POTASSIUM TETRACYANOPLATINATE (II) TRIHYDRATE (K2PT(CN)(4)CENTER-DOT-3H(2)O) STUDIED BY HIGH-RESOLUTION SOLID-STATE C-13 MAS NMR

Prudent analysis of the solid state C-13 MAS NMR spectra of polycrysta lline K2Pt(CN)(4) . 3H(2)O (KTCP)(-) reveals that in crystals of this compound there are two types of carbon nuclei with slightly different C-13 chemical shift tensors, contrary to what is found for the solutio n NMR spectrum and previous static powder NMR studies on this compound and the high resolution solid state NMR studies on other similar comp ounds. The C-13 MAS spectra measured at different rotor spinning speed s are satisfactorily simulated though the use of a newly developed com puter program based on a novel density matrix formulation. The present method is eminently successful even though the spectra are rather com plicated because of (1) the relatively large anisotropies of the chemi cal shift tensors; (2) the high-order dipolar interactions between C-1 3 and N-14 nuclei because of the strong quadrupolar coupling constants of N-14 nuclei; and (3) the indirect J-coupling between the C-13 and Pt-195. The principal elements as well as their orientations of the mi o C-13 chemical shift tensors are evaluated from the spectral simulati ons. (C) 1998 Elsevier Science B.V.