The temperature dependence of the deuterium quadrupole coupling constant and the molecular rotational correlation time in liquid methanol

Complexing between the hexacyanocobaltate(III) anion and ten substituted phenols, eight substituted anilines, and eight substituted benzoic acids has been studied in dimethyl sulfoxide solutions by means of 59Co nmr. For the phenols substantial changes in the chemical shifts and in the line widths are observed and are attributed to hydrogen bonding interactions. Effective equilibrium constants and chemical shifts for the hydrogen bonded species have been calculated. The equilibrium constants vary with the phenol substituent, being largest for electron withdrawing substituents and smallest for electron donating substituents. The chemical shifts are virtually independent of substituent. The data show that the lifetimes of the hydrogen bonded complexes are long compared to the rotational correlation time. The complex with para-nitrophenol has also been studied by measuring 1H and 13C spin–lattice relaxation times. These measurements allow the separation of the increase in 59Co line width due to increase in correlation time and that due to increase in quadrupole coupling constant. From the 13C measurements a value of the correlation time for the complex of 2.8 10−1 s is obtained together with a 59Co quadrupole coupling constant of 8.34 MHz. The equilibrium constants for complex formation with the anilines are small and only the products of the equilibrium constant and the chemical shift of the hydrogen bonded complex can be derived from the experimental data. The benzoic acids show evidence of dimerization in solution and this again prevents the calculation of absolute equilibrium constants. The data, however, do indicate that the ability to form hydrogen bond complexes does not vary dramatically with the acid strength of the hydrogen donor. With phenols and benzoic acids there is considerable line broadening on complex formation but with anilines only a small line broadening is observed. This is consistent with very short hydrogen bond lifetimes for the aniline complexes.

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The Temperature Dependence of 121,123Sb, 35Cl, 79,81Br and 127I NQR Spectra in Complexes Cs3Sb2X9 (X = Cl, Br, I)

Zeitschrift für Naturforschung A ◽

10.1515/zna-2000-1-223 ◽

2000 ◽

Vol 55 (1-2) ◽

pp. 134-138 ◽

Cited By ~ 4

Author(s):

L. A. Zemnukhova ◽

S. I. Kuznetsov ◽

G. A. Fedorishcheva ◽

R. L. Davidovich

Keyword(s):

Electric Field ◽

Aqueous Solutions ◽

Electric Field Gradient ◽

Temperature Dependence ◽

Quadrupole Coupling Constant ◽

Coupling Constant ◽

Quadrupole Transition ◽

Quadrupole Coupling ◽

Coeffi Cients ◽

Constant E

The 123,123Sb, 35Cl, 79,81Br and 127I NQR Spectra of the complexes Cs3Sb2X9 (X = Cl, Br, I), prepared from CsX and SbX3 aqueous solutions, were studied at 77-400 K. Analysis of the^ temperature coeffi-cients of the quadrupole transition frequency (v), quadrupole coupling constant (e2Qqzz) and asymme-try parameter of the electric field gradient (η) was carried out.

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TEMPERATURE DEPENDENCE OF THE PURE NUCLEAR QUADRUPOLE RESONANCE FREQUENCY IN KClO3

Canadian Journal of Physics ◽

10.1139/p60-146 ◽

1960 ◽

Vol 38 (11) ◽

pp. 1397-1405 ◽

Cited By ~ 25

Author(s):

J. Vanier

Keyword(s):

Temperature Dependence ◽

Room Temperature ◽

Quadrupole Coupling Constant ◽

Nuclear Quadrupole Resonance Frequency ◽

Lattice Vibrations ◽

Coupling Constant ◽

Air Temperatures ◽

Quadrupole Coupling ◽

Quadrupole Resonance ◽

Nuclear Quadrupole

The resonant frequency of the Cl35 nuclear quadrupole in KClO3 has been measured as a function of temperature in the range 15 deg;K to 77 deg;K; previous work between 77 deg;K and room temperature has been confirmed. Comparison has been made with Bayer's theory based on lattice vibrations and agreement is excellent. The ratio of the quadrupole coupling constant eQqzz of the two isotopes (Cl35 and CI37) has been measured at room and liquid air temperatures; significant changes have been observed in the measurements. Finally the possibility of using this temperature dependence as the basis of a sensitive thermometer has been studied; the accuracy of such a thermometer would be ±0.005 deg;K at 60 deg;K and ±0.05 deg;K at 20 deg;K.

