Two-bond 13C–13C spin-coupling constants in saccharides: dependencies on exocyclic hydroxyl group conformation

2021 ◽  
Author(s):  
Jieye Lin ◽  
Reagan J. Meredith ◽  
Allen G. Oliver ◽  
Ian Carmichael ◽  
Anthony S. Serianni
Keyword(s):  
Solid State ◽  
Torsion Angle ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Hydroxyl Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
Spin Coupling Constants ◽  
C Nmr

13C-Labeled mono- and disaccharides were studied by X-ray crystallography and solid-state 13C NMR to determine the dependence of 2JC1,C3 in aldopyranosyl rings on the C1–C2–O2–H torsion angle, θ2, involving C2 of the C1–C2–C3 coupling pathway.

Zur Struktur des Enols von Benzoylaceton / On the Structure of the Enol of Benzoylacetone

1979 ◽  
Vol 34 (11) ◽  
pp. 1606-1611 ◽  
Author(s):  
W. Winter ◽  
K.-P. Zeller ◽  
S. Berger
Keyword(s):  
Structural Model ◽  
Chemical Shifts ◽  
Ring System ◽  
Coupling Constants ◽  
Spin Coupling ◽  
X Ray ◽  
Wide Range ◽  
Spin Coupling Constants ◽  
C Nmr ◽  
Oxygen Atoms

Abstract A low temperature X-ray study of the enol of benzoylacetone indicates fixed positions of the C and O atoms within the enolic ring system and an extensive bond delocalisation over these atoms. The distribution of electron density between the two oxygen atoms shows that the enolic hydrogen is spread over a wide range. This is in accordance with a structural model proposed by de la Vega, whereupon the C and O atoms are kept fixed in their average positions during a tunneling process of the hydrogen between the two oxygen atoms. With this conception, the chemical shifts in the 17O and 13C NMR spectra, the 13C13C spin coupling constants and the temperature independance of these values can be explained.

scholarly journals 13C–13C spin-coupling constants in crystalline 13C-labeled saccharides: conformational effects interrogated by solid-state 13C NMR spectroscopy

2019 ◽  
Vol 21 (42) ◽  
pp. 23576-23588
Author(s):  
Wenhui Zhang ◽  
Mi-Kyung Yoon ◽  
Reagan J. Meredith ◽  
Jaroslav Zajicek ◽  
Allen G. Oliver ◽  
...  
Keyword(s):  
Solid State ◽  
Density Functional ◽  
13C Nmr Spectroscopy ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Functional Theory ◽  
Conformational Effects ◽  
Spin Coupling Constants ◽  
C Nmr ◽  
Solid State 13C Nmr

Solid-state 13C NMR reveals differences in O-glycosidic linkage conformation in solution and in crystalline disaccharides. Experimental JCC values in crystalline samples provide a means of validating JCC calculated from density functional theory.

scholarly journals Simple Methylcadmium Alkoxides

2007 ◽  
Vol 62 (10) ◽  
pp. 1339-1342 ◽  
Author(s):  
Surajit Jana ◽  
Tania Pape ◽  
Norbert W. Mitzel
Keyword(s):  
Mass Spectrometry ◽  
Solid State ◽  
Molecular Formula ◽  
Equimolar Ratio ◽  
X Ray ◽  
X Ray Crystallography ◽  
Elemental Analyses ◽  
Solid State Structures ◽  
Structural Aspects ◽  
C Nmr

The reaction of dimethylcadmium with alcohols R-OH in equimolar ratio leads to the formation of tetrameric methylcadmium alkoxides with molecular formula [(MeCd)4 (OR)4] [R = Me (1), Et (2) and iPr (3)]. These compounds have been characterised by 1H, 13C NMR and IR spectroscopy, by mass spectrometry, elemental analyses and by X-ray crystallography (for 2 and 3). The solid state structures show distorted cubane-type aggregates with Cd4O4 cores. The structural aspects and the spectroscopic characterisations of these compounds are discussed.

