Chlorine nuclear quadrupole resonance in mercury chlorides and complex chlorides

1971 ◽  
Vol 24 (9) ◽  
pp. 1753 ◽  
Author(s):  
DE Scaife
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Covalent Bonding ◽  
Distorted Octahedral ◽  
Resonance Frequencies ◽  
Quadrupole Resonance ◽  
Unknown Structure ◽  
Linear Molecules ◽  
Nuclear Quadrupole ◽  
Solid Compounds

Chlorine nuclear quadrupole resonance frequencies are reported for solid compounds of known structure containing linear molecules HgCl2 and Hg2Cl2, approximately trigonal HgCl3-, and a variety of distorted octahedral forms including NH4HgCl3, CsHgCl3, and K2HgCl4,H2O. Compounds of unknown structure of the type (cation+)HgCl3, (cation+)2HgCl4, (cation+)Hg2Cl5, (cation+)2Hg9Cl20, and (cation+)4HgCl6 have also been studied. There are clear correlations between observed n.q.r. frequencies and Hg-Cl infrared stretching frequencies and bond distances. These correlations show the dependence of the degree of covalent bonding in the Hg-Cl bond with distance. The n.q.r. data confirm that many of the complex chlorides of mercury are built up by the joining of octahedral HgCl6 units, distorted in such a way as to preserve to varying extents the identity of the HgCl2 molecule. ��� Predictions of the structures are made for some complex chlorides of unknown structure, and the role of bridging in building up the compounds is discussed in terms of observed n.q.r. data for bridging chlorines.

Chlorine nuclear quadrupole resonance in some chloro complexes of divalent copper

1971 ◽  
Vol 24 (10) ◽  
pp. 1993 ◽  
Author(s):  
DE Scaife
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Covalent Bonding ◽  
Divalent Copper ◽  
Chloro Complexes ◽  
35Cl Nucleus ◽  
Square Planar ◽  
Bonding Interaction ◽  
Quadrupole Resonance ◽  
Square Planar Complexes ◽  
Nuclear Quadrupole

Nuclear quadrupole resonance for the 35Cl nucleus has been observed in some chloro complexes of divalent copper. Square-planar complexes each show two resonance lines, with the following frequencies (at 77�K): (CH3NH3)2CuCl4, 10.780, 12.157 MHz; (C2H5NH3)2CuCl4, 10.817, 12.074 MHz; (enH2)CuCl4, 10.271, 11.901 MHz; and (C3H7NH3)2CuCl4 at 223�K, 11.290 and 11.781 MHz. NH4CuCl3, containing dimeric Cu2Cl62- units, has resonances, at 77�K, at 11.907, 11.993, and 12.448 MHz. The trigonal pyramidal anion in Co(NH3)6CuCl5 has two resonances at 9.642 and 10.352 MHz at 77�K. ��� These results are compared with previous results for copper chloro complexes, and the implications of covalent bonding are discussed. In particular, it is suggested that the long-bond interaction between units in square-planar complexes amounts to 7-16% of the bonding interaction within the units.

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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