Synthesis and Reactivity of Multinuclear Gold Complexes with (Diphenylphosphanyl)ferrocene and Oxygen Ligands.

AuI complexes combining hard oxygen and soft (diphenylphosphanyl)ferrocene (L) ligands in their molecules were synthesized, viz. the gold hydroxides [Au(OH)(L-κP)] (5) and [{Au(L-κP)}2 (μ-OH)][BF4 ] (4), and the oxonium cluster [{Au(L-κP)}3 (μ3 -O)][BF4 ] (1). In-situ auration of 1 produced [{Au(L-κP)}4 (μ4 -O)][BF4 ]2 (2), which spontaneously converted into a dimeric tetragold complex featuring bridging phosphanylferrocenyl groups geminally diaurated in position 2 of the ferrocene scaffold. The same complex and its isomer incorporating ferrocene-1,1'-diyl bridges resulted similarly from 4. Upon crystallization, compound 5 underwent a redox reaction, producing a structurally unique, crown-like, mixed-valent Au0 /AuI cluster, [Au7 (L-κP)6 ]OH. Compounds 1 and 5 were used to prepare the analogous, N-bridged complexes, [{Au(L-κP)}3 (μ3 -NFc)][BF4 ] (Fc=ferrocenyl) and [{Au(L-κP)}4 (μ4 -N)][BF4 ]. The compounds were structurally characterized and further studied by DFT calculations.