SOLID-STATE C-13 NMR CHEMICAL-SHIFT TENSORS IN SQUARE-PLANAR TETRACYANOMETALATES (M = NI, PD, PT)

The principal elements of the C-13 NMR chemical shift tensors have been determined for three square-planar tetracyanometalates, K2Ni(CN)4.H2O, K2Pd(CN)4.3H2O, and K2Pt(CN)4.3H2O, from the solid-state C-13 NMR powder patterns. The orientation of the C-13 chemical shift tensor is partially assigned on the basis of the dipolar coupling analysis to N-14. The chemical shift tensors are nearly axial and for all three complexes have almost the same values and, in turn, are quite similar to the values for acetonitrile. The most shielded element, about -90 ppm, is aligned with the M-CN vector.