title: Step-by-step synthesis of the endohedral stannaspherene [Ir@Sn12]3- via the capped cluster anion [Sn9Ir(cod)]3-.
abstract: The endohedral stannaspherene cluster anion [Ir@Sn(12)](3-) was synthesized in two steps. The reaction of K(4)Sn(9) with [IrCl(cod)](2) (cod: 1,5-cyclooctadienyl) in ethylenediamine (en) solution first yielded the [K(2,2,2-crypt)](+) salt (2,2,2-crypt: 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane) of the capped cluster anion [Sn(9)Ir(cod)](3-). Subsequently, crystals of this compound were dissolved in en, followed by the addition of triphenylphosphine or 1,2-bis(diphenylphosphino)ethane and treatment at elevated temperatures. [Ir@Sn(12)](3-) was obtained and characterized as the [K(2,2,2-crypt)](+) salt. The isolation of [Sn(9)Ir(cod)](3-) as an intermediate product establishes that the formation of the stannaspherene [Ir@Sn(12)](3-) occurs through the oxidation of [Sn(9)Ir(cod)](3-). Among the structurally characterized tetrel cluster anions, [Ir@Sn(12)](3-) is a unique example of a stannaspherene, and one of the rare spherical clusters encapsulating a metal atom that is not a member of Group 10. Single-crystal structure determination shows that the novel Zintl ion cluster has nearly perfect icosahedral I(h) point symmetry.
authors.affiliation: Department Chemie, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching/München, Germany.
authors.forename: Jian-Qiang
authors.initials: JQ
authors.lastname: Wang
authors.forename: Saskia
authors.initials: S
authors.lastname: Stegmaier
authors.forename: Bernhard
authors.initials: B
authors.lastname: Wahl
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Fässler