title: Geminal tetraauration of acetonitrile: hemilabile-phosphine-stabilized Au8Ag4 cluster compounds.
abstract: Unprecedented geminal tetraauration of acetonitrile has been realized through C-H activation by Au(I)-Ag(I) clusters under mild conditions. The reaction of [OAu3Ag(dppy)3](BF4)2 (dppy = diphenylphosphino-2-pyridine) (1), AgBF4, and acetonitrile in the presence of methanol at room temperature resulted in the isolation of the novel cluster [(CCN)2Au8Ag4(dppy)8(CH3CN)2](BF4)6 (2). The centrosymmetric structure consists of two Au4Ag2 motifs stabilized by hemilabile phosphines. Triply deprotonated acetonitrile (CCN(3-)) is found in a Au4Ag environment with the terminal carbon bridging four Au(I) centers and the nitrogen donor linking a Ag(I) ion, which is the first example of a μ5-CCN(3-) coordination mode. A concerted metalation/deprotonation process for the C-H activation of acetonitrile that indicates the importance of the oxo ion of the oxonium Au(I) cluster is proposed. Cluster 2 emits bright green light in the solid state at room temperature upon UV irradiation.
authors.affiliation: State Key Lab of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, People' s Republic of China.
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Pei
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.forename: Zhen
authors.initials: Z
authors.lastname: Lei
authors.forename: Quan-Ming
authors.initials: QM
authors.lastname: Wang