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摘要
Several 1:1 adducts of gallium trihalides with triarylphosphines, X3Ga(PR3) (X=Cl, Br, and I; PR3=triarylphosphine ligand), were investigated by using solid-state 69/71Ga and 31PNMR spectroscopy at different magnetic-field strengths. The 69/71Ga nuclear quadrupolar coupling parameters, as well as the gallium and phosphorus magnetic shielding tensors, were determined. The magnitude of the 71Ga quadrupolar coupling constants (CQ(71Ga)) range from approximately 0.9 to 11.0MHz. The spans of the gallium magnetic shielding tensors for these complexes, 1133, range from approximately 30 to 380ppm; those determined for phosphorus range from 10 to 40ppm. For any given phosphine ligand, the gallium nuclei are most shielded for X=I and least shielded for X=Cl, a trend previously observed for InIIIphosphine complexes. This experimental trend, attributed to spin-orbit effects of the halogen ligands, is reproduced by DFT calculations. The signs of CQ(69/71Ga) for some of the adducts were determined from the analysis of the 31PNMR spectra acquired with magic angle spinning (MAS). The 1J(69/71Ga,31P) and J(69/71Ga, 31P) values, as well as their signs, were also determined; values of 1J(71Ga,31P) range from approximately 380 to 1590Hz. Values of 1J(69/71Ga,31P) and J(69/71Ga,31P) calculated by using DFT have comparable magnitudes and generally reproduce experimental trends. Both the Fermi-contact and spin-dipolar Fermi-contact mechanisms make important contributions to the 1J(69/71Ga,31P) tensors. The 31PNMR spectra of several adducts in solution, obtained as a function of temperature, are contrasted with those obtained in the solid state. Finally, to complement the analysis of NMR spectra for these adducts, single-crystal X-ray diffraction data for Br3Ga[P(p-Anis)3] and I3Ga[P(p-Anis)3] were obtained.
- 出版日期2013-2
