Study of polymorphism and torsional motions in 3-chloro-4-methylaniline using 35Cl NQR (nuclear quadrupole resonance)

1992 ◽  
Vol 70 (2-3) ◽  
pp. 119-121 ◽  
Author(s):  
S. K. Roy ◽  
B. Amitha ◽  
J. Uchil
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
The Other ◽  
Temperature Coefficients ◽  
Β Phase ◽  
Time Out ◽  
Quadrupole Resonance ◽  
35Cl Nqr ◽  
Nuclear Quadrupole ◽  
Two Phases ◽  
First Time

35Cl nuclear quadrupole resonance (NQR) in three polymorphic phases of 3-chloro-4-methylaniline is detected for the first time. Out of these, two phases (α and γ) are stable and the other (β) is found to be metastable. The β phase is found to transform to the stable γ phase with respect to time. The formation of the β and γ phases are discussed in terms of defects and strains. The temperature dependence of NQR lines in the range 77–292 K in all three phases is studied in detail. On the basis of a modified Bayer's theory the torsional frequencies and their temperature coefficients are computed.

35Cl NQR Study of Guest Dynamics in Thiourea-CCl4 Inclusion Complex

1990 ◽  
Vol 45 (3-4) ◽  
pp. 519-522 ◽  
Author(s):  
Takasuke Matsuo ◽  
Masako Sekii ◽  
Hiroshi Suga ◽  
Nobuo Nakamura ◽  
Hideaki Chihara
Keyword(s):  
Activation Energy ◽  
Inclusion Complex ◽  
Nuclear Quadrupole Resonance ◽  
Intensity Ratio ◽  
Resonance Frequencies ◽  
Quadrupole Resonance ◽  
35Cl Nqr ◽  
Nuclear Quadrupole

Abstract35Cl nuclear quadrupole resonance measurements on thiourea-CCl4 inclusion complex yielded two resonance lines with intensity ratio 1:3. This indicates that the guest CCl4 molecule occupies the three-fold symmetry site in the channel formed by the thiourea framework. The resonance frequencies closely follow Bayer's equation between 4.2 K and 27 K. At higher temperatures the resonance lines faded out. This is attributed to the onset of reorientation of the CCl4 molecule. The activation energy for this motion was estimated to be 6 kJ mol-1 .

Temperature and Pressure Dependence of 35Cl Nuclear Quadrupole Resonance in BiCl3

1973 ◽  
Vol 51 (14) ◽  
pp. 2290-2291 ◽  
Author(s):  
G. C. Gillies ◽  
R. J. C. Brown
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Pressure Dependence ◽  
Constant Pressure ◽  
Temperature Coefficients ◽  
Quadrupole Resonance ◽  
Intermolecular Bonding ◽  
Temperature And Pressure ◽  
Nuclear Quadrupole ◽  
35Cl Nuclear Quadrupole Resonance ◽  
Volume Effects

The temperature and pressure dependences of the two 35Cl nuclear quadrupole resonances in BiCl3 have been measured. At constant pressure, the temperature coefficients are markedly different and this difference is shown to be due to volume effects associated with different intermolecular bonding.

An arsenic-75 nuclear quadrupole resonance study of α and β As4S3

1972 ◽  
Vol 25 (11) ◽  
pp. 2291 ◽  
Author(s):  
TJ Bastow ◽  
ID Campbell ◽  
HJ Whitfield
Keyword(s):  
Thermal Expansion ◽  
Temperature Dependence ◽  
Nuclear Quadrupole Resonance ◽  
Electrostatic Field ◽  
Β Phase ◽  
Field Gradients ◽  
Α Phase ◽  
Resonance Frequencies ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

The nuclear quadrupole resonance frequencies of 75As in the α and β forms of As4S3 have been measured at 77, 195, and 293 K. The frequencies at 77 K were: α phase 64.87 65.94 79.56 MHz β phase 65.42 67.16 79.65 MHz An analysis is presented in terms of Townes-Dailey theory and of the temperature dependence in terms of Bayer-Brown theory. The differences in frequencies of the α and β forms were attributed to the effect of electrostatic field gradients, estimated by lattice sums. Allowance must be made for the thermal expansion of the lattice to obtain a consistent interpretation.

Studies of the Substituent Effect in Aromatic Systems by Chlorine Nuclear Quadrupole Resonance (35Cl-NQR). Chloroanilinium Salts, [ClxC6Η5-xΝΗ3⊕]Χ⊖ with X⊖. =Cl⊖, Br⊖, etc.

1971 ◽  
Vol 26 (6) ◽  
pp. 555-560 ◽  
Author(s):  
W. Pies ◽  
Alarich Weiss
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Charge Distribution ◽  
Benzene Ring ◽  
Substituent Effect ◽  
Aromatic System ◽  
Quadrupole Resonance ◽  
35Cl Nqr ◽  
Aromatic Systems ◽  
Nuclear Quadrupole ◽  
Substituent Influence

The 35Cl-NQR spectra of 27 chloroanilinium salts, [ClxC6H5-xNH3⊕] X⊖, mainly chlorides and bromides, were investigated at 77 °K. The 35Cl-NQR frequencies were tentatively assigned to certain chlorine atoms at the benzene ring. The substituent influence of the — NH3⊕X⊖ group is discussed in terms of the NQR substituent parameter x. The electron attracting power of this group is clearly revealed. It decreases in the order ortho > meta > para of the substitution at the benzene ring with regard to the chlorine position. The substituent parameters x and σ(Hammett) are compared for the —NH3⊕X⊖ group and the — NH2 group. The anion in the anilinium salts, Xe, seems to have no influence on the charge distribution within the aromatic system.

Nutation Spectra of Nuclear Quadrupole Resonance in Off-Resonance Conditions

2004 ◽  
Vol 59 (4-5) ◽  
pp. 228-234 ◽  
Author(s):  
Nicolay Sinyavsky ◽  
Mariusz Mackowiak
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Chloral Hydrate ◽  
Experimental Spectrum ◽  
Optimal Filtration ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole ◽  
First Time

The modes of recording the multidimensional NQR nutation spectra have been analyzed using different off-resonance methods. A method of recording the nutation spectra in off-resonance conditions, based on optimal filtration, has been proposed. For the first time, an experimental spectrum of 3D-35Cl NQR nutation of chloral hydrate is presented.

1H - 17O Nuclear Quadrupole Double Resonance in DL-Proline

1990 ◽  
Vol 45 (5) ◽  
pp. 733-735 ◽  
Author(s):  
J. Seliger ◽  
V. Žagar ◽  
R. Blinc ◽  
P. K. Kadaba ◽  
D. Fiat
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Double Resonance ◽  
Unit Cell ◽  
The Other ◽  
Resonance Technique ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

Abstract 17O nuclear quadrupole resonance spectra have been measured in an 17O enriched polycristalline sample of DL-proline with the help of 1H - 17O nuclear quadrupole double resonance technique. The results show the presence of eight chemically inequivalent oxygen sites corresponding to four inequivalent proline molecules in the unit cell. The oxygen sites may be grouped into two sets of four sites. One set with the short proton-oxygen distances belongs to the C - O • • • H groups whereas the other with the long proton-oxygen distances to the C = O groups

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