O- and C-metallation of 2-alkoxyphenylphosphines by platinum(II)

Abstract

The tertiary phosphines (L) PPh₂(2-methoxyphenyl), PBu^tMe(2-methoxyphenyl), PBu^t₂(2-methoxyphenyl), and PPh₂(2-ethoxyphenyl) were prepared. Complexes of these ligands and of PMe₂(2-methoxyphenyl) with platinum-(II) halides are described. These complexes on heating are converted to O-metallated chelates, e.g. trans-[PtCl₂{Ph₂P(2-methoxyphenyl)}₂] gives cis-[Pt(Ph₂PC₆H₄O)₂]. PMe₂(2-methoxyphenyl) is much more difficult to metallate but the complex [Ptl(Me₂PC₆H₄O)(Me₂PC₆H₄OMe)] was prepared. C-Metallated derivatives containing six-membered chelate rings were prepared by heating the ligand or [PtCl₂L₂] with [PtCl₂(RCN)₂] in xylene. Metathesis and bridge splitting reactions are described. ¹H and ³¹P N.m.r. and i.r. data are given and discussed.