A solid-state 31P NMR study of 1:1 silver–triphenylphosphine complexes — Interpretation of 1J(107,109Ag,31P) values,

2009 ◽  
Vol 87 (7) ◽  
pp. 1090-1101 ◽  
Author(s):  
Fu Chen ◽  
Se-Woung Oh ◽  
Roderick E. Wasylishen
Keyword(s):  
Solid State ◽  
Spin Coupling ◽  
Coupling Mechanism ◽  
P Values ◽  
X Ray Crystallography ◽  
Phosphine Complexes ◽  
Nmr Study ◽  
Fermi Contact ◽  
Spin Spin Coupling ◽  
Cp Mas Nmr

High-resolution solid-state 31P NMR spectroscopy was used to investigate a series of 1:1 silver–triphenylphosphine complexes, [Ph3PAgX]n, where X is a monovalent anion and n = 1, 2, 3, 4, or ∞. The 31P CP MAS NMR spectra reveal the number of distinct phosphorus sites in these complexes as well as the |1J(109Ag,31P)| values, which range from 401 ± 10 Hz (X = N3–) to 869 ± 10 Hz (X = SO3CF3–). The data obtained here and in earlier investigations indicate that |1J(109Ag,31P)| values for silver–tertiary phosphine complexes decrease as Ag–P bond lengths increase. This experimental conclusion is supported by DFT calculations, which also indicate that the Fermi-contact mechanism is the only important spin–spin coupling mechanism for 1J(109Ag,31P) in these complexes. In addition, the crystal structure of a silver–triphenylphosphine trifluoroacetate tetramer was determined using X-ray crystallography, and the structure of a silver–triphenylphosphine chloride tetramer was reinvestigated.

X-ray diffraction, Raman spectroscopic, and solid-state NMR studies of the group 14 metal-(tetracarbonyl)cobalt complexes Ph3MCo(CO)4 (M = Si, Sn, Pb)

2002 ◽  
Vol 80 (7) ◽  
pp. 813-820 ◽  
Author(s):  
J M Geller ◽  
J H Wosnick ◽  
I S Butler ◽  
D FR Gilson ◽  
F G Morin ◽  
...  
Keyword(s):  
Solid State ◽  
Spin Coupling ◽  
Chemical Shift Tensor ◽  
Coupling Constant ◽  
X Ray Diffraction ◽  
Group 14 ◽  
X Ray ◽  
Fermi Contact ◽  
Spin Spin Coupling ◽  
Cp Mas Nmr

Single-crystal X-ray diffraction studies illustrate that the three title compounds are isomorphous, belonging to the triclinic space group P[Formula: see text], with slightly distorted trigonal bipyramidal geometry about cobalt. The solid-state 29Si, 119Sn, and 207Pb cross-polarization magic angle spinning (CP MAS) NMR spectra are presented. The indirect spin–spin coupling constant (J), quadrupolar–dipolar shift (d), direct dipolar coupling constant (D' ), anisotropy in spin–spin coupling (ΔJ), and the chemical shift tensor were extracted. A plot of the reduced coupling constant vs. s-electron densities at the nucleus indicates that the Fermi contact term may be dominant for the tin and lead complexes; however, the large ΔJ for all complexes indicate that there are also significant anisotropic terms. Trends in the Raman scattering spectra are also discussed.Key words: 29Si, 119Sn, and 207Pb CP MAS NMR, tetracarbonyl cobalt, spin–spin coupling, chemical shift tensor, quadrupole coupling, Fermi contact, cobalt–group 14.

scholarly journals Probing interactions through space using spin–spin coupling

2014 ◽  
Vol 43 (17) ◽  
pp. 6548-6560 ◽  
Author(s):  
Martin W. Stanford ◽  
Fergus R. Knight ◽  
Kasun S. Athukorala Arachchige ◽  
Paula Sanz Camacho ◽  
Sharon E. Ashbrook ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Spin Coupling ◽  
X Ray ◽  
Solid State Nmr Spectroscopy ◽  
X Ray Crystallography ◽  
B3lyp Calculations ◽  
Spin Spin Coupling

A series of eight 5-(TeAr)-6-(SePh)acenaphthenes (Ar = aryl) were prepared and structurally characterised by X-ray crystallography, solution and solid-state NMR spectroscopy and DFT/B3LYP calculations.

