FLUORINE-19 NUCLEAR MAGNETIC RESONANCE STUDIES OF DIAMAGNETIC FLUORIDE COMPLEXES OF NICKEL(4) PALLADIUM(4) AND PLATINUM(4) IN ANHYDROUS HYDROGEN FLUORIDE SOLUTIONS

The 19F nuclear magnetic resonance spectra of the complexes MF62- [M represents Ni(IV), Pd(IV), and Pt(IV)], prepared by dissolving the K+ or Rb+ salts in anhydrous HF, have been studied over the temperature range -60 to +15°. These diamagnetic complexes, having M(IV) in the low-spin d6 electronic configuration, exhibit extremely large diamagnetic 19F shifts which are independent of the temperature: NiF62-, +253 ppm; Pdf62-, +284 ppm; and PtF62-, +297 ppm, with respect to the doublet signal of the external standard, CFCl2CF2Cl. The 19F line widths of the PtF62- and Pdf62- ions are narrow at all temperatures indicating that the ions are nonlabile. The line widths obtained for the solutions of K2NiFe and Rb2NiF6 are large, but evidence is presented that these are due, not to the lability of NiF62- but to the presence of small amounts of a paramagnetic Ni (III) complex in the salts. The 195Pt-19F spin-spin coupling constant, 2082 Hz, was obtained from the spectra of PtF62-. © 1969, American Chemical Society. All rights reserved.