Hyperconjugation In Trialkylboranes Shown By Indirect Nuclear Spin-Spin Coupling Constants. Experimental Data And Density Functional Theory (Dft) Calculations

2005 ◽  
Vol 60 (3) ◽  
pp. 259-264 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Oleg L. Tok
Keyword(s):  
Experimental Data ◽  
Dft Calculations ◽  
Density Functional ◽  
Calculated Data ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Functional Theory ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
C Nmr

Trimethylborane (1), triethylborane (2), 1,3-dimethyl-1-boracyclopentane (3), 1-methyl-1- boracyclohexane (4), 9-methyl- and 9-ethyl-9-borabicyclo[3.1.1]nonane [5(Me) and 5(Et)], and 1- boraadamantane (6) were studied by 11B and 13C NMR spectroscopy with respect to coupling constants 1J(13C,11B) and 1J(13C,13C). Results of DFT calculations at the B3LYP/6-311+g(d,p) level of theory show satisfactory agreement with the experimental data. Hyperconjugation arising from C-C σ bonds adjacent to the tricoordinate boron atom is indicated, in particular for 1-boraadamantane (6), by the optimised calculated structures, and by the experimental and calculated data 1J(13C,13C). The calculated magnitude of 1J(13C,1H) for carbon atoms adjacent to boron becomes significantly smaller if the optimised structures suggest hyperconjugative effects arising from these C-H bonds

The relative stabilities of PhE(NH-t-Bu)2 and PhE(μ-N-t-Bu)2EPh (E = As, Sb, and Bi): X-ray structures of {Li2[PhAs(N-t-Bu)2]}2 and PhE(μ-N-t-Bu)2EPh (E = Sb, Bi)

2003 ◽  
Vol 81 (2) ◽  
pp. 169-174 ◽  
Author(s):  
Glen G Briand ◽  
Tristram Chivers ◽  
Masood Parvez
Keyword(s):  
Solid State ◽  
Nmr Spectra ◽  
Phenyl Group ◽  
Synthetic Approach ◽  
Relative Stabilities ◽  
X Ray ◽  
X Ray Crystallography ◽  
In Trans ◽  
C Nmr

The reaction of PhECl2 with 2 equiv of LiHN-t-Bu has been studied for the series E = As, Sb, and Bi to determine the effect of the phenyl group on subsequent amine condensation processes. For PhAsCl2, the metathesis product PhAs(NH-t-Bu)2 4 was obtained as a colourless oil. Similar reactions involving PhECl2, where E = Sb or Bi, yielded the cyclodipnict(III)azanes PhE(μ-N-t-Bu)2EPh 5 (E = Sb) and 6 (E = Bi), respectively. Treatment of 4 with 2 equiv of n-BuLi produced the dilithium salt Li2[PhAs(N-t-Bu)2] 7a. Products 4, 5, 6, and 7a were characterized by 1H, 7Li (7a), and 13C NMR spectra, while 5, 6, and 7a were also structurally characterized by X-ray crystallography. Compound 7a is dimeric in the solid state via intermolecular Li···N and η6-Li···Ph interactions. The cyclodipnict(III)azanes 5 and 6 have similar structures, with the exocyclic phenyl groups in trans positions relative to the E2N2 ring. This synthetic approach provides a new route to the four-membered rings RE(μ-N-t-Bu)2ER (E = Sb, Bi) and the first example of a bis(organyl)cyclodibism(III)azane.Key words: arsenic, antimony, bismuth, amides, imides.

scholarly journals Solid-state tautomeric structure and invariom refinement of a novel and potent HIV integrase inhibitor

2013 ◽  
Vol 69 (3) ◽  
pp. 285-288 ◽  
Author(s):  
John Bacsa ◽  
Maurice Okello ◽  
Pankaj Singh ◽  
Vasu Nair
Keyword(s):  
Solid State ◽  
Integrase Inhibitor ◽  
Correlation Spectroscopy ◽  
Hiv Integrase ◽  
Acta Cryst ◽  
X Ray ◽  
X Ray Crystallography ◽  
Molecular Charge ◽  
Intramolecular Hydrogen ◽  
C Nmr

