Oxidative addition of halogens to [Pt(S2N2H)(PR3)2]BF4. X-Ray crystal structures of [Pt(S2N2H)X(PMe2Ph)](X = Br or I) and the monoclinic and triclinic polymorphs of [Pt(S2N2H)Br2(PMe2Ph)2]BF4

Abstract

[Pt(S₂N₂H)(PMe₂Ph)₂]BF₄(1a) reacts with bromine to give the Pt^IVtrans-dibromo compound [Pt(S₂N₂H)Br₂(PMe₂Ph)₂]BF₄(2). This rapidly isomerises to the cis isomer (α and β forms) which readily undergoes reductive elimination to give [Pt(S₂N₂H)Br(PMe₂Ph)](3). [Pt(S₂N₂H)I(PMe₂Ph)](4) was obtained by the reaction of (1a) with iodine. Similarly, treatment of [Pt(S₂N₂H)(PR₃)₂]BF₄(PR₃= PMe₃ or PPrⁿ₃) with bromine leads to [Pt(S₂N₂H)Br(PR₃)]. The α and β forms of (2) together with (3) and (4) have been characterised by X-ray crystallography.