Crystal structure of E-1-(2,4,6-trimethylphenyl)ethanone oxime. The aryl–oxime rotational barrier problem and 13C—15N nmr coupling constant calculations

1980 ◽  
Vol 58 (2) ◽  
pp. 191-196 ◽  
Author(s):  
Suzanne Fortier ◽  
George I. Birnbaum ◽  
Gerald W. Buchanan ◽  
Brian A. Dawson
Keyword(s):  
Crystal Structure ◽  
Large Angle ◽  
Molecular Geometry ◽  
Coupling Constants ◽  
15N Nmr ◽  
Oxime Group ◽  
Internal Ring ◽  
Coupling Constant ◽  
X Ray ◽  
Barrier Problem

From an X-ray analysis of the title compound it is found that the dihedral angle between the plane of the aromatic ring and the oxime plane is 70.8 °. This large angle precludes a significant π electron overlap between the oxime function and the benzene ring. The distortions of the internal ring angles attributable to the four substituents are examined in detail, and parameters are derived for the oxime group. The aryl–oxime C—C bond length (1.491 Å) is the longest yet reported for an aromatic oxime. Using the X-ray derived geometry as input for the calculation of 13C—15N coupling constants, one obtains markedly better agreement between calculated and observed couplings than was the case when a force-field calculated molecular geometry was employed. The barrier to rotation about the aryl–oxime bond is estimated to be about 5.8 kcal/mol.

scholarly journals Homopiperazine (Hexahydro-1,4-diazepine)

Molbank ◽  
10.3390/m1200 ◽  
2021 ◽  
Vol 2021 (2) ◽  
pp. M1200
Author(s):  
R. Alan Aitken ◽  
Dheirya K. Sonecha ◽  
Alexandra M. Z. Slawin
Keyword(s):  
13C Nmr ◽  
Title Compound ◽  
Coupling Constants ◽  
15N Nmr ◽  
Time Data ◽  
Nmr Spectrum ◽  
X Ray ◽  
First Time

The X-ray structure of the title compound has been determined for the first time. Data on its 1H–13C-NMR coupling constants and 15N-NMR spectrum are also given.

Nuclear magnetic resonance studies on the anions [M(SnCl3)5Cl]4− (M = Ru, Os) and [Ru(SnCl3)5(MeCN)]3−: the X-ray crystal structure of [N(C2H5)4]4[Ru(SnCl3)5Cl]

1982 ◽  
Vol 60 (11) ◽  
pp. 1304-1316 ◽  
Author(s):  
Louis J. Farrugia ◽  
Brian R. James ◽  
Claude R. Lassigne ◽  
Edward J. Wells
Keyword(s):  
Crystal Structure ◽  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Octahedral Geometry ◽  
Coupling Constants ◽  
Order Effects ◽  
Magnetic Resonance Studies ◽  
X Ray ◽  
Crystallographic Study

The octahedral anions [M(SnCl3)5Cl]4− (M = Ru, Os) have been fully characterized by 119Sn FT nmr spectroscopy. For M = Ru, 117Sn and 115Sn nmr spectra were also recorded, and an X-ray crystallographic study was carried out on the tetraethylammonium salt, isolated as a disolvate from acetonitrile. The Ru—Sn bond lengths indicate some degree of dπ–dπ interactions. The slight distortions from octahedral geometry are discussed in connection with the packing of the chlorine atoms. The Sn nmr spectra reveal the first observed coupling to a 99Ru nucleus (I = 5/2, 12.7% natural abundance), very large 2J(119Sn—117Sn) coupling constants, and the first observed second-order effects on a heteronuclear system. The octahedral anion [Ru(SnCl3)5(MeCN)]3− was also synthesized as the tetraethylammonium salt and characterized spectroscopically.

Crystal structure of Tetracyclo[5,3,1,12,6,04,9]dodecane (iceane)

1977 ◽  
Vol 30 (8) ◽  
pp. 1837 ◽  
Author(s):  
DPG Hamon ◽  
CL Raston ◽  
GF Taylor ◽  
JN Varghese ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Rigid Body ◽  
Least Squares ◽  
Title Compound ◽  
Molecular Geometry ◽  
Thermal Motion ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray ◽  
Hexagonal Close Packed

The crystal structure of the title compound, C12H18, has been determined at 295 K by X-ray diffraction and refined by full-matrix least squares to a residual of 0.049 for 216 ?observed? reflections; molecular geometry has been corrected for the effects of thermal motion using a rigid body approximation. Crystals are hexagonal, P63/m, a = 6.582(1), c = 11.843(3) Ǻ, Z = 2, the molecules occupying a hexagonal close- packed array.

