Chlorine Nuclear Quadrupole Resonance Spectra of 1-Substituted 2-Chloropolyfluorocycloalkenes

1974 ◽  
Vol 52 (20) ◽  
pp. 3484-3488 ◽  
Author(s):  
Lian Sai Chia ◽  
William R. Cullen ◽  
Michael C. L. Gerry ◽  
Poh Siew Yiaw
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Ring Size ◽  
Temperature Coefficients ◽  
Mean Temperature ◽  
Resonance Frequencies ◽  
Quadrupole Resonance ◽  
The Mean ◽  
Nuclear Quadrupole

Chlorine nuclear quadrupole resonance frequencies are reported for the compounds [Formula: see text] (n = 2,3,4; Y = H, CH3, C2H5, Si(CH3)3, F. OCH3, N3, NR2, Cl, SCH3, P(C6H5)2, As(CH3)2, Mn(CO)5, π-C5H5Fe(CO)2, but not all combinations). The values range from 38.999 MHz (n = 3; Y = F) to 34.668 MHz (n = 2; Y = π-C5H5Fe(CO)2) and are roughly related to the electronegativity of Y and to the ring size. The mean temperature coefficients of the frequencies lie in the range −0.9 × 10−4 to −8 × 10−4/°K.

scholarly journals Rapid Survey of Nuclear Quadrupole Resonance by Broadband Excitation with Comb Modulation and Dual-Mode Acquisition

2020 ◽  
Author(s):  
Yuta Hibe ◽  
Yasuto Noda ◽  
K. Takegoshi ◽  
Kazuyuki Takeda
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Frequency Comb ◽  
Spin Dynamics ◽  
Signal Acquisition ◽  
Dual Mode ◽  
Rapid Scan ◽  
Resonance Frequencies ◽  
Wide Range ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

Nuclear Quadrupole Resonance (NQR) provides spectra carrying information as to the electric-field gradient around nuclei with a spin quantum number I > 1/2 and offers helpful clues toward characterizing the electronic structure of materials of chemical interest. A major challenge in NQR is finding hitherto unknown resonance frequencies, which can scatter over a wide range, requiring time consuming repetitive measurements with stepwise frequency increments. Here, we report on an efficient, two-step NQR protocol by bringing rapid-scan and frequency-comb together. In the first step, wideband excitation and simultaneous signal acquisition, both realized by a non-adiabatic, frequency-swept hyperbolic secant (HS) pulse with comb modulation, offers a clue for the existence/absence of the resonance within the frequency region under investigation. When and only when the sign of the resonance has been detected, the second step is implemented to compensate the limited detection bandwidth of the first and to unambiguously determine the NQR frequency. We also study the spin dynamics under the comb-modulated HS pulse by numerical simulations, and experimentally demonstrate the feasibility of the proposed scheme, which is referred to as RApid-Scan with GApped excitation with Dual-mode Operation (RASGADO) NQR<br>

Nuclear Quadrupole Resonance Studies of Chelated Antimony Complexes. Part III. The Carboxylates: RCO2SbCl4

1986 ◽  
Vol 41 (1-2) ◽  
pp. 179-185
Author(s):  
Claudine Gerard-Dion ◽  
Joyce Rupp-Bensadon ◽  
Edwin A. C. Lucken
Keyword(s):  
Phase Change ◽  
Nuclear Quadrupole Resonance ◽  
Chlorine Atoms ◽  
Resonance Frequencies ◽  
Quadrupole Resonance ◽  
Antimony Complexes ◽  
Quantitative Basis ◽  
Nuclear Quadrupole ◽  
The Difference

The 35Cl, 121Sb and 123Sb resonance frequencies for seventeen tetrachloro(carboxylato)antimony V compounds, RCO2SbCl4, are reported. The results confirm the difference in the effects of the substituent on the equatorial chlorine atoms and the axial chlorine atoms of the SbCl4 group, previously remarked in Parts I and II of this series, and this effect has been put on a more quantitative basis by correlating the observed frequencies with the pK’s of the corresponding acids.The compounds with R = isopropyl and R = cyclopropyl both show a phase change in the region of 140 K which may correspond to reorientation of the substituent about the R - CO2 axis.

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