Immobilization of [Pt₂(μ-S)₂(PPh₃)₄] on Polymeric Supports by Sulfide Alkylation and Phosphine Exchange Reactions

Abstract

The immobilization of the dinuclear platinum(II) sulfido complex [Pt₂(μ-S)₂ (PPh₃)₄] on solid supports has been investigated. Reaction with haloalkyl functionalized polymers [Merrifield's resin (chloromethylated polystyrene), chloropropyl silica, chloropropyl controlled pore glass, and bromopropyl polysiloxane] gives complexes immobilized through alkylation of one of the sulfide ligands, forming a μ-thiolate ligand acting as an anchor to the polymer support, akin to well-established reactions of [Pt₂(μ-S)₂(PPh₃)₄] with molecular alkylating agents. The model complex [Pt₂(μ-S)(μ-SCH₂SiMe₃)(PPh₃)₄]PF₆ was prepared as the first molecular silicon-containing derivative of [Pt₂(μ-S)₂(PPh₃)₄] and was fully characterized by NMR spectroscopy, electrospray ionization-mass spectrometry, and single-crystal X-ray diffraction. Immobilization of [Pt₂(μ-S)₂(PPh₃)₄] by phosphine exchange reactions was also achieved using commercial polystyrene-grafted triphenylphosphine or a new immobilized phosphine [derived by sequential functionalization of Merrifield's resin with a polyether amine and then Ph₂PCH₂OH].

GRAPHICAL ABSTRACT

Keywords:

• Platinum complexes
• sulfide complexes
• immobilization reactions
• alkylation reactions
• phosphine exchange

Acknowledgments

We thank the University of Waikato for financial support of this work. OTU thanks the University of Waikato for scholarship support. We thank Dr. Tania Groutso (University of Auckland) for the collection of the X-ray data set, Steve Cameron (University of Waikato) for inductively coupled plasma mass spectrometry data, and Texaco Chemical Company for a generous donation of Jeffamine T403. Rina McCarthy is thanked for carrying out some preliminary experiments.