Coupling and “virtual” coupling in the nuclear magnetic resonance spectra of phosphine complexes

Pidcock, Alan

doi:10.1039/c19680000092

Cited by 12 publications

(42 citation statements)

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“…They are homotopic, (35) therefore two of the three ligands are symmetry equivalent in the solid. The CP/MAS 31 P NMR spectrum of [(DBP) 3 AgBr] is similar to that of the chloride in that it shows two well-separated signals of 2:1 relative intensity, each of which is further split by 1 J(AgP) coupling (Table 10). However, the resolution is insufficient to allow for any 2 J(PP) coupling to be Table 10 and 1/2 = 40 Hz; (c) X = I, experimental spectrum; (d) X = I, simulated spectrum using the parameters in Table 10 and 1/2 = 40 Hz.…”

Section: Silver Complexesmentioning

confidence: 90%

“…For 1,1-difluoroethylene, even though H 1 and H 2 are related by C 2 and symmetry operations and are therefore chemical shift equivalent, they are not magnetically equivalent because the geometrical relationship of H 1 to F 1 (cis) is not the same as that of H 1 to F 2 (trans). In this case 3 J H 1 F 1 = 3 J H 1 F 2 . The resulting spin system is AA XX , which is second order.…”

Section: Symmetry Relations Among Nucleimentioning

confidence: 92%

“…The resolution in the spectrum of [(DBP) 3 AgI] is poorer, but an analysis similar to that of the bromide complex is still possible.…”

Section: Silver Complexesmentioning

confidence: 96%

“…The crystal structure of (Ph 3 P 3 AuCl (49) shows that it contains three crystallographically inequivalent phosphorus atoms. In this complex, the three Ph 3 P ligands can attain similar environments by way of low-energy librations of the phenyl groups, whereas for (DBP 3 AuCl two of the ligands are held in a parallel arrange- (Fig. 33) would be expected to show coupling to 197 Au as observed for [Au(dppen) 2 ]X, but as is evident from this figure, no coupling is observed and the spectrum is very similar to that observed in solution.…”

Section: Gold Complexesmentioning

confidence: 97%

“…To eliminate the effect of the different magnetic moments of the metal nuclei on these coupling constants, they have been divided by the gyromagnetic ratio of the metal nucleus concerned (the values that were used for each metal nucleus are the weighted means of those for the naturally occurring isotopes 63 Cu, 65 Cu and 107 Ag, 109 Ag, because separate signals for the two isotopes were not resolved in most cases). This yields a reduced coupling constant J r , which is essentially the magnitude of the magnetic field at the metal nucleus that is induced by the magnetic moment 3 AgCl]: (a) experimental spectrum; (b) simulated spectrum using the parameters in Table 10 and 1/2 = 40 HZ.…”

Section: Silver Complexesmentioning

confidence: 99%

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Aspects of equivalence as illustrated by phosphine complexes of transition metals

Nelson¹

2001

Concepts Magn. Reson.

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ABSTRACT:The various types of symmetry-related nuclei present in transition metal complexes of phosphines are discussed. Differences between the solution and the solid states are considered. Examples of spectra are presented to illustrate the relationships between the types of equivalences and observed spectral line shapes. An introduction to solid-state NMR spectroscopy is followed by descriptions of spectra that illustrate some of the types of information, which may be obtained from NMR spectroscopy of solid samples.

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Section: Silver Complexesmentioning

confidence: 90%

Section: Symmetry Relations Among Nucleimentioning

confidence: 92%

“…The resolution in the spectrum of [(DBP) 3 AgI] is poorer, but an analysis similar to that of the bromide complex is still possible.…”

Section: Silver Complexesmentioning

confidence: 96%

Section: Gold Complexesmentioning

confidence: 97%

Section: Silver Complexesmentioning

confidence: 99%

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Aspects of equivalence as illustrated by phosphine complexes of transition metals

Nelson¹

2001

Concepts Magn. Reson.

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Trans-chelating diphosphines, the elusive ligands!

Freixa

Leeuwen

2008

Coordination Chemistry Reviews

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Interdependent Metal–Metal Bonding and Ligand Redox-Activity in a Series of Dinuclear Macrocyclic Complexes of Iron, Cobalt, and Nickel

et al. 2019

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This report describes an isostructural series of dinuclear iron, cobalt, and nickel complexes bound by a redox-active macrocyclic ligand. The series spans five redox levels (34–38 e–/cluster core), allowing for a detailed investigation into both the degree of metal–metal interaction and the extent of ligand-based redox-activity. Magnetometry, electrochemistry, UV–vis–NIR absorption spectroscopy, and crystallography were used in conjunction with DFT computational analyses to extract the electronic structures of the six homodinuclear complexes. The isoelectronic, 34 e– species [(3PDI2)Fe2(PMe3)2(μ-Cl)](OTf) and [(3PDI2)Co2(PMe3)2(μ-Cl)](OTf)3 exhibit metal–metal single bonds, with varying amounts of electron density delocalization into the ligand as a function of the effective nuclear charge of the metal ions. One- and two-electron reductions of [(3PDI2)Co2(PMe3)2(μ-Cl)](OTf)3 lead to isolable products, which show successive increases in both the Co–Co distances and the extent of reduction of the ligand manifold. This trend results from reduction of a Co–Co σ* orbital, which was found to be heavily mixed with the redox-active manifold of the 3PDI2 ligand. A similar trend was observed in the 37 and 38 e– dinickel complexes [(3PDI2)Ni2(PMe3)2(μ-Cl)](OTf)2 and [(3PDI2)Ni2(PMe3)2(μ-Cl)](OTf); however, their higher electron counts lead to high-spin ground states that result from occupation of a high-lying δ/δ* manifold with significant Ni–NPDI σ* character. This change in ground state configuration reforms a M–M bonding interaction in the 37 e– complex, but formation of the 38 e– species again disrupts the M–M bond alongside the transfer of electron density to the ligand.

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Coupling and “virtual” coupling in the nuclear magnetic resonance spectra of phosphine complexes

Cited by 12 publications

References 0 publications

Aspects of equivalence as illustrated by phosphine complexes of transition metals

Aspects of equivalence as illustrated by phosphine complexes of transition metals

Trans-chelating diphosphines, the elusive ligands!

Interdependent Metal–Metal Bonding and Ligand Redox-Activity in a Series of Dinuclear Macrocyclic Complexes of Iron, Cobalt, and Nickel

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