Synthesis of gold(I), silver(I) and copper(I) complexes containing substituted (2-aminophenyl)phosphines. Molecular structures of [AuI(2-H2NC6H4PPh2)], [AuI{(±)-2-H2NC6H4PMePh}] and (±)-[Cu(2-H2NC6H4PPh2)2];PF6

Abstract

Linear gold(I) complexes of type [AuI(L)] and [AuL₂]I (L = 2-H₂NC₆H₄PPhR, R = Me or Ph) have been prepared by the reaction of the appropriate ligand with [NBuⁿ₄][AuI₂] in ethanol. The neutral ligand L is co-ordinated to the metal centre via the phosphorus donor atom. The structures of the complexes [AuI(2-H₂NC₆H₄PPh₂)] and [AuI{(±)-2-H₂NC₆H₄PMePh}] have been confirmed by X-ray analyses with the latter, but not the former, complex exhibiting auriophilicity. Metathesis of these compounds with NH₄PF₆ gave the corresponding hexafluorophosphate salts [AuL_n]PF₆ (n = 1 or 2). Tetrahedral complexes of the type [ML_n]PF₆ (L = 2-H₂NC₆H₄PPhR; R = Ph, M = Ag or Cu, n = 2 or 3; R = Me, M = Cu, n = 2 or 3; R = Me, M = Ag, n = 3) have also been prepared via reaction of the appropriate ligand with [Cu(NCMe)₄]PF₆ in acetonitrile or AgNO₃ in ethanol followed by metathesis with NH₄PF₆. The molecular structure of (±)-[Cu(2-H₂NC₆H₄PPh₂)₂]PF₆ has been confirmed by X-ray crystallography. All of the complexes have been shown by NMR spectroscopy to undergo facile ligand-exchange reactions in solution. These complexes are seen as potential anticancer agents. Preliminary biological studies have shown them to be active against three mouse tumour cell lines in vitro with cytotoxicities of certain of these complexes being comparable to that of cis-diamminedichloroplatinum(II), cisplatin, and bis[1,2-bis(diphenylphosphino)ethane]gold(I) iodide.