Novel diphosphine platinum cations: NMR and Mossbauer spectra and catalytic studies

The reaction of PtCl2(diphosphine) with mono and bidentate phosphines has been investigated by NMR spectroscopy. [Pt(diphos-phine)PMe(3))(2)](2+), [Pt(diphosphine)(2)](2+) and [Pt((S,S)-bdpp)((S,S)-chiraphos)](2+) cations have been characterized by P-31 NMR and conductivity measurements. The presence of tin(II) chloride promotes the formation of the complex cations. Evidence for coordination of the diphosphine in monodentate mode has been obtained by NMR spectroscopy. The platinum species possessing a platinum-tin bond and ionic complexes with an SnCl3- counterion can easily be distinguished by Sn-119 Mossbauer spectroscopy. Asymmetric hydroformylation of styrene with [Pt((S,S)-bdpp)(2)](2+) (SnCl3-)(2) as catalyst precursor gave chemo-, regio- and enantio-selectivities different from those obtained with the covalent PtCl(SnCl3)((S,S)-bdpp) as catalyst precursor.