Anisotropy in the31P,63/65Cu Indirect Spin–Spin Coupling and31P Nuclear Shielding Tensors of Linear Copper(I) Phosphines
✍ Scribed by Scott Kroeker; John V. Hanna; Roderick E. Wasylishen; Eric W. Ainscough; Andrew M. Brodie
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 178 KB
- Volume
- 135
- Category
- Article
- ISSN
- 1090-7807
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✦ Synopsis
Phosphorus-31 CP/MAS NMR spectra of two linear bis(tribenzylphosphine)cuprate(I) salts reveal significant anisotropy in the one-bond 31 P, 63,65 Cu J tensors. The parallel and perpendicular components of 1 J( 31 P, 63 Cu), for example, are ؉2.0 and ؉1.3 kHz, respectively. The well-characterized space group and point symmetry in one of these compounds greatly simplifies the 31 P lineshape analysis, thus dispensing with the need to make assumptions about the interaction tensors involved. This offers an unique opportunity to study ⌬J by calculating dipolar coupling constants from known internuclear distances, and by using zero-field nuclear quadrupole resonance spectroscopy to obtain the magnitudes of the 63/65 Cu nuclear quadrupole coupling constants, C Q . Copper-63 C Q values in these complexes exceed 80 MHz, proving to be the largest reported for copper(I) phosphines. Phosphorus-31 NMR spectra of non-spinning samples at three applied magnetic fields are also presented, along with lineshape calculations based on full-matrix Zeeman-quadrupolar Hamiltonian diagonalization. It is shown that exact 31 P lineshape calculations provide the relative signs of C Q , the isotropic J-coupling, and the effective dipolar coupling constant. This appears to be the first unambiguous determination of ⌬ 1 J( 31 P, 63/65 Cu).