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Temperature Dependence of 14N NQR and Phase Transitions in KNO2 Powder

Zeitschrift für Naturforschung A ◽

10.1515/zna-1996-5-669 ◽

1996 ◽

Vol 51 (5-6) ◽

pp. 769-772 ◽

Cited By ~ 2

Author(s):

Hae Jin Kim ◽

Kee Tae Han ◽

Sung Ho Choh

Keyword(s):

Phase Transitions ◽

Temperature Dependence ◽

Asymmetry Parameter ◽

Quadrupole Coupling Constant ◽

Coupling Constant ◽

Nuclear Quadrupole Coupling Constant ◽

Quadrupole Coupling ◽

Two Temperatures ◽

Nuclear Quadrupole

Abstract The temperature dependence of 14N NQR, measured at 77 to 300 K, is in better agreement with the model proposed by Blinc et al. than the Bayer theory. The nuclear quadrupole coupling constant and asymmetry parameter show a discontinuity at about 160 K and 230 K, respectively. The linewidths are broadened at these temperatures up to 22 kHz and 18 kHz, respectively. These results indicate that KNO2 undergoes phase transitions at these two temperatures.

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Temperature Dependence of the123Sb Quadrupole Coupling Constant in CsSbCIF3

physica status solidi (b) ◽

10.1002/pssb.2221650131 ◽

1991 ◽

Vol 165 (1) ◽

pp. K13-K16

Author(s):

V. N. Rykovanov ◽

R. Sh. Lotfullin ◽

L. A. Zemnukhova ◽

A. A. Boguslavskii ◽

R. L. Davidovich

Keyword(s):

Temperature Dependence ◽

Quadrupole Coupling Constant ◽

Coupling Constant ◽

Quadrupole Coupling

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Temperature dependence of the 59Co quadrupole coupling constant in K3Co(CN)6

Canadian Journal of Physics ◽

10.1139/p80-011 ◽

1980 ◽

Vol 58 (1) ◽

pp. 68-73 ◽

Cited By ~ 4

Author(s):

J. A. J. Lourens ◽

E. Smit

Keyword(s):

Temperature Dependence ◽

Structural Phase ◽

Intermediate Frequency ◽

Quadrupole Coupling Constant ◽

Coupling Constants ◽

Positive Contribution ◽

Coupling Constant ◽

Quadrupole Coupling ◽

Bond Stretching ◽

Modes Of Vibration

Expressions are presented for calculating the effects of bond-stretching and rotational modes of vibration on the temperature dependence of quadrupole coupling constants in crystals. Contributions to the motional averaging of the electric field gradient tensor arising from point charges, point dipoles, and overlap of closed wave functions are evaluated and the resulting expressions applied to analyse the temperature variation of the 59Co quadrupole coupling constant in K3Co(CN)6. Both stretching and rotational internal modes of vibration of the Co(CN)6 octahedron had to be taken into account to analyse the data. In particular, an intermediate frequency mode of wavenumber 414 cm−1 has been found to make a substantial and positive contribution to the shift in coupling constant arising from the low (~ 100 cm−1) and intermediate frequency (~ 400 cm−1) modes. The remainder of the shift (~ 90%) has been attributed to a rotary mode of wavenumber 26 cm−1. The extracted temperature dependence of this mode points to the possible existence of a structural phase transition in K3Co(CN)6 below 100 K.

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