Solid-state N.M.R. studies of platinum and tin compounds

Abstract

High-resolution solid-state N.M.R. studies of dilute spins are now possible using cross-polarisation and MAS techniques. A systematic evaluation has been undertaken to determine their applicability to spin-½ metal nuclei, in particular (^195)Pt and (^119)Sn. In addition, an extensive (^13)C and (^31)p solid-state N.M.R. study has been carried out on a selection of Pt(II) complexes, supplying information on isotropic (scalar) coupling constants and shielding anisotropy. The majority of (^119)Sn and (^195)Pt spectra exhibit a multitude of spinning sidebands due to the large shielding anisotropy present. The tin systems under study have been of type R(_3)SnX (where R = Alkyl, phenyl and X = F, OH, CI); some are shown to be polymeric in the solid-state with penta-coordinate tin present. Where possible, correlations with X-ray crystallographic data and solution-state N.M.R. studies are giving. The interactions present in Pt(IV) compounds containing directly bonded quadrupolar nuclei have been studied and imply motional activity present in the solid- state. A more comprehensive study of these effects is given for two tin systems (Ph(_3)SnCl and (NH(_4))(_2)SnCl(_6)), whereby observed splittings can be accounted for by a combination of (^119)Sn-Cl dipolar and scalar coupling. The interplay of tensor properties between spin-½ nuclei, namely (1) dipolar coupling, (11) indirect (scalar) coupling and (111) shielding anisotropy is explored in solid-state (^195)pt-(^31)p and (^119)sn-(^19)f systems. The theory for such tensorial interplay is given for an AX(_2) system.