The effects of high temperatures (29–123 °C) on critical micelle concentrations in solutions of potassium n-octanoate in deuterium oxide: A nuclear magnetic resonance study

1986 ◽  
Vol 64 (9) ◽  
pp. 1823-1828 ◽  
Author(s):  
M. A. Desando ◽  
L. W. Reeves
Keyword(s):  
Chemical Shifts ◽  
Deuterium Oxide ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Nuclear Magnetic Resonance Study ◽  
Spin Lattice Relaxation ◽  
Spectral Parameters ◽  
Critical Micelle Concentrations ◽  
Temperature Range ◽  
Spin Lattice

Critical micelle concentrations have been determined for potassium n-octanoate in deuterium oxide over a wide temperature range, 29–123 °C, from the concentration dependence of proton nmr spectral parameters (peak positions, and vicinal splitting values of the α-CH2 multiplet) and carbon-13 nmr chemical shifts. The c.m.c. varies from ca. 0.30 m at ca. 30 °C to ca. 0.50 m at ca. 120 °C and is at a minimum (0.30–0.35 m) in the temperature range ca. 30–50 °C. 23Na+ spin-lattice relaxation times reveal that a co-counterion (Na+) different from that of the surfactant counterion (K+) reflects the micellization process. A second critical micelle concentration has been observed around 1.0 m at ca. 30 °C.

A nuclear magnetic resonance study of 1H, 23Na, and 31P relaxation and molecular dynamics in the sodium salts of some pyrophosphates

1989 ◽  
Vol 67 (6) ◽  
pp. 592-598 ◽  
Author(s):  
E. C. Reynhardt
Keyword(s):  
Relaxation Times ◽  
Lattice Relaxation ◽  
Laboratory Frame ◽  
Nuclear Magnetic Resonance Study ◽  
Spin Lattice Relaxation ◽  
Molecular Reorientation ◽  
Temperature Range ◽  
Spin Lattice ◽  
Second Moments ◽  
31P Relaxation

Proton second moments and spin-lattice relaxation times in the laboratory and rotating frames and 31P and 23Na spin-lattice relaxation times in the laboratory frame have been measured over the temperature region 295 > T > 100 K for the sodium pyrophosphate salts, Na2P2O7∙10H2O and Na2H2P2O7. Laboratory-frame 31P and 23Na spin-lattice relaxation times have also been measured over the same temperature range for Na4P2O7. In the case of Na4P2O7∙10H2O, the results show clearly that the H2O molecules execute a twofold jump motion at higher temperatures. The potential barriers to these motions range from 30 to 40 kJ/mol. The 31P and 23Na relaxations are also influenced by these motions. The [Formula: see text] ion in Na2H2P2O7 is stationary over the temperature range studied. T1(Na) is most probably dominated by acoustical lattice vibrations. The [Formula: see text] ion in Na4P2O7 is not involved in a molecular reorientation. A shallow T1(P) minimum of 55 s is associated with a limited motion of the pyrophosphate molecule.

Carbon-13 NMR and Raman Scattering Studies of Potassium Propoxybenzoate and Potassium Butoxybenzoate. Conformational Change Due to Micellization

1981 ◽  
Vol 36 (12) ◽  
pp. 1352-1356
Author(s):  
Hirofumi Okabayashi ◽  
Tadayoshi Yoshida ◽  
Yukimasa Terada ◽  
Teruki Ikeda ◽  
Kazuhiro Matsushita
Keyword(s):  
Conformational Change ◽  
Chemical Shifts ◽  
Deuterium Oxide ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Alkoxy Group ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Methylene Groups

Abstract Carbon-13 NMR chemical shifts and carbon-13 spin-lattice relaxation times of potassium propoxybenzoate and potassium butoxybenzoate in deuterium oxide solution were measured at various concentrations. For the alkoxy group, the earbon-13 resonance peak of the O-CH2 segment is shifted rapidly up-field upon micellization, while the resonance peaks of other methylene groups are shifted downfield. This observation is ascribed to the conformational change of the alkoxy group on micellization. In the monomolecular solution of potassium butoxybenzoate, the restricted state of the O-CH2 bond was estimated by carbon-13 spin-lattice relaxation time measurement. It was also found that micellization brings about a further restricted internal rotation about the O-CH2 bond.

