Nuclear magnetic resonance studies on cis-bicyclo[3.3.0] oct-7-en-2-yl derivatives. Long range magnetic anisotropic effect on olefinic protons by the endo-carbonyl group

1973 ◽  
Vol 38 (15) ◽  
pp. 2640-2644 ◽  
Author(s):  
Kahee Fujita ◽  
Kazuhiko Hata ◽  
Ryohei Oda ◽  
Iwao Tabushi
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Carbonyl Group ◽  
Long Range ◽  
Magnetic Resonance Studies ◽  
Anisotropic Effect ◽  
Nuclear Magnetic

Nuclear magnetic resonance studies. XVIII.The proton parameters of some bicyclo[2•2•2]octane derivatives

1969 ◽  
Vol 47 (19) ◽  
pp. 3515-3528 ◽  
Author(s):  
Gurudata Gurudata ◽  
J. B. Stothers
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
High Resolution ◽  
Long Range ◽  
Coupling Constants ◽  
Magnetic Resonance Studies ◽  
Anisotropic Effect ◽  
Shielding Effects ◽  
Nuclear Magnetic

The high resolution proton spectra of ten substituted bicyclo[2•2•2]octenes and octanes have been analyzed. The proton shieldings and coupling constants are discussed with particular emphasis on the stereochemical dependence of these parameters. Evidence bearing on the anisotropic effect of carbonyl bonds is presented to substantiate other recent findings on these shielding effects. Certain long-range couplings permit stereochemical assignments.

Nuclear Magnetic Resonance Studies. XXIII. Long-range 1H–1H Couplings (JHCCOCH) in some Methyl Bicyclo[2.2.1]heptane-2-carboxylates

1971 ◽  
Vol 49 (12) ◽  
pp. 2152-2155 ◽  
Author(s):  
H. Brouwer ◽  
J. B. Stothers
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Long Range ◽  
Coupling Constants ◽  
Magnetic Resonance Studies ◽  
Nuclear Magnetic

The methoxyl proton signals of several 3-substituted 2-carbomethoxybicyclo[2.2.1]hept-5-enes and -heptanes appear as doublets because of 1H–1H coupling over five σ-bonds (5J). The dependence of these long-range coupling constants on the nature and orientation of 2- and 3- substituents is discussed in terms of the probable conformations of the 2-carbomethoxyl groups.

Fluorine magnetic resonance studies. III. Fluorine-fluorine coupling over six and seven bonds in fluorostyrenes

1977 ◽  
Vol 30 (3) ◽  
pp. 543 ◽  
Author(s):  
DA Burgess ◽  
ID Rae ◽  
JD Snell
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Aromatic Ring ◽  
Long Range ◽  
Magnetic Resonance Studies ◽  
Nuclear Magnetic Resonance Spectra ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The 19F nuclear magnetic resonance spectra of β,β-difluorostyrenes and 1-difluoromethyleneindans bearing fluorine substituents in the aromatic ring have been recorded and the long-range couplings 6JF,F and 7JF,F are discussed. In each compound the larger couplings are to the olefinic fluorine trans to the aromatic ring. The couplings are maximum in the planar indans, reducing to unobservable values when non-planarity is achieved in suitably substituted styrenes. The allylic coupling 4JH,F involving olefinic fluorines shows only slight stereochemical dependence.

13C Nuclear Magnetic Resonance Studies. 47. 13C Spectra of some exo-Methylenecycloalkanes and -norbornanes

1975 ◽  
Vol 53 (4) ◽  
pp. 589-595 ◽  
Author(s):  
S. H. Grover ◽  
J. B. Stothers
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Carbonyl Group ◽  
Ring System ◽  
Magnetic Resonance Studies ◽  
13C Nuclear Magnetic Resonance ◽  
Methylene Group ◽  
Shielding Effects ◽  
Nuclear Magnetic

The shielding effects of the exo-methylene group on neighboring carbons in several cycloalkanes, methylcyclohexanes, and in the norbornane ring system have been characterized by 13C n. m. r. examination of 28 compounds. The results are compared with those for the carbonyl group and the utility of these data for structural elucidations is discussed. The more distinctive trends exhibited by the methyl carbons in these systems are compared with those for cyclohexanes, cyclohexanones, norbornanes, and norcamphors.

Carbonyl halides of the Group VI transition metals. XXVII. Carbon-13 N.M.R. studies on molybdenum compounds

1982 ◽  
Vol 35 (5) ◽  
pp. 895 ◽  
Author(s):  
R Colton ◽  
J Kevekordes
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Transition Metals ◽  
Carbonyl Group ◽  
High Frequency ◽  
Circumstantial Evidence ◽  
Large Shift ◽  
Group Vi ◽  
Magnetic Resonance Studies ◽  
Nuclear Magnetic

Carbon-13 nuclear magnetic resonance studies have been carried out on a number of molybdenum(II) carbonyl halide species. It has been found that for these seven-coordinate capped octahedral complexes there is a very large shift to high frequency for a carbonyl group in the capping position. Thus carbon-13 n.m.r. provides a useful tool to distinguish between possible isomers. Trends in stability and isomer formation previously suspected from circumstantial evidence can now be rationalized.

scholarly journals Further Nuclear Magnetic Resonance Studies of Flavone

1994 ◽  
Vol 12 (2) ◽  
pp. 85-89 ◽  
Author(s):  
Cirilo García-Martínez ◽  
Martha S. Morales-Rios ◽  
Pedro Joseph-Nathan
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Carbonyl Group ◽  
Isotope Shift ◽  
Coupling Constants ◽  
Magnetic Resonance Studies ◽  
Isotope Shifts ◽  
Nuclear Magnetic

The incorporation of 92.7% of13C at the carbonyl group of flavone allowed to measure two- and three-bond carbon-carbon coupling constants which range from 1.4 to 3.5 Hz, and to measure two-, three- and four-bond carbon-hydrogen coupling constants which range from 0.3 to 3.8 Hz. A mixture of unlabelled flavone1with its 4-13C labelled analogue2further allowed to measure one-bond induced isotope shifts of -15.5 and -16.2 ppb for C-3 and C-4a, respectively, and a three bond induced isotope shift of +3.7 ppb for C-I'.

Sign in / Sign up

Export Citation Format

Share Document