Faraday communications. Carbon–halogen second-order quadrupolar and indirect spin–spin coupling effects in high-resolution solid-state13C NMR spectra of halobenzenes

1994 ◽  
Vol 90 (24) ◽  
pp. 3729-3730 ◽  
Author(s):  
Abil E. Aliev ◽  
Kenneth D. M. Harris ◽  
Patrick J. Barrie ◽  
Stéphanie Camus
Keyword(s):  
High Resolution ◽  
Nmr Spectra ◽  
Second Order ◽  
Spin Coupling ◽  
Coupling Effects ◽  
Spin Spin Coupling

Heteronuclear second-order coupling effects in high-resolution Tin NMR spectra

1981 ◽  
Vol 43 (3) ◽  
pp. 488-490
Author(s):  
Claude R Lassigne ◽  
E.J Wells ◽  
Louis J Farrugia ◽  
Brian R James
Keyword(s):  
High Resolution ◽  
Nmr Spectra ◽  
Second Order ◽  
Coupling Effects

Article

1999 ◽  
Vol 77 (11) ◽  
pp. 1962-1972
Author(s):  
Scott Kroeker ◽  
Roderick E Wasylishen
Keyword(s):  
Nmr Spectra ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Spin Coupling ◽  
Group Symmetry ◽  
Magic Angle ◽  
Chemical Shielding ◽  
Shielding Tensor ◽  
Angle Spinning ◽  
Spin Spin Coupling

Direct NMR observation of copper-63/65 nuclei in solid K3Cu(CN)4 provides the first experimental example of anisotropic copper chemical shielding. Axially symmetric by virtue of the space group symmetry, the shielding tensor spans 42 ppm, with the greatest shielding when the unique axis is perpendicular to the applied magnetic field. The nuclear quadrupole coupling constant is also appreciable, CQ(63Cu) = -1.125 MHz, reflecting a deviation of the Cu(CN)43- anion from pure tetrahedral symmetry. Spin-spin coupling to 13C nuclei in an isotopically enriched sample is quantified by line-shape simulations of both 13C and 63/65Cu magic-angle spinning (MAS) NMR spectra to be 300 Hz. It is shown that this information is also directly available by 63/65Cu triple-quantum (3Q) MAS NMR. The relative merits of these three approaches to characterizing spin-spin couplings involving half-integer quadrupolar nuclei are discussed. Chemical shielding tensors for nitrogen-15 and carbon-13 are obtained from NMR spectra of non-spinning samples, and are compared to those of tetrahedral group 12 tetracyanometallates. Finally, 2J(63/65Cu,15N) detected in 15N MAS experiments are found to be 19 and 20 Hz for the two crystallographically distinct cyanide ligands.Key words: NMR, quadrupolar nucleus, chemical shielding tensor, multiple-quantum magic-angle spinning, metal cyanide, spin-spin coupling.

Nuclear spin coupling effects in phosphorus-31 MAS NMR spectra of solid bis(triphenylphosphine)(phenylcyanamido)copper(I) complexes

1992 ◽  
Vol 96 (19) ◽  
pp. 7560-7567 ◽  
Author(s):  
John V. Hanna ◽  
Mark E. Smith ◽  
S. N. Stuart ◽  
Peter C. Healy
Keyword(s):  
Nuclear Spin ◽  
Nmr Spectra ◽  
Mas Nmr ◽  
Spin Coupling ◽  
Coupling Effects

NMR spectra, MO calculations of spin-spin coupling constants and conformational analysis of substituted 1,3-dioxolanes

1980 ◽  
Vol 13 (1) ◽  
pp. 17-25 ◽  
Author(s):  
Rois Benassi ◽  
Luisa Schenetti ◽  
Ferdinando Taddei ◽  
Luigi Villa ◽  
Vincenzo Ferri
Keyword(s):  
Conformational Analysis ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Mo Calculations ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

11B-NMR-Spektren von Alkyl-, Halogeno- und Rhodanohydrohexaboraten / 11B NMR Spectra of Alkyl-, Halogeno- and Rhodanohydrohexaborates

1988 ◽  
Vol 43 (12) ◽  
pp. 1647-1652 ◽  
Author(s):  
A. Heinrich ◽  
W. Preetz ◽  
H. C. Marsmann
Keyword(s):  
Temperature Dependence ◽  
Nmr Spectra ◽  
Spin Coupling ◽  
Bronsted Acids ◽  
11B Nmr ◽  
Spin Spin Coupling

Abstract The temperature dependence of the 11B NMR spectra of the monosubstituted and protonated c/oso-hexaborates RB6H6-, R=CH3, C2H5, C3H7, C4H9 C8H17, (SCN)B6H6- and XB6H6 X = Cl. Br. I, has been determined in the range 180-300 K. The extra proton migrates at higher temperatures intramolecularly, probably across the edges of the B6 core. The extra proton is fixed to a facet of the octahedron below the coalescence temperatures 240 K (RB6H6-) and 210 K (XB6H6-) as recognized by the splitting of the signal of the equatorial B atoms due to the lowering of the symmetry from C4v to Cs . From the spin-spin coupling it can be deduced that the proton prefers with the softer Brönsted acids RB6H6- facets adjacent to the substituent, while with the stronger Brönsted acids XB6H6- facets including the antipodal B atom are occupied.

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