Organometallic compounds in synthesis. VIII. Carbon-13 nuclear magnetic resonance spectroscopic study of tricarbonylcyclohexadienyliron salts

The carbon-13 N.M.R. spectra of eleven substituted tricarbonylcyclohexadienyliron salts (1) have been determined and individual resonances assigned. Substituent effects have been deduced and compared with corresponding effects in cyclohexadienyl cations. The structures of the tricarbonylcyclohexadienyliron salts are discussed with reference to chemical shift data. The proportions of irreversible nucleophilic attack at the terminal positions in the unsymmetrical 2-substituted salts are compared with the observed chemical shifts at these carbon atoms.

Download Full-text

17O nuclear magnetic resonance spectroscopic study of substituted phthalic anhydrides and phthalides

Canadian Journal of Chemistry ◽

10.1139/v87-204 ◽

1987 ◽

Vol 65 (6) ◽

pp. 1214-1217 ◽

Cited By ~ 14

Author(s):

David W. Boykin ◽

Alfons L. Baumstark ◽

Margaret M. Kayser ◽

Chantal M. Soucy

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Chemical Shift ◽

Chemical Shifts ◽

Carbonyl Groups ◽

Chemical Shift Data ◽

The Relationship ◽

Electronic Character ◽

Shift Data ◽

Phthalic Anhydrides

17O chemical shift data (natural abundance) for 3-substituted phthalic anhydrides and 4- and 7-substituted phthalides in acetonitrile at 75 °C are reported. Steric interactions of substituents ortho to the carbonyl groups result in deshielding effects (9–22 ppm) relative to parent compounds regardless of the electronic character of the substituents. Factors contributing to the deshielding effects are discussed. The relationship between 17O chemical shifts and regiochemistry of the phthalic anhydrides is discussed.

Download Full-text

Carbon-13 Nuclear Magnetic Resonance Spectra of Isothiazole, 1,2-Dithiole, and 1,3-Dithiole Derivatives

Canadian Journal of Chemistry ◽

10.1139/v75-117 ◽

1975 ◽

Vol 53 (6) ◽

pp. 836-844 ◽

Cited By ~ 32

Author(s):

N. Plavac ◽

I. W. J. Still ◽

M. S. Chauhan ◽

D. M. McKinnon

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Chemical Shift ◽

Carbonyl Compounds ◽

Heterocyclic Compounds ◽

Chemical Shifts ◽

Conjugated Systems ◽

Nuclear Magnetic Resonance Spectra ◽

Chemical Shift Data ◽

Shift Data

Carbon-13 chemical shift data have been obtained for a number of isothiazole, benzo[c]isothiazole, 1,2-dithiole, and 1,3-dithiole derivatives. A number of these compounds are thiones and the chemical shifts of the C=S carbons are discussed in the light of recent attempts to predict such chemical shifts from those of the analogous carbonyl compounds. Comparisons of substituent chemical shift (s.c.s.) effects in these heterocyclic compounds with those in simpler aromatic or conjugated systems have been made and additivity correlations tested in a number of cases.

Download Full-text

Metabolites of bird's nest fungi. Part 10. Carbon-13 nuclear magnetic resonance studies on the cyathins

Canadian Journal of Chemistry ◽

10.1139/v78-360 ◽

1978 ◽

Vol 56 (16) ◽

pp. 2197-2199 ◽

Cited By ~ 21

Author(s):

William A. Ayer ◽

Thomas T. Nakashima ◽

Dale E. Ward

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Chemical Shift ◽

Chemical Shifts ◽

Magnetic Resonance Studies ◽

Chemical Shift Data ◽

Related Compounds ◽

Shift Data ◽

Methyl Acetal ◽

Magnetic Resonance Spectra

The carbon-13 magnetic resonance spectra of cyathin A3 and several related compounds have been measured and the chemical shifts have been assigned. The chemical shift data have been used to determine the stereochemistry at C-1 in cyafrin A4 and to determine the position of the bromine in 1-bromoallocyathin A3 methyl acetal.

