Preparation and characterisation of [Pt(SeSN2)(PR3)2], [Pt(Se2N2)(PR3)2], [Pt(SeSN2H)(PR3)2]BF4, and [Pt(Se2N2H)(PR3)2]BF4

Abstract

Reaction of [Se₂N₂S]₂Cl₂, or SeCl₄–[S₄N₃]Cl, with [PtCl₂(PR₃)₂](PR₃= PEt₃, PMe₂Ph, PMePh₂, PPh₃, or ½ Ph₂PCH₂CH₂PPh₂) in liquid ammonia gives complexes of the type [Pt(SeSN₂)(PR₃)₂](ca. 70% yield). Reaction of SeCl₄ with [PtCl₂(PR₃)₂](PR₃= PEt₃, PMe₂Ph, PMePh₂, PPh₃, or ½ Ph₂PCH₂CH₂PPh₂) in liquid ammonia produces [Pt(Se₂N₂)(PR₃)₂] in variable yield (ca. 24–74%). Treatment of [Pt(SeSN₂)(PR₃)₂] or [Pt(Se₂N₂)(PR₃)₂] with HBF₄in tetrahydrofuran–benzene produces [Pt(SeSN₂H)(PR₃)₂] BF₄ or [Pt(Se₂N₂H)(PR₃)₂] BF₄ quantitatively according to ³¹P n.m.r. spectroscopy (ca. 75% isolated). The identity of the complexes was established by ³¹P n.m.r., i.r., mass spectra, and microanalyses. Proton-exchange reactions reveal increasing basicity in the series [Pt(S₂N₂)(PR₃)₂]≈[Pt(SeSN₂)(PR₃)₂], [Pd(S₂N₂)(PR₃)₂], [Pt(Se₂N₂)(PR₃)₂].