Use of phosphine gold acetylides [(R3P)AuCtriple bond; length of mdashCR] to form phosphine gold derivatives of tetra-iron and penta-iron clusters

Five new gold acetylides, [AuCtriple bond; length of mdashCR], with hydroxyl or amino functions in the organic radical R have been prepared. From these, nine phosphine complexes [(R3P)AuCtriple bond; length of mdashCR] with R = Ph or Cy were synthesised. Reactions between the phosphine gold acetylides [(Ph3P)AuCtriple bond; length of mdashCC(Me)(OH)Et] or [(Cy3P)AuCtriple bond; length of mdashCC(Me)(OH)Et] and the iron carbonyl cluster [Et4N][Fe4N(CO)12] gave both neutral [(R3P)AuFe4N(CO)12] and ionic compounds [(R3P)2Au][Fe4N(CO)12]. Reaction with the penta-iron cluster [Et4N][Fe5N(CO)14] afforded [(R3P)2Au][Fe5N(CO)14], [(R3P)2Au][Fe4N(CO)12] and [(R3P)AuFe4N(CO)12]. The gold–iron clusters were characterised with spectroscopic methods (IR, NMR and Mössbauer) and in the case of [(Cy3P)AuFe4N(CO)12] a single-crystal X-ray analysis.