Darstellung und Spektroskopische Charakterisierung von [4.7-13C2]-Azulen/ Preparation and Spectroscopic Characterisation of [4,7-13C2] Azulene

AbstractA multistep synthesis of [4.7-13C2] azulene (10) using Na13CN as source for the labelled carbon atom is described. The electron impact induced elimination of acetylene from the molecular ions of 10 proceeds with almost statistical participation of the carbon atoms, thus indicating an extensive scrambling of the azulene carbon skeleton prior to fragmentation. From the 13C NMR spectrum of 10, 13C13C spin spin coupling constants have been determined. The measured values confirm our earlier interpretation of the transmission of the 13C13C spin spin coupling constants in terms of a π-mechanism.

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

Zeitschrift für Naturforschung B ◽

10.1515/znb-2005-0304 ◽

2005 ◽

Vol 60 (3) ◽

pp. 259-264 ◽

Cited By ~ 29

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

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Sixteen 13C-19F Spin-Spin Coupling Constants in the 13C NMR Spectrum of 1-Fluoropyrene (C16H9F).

Acta Chemica Scandinavica ◽

10.3891/acta.chem.scand.26-2159 ◽

1972 ◽

Vol 26 ◽

pp. 2159-2161 ◽

Cited By ~ 12

Author(s):

A. Berg ◽

P. E. Hansen ◽

H. J. Jakobsen ◽

H. A. Øye ◽

Sigfrid Svensson

Keyword(s):

13C Nmr ◽

Coupling Constants ◽

Spin Coupling ◽

Nmr Spectrum ◽

Spin Coupling Constants ◽

Spin Spin Coupling

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Complete Prediction of the1H NMR Spectrum of Organic Molecules by DFT Calculations of Chemical Shifts and Spin-Spin Coupling Constants

Chemistry - A European Journal ◽

10.1002/1521-3765(20010417)7:8<1652::aid-chem16520>3.0.co;2-v ◽

2001 ◽

Vol 7 (8) ◽

pp. 1652-1661 ◽

Cited By ~ 78

Author(s):

Alessandro Bagno

Keyword(s):

Dft Calculations ◽

Organic Molecules ◽

Chemical Shifts ◽

Coupling Constants ◽

Spin Coupling ◽

Nmr Spectrum ◽

Spin Coupling Constants ◽

Spin Spin Coupling

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73 Ge Nuclear Magnetic Resonance Studies

Zeitschrift für Naturforschung A ◽

10.1515/zna-1971-0902 ◽

1971 ◽

Vol 26 (9) ◽

pp. 1384-1389 ◽

Cited By ~ 10

Author(s):

J . Kaufmann ◽

W. Sahm

Keyword(s):

Chemical Shifts ◽

Spin Echo ◽

Relaxation Times ◽

Least Square ◽

Coupling Constants ◽

Spin Coupling ◽

Nmr Spectrum ◽

Spin Coupling Constants ◽

Spin Echo Technique ◽

Spin Spin Coupling

Abstract The 73Ge spectra of some germanium-tetra-halides, germanium-tetra-alkyles, and of germanium-tetra-methoxide have been observed. The chemical shifts of these 73Ge NMR-lines were measured as functions of the temperature in the range up to 50 °C. In CS2-and benzene-solutions of Gel4 , two 73Ge-lines were found. The 73Ge NMR-spectrum of Ge(CH3)4 caused by indirect spin-spin-coupling between the 73Ge nucleus and the protons is well resolved. The spin-spin-coupling constants of Ge(CH3)4 and of Ge(OCH3)4, which shows an unresolved spectrum, were evaluated by an iterative least square fitting routine. The relaxation times T2 (in the range 30...740 msec) measured by the Carr-Purcell spin-echo-technique and calculated from the line widths are in good agreement. Precision measurements of the ratios of the Larmor frequencies of 73Ge in GeCl4, 41K in aqueous KF-solution and 2H in pure heavy water lead to a magnetic moment of 73Ge: μ = -(0.876 78 ± 0.000 01) μN (uncorrected).

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

Zeitschrift für Naturforschung B ◽

10.1515/znb-1978-0325 ◽

1978 ◽

Vol 33 (3) ◽

pp. 353-354 ◽

Cited By ~ 19

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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