Reactivity of Liquid Ammonia Solutions of the Zintl Phase K 12 Sn 17 towards Mesitylcopper(I) and Phosphinegold(I) Chloride

To gain more insight into the reactivity of intermetalloid clusters, the reactivity of the Zintl phase K 12 Sn 17 , which contains [Sn 4 ] 4− and [Sn 9 ] 4− cluster anions, was investigated. The reaction of K 12 Sn 17 with gold(I) phosphine chloride yielded K 7 [(η 2 ‐Sn 4 )Au(η 2 ‐Sn 4 )](NH 3 ) 16 ( 1 ) and K 17 [(η 2 ‐Sn 4 )Au(η 2 ‐Sn 4 )] 2 (NH 2 ) 3 (NH 3 ) 52 ( 2 ), which both contain the anion [(Sn 4 )Au(Sn 4 )] 7− ( 1 a ) that consists of two [Sn 4 ] 4− tetrahedra linked through a central gold atom. Anion 1 a represents the first binary AuSn polyanion. From this reaction, the solvate structure [K([2.2.2]crypt)] 3 K[Sn 9 ](NH 3 ) 18 ( 3 ; [2.2.2]crypt=4,7,13,16,21,24‐hexaoxa‐1,10‐diazabicyclo[8.8.8]hexacosane) was also obtained. In the analogous reaction of mesitylcopper with K 12 Sn 17 in the presence of [18]crown‐6 in liquid ammonia, crystals of the composition [K([18]crown‐6)] 2 [K([18]crown‐6)(MesH)(NH 3 )][Cu@Sn 9 ](thf) ( 4 ) were isolated ([18]crown‐6=1,4,7,10,13,16‐hexaoxacyclooctadiene, MesH=mesitylene, thf=tetrahydrofuran) and featured a [Cu@Sn 9 ] 3− cluster. A similar reaction with [2.2.2]crypt as a sequestering agent led to the formation of crystals of [K[2.2.2]crypt][MesCuMes] ( 5 ). The cocrystallization of mesitylene in 4 and the presence of [MesCuMes] − ( 5 a ) in 5 provides strong evidence that the migration of a bare Cu atom into an Sn 9 anion takes place through the release of a Mes − anion from mesitylcopper, which either migrates to another mesitylcopper to form 5 a or is subsequently protonated to give MesH.