scholarly journals Spin-Spin Coupling Constants 1J(15N,11B) in Boron-Nitrogen Compounds. Experimental Data and DFT Calculations

2007 ◽  
Vol 62 (2) ◽  
pp. 220-224 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Oleg L. Tok
Keyword(s):  
Experimental Data ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Positive Sign ◽  
Nitrogen Compounds ◽  
Dft Methods ◽  
Spin Coupling Constants ◽  
Fermi Contact ◽  
Spin Spin Coupling ◽  
Boron Nitrogen

Boron-nitrogen compounds were studied with respect to indirect nuclear 15N-11B spin-spin coupling (1J(15N,11B)). Some new experimental data were determined for aminoboranes and tetra-Npyrrolylborate, and a variety of compounds with B-N single, double and triple bonds were examined using DFT methods for the calculation of 1J(15N,11B) at the B3LYP/6-311+G(d,p) level of theory. The calculations predict magnitude and sign of 1J(15N,11B) reasonably well, and the Fermi contact term was found to be dominant. A positive sign of 1J(15N,11B) was calculated in the case of 1-azacloso- dodecaborane(12), in contrast to all other compounds studied.

Experimental and Theoretical-Study of Carbon-Fluorine Couplings in the NMR-Spectra of 2-Fluoroaryl Ketones

1985 ◽  
Vol 38 (12) ◽  
pp. 1779 ◽  
Author(s):  
RH Contreras ◽  
CG Giribet ◽  
MA Natiello ◽  
J Perez ◽  
ID Rae ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Side Chain ◽  
Aliphatic Carbon ◽  
Spin Coupling Constants ◽  
Fermi Contact ◽  
Spin Spin Coupling ◽  
Fermi Contact Term ◽  
Good Agreement

Calculations by the IPPP-INDO method give the spin-spin coupling constants for the side-chain carbons, 3JCF and 4JCF, as 4.97 and 6.86 Hz respectively with substantial contributions to through-space coupling from the pathway CO-C-H…F. The observed values for 1-(2- fluorophenyl ) ethanone , 3.3 and 7.2 Hz, and for 1-(2,5- difluorophenyl ) ethanone , 3.7 and 7.3 Hz, are in good agreement with these predictions. Two compounds, a dihydroindenone and a naphthalenone, in which this pathway cannot be effective, show no fluorine coupling to the aliphatic carbon next to the carbonyl and the values of 3JCF are reduced to 2.2 and 2.5 Hz, consistent with the loss of a through-space Fermi contact term of the kind described above.

scholarly journals One and Multiple Bonds Interatomic Spin-Spin Coupling inη6-Cymene Ru(II) of 3,5-Dimethyl-, 3,5-Dicarboxylic-, and 5-Phenyl-pyrazole Derivatives

2015 ◽  
Vol 2015 ◽  
pp. 1-11
Author(s):  
Adebayo A. Adeniyi ◽  
Peter A. Ajibade
Keyword(s):  
Ruthenium Complexes ◽  
Spin Coupling ◽  
Multiple Bonds ◽  
Interatomic Distances ◽  
Spin Interactions ◽  
Fermi Contact ◽  
Shielding Tensor ◽  
Spin Spin Coupling ◽  
Hydrolysis Of ◽  
Derivatives Of

The changes in the interatomic distances and the corresponding spin-spin coupling as a result of the hydrolysis of the ruthenium complexes and the effects of different derivatives of the pyrazole ligands and the substituents methyl, carboxylic, and phenyl on the pyrazole rings were studied. A good agreement was obtained between the experimental and the theoretical proton NMR. Significant changes are observed in the isotropic and anisotropic shielding tensor of the atoms and related spin-spin coupling of their bonds due to hydrolysis of the complexes. This observation gives more insight into the known mechanism of activation of the ruthenium complexes by hydrolysis. There are no direct effects of interatomic distances on many of the computed spin-spin couplings with the exception of1J(Ru-N) which shows significant changes especially within the pair of1J(Ru-N) in the complexes with two nitrogen atoms of the bis-pyrazole moiety. The magnitude of interatomic spin-spin coupling of the Ru-X follows the order of Ru-Cl > Ru-N > Ru-C > Ru-O. The Ramsey term Fermi contact (FC) has the most significant contribution in most of the computed spin-spin interactions except in1J(Ru-Cl) and1J(N-N⁎) which are predominantly defined by the contribution from the paramagnetic spin orbit (PSO).

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