Mikami Kaiyu, Hui Shen, Kubo Kazuyuki, Kume Shoko, Mizuta Tsutomu
Department of Chemistry, Graduate School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-hiroshima 739-8526, Japan.
Dalton Trans. 2021 Apr 28;50(16):5659-5665. doi: 10.1039/d1dt00294e.
Copper alkynyl complexes [CuAg3(C[triple bond, length as m-dash]CAr)3(PPh3)3]+ (Ar = Ph, p-C6H4Me), in which three Ag(PPh3) units are bound among three C[triple bond, length as m-dash]CAr arms of trigonal-planar [Cu(C[triple bond, length as m-dash]CAr)3]2-, were selected as a protecting unit to cover the metal core of an atomically precise core-shell-type cluster. First, the formation of the protecting unit through the reaction of Cu(NCMe)4(PF6) with Ag(C[triple bond, length as m-dash]CAr) and PPh3 in a 1 : 3 : 3 ratio was confirmed. The reaction gave dimeric [CuAg3(C[triple bond, length as m-dash]CAr)3(PPh3)3]22+, in which the two planar [CuAg3(C[triple bond, length as m-dash]CAr)3(PPh3)3]+ units were stacked. Next, core-shell-type clusters were synthesized by adding NaBH4 and Et4NX (X = Cl, Br) to a solution similar to that used to prepare the protecting unit. The trigonal-planar protecting units nicely formed core-shell-type Ag nanoclusters formulated as [Ag13H8X6{CuAg3(C[triple bond, length as m-dash]CAr)3(PPh3)3}4]3+ (X = Cl, Ar = p-C6H4Me; X = Br, Ar = p-C6H4Me; X = Br, Ar = Ph). Their crystal structures revealed that the four [CuAg3(C[triple bond, length as m-dash]CAr)3(PPh3)3]+ units are linked by six halogen ions to form a tetrahedral cage that accommodates a polyhydride-Ag cluster formulated as Ag13H85+. As a concrete proof of the existence of the polyhydride, deuterated analogs Ag13D85+ were synthesized and subsequently characterized by high-resolution electrospray-ionization mass spectrometry measurements.
炔基铜配合物[CuAg₃(C≡CAr)₃(PPh₃)₃]⁺（Ar = Ph，p-C₆H₄Me），其中三个Ag(PPh₃)单元连接在三角平面[Cu(C≡CAr)₃]²⁻的三个C≡CAr臂之间，被选作保护单元来覆盖原子精确的核壳型簇的金属核。首先，通过以1∶3∶3的比例使Cu(NCMe)₄(PF₆)与Ag(C≡CAr)和PPh₃反应，确认了保护单元的形成。该反应生成二聚体[CuAg₃(C≡CAr)₃(PPh₃)₃]₂²⁺，其中两个平面[CuAg₃(C≡CAr)₃(PPh₃)₃]⁺单元堆叠在一起。接下来，通过向类似于用于制备保护单元的溶液中加入NaBH₄和Et₄NX（X = Cl，Br）来合成核壳型簇。三角平面保护单元很好地形成了核壳型Ag纳米簇，其化学式为[Ag₁₃H₈X₆{CuAg₃(C≡CAr)₃(PPh₃)₃}₄]³⁺（X = Cl，Ar = p-C₆H₄Me；X = Br，Ar = p-C₆H₄Me；X = Br，Ar = Ph）。它们的晶体结构表明，四个[CuAg₃(C≡CAr)₃(PPh₃)₃]⁺单元通过六个卤素离子相连，形成一个四面体笼，该笼容纳一个化学式为Ag₁₃H₈⁵⁺的多氢化物-Ag簇。作为多氢化物存在的具体证据，合成了氘代类似物Ag₁₃D₈⁵⁺，随后通过高分辨率电喷雾电离质谱测量对其进行了表征。
