Ferrocenyl-Functionalized Tetranuclear Gold(I) and Gold(I)–Copper(I) Complexes Based on Tridentate Phosphanes



Tetranuclear AuI–FeII dimetallic and AuI–CuI–FeII trimetallic complexes bearing ferrocenyl (Fc) groups have been assembled by using two triphosphane ligands, namely, (PPh2CH2)2PPh (dpmp) and (PPh2)3CH (tppm). The compositions and structural type of the clusters are dependent on the stereochemistry of the P donor ligands. The complexes [tppmAu3Cu(C2R)3]PF6 [R = Fc (1) and 4-C6H4-Fc (2)] adopt a trigonal pyramidal {Au3Cu} arrangement of the coordinating metal core, whereas for the compounds with the linear triphosphane [Au4(dpmp)2(C2R)2](PF6)2 [R = Fc (3) and 4-C6H4-Fc (4)], a planar rhomboidal {Au4} framework was found. Clusters 14 were characterized by NMR spectroscopy and ESI-MS measurements. The solid-state structures of 1, 3, and 4 have been determined by X-ray crystallography. The electrochemical properties of 14 were studied and revealed redox processes attributed to the Fc functions. Oxidation of the Fc units in 1, 2, and 4 occurs independently. In 3, an electron transfer process mediated by the {Au4} metal core was observed.