Structural variety and stereochemical features of bis(diphenylphosphinyl)[3]ferrocenophane gold(I) complexes

The P,N-[3]ferrocenophane ligand 3 forms a (κP-ligand)AuCl complex (5) upon treatment with (Me2S)AuCl. The corresponding P,P-[3]ferrocenophane system 4 yields a binuclear (κP,κP-chelate ligand)(AuCl)2 complex (6) when reacted with 2 equivalents of the (Me2S)AuCl reagent. Complex 6 features an intramolecular aurophilic Au⋯Au interaction. Treatment of the P,P-[3]ferrocenophane 4 with 1.0 equiv. of (PPh3)AuCl gives the tetra-coordinated mono-gold(I) complex (P,P-ligand)(PPh3)AuCl (7), whereas the cationic [(P,P-ligand)2Au]+[Cl−] system is obtained from 4 and 0.5 equivalents of (Me2S)AuCl. The [(P,P-ligand)2Au]+ system is obtained in different diastereoisomeric forms (8 and 9) depending on the stereochemistry of the pair of P,P-[3]ferrocenophane chelate ligand used. Examples of the complexes 5, 6, 7 and 8 were characterized by X-ray diffraction.