title: Reactivity of liquid ammonia solutions of the Zintl phase K12Sn17 towards mesitylcopper(I) and phosphinegold(I) chloride.
abstract: To gain more insight into the reactivity of intermetalloid clusters, the reactivity of the Zintl phase K12 Sn17 , which contains [Sn4 ](4-) and [Sn9 ](4-) cluster anions, was investigated. The reaction of K12 Sn17 with gold(I) phosphine chloride yielded K7 [(η(2) -Sn4 )Au(η(2) -Sn4 )](NH3 )16 (1) and K17 [(η(2) -Sn4 )Au(η(2) -Sn4 )]2 (NH2 )3 (NH3 )52 (2), which both contain the anion [(Sn4 )Au(Sn4 )](7-) (1 a) that consists of two [Sn4 ](4-) tetrahedra linked through a central gold atom. Anion 1 a represents the first binary AuSn polyanion. From this reaction, the solvate structure [K([2.2.2]crypt)]3 K[Sn9 ](NH3 )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 K12 Sn17 in the presence of [18]crown-6 in liquid ammonia, crystals of the composition [K([18]crown-6)]2 [K([18]crown-6)(MesH)(NH3 )][Cu@Sn9 ](thf) (4) were isolated ([18]crown-6=1,4,7,10,13,16-hexaoxacyclooctadiene, MesH=mesitylene, thf=tetrahydrofuran) and featured a [Cu@Sn9 ](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 Sn9 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.
authors.affiliation: Department Chemie, Technische Universität München, Lichtenbergstraße 4, 85747 Garching (Germany), Fax: (+49) 89-289-13186.
authors.forename: Christian B
authors.initials: CB
authors.lastname: Benda
authors.forename: Markus
authors.initials: M
authors.lastname: Waibel
authors.forename: Tobias
authors.initials: T
authors.lastname: Köchner
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Fässler
keywords: Zintl anions; cluster compounds; copper; structure elucidation; tin