Download Full-text

Nuclear magnetic resonance spectra, stereochemistry, and conformation of flavan derivatives

Australian Journal of Chemistry ◽

10.1071/ch9640632 ◽

1964 ◽

Vol 17 (6) ◽

pp. 632 ◽

Cited By ~ 77

Author(s):

JW Clark-Lewis ◽

LM Jackman ◽

TM Spotswood

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Chemical Shift ◽

Heterocyclic Ring ◽

Coupling Constant ◽

Nuclear Magnetic Resonance Spectra ◽

Chemical Shift Data ◽

Shift Data ◽

Magnetic Resonance Spectra ◽

Nuclear Magnetic

Chemical-shift and coupling-constant data for protons in 68 flavan derivatives are reported. Coupling-constant data for interactions involving the 2-, 3-, and 4-protons have been used to define the configuration of the 2-, 3-, and 4-substituents and the conformation of the heterocyclic ring. It is shown that chemical-shift data for protons of the heterocyclic ring and of 3- and 4-acetoxyl groups are of little value in stereochemical studies. Analysis of the absorptions of the aromatic protons shows that N.M.R. is useful for determining the oxygenation pattern in rings A and B.

Download Full-text

Determination of for aliphatic ketones from nuclear magnetic resonance chemical shift data

Canadian Journal of Chemistry ◽

10.1139/v70-315 ◽

1970 ◽

Vol 48 (12) ◽

pp. 1919-1923 ◽

Cited By ~ 9

Author(s):

Donald G. Lee

Keyword(s):

Nuclear Magnetic Resonance ◽

Raman Spectroscopy ◽

Magnetic Resonance ◽

Chemical Shift ◽

Aliphatic Ketones ◽

Chemical Shift Data ◽

Shift Data ◽

Good Agreement ◽

Nuclear Magnetic

The [Formula: see text] values for 3-pentanone, 2-butanone, and 3-methyl-2-butanone have been determined from chemical shift data. The values (−7.6, −7.1, and −7.2, respectively) are in good agreement with those previously determined for aliphatic ketones by use of ultraviolet–visible and Raman spectroscopy.

Download Full-text

Substituent effects on the 13C chemical shifts of monosubstituted twistanes

Canadian Journal of Chemistry ◽

10.1139/v77-443 ◽

1977 ◽

Vol 55 (17) ◽

pp. 3161-3165 ◽

Cited By ~ 15

Author(s):

Helmut Beierbeck ◽

John K. Saunders

Keyword(s):

Chemical Shift ◽

Substituent Effect ◽

Chemical Shifts ◽

Substituent Effects ◽

13C Chemical Shifts ◽

Bond Interaction ◽

Chemical Shift Data ◽

Shift Data ◽

Deshielding Effect

The 13C chemical shift data for some hydroxy, chloro, bromo, and oxo twistane derivatives are presented and compared to the shifts observed in corresponding adamantanes. The substituent effect at the α and β carbons is more pronounced in twistanes than in adamantanes. The substituent shift induced at an antiperiplanar γ carbon is shown to depend on the presence or absence of 1,3-diaxial hydrogen–hydrogen interactions between the substituted and γ carbons. If such an interaction is present the effect is of shielding whereas if it is absent, the effect is of deshielding. The deshielding effect appears to occur via a through bond interaction.

Download Full-text

IR and NMR Correlations for 3-x and 4-x Substituted Anilines

Applied Spectroscopy ◽

10.1366/0003702934334976 ◽

1993 ◽

Vol 47 (4) ◽

pp. 411-422 ◽

Cited By ~ 7

Author(s):

R. A. Nyquist

Keyword(s):

Nuclear Magnetic Resonance ◽

Carbon Tetrachloride ◽

Magnetic Resonance ◽

Chemical Shift ◽

Vapor Phase ◽

Reference Frequency ◽

Substituted Anilines ◽

Nmr Chemical Shift ◽

Chemical Shift Data ◽

Shift Data

Infrared (IR) and/or Nuclear Magnetic Resonance (NMR) carbon-13 data are presented for 3- x and 4- x substituted anilines. Correlations are presented for the δ13C-1 chemical shift vs. Hammett δ p and δ m values, vasym., NH2 vs. δ13C-1, vsym. NH2 vs. δ13C-1, δ13C-1 vs. vasym. NH2, δ13C-1 vs. the absorbance ratio A( vasym. NH2/ A( vsym. NH2), and δ13C-l vs. Taft δ R°. The IR data for these compounds are recorded in the vapor phase, and in hexane, carbon tetrachloride, and chloroform solutions. The NMR chemical shift data for these compounds in solution with chloroform were obtained with the use of tetramethylsilane as the δ13C resonance reference frequency.

Download Full-text