NQR Relaxation Studies on Halogenomethyl Groups in Halogenoacetates

1998 ◽  
Vol 53 (6-7) ◽  
pp. 480-483 ◽  
Author(s):  
Maria Zdanowska-Fnjczek
Keyword(s):  
Room Temperature ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Effect Of Temperature ◽  
Relaxation Theory ◽  
Temperature Range ◽  
Spin Lattice ◽  
Relaxation Studies

Abstract The effect of temperature on the chlorine NQR spin-lattice relaxation times in CsH(ClH2-CCOO)2 , KH(Cl3 CCOO) 2 and N(CH3)4 H(ClF2CCOO)2 has been studied in the temperature range 77 K to room temperature. The results were discussed on the basis of NQR relaxation theory.

Conformation of ring A in triterpenoid ketones. Carbon-13 chemical shifts and spin-lattice relaxation times of lupane and 18α-oleanane derivatives

1989 ◽  
Vol 54 (7) ◽  
pp. 1928-1939 ◽  
Author(s):  
Miloš Buděšínský ◽  
Jiří Klinot
Keyword(s):  
Chemical Shifts ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Chair Conformation ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Structural Assignment ◽  
Boat Form ◽  
The One ◽  
C Nmr

13C NMR spectra of sixteen lupane and 19β,28-epoxy-18α-oleanane triterpenoids I-XVI were measured and a complete structural assignment of chemical shifts was made. For most compounds also the carbon spin-lattice relaxation times T1 were obtained. Characteristic differences in chemical shifts of some carbon atom signals were found between 2α-methyl-3-oxo and 2α-methyl-1-oxo derivatives II, V and VIII with chair conformation of the ring A on the one hand and their 2β-isomers III, VI and IX (boat form) on the other. Using these 2-methyl ketones as models, the chair-boat population in allobetulone (I), 3-oxo-28-lupanenitrile (IV) and 1-oxo derivative VII was determined. The results agree well with the data obtained by other physical methods.

Germanium-73 chemical shifts and spin-lattice relaxation times of some tetrasubstituted germanes

1984 ◽  
Vol 23 (23) ◽  
pp. 3835-3836 ◽  
Author(s):  
Yoshito Takeuchi ◽  
Toshie Harazono ◽  
Norihiro Kakimoto
Keyword(s):  
Chemical Shifts ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Spin Lattice

Synthesis of Multifunctional, Nonionic Vinyl Polymers and Their13C Spin-Lattice Relaxation Times in Deuterium Oxide Solutions

1996 ◽  
Vol 29 (16) ◽  
pp. 5375-5383 ◽  
Author(s):  
Takehisa Matsuda ◽  
Takashi Sugawara
Keyword(s):  
Deuterium Oxide ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Vinyl Polymers

13C Fourier transform nuclear magnetic resonance. XII. Structure of the phytol–lecithin bilayer. Application of electric field effects

1976 ◽  
Vol 54 (13) ◽  
pp. 2059-2067 ◽  
Author(s):  
Robert J. Cushley ◽  
Bruce J. Forrest
Keyword(s):  
Electric Field ◽  
Chemical Shifts ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Hydrocarbon Chain ◽  
Spin Lattice Relaxation ◽  
Head Group ◽  
Electric Field Effect ◽  
Spin Lattice ◽  
Lipid Head Group

Phytol has been incorporated into lecithin bilayers. 13C spin–lattice relaxation times, which have been measured for both components of the model membrane, indicate a marked destabilization of the bilayer due to intercalated phytol. The disruption of normal phospholipid packing is due to the highly branched nature of the phytyl hydrocarbon chain. In addition, the position of phytol in the bilayer has been determined by means of a linear electric field effect of the polar lipid head group upon the 13C chemical shifts of the phytol olefinic carbons.

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