The conformation and tautomeric structure of (Z)-4-[5-(2,6-difluorobenzyl)-1-(2-fluorobenzyl)-2-oxo-1,2-dihydropyridin-3-yl]-4-hydroxy-2-oxo-N-(2-oxopyrrolidin-1-yl)but-3-enamide, C27H22F3N3O5, in the solid state has been resolved by single-crystal X-ray crystallography. The electron distribution in the molecule was evaluated by refinements with invarioms, aspherical scattering factors by the method of Dittrichet al.[Acta Cryst.(2005), A61, 314–320] that are based on the Hansen–Coppens multipole model [Hansen & Coppens (1978).Acta Cryst.A34, 909–921]. The β-diketo portion of the molecule exists in the enol form. The enol –OH hydrogen forms a strong asymmetric hydrogen bond with the carbonyl O atom on the β-C atom of the chain. Weak intramolecular hydrogen bonds exist between the weakly acidic α-CH hydrogen of the keto–enol group and the pyridinone carbonyl O atom, and also between the hydrazine N—H group and the carbonyl group in the β-position from the hydrazine N—H group. The electrostatic properties of the molecule were derived from the molecular charge density. The molecule is in a lengthened conformation and the rings of the two benzyl groups are nearly orthogonal. Results from a high-field1H and13C NMR correlation spectroscopy study confirm that the same tautomer exists in solution as in the solid state.

A proton magnetic resonance estimate of the extent of intramolucular hydrogen bonding in derivatives of 2-trifluoromethyl phenol. Solvent effects

1976 ◽  
Vol 54 (14) ◽  
pp. 2243-2248 ◽  
Author(s):  
Ted Schaefer ◽  
J. Brian Rowbotham
Keyword(s):  
Free Energy ◽  
Hydrogen Bonding ◽  
Vapor Phase ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Hydroxyl Group ◽  
Spin Coupling Constants ◽  
Hydroxyl Protons ◽  
Spin Spin Coupling ◽  
Derivatives Of

The long-range spin–spin coupling constants between hydroxyl protons and ring protons or fluorine nuclei are used to establish the conformer populations in iodine and brornine derivatives of 2-trifluoromethylphenol in C6H12, CCl4, and C6D6 solutions. The sequence Cl, [Formula: see text] is established for the so-called hydrogen bonding preferences of the hydroxyl group in 2,4,6-trisubstituted phenols, the corresponding free energy sequence being −ΔG = 1690, 1690 > 1300 > 1230 > 0 ± 200 cal/mol at 32 °C in CCl4 solution. An indirect estimate of the free energy differences in the vapor phase suggests the sequence −ΔG = 2800, 2800 > 2400 > 2300 > 1100 ± 300 cal/mol; the latter value meaning that the hydroxyl group in 4-bromo-2-trifluoromethylphenol prefers the CF3 group by this amount in the vapor phase. Benzene interacts preferentially with the OH group in this compound to the extent of 1300 cal/mol (ΔG), referenced to the vapor phase.

scholarly journals Probing interactions through space using spin–spin coupling

2014 ◽  
Vol 43 (17) ◽  
pp. 6548-6560 ◽  
Author(s):  
Martin W. Stanford ◽  
Fergus R. Knight ◽  
Kasun S. Athukorala Arachchige ◽  
Paula Sanz Camacho ◽  
Sharon E. Ashbrook ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Spin Coupling ◽  
X Ray ◽  
Solid State Nmr Spectroscopy ◽  
X Ray Crystallography ◽  
B3lyp Calculations ◽  
Spin Spin Coupling

A series of eight 5-(TeAr)-6-(SePh)acenaphthenes (Ar = aryl) were prepared and structurally characterised by X-ray crystallography, solution and solid-state NMR spectroscopy and DFT/B3LYP calculations.

13C, 1H-Spin-Spin Kopplungskonstanten Teil III: Naphthalin / 13C, 1H Spin-Spin Coupling Constants Part III: Naphthalene

1978 ◽  
Vol 33 (3) ◽  
pp. 353-354 ◽  
Author(s):  
Horst Seel ◽  
Rafet Aydin ◽  
Harald Günther
Keyword(s):  
Linear Dependence ◽  
Bond Order ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
C Nmr

Abstract Using a newly developed technique that employs highly deuterated compounds and 2H broadband decoupling the 13C, 1H spin-spin coupling constants for naphthalene have been measured from the 13C NMR spectra of α-and β-H-[D7]naphthalene. A linear dependence of the 3J(13C, 1H) data on the central π-bond order is indicated.

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