title: Ruthenium complexes with the stanna-closo-dodecaborate ligand: coexistence of eta1(Sn) and eta3(B-H) coordination.
abstract: Four stanna-closo-dodecaborate complexes of ruthenium have been prepared and characterized by multinuclear NMR studies in solution and in the solid state. The solid-state structures of the dimeric zwitterions [[Ru(dppb)(SnB11H11)]2] (2) (dppb = bis(diphenylphosphino)butane), [[Ru(PPh3)2(SnB11H11)]2] (3), and the dianionic ruthenium complex [Bu3MeN]2[Ru(dppb)[2,7,8-(mu-H)3-exo-SnB11H11](SnB11H11)] (4) were determined by X-ray crystal structure analysis; they establish an unprecedented structural motif in the chemistry of heteroboranes and transition-metal fragments with the stanna-closo-dodecaborate moiety as a two-faced ligand that exhibits eta1(Sn) as well as eta3(B-H) coordination. The eta3-coordinated stannaborate in 4 and in the isostructural compound [Bu3MeN]2[Ru(PPh3)2[2,7,8-(mu-H)3-exo-SnB11H11](SnB11H11)] (5) shows fluxional behavior, which was studied in detail by using 31P[1H] EXSY and DNMR experiments. The activation parameters for the dynamic process of 5 are given.
authors.affiliation: Institut für Anorganische Chemie der Universität Tübingen, Auf der Morgenstelle 18, Tübingen, 72076, Germany.
authors.forename: Torben
authors.initials: T
authors.lastname: Gädt
authors.forename: Beatrice
authors.initials: B
authors.lastname: Grau
authors.forename: Klaus
authors.initials: K
authors.lastname: Eichele
authors.forename: Ingo
authors.initials: I
authors.lastname: Pantenburg
authors.forename: Lars
authors.initials: L
authors.lastname: Wesemann