Darstellung, 11B-und 19F-NMR-Spektren des Monofluoropentaiodo- closo-hexaboratanions sowie Kristallstruktur von (CH2Py2)[B6FI5]/ Synthesis, 11B and 19F NMR Spectra of the Monofluoropentaiodo-closo-hexaborate Anion and the Crystal Structure of (CH2Py2)[B6FI5]

1998 ◽  
Vol 53 (8) ◽  
pp. 829-832 ◽  
Author(s):  
H. Thomsen ◽  
W. Preetz
Keyword(s):  
Crystal Structure ◽  
Nmr Spectra ◽  
19F Nmr ◽  
Coupling Constant ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
19F Nmr Spectra ◽  
Nmr Spectrum ◽  
X Ray ◽  
Excess Iodine

Abstract By reaction of closo-[B6H5F]2- in alkaline solution with excess iodine the monofluoropentaiodo- closo-hexaborate anion [B6FI5]2- is formed in good yield. The crystal structure of (CH2Py2)[B6FI5] has been determined by single crystal X-ray diffraction analysis (orthorhombic, space group Pnma, a = 13.803(2), b = 11.759(2), c = 13.936(2) Å, Z = 4). The B-F-bond length is 1.41 Å, the B-I distances range from 2.13 to 2.17 Å, the B-B distances from 1.69 to 1.76 A. According to the C4v point symmetry the 11B NMR spectrum of the anion exhibits three singlets at +3.8,-30.1 and-33.3 ppm with the intensity ratio 1:4:1, the 19F NMR spectrum one quartet at -247.6 ppm with the coupling constant 1J (19F, 11B) = 54 Hz.

Darstellung und Kristallstruktur von endo-2-Dimethylphospliono-exo-2-liydroxy-(—)-camphan zur Bestimmung von 3J(CCCP)-Vicinalkopplungen / Synthesis and Crystal Structure of endo-2-Dimethylphosphono-exo-2-hydroxy-(—)-camphane for the Determination of 3J(CCCP) Vicinal Coupling Constants

1979 ◽  
Vol 34 (11) ◽  
pp. 1547-1551 ◽  
Author(s):  
Gunadi Adiwidjaja ◽  
Bernd Meyer ◽  
Joachim Thiem
Keyword(s):  
Coupling Constants ◽  
Coupling Constant ◽  
Nmr Spectrum ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Vicinal Coupling Constants ◽  
Complete Assignment ◽  
Hydroxy Phosphonates ◽  
C Nmr

endo-2-Dimethylphosphono-exo-2-hydroxy-(-)-camphane (2) is prepared and the structure confirmed by X-ray data. The complete assignment of the 13C NMR spectrum of this conformationally rigid derivative leads to a Karplus-type function for the vicinal 3J(CCCP) coupling constant in α-hydroxy phosphonates.

Notizen: Kristallstruktur eines mesomeren Organozinnradikals1 / Crystal Structure of a Mesomeric Organo Tin Radical

1977 ◽  
Vol 32 (3) ◽  
pp. 355-356 ◽  
Author(s):  
Wolfgang Uber ◽  
Hartmut B. Stegmann ◽  
Klaus Scheeffleb ◽  
Joachim Strähle
Keyword(s):  
Crystal Structure ◽  
Nitrogen Atom ◽  
Additional Contribution ◽  
Coupling Constant ◽  
Tin Compounds ◽  
X Ray ◽  
X Ray Crystallography

o-Aminophenols react with organo tin compounds forming stable mesomeric complexes. The structure of one compound was determined by X-ray crystallography. The tin atom is chelated by two oxygen and one nitrogen atom. The nitrogen atom and the associated C and Sn atoms are in a plane and therefore the ESR tin coupling constant has an additional contribution by a π-σ-interaction through the N—Sn bond.

Lupin alkaloids 6. Stereochemistry of bis-quinolizidine alkaloids with γ-oxo-α,β-enamine system

1994 ◽  
Vol 72 (1) ◽  
pp. 193-199 ◽  
Author(s):  
Tadeusz Brukwicki ◽  
Waleria Wysocka ◽  
Barbara Nowak-Wydra
Keyword(s):  
Conformational Changes ◽  
Chemical Shifts ◽  
Molecular Geometry ◽  
Coupling Constants ◽  
Hydroxyl Group ◽  
Coupling Constant ◽  
H Nmr ◽  
Time Signals ◽  
Low Sensitivity ◽  
First Time

1H nmr, 1H,1H and 1H,13C COSY, and 2D J-resolved spectra of multiflorine (1) and 13α-hydroxymultiflorine (2) in CDCl3 were taken. Some erroneously determined chemical shifts in 1 were corrected and for the first time signals in 2 were assigned. Most of the coupling constants in 1 and 2 were established. A coupling constant of H7–H17β and chemical shifts for H17β, C14, and C8 were used to define the conformational equilibrium of boat or chair forms in the C rings, in 1 and 2 in solution. The results obtained confirm the previous findings based on chemical shifts of C12: ca. 75 and 70% of the "boat" conformer in 1 and 2, respectively, at room temperature. Of all the criteria used, the H7–H17β coupling constant seems to be least sensitive to the influence of substituents at rings A and D. From the Haasnoot equation, torsion angles of HCCH in regions of molecular geometry featuring low sensitivity to conformational changes were calculated. The hydroxyl group at position 13α has a slight influence on the geometry of ring D.

