Synthesis and characterisation of isomeric cycloaurated complexes derived from the iminophosphorane Ph3P=NC(O)Ph

Using different organomercury substrates, two isomeric cycloaurated complexes derived from the stabilised iminophosphorane Ph3P=NC(O)Ph were prepared. Reaction of Ph3P=NC(O)Ph with PhCH2Mn(CO)(5) gave the manganated precursor (CO)(4)Mn(2-C6H4C(O)N=PPh3), metallated on the C(O)Ph substituent, which yielded the organomercury complex ClHg(2-C6H4C(O)N=PPh3) by reaction with HgCl2 in methanol. Transmetallation of the mercurated derivative with Me4N[AuCl4] gave the cycloaurated iminophosphorane AuCl2(2-C6H4C(O)N=PPh3) with an exo PPh3 substituent. The endo isomer AuCl2(2-C6H4Ph2P=NC(O)Ph) [aurated on a PPh3 ring] was obtained by an independent reaction sequence, involving reaction of the diarylmercury precursor Hg(2-C6H4P(=NC(O)Ph)Ph-2)(2) [prepared from the known compound Hg(2-C6H4PPh2)(2) and PhC(O)N-3] with Me4N[AuCl4]. Both of the isomeric iminophosphorane derivatives were structurally characterised, together with the precursors (2-HgClC6H4)C(O)N=PPh3 and (CO)(4)Mn(2-C6H4C(O)N=PPh3). The utility of P-31 NMR spectroscopy in monitoring reaction chemistry in this system is described. (C) 2009 Elsevier B.V. All rights reserved.