389(3) Å, O—B(sp3)—O = 110.5(5), O—B(sp2)—O = 121.7(6), B(sp2)—O—B(sp2) = 118.9(5), and B(sp3)—O—B(sp2) = 122.9(1)°.

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