15N–13C spin–spin coupling constants in some aniline derivatives

1976 ◽  
Vol 54 (5) ◽  
pp. 833-839 ◽  
Author(s):  
Roderick E. Wasylishen
Keyword(s):  
Fourier Transform ◽  
Nmr Spectroscopy ◽  
Bond Order ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Aniline Derivatives ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
Order Comparison ◽  
Mo Theory

Nitrogen–carbon spin–spin coupling constants in aniline-15N and some of its derivatives have been measured using 13C Fourier transform nmr spectroscopy. Observed values of 1J(15N,13C) in these aniline derivatives are dependent on the nature of the substituent as well as the solvent. Observed values of 1J(15N,13C) in the amino fragment of a number of amine derivatives are linearly related to the corresponding 1J(15N,H) values in these compounds. The 1J(15N,13C) values in these compounds also appear to be related to the N(s)—C(s) bond order. Comparison of observed 1J(15N,13C) values in a number of compounds with those calculated using INDO–MO theory indicate that 1J(15N,13C) in aniline and its derivatives is negative, that is, 1K(N,C) is positive. Observed and calculated 15N–13C spin–spin coupling constants over two and three bonds are also presented.

9-Borafluorenes – NMR spectroscopy and DFT calculations. Molecular structure of 1,2-(2,2′-diphenylylene)-1,2-diethyldiborane

2010 ◽  
Vol 75 (7) ◽  
pp. 743-756 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Peter Thoma ◽  
Rhett Kempe ◽  
Germund Glatz
Keyword(s):  
Molecular Structure ◽  
Nmr Spectroscopy ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Spin Coupling ◽  
X Ray Diffraction ◽  
Data Set ◽  
Chemical Shift Tensors ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

9-Borafluorene derivatives 1 (9-R = Et (a), Ph (b), Cl (c), NEt2 (d)), the pyridine adduct 1py+ and 1,2-(2,2′-biphenylylene)-1,2-diethyldiborane(6) (3), were studied by 11B and 13C NMR spectroscopy to obtain a fairly complete data set for the first time. The molecular structure of the doubly hydrogen-bridged 1,2-diphenylenediborane 3 was determined by X-ray diffraction. The gas-phase structures of the compounds 1, related derivatives, and of some doubly hydrogen-bridged 1,2-diphenylenediboranes were optimized by quantum chemical calculations (B3LYP/6-311+G(d,p) level of theory) and NMR parameters, such as chemical shifts, 11B chemical shift tensors and indirect nuclear 13C–11B spin–spin coupling constants were calculated at the same level of theory and compared with experimental data.

69/71Ga and 115In NMR Spectroscopy of Lithium Tetra(tert-butyl)gallate and -indate: Spin-Spin Coupling Constants 1J(69/71Ga,13C) and 1J(115In,13C)

2009 ◽  
Vol 64 (1) ◽  
pp. 41-46
Author(s):  
Bernd Wrackmeyer ◽  
Elena V. Klimkina
Keyword(s):  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Tert Butyl ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
First Time

The 13C, 69/71Ga and 115In NMR spectra of lithium tetra(tert-butyl)gallate and -indate were measured under various conditions. It proved possible to determine for the first time the coupling constants 1J(69/71Ga,13C) = 182 Hz/232 Hz and 1J(115In,13C) = 310±10 Hz for these metallates under conditions for solvent-separated ions. DFT calculations [B3LYP/6-311+G(d,p)] were carried out for organogallium compounds such as tri(tert-butyl)gallium, trimethylgallium and tetramethylgallate in order to predict and confirm coupling constants 1J(Ga,13C).

Signs of long-range proton–fluorine spin–spin coupling constants in 2-amino-5-bromobenzotrifluoride

1968 ◽  
Vol 46 (4) ◽  
pp. 652-654 ◽  
Author(s):  
D. J. Blears ◽  
S. S. Danyluk ◽  
T. Schaefer
Keyword(s):  
Long Range ◽  
Bond Order ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Trifluoromethyl Group ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

The signs of the spin–spin coupling constants between the fluorine nuclei in the trifluoromethyl group and the ring protons in 2-amino-5-bromobenzotrifluoride are reported. [Formula: see text] and [Formula: see text] are negative while [Formula: see text] is positive. These signs are in agreement with fluorine contact shifts in certain Ni(II) chelates and therefore provide evidence for hyperconjugation of the CF3 group with the ring. The magnitude of [Formula: see text] is rather larger than expected on the basis of a relationship between the square of the bond order between the relevant ring carbons and the size of the coupling.

Vinylsilylferrocenes and Ethynyl(vinyl)silylferrocenes. Synthesis, Multinuclear Magnetic Resonance Study and DFT Calculations

2014 ◽  
Vol 69 (6) ◽  
pp. 704-714 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Elena V. Klimkina
Keyword(s):  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Magnetic Resonance Study ◽  
Nmr Parameters ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
Multinuclear Magnetic Resonance

Ferrocenylsilanes with various functions at silicon (chlorine, vinyl, ethynyl) were prepared and studied by multinuclear magnetic resonance methods (1H, 13C, 29Si NMR spectroscopy). The gasphase geometries of the silanes were optimized by calculations at the B3LYP=6-311+G(d,p) level of theory, and NMR parameters (chemical shifts δ13C, δ29Si, spin-spin coupling constants) were calculated at the same level of theory.

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.

Hydrogen bonding and long-range proton coupling constants in some ortho disubstituted aniline derivatives. Intramolecular proton exchange and degree of nonplanarity of the amino group

1970 ◽  
Vol 48 (8) ◽  
pp. 1263-1268 ◽  
Author(s):  
R. Wasylishen ◽  
T. Schaefer
Keyword(s):  
Long Range ◽  
Proton Exchange ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Amino Group ◽  
Aniline Derivatives ◽  
Proton Coupling ◽  
Intramolecular Exchange ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

Long-range spin–spin coupling constants over five bonds between the two amino protons and the ring protons are reported for some ortho disubstituted aniline derivatives in cyclohexane and benzene-d6 solutions. Equal coupling of both amino protons to the meta protons in unsymmetrically ortho disubstituted aniline derivatives indicates the occurrence of intramolecular exchange of the amino protons. The absence of any observable coupling over six bonds to the para proton places an upper limit on the degree of nonplanarity of the amino group in the 2,6-dibromo- and 2,6-dichloroanilines. A relatively basic compound like 2,4,6-trimethylaniline does not display long-range couplings of the amino protons, very likely because intermolecular proton exchange occurs.

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