Oxidative addition reactions of [Pt(CN)4]2?; A 13C and 195Pt NMR study

¹³C and ¹⁹⁵Pt NMR measurements show that complexes of the type trans-Pt(CN)₄X₂]^2? are formed on addition of X₂ (X = Br, Cl, I) to M₂Pt(CN)₄] (M = K or NBu₄) in aqueous and chloroform solution respectively. Addition of ICN to K₂Pt(CN)₄] (60% ¹³CN^?) in aqueous solution results in the formation of potassium pentacyanoiodoplatinate(IV) with complete¹³CN^?/¹²CN^?scrambling. The reaction of equi-molar amounts of trans-PtX₂(CN)₄]^2? (X = Br and Cl), which was previously claimed to result in complete transformation into trans-PtBrCl(CN)₄]^2?, is instead shown to result in an approximately statistical redistribution of halogens. A progressive shift of δ_Pt to high field is observed on successive replacement of ¹²CN^? by ¹³CN^? in Pt(CN)₄]^2?.