crypt)]2(K,Rb)4⋅13.4 NH3 – The First Tungsten Functionalized Silicon Zintl Cluster

The reaction between the heteroleptic metal carbonyl complex [W(CO)4(tmeda)] ((tmeda)=N,N,N′,N′‐Tetramethylethane‐1,2‐diamine) with [Si9]4− silicon Zintl clusters in presence of [2.2.2]crypt ([2.2.2]crypt=4,7,13,16,21,24‐Hexaoxa‐1,10‐diazabicyclo[8.8.8]‐hexacosane) in liquid ammonia yielded the compound [(K,Rb)@([2.2.2]crypt)]2(K,Rb)4[Si9W(CO)4] ⋅ 13.4 NH3. The compound was analyzed by single crystal X‐ray diffraction and crystallizes in the space group P1‾${P\bar{1}}$(a=11.48390(10) Å, b=19.7383(2) Å, c=19.8983(2) Å, α=112.5760(10)°, β=97.4210(10)°, γ=95.3760(10)°, V=4079.01(7) Å3). The compound represents the first group 6 carbonylate‐functionalized silicon Zintl cluster. The central moiety is composed of a tricapped trigonal prismatic nine‐atom silicon species which coordinates with the lone pair of one capping atom to the tungsten tetracarbonylate, forming a pseudo trigonal bipyramidal carbonylate cluster anion [Si9W(CO)4]6−. The chemical bonding in the new cluster entity is analyzed using theoretical calculations and subsequent analysis using QTAIM and NBO.On the occasion of the 125th birthday of Prof. Dr. Eduard Zintl.