Spectroscopic studies of inorganic fluoro-complexes. Part IV. Fluorine-19 nuclear magnetic resonance studies of platinum(IV) fluoro-complexes

Abstract

A number of chlorofluoro-, fluorohydroxo-, and chlorofluorohydroxo-platinate(IV) species have been characterized in solution by ¹⁹F n.m.r. spectroscopy. The ¹⁹F chemical shifts, δ, are given to a good approximation by δ=pC+qT, where C and T are constants characteristic of Cl^– or OH^– and p and q are the number of substituents cis and trans to the fluorine atom, respectively. The fluorohydroxoplatinate complexes are protonated in acid solution, and pK values of the aqua-species have been determined from the ¹⁹F chemical shifts as a function of pH. The observed reactions can be rationalized in terms of a trans effect of ligands, in the order Cl^– > OH^– F^–. Solvent shifts of ¹⁹⁵Pt–¹⁹F coupling constants are reported.