Proton magnetic resonance spectra of platinum(II) complexes. I. Pyramidal configuration and inversion at sulfur in cis-bis(dibenzyl sulfide)dichloroplatinum(II). Temperature and solvent effects on AB chemical shifts

1967 ◽  
Vol 89 (18) ◽  
pp. 4611-4616 ◽  
Author(s):  
Paul. Haake ◽  
Patricia C. Turley
Keyword(s):  
Magnetic Resonance ◽  
Solvent Effects ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Pyramidal Configuration ◽  
Dibenzyl Sulfide ◽  
In Cis ◽  
And Inversion ◽  
Magnetic Resonance Spectra

Proton magnetic resonance studies at 220 MHz of alanine transfer RNA

1969 ◽  
Vol 47 (4) ◽  
pp. 480-484 ◽  
Author(s):  
Ian C. P. Smith ◽  
Tetsuo Yamane ◽  
R. G. Shulman
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Transfer Rna ◽  
Magnetic Resonance Studies ◽  
The Common ◽  
Line Widths ◽  
Increasing Temperature ◽  
Magnetic Resonance Spectra

Proton magnetic resonance spectra at 220 MHz of alanine transfer RNA do not permit assignments of individual peaks due to each of the common bases; only a peak attributable to protons at position eight in adenine can be assigned with certainty. Measurements of the relative areas of proton magnetic resonance peaks due to the base and ribose-1′ protons indicate that the ribose moieties of tRNA are not involved in bonds stronger than those experienced by the bases. Proton magnetic resonance peaks attributable to the methyl and dihydro protons of the rare bases can be distinguished in the 220 MHz spectra; the variation of their line widths and chemical shifts with increasing temperature indicates that the rare bases are located in regions of the alanine transfer RNA molecule which are more highly organized than indicated by an open cloverleaf model.

Proton magnetic resonance spectra of some benzo[b]thiophens. An investigation of substituent effects in a heteroaromatic system

1968 ◽  
Vol 21 (7) ◽  
pp. 1853 ◽  
Author(s):  
B Caddy ◽  
M Martin-Smith ◽  
RK Norris ◽  
ST Reid ◽  
S Sternhell
Keyword(s):  
Magnetic Resonance ◽  
Long Range ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Spin Coupling ◽  
Heteroaromatic System ◽  
Spin Spin Coupling ◽  
Magnetic Resonance Spectra

N.m.r. data for 19 5-substituted and 13 polysubstituted benzo[b]thiophens are tabulated. The influence of the substituents at C5 on the chemical shifts of H4 and H6 is discussed. Long-range interproton spin-spin coupling between H3 and H7, and between H2 and H6, is general in benzo[b]thiophens. The vicinal coupling J6,7 in 5-substituted benzo[b]thiophens varies directly and linearly with the electronegativity of the substituents at C5.

Protonenresonanz-Spektroskopie ungesättigter Ringsysteme I

1965 ◽  
Vol 20 (10) ◽  
pp. 948-956 ◽  
Author(s):  
Harald Günther
Keyword(s):  
Magnetic Resonance ◽  
Concentration Dependence ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Electron System ◽  
Coupling Constants ◽  
Resonance Signal ◽  
Aromatic Character ◽  
Additional Support ◽  
Magnetic Resonance Spectra

The proton magnetic resonance spectra of 1.6-methano- and 1.6-oxido-cyclodecapentaene are described and analyzed in terms of chemical shifts and coupling constants. The results are discussed in connection with the structure and possible aromatic character of these compounds. Measurements of the concentration dependence of the chloroform resonance signal in solutions of both compounds give additional support for the presence of a delocalized 10 π-electron system.

SOLVENT EFFECTS IN THE NUCLEAR MAGNETIC RESONANCE SPECTRA OF BENZALMALONONITRILES

1965 ◽  
Vol 43 (9) ◽  
pp. 2585-2593 ◽  
Author(s):  
M. A. Weinberger ◽  
R. M. Heggie ◽  
H. L. Holmes
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Solvent Effects ◽  
Benzene Solution ◽  
Chemical Shifts ◽  
Olefinic Proton ◽  
Solvent Molecule ◽  
Nuclear Magnetic Resonance Spectra ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The nuclear magnetic resonance spectra of a series of substituted benzalmalononitriles were examined in various solvents. The chemical shifts for the olefinic protons are susceptible to large solvent effects which are interpreted as arising from association of a solvent molecule with the olefinic proton (acetone) or a site in its vicinity (benzene). With acetone this leads to a downfield shift from values observed in chloroform. In benzene solution the association produces increased shielding and is present in addition to a second solvation complex, the arrangement of which is governed by the substituent. The difference in behavior of the ethylenic proton in benzalmalononitriles from the formyl proton in benzaldehyde is ascribed to its more highly acidic nature.

