Synthesis and characterization of new trimetallic complexes with {Pt2Au(μ-S)2}n+ (n = 2, 3) cores containing C, N and N, N donor ligands

Abstract

Reactions of the dinuclear platinum(II) sulfide complex [Pt 2(μ-S) 2(PPh 3) 4] with a range of gold(III) dichloride complexes [AuLCl 2] containing C, N- or N, N-cycloaurated ligands L gives a new series of dicationic adducts [Pt 2(μ-S) 2(PPh 3) 4AuL] 2+, isolated as their PF 6- salts. The complexes investigated are [Au{C 6-H 4(CH 2NMe 2)-2}Cl 2], [Au{C 6H 3(CH 2NMe 2)-2-(OMe)-5}Cl 2], [Au{NC 5H 4(CH 2C 6H 4)-2}Cl 2], [Au{NC 5H 4(COC 6H 4)-2}Cl 2] and [Au{NC 5H 4(CONH)-2}Cl 2]. An X-ray structure determination on the picolinamide-derived complex [Pt 2(μ-S) 2(PPh 3) 4Au{NC 5H 4(CONH)-2} ](PF 6) 2 was not of sufficiently high quality for detailed discussion, but confirmed the atom connectivity. Reactions of [Pt 2(μ-S) 2(PPh 3) 4] with [AuCl 2(bipy)]PF 6 (L = bipy = 2,2'-bipyridine) and [AuCl 2(phen)]Cl (L = phen = 1,10-phenanthroline) gives the corresponding tricationic adducts [Pt 2(μ-S) 2(PPh 3) 4AuL] 3+, also isolated as their PF 6- salts. The complexes are characterised by NMR spectroscopy, electrospray mass spectrometry and microelemental analyses. Biological assay data of a selection of these new complexes towards the P388 murine leukemia cell line, as well as a range of antimicrobial tests, reveals overall low activity compared to other cycloaurated gold(III) complexes. © 2012 Elsevier B.V. All rights reserved.