Syntheses and Spectroscopic Studies of Some New Diazaphospholes and Diazaphosphorinanes. Crystal Structure of 4

2005 ◽  
Vol 60 (10) ◽  
pp. 1021-1026 ◽  
Author(s):  
Khodayar Gholivand ◽  
Zahra Shariatinia ◽  
Mehrdad Pourayoubi ◽  
Sedigheh Farshadian
Keyword(s):  
Crystal Structure ◽  
Ir Spectroscopy ◽  
Spectroscopic Studies ◽  
Coupling Constants ◽  
Crystalline Lattice ◽  
Polymeric Chain ◽  
Ring Strain ◽  
One Dimensional ◽  
X Ray ◽  
X Ray Crystallography

New diazaphospholes and diazaphosphorinanes with formula were synthesized and characterized by 1H, 13C, 31P NMR and IR spectroscopy and elemental analysis. The structure of compound 1 has been determined by X-ray crystallography. A one-dimensional polymeric chain was observed in the crystalline lattice produced by intermolecular -P=O. . .H-N- and -C=O. . .H-N-hydrogen bonds. Compounds 1 and 2 contain five-membered rings and show high values for 2J(PNH) and 2J(P,C) coupling constants due to the ring strain. These constants are reduced seriously in compounds with six-membered rings. In compound 6 with CCl3C(O)NH moiety, all phosphorus-hydrogen couplings are zero.

Cyclische Schwefeldiimide des Siliciums. 15N-NMR-Spektroskopie und die Röntgenstrukturanalyse des Achtrings tBu2Si(NSN)2SitBu2 / Cyclic Sulfur Diimides of Silicon. 15N NMR Spectroscopy and the X-Ray Analysis of the Eight-Membered Ring tBu2Si(NSN)2SitBu2

1993 ◽  
Vol 48 (8) ◽  
pp. 1041-1050 ◽  
Author(s):  
Max Herberhold ◽  
Silke Gerstmann ◽  
Wolfgang Milius ◽  
Bernd Wrackmeyer
Keyword(s):  
Nmr Spectroscopy ◽  
Pulse Sequences ◽  
Ring System ◽  
Membered Ring ◽  
Coupling Constants ◽  
Primary Amines ◽  
15N Nmr ◽  
Monoclinic Space Group ◽  
Small Magnitude ◽  
X Ray

Various six-membered cyclic sulfur diimides (3a—f) were prepared by aminolysis of the bis(chloro-dimethylsilyl)sulfur diimide (2) using NH3 (a) and primary amines RNH2 [R = Me (b), Et (c), nPr (d), nBu (e), iPr (f)]. Except for R = H, non-cyclic intermediates, the Si-monoamino- (7) and Si,Si′-diamino derivatives of 2 (8), were detetected for all groups R, including R = tBu (g). The reaction between R2SiCl2 and the sulfur diimide anion K[(NSN)SiMe3] gave non-cyclic silanes (9,10) and the eight-membered rings of the type R2Si(NSN)2SiR2 [R = Me (4), tBu (5)] of which 5 was studied by X-ray analysis (monoclinic, space group P21/c; planar ring system) and solid-state 15N and 29Si CP/MAS NMR spectroscopy. The ten-membered ring system 6 was obtained from the reaction between 1,2-dichlorotetramethyldisilane and bis(trimethylstannyl)sulfur diimide. All compounds were studied by 1H,13C, 15N and 29Si NMR. The δ15N NMR data proved useful to distinguish between fluxional systems with fast E/Z—Z/E isomerization (non-cyclic compounds 8 and the ten-membered cycle 6). Hahn-Echo-extended (HEED) polarization transfer (INEPT) pulse sequences served to measure coupling constants 1J(29Si15Namine) for the compounds 3 and 8. This also proved that the magnitude of 1J(29Si15NNSN) must be small (< 1 Hz). In the case of the compounds 3, the rather small magnitude of both 1J(29Si15Namine) and 1J(15N1H) (3a) indicated that the aminonitrogen atom adopts a pyramidal environment.

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