Determination of 113Cd shielding tensor components in cadmium-phosphine complexes from 31P-decoupled 113Cd cross-polarisation/magic angle spinning spectra.

Owing to the simultaneous presence of various anisotropic interactions within the isolated M-31P and M(31P)2 fragments in solid transition metal phosphine complexes MX2.PR3 and MX2.2PR3 with, for instance, M = Cd, Hg or Pt, it is not normally possible to unequivocally determine the shielding tensor components of the metal nucleus M from simple 113Cd, 199Hg or 195Pt cross-polarisation/magic angle spinning (CP/MAS) spectra. In this paper it is shown that additional 31P on-resonance high-power decoupling during the acquisition time does allow the determination of the shielding tensor components of M from CP/MAS spectra. Two cadmium(II) complexes, Cd(OAc)2.Pchex3, (chex = cyclohexyl) and Cd(ClO4)2.2Pchex3 were chosen as examples; the 113Cd CP/MAS experiments were carried out at a low external magnetic field strength B0 = 2.35 T.