Coordination isomerism in salicylhydroxamate complexes of platinum(ii) and palladium(ii)

Abstract

The syntheses of a range of platinum(II) and palladium(II) complexes containing salicylhydroxamate ligands are described. The ancillary ligands, together with the synthetic route, influence the coordination mode of the salicylhydroxamate ligand. Reaction of cis-[PtCl₂(PPh₃)₂] with salicylhydroxamic acid and trimethylamine in hot methanol gave O,O′-bonded [Pt{OC(NO)C₆H₄OH}(PPh₃)₂], but [PtCl₂(cod)] (cod = cycloocta-1,5-diene) gave N,O-bonded [Pt{OC₆H₄C(O)NOH}(cod)]. Ligand substitution gives other N,O bonded complexes, including [Pt{OC₆H₄C(O)NOH}(PPh₃)₂]. Reaction of K₂PtCl₄ with 2 equiv. of EPh₃ (E = As or Sb), salicylhydroxamic acid and excess trimethylamine gives products whose structures depend on E; AsPh₃ gives [Pt{OC(NO)C₆H₄OH}(AsPh₃)₂], while SbPh₃ gives [Pt{OC₆H₄C(O)NOH}(SbPh₃)₂].