The analysis of the proton magnetic resonance spectra of heteroaromatic systems. V. Diazanaphthalenes

1965 ◽  
Vol 18 (5) ◽  
pp. 707 ◽  
Author(s):  
PJ Black ◽  
ML Heffernan
Keyword(s):  
Carbon Tetrachloride ◽  
Magnetic Resonance ◽  
Long Range ◽  
Iterative Procedure ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Direct Calculation ◽  
Coupling Constants ◽  
Dilute Solutions ◽  
Magnetic Resonance Spectra

The proton magnetic resonance spectra of the four isomeric diazanaphthalenes, quinoxaline, phthalazine, quinazoline, and cinnoline, all as dilute solutions in carbon tetrachloride and acetone, have been investigated at 100 Mc/s. The chemical shifts and coupling constants have been obtained by direct calculation or, where appropriate, by an iterative procedure. Long-range coupling constants between protons separated by five and six bonds have been observed.

Proton magnetic resonance spectra of 3,4-dehydroproline derivatives

1966 ◽  
Vol 19 (1) ◽  
pp. 115 ◽  
Author(s):  
LF Johnson ◽  
AV Robertson ◽  
WRJ Simpson ◽  
B Witkop
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Deuterium Oxide ◽  
Methyl Esters ◽  
Amide Bond ◽  
Order Analysis ◽  
System A ◽  
Full Analysis ◽  
Magnetic Resonance Spectra

Slight changes in the chemical shifts of protons in 3,4-dehydroproline derivatives cause the appearance of their proton magnetic resonance spectra to change markedly, and this can be effected by taking one compound in two different solvents or by observing closely related derivatives in the same solvent. The explanation involves a previously undescribed type of deceptively simple coupling and the necessary conditions are discussed. A first-order analysis of the ABMXX' pattern for 3,4-dehydroprolinamide in deuterium oxide is given. A full analysis is made of the ABXX' and ABXY patterns for this amide in deuterium oxide and deuterochloroform respectively after deuterium exchange of the labile H2; a very large homoallylic coupling is required. Two conformations exist at 40� in solution for all N-benzyloxycarbonyl methyl esters of proline and its derivatives due to restricted rotation about the amide bond. Free rotation of the amide bond of corresponding N-acetyl and AT-benzoyl derivatives still occurs at -50�. The deceptively simple spectrum of N-benzyloxycarbonyl-2,5-dihydroxy-Δ3-pyrolne is discussed and that of its diacetate is analysed as an A2X2 system; a very small homoallylic coupling is required.

Proton magnetic resonance spectra of indolizine and its methyl derivatives and aza analogues

1964 ◽  
Vol 17 (10) ◽  
pp. 1128 ◽  
Author(s):  
PJ Black ◽  
ML Heffernan ◽  
LM Jackman ◽  
QN Porter ◽  
GR Underwood
Keyword(s):  
Magnetic Resonance ◽  
Long Range ◽  
Iterative Procedure ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Methyl Derivatives ◽  
Magnetic Resonance Spectra

The proton magnetic resonance spectra of indolizine, indolizine-1,3-d2, 1- and 2-methylindolizine, 2,3-, 2,5-, 2,6-, and 2,7-dimethylindolizine and 1-, 2-, and 3-azaindolizine have been determined at 100 and/or 60 Mc/s. Unequivocal assignments have been made to all protons and the coupling constants and chemical shifts for indolizine and its aza analogues have been obtained by an iterative procedure. Long-range coupling constants involving protons separated by five and six bonds have been observed.

Carbon-13 Magnetic Resonance: the Stereochemistry of 1,2- and 1,3-Dimethyl-4-phenylpiperidine Derivatives

1973 ◽  
Vol 51 (11) ◽  
pp. 1782-1789 ◽  
Author(s):  
Alan J. Jones ◽  
A. F. Casy ◽  
K. M. J. McErlane
Keyword(s):  
Magnetic Resonance ◽  
Conformational Change ◽  
Solvent Effects ◽  
Chemical Shifts ◽  
Phenyl Group ◽  
Steric Effects ◽  
Methyl Group ◽  
Charge Polarization ◽  
Magnetic Resonance Spectra

The carbon-13 magnetic resonance spectra of the diastereoisomers of 1,2-dimethyl- (1) and 1,3-dimethyl-4-phenylpiperidin-4-ol (2), their esters and corresponding hydrochlorides have been determined. The observed chemical shifts can be ascribed to charge polarization or steric effects. The latter is particularly important in establishing the axial configuration of the 4-phenyl group and 3-methyl group in the preferred conformations of α-1 and β-2, respectively, and consequently the stereochemistry of these systems. Substituent additivity effects are similar to those in the piperidones and cyclohexanes. Solvent effects on 13C resonances remove the ambiguities of conformational change suggested in earlier proton studies.

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