Synthesis and structural characterization of stable coinage metal (Cu, Ag, Au) cyclopentadienyl complexes

The electron withdrawing and oxidatively stable perfluorinated Cp* ligand [C5(CF3)5]- allowed for the isolation of rare and unusually stable coinage metal complexes [M(C5(CF3)5)(PtBu3)] (M = Cu, Ag, Au), representing the first complete and structurally comparable series of group 11 Cp coordination compounds. Full characterization and structure analysis revealed distinct and partly unknown coordination motifs with hapticities ranging from eta 1, eta 3/eta 1 and eta 3/eta 2 for gold, silver and copper, respectively. Quantum-chemical studies using DFT methods confirm these findings and connect them to the unique electronic structure of the given ligand system. We report the first complete series of structurally characterized cyclopentadienyl complexes of coinage metals. Their unusually high stability is due to the high oxidative stability of the perfluorinated Cp* ligand [C5(CF3)5]-.