Proton nuclear magnetic resonance spectroscopic studies of aromatic hydrocarbons: induced paramagnetic ring-current in the four-membered ring of biphenylene and related hydrocarbons

1967 ◽  
pp. 495 ◽  
Author(s):  
H. P. Figeys
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Aromatic Hydrocarbons ◽  
Ring Current ◽  
Spectroscopic Studies ◽  
Membered Ring ◽  
Proton Nuclear Magnetic Resonance ◽  
Nuclear Magnetic

Synthesis of Methyl-5,6,11,12-tetrahydrodibenzo[a,e]cyclooctenols and a conformational study by proton nuclear magnetic resonance

1983 ◽  
Vol 36 (3) ◽  
pp. 517 ◽  
Author(s):  
KE White ◽  
BJ Slater ◽  
SH Graham
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Membered Ring ◽  
Proton Nuclear Magnetic Resonance ◽  
Boat Conformation ◽  
Geminal Proton ◽  
Twist Boat ◽  
Axial Site ◽  
Nuclear Magnetic

A series of methyl-5,6,11,12-tetrahydrodibenzo[a,e]cycloocten-5-ols were synthesized, and their conformations assigned by means of proton nuclear magnetic resonance. Placing substituents in three of the four available sites on the eight-membered ring enabled the chemical shifts of the geminal proton to be observed. It was found that the three sites have intrinsic chemical shifts. The compounds studied were found to populate a twist-boat conformation, with bulky substituents preferentially populating the axial site.

A proton nuclear magnetic resonance relaxation study of the glycine, alanine, and lactate complexes of gadolinium(III) in aqueous solution

1987 ◽  
Vol 65 (7) ◽  
pp. 1508-1512 ◽  
Author(s):  
R. Stephen Reid ◽  
Benjamin Podányi
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Membered Ring ◽  
Proton Nuclear Magnetic Resonance ◽  
Proton Relaxation ◽  
Carboxylate Group ◽  
Relaxation Rates ◽  
Spin Lattice ◽  
Resonance Spin ◽  
Nuclear Magnetic

The 1H nuclear magnetic resonance spin-lattice and spin–spin relaxation rate enhancements induced by the gadolinium(III) ion were measured in solutions of glycine, alanine, and sodium lactate containing different amounts of Gd(III). The proton relaxation rates in the Gd(III) complexes were calculated from these data, and were used to calculate metal–hydrogen atom distances. Comparison of these data with corresponding distances calculated from literature X-ray crystallographic data for model compounds shows that in the two amino acid complexes the Gd(III) ion is coordinated in a four-membered ring through the two oxygen atoms of the carboxylate group. By contrast, in the lactate complex coordination is via a five-membered ring involving one oxygen atom of the carboxylate group and the α-hydroxyl oxygen.

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