Synthesis and Characterization of [3]Ferrocenophane-derived P,P-Chelate Ligand Gold Complexes Featuring an Aurophilic Interaction

The P, P-chelate ligand (rac)-4 was prepared starting from the alpha-dimethylamino-[3]ferrocenophane by a series of directed ortho-lithiation, phosphination with ClPPh2 and substituent exchange using HP'Pr-2. Treatment with two molar equivalents of (Me2S)AuCl subsequently gave the corresponding kappa P, kappa P(AuCl)(2) complex (rac)-9. In similar sequences the alpha-PCy2/o-PPh2 ligands (S,S,S-pl)-2 and the "substituent-invertomer" (R,R,R-pl)-3 (alpha-PPh2'/o-PCy2) were prepared. Treatment with (Me2S)AuCl in a 1 : 2 ratio gave the chelate ligand-(AuCl)(2) complexes (S,S,S-pl)-8 and (R,R,R-pl)-11, respectively. The ligand (rac)-4 and the gold complexes 8, 9 and 11 were characterized by X-ray diffraction. All three show an intramolecular Au center dot center dot center dot Au interaction.