Beiträge zur Zintl-Chemie der Elemente der 6. Periode im Festkörper und in Lösung

Im Rahmen der Doktorarbeit wurde die Chemie binärer Zintl-Anionen mit Trielelementen untersucht. Hierzu wurden sowohl neue Edukte zur Darstellung der Anionen als auch deren Folgechemie mit Übergangsmetallkomplexen näher betrachtet. Die Synthese des bereits in meiner Masterarbeit erstmals dargestel...

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Bibliographic Details
Main Author: Lichtenberger, Niels
Contributors: Dehnen, Stefanie (Prof. Dr.) (Thesis advisor)
Format: Doctoral Thesis
Published: Philipps-Universität Marburg 2018
Online Access:PDF Full Text
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The main focus of this doctoral thesis was on the chemistry of binary Zintl anions comprising group 13 elements. During the course of these studies both new starting materials for their syntheses as well as their reactivity towards transition metal complexes were investigated. Initially the synthesis of the (TlBi3)2– anion, previously characterized in my master thesis, was optimized to an extent that allowed for its subsequent use in reactions. This was achieved by detailed investigations of the intermetallic compounds used for the preparation. Herein I observed complex relationships between the initial stoichiometry, the resulting products and the Zintl anions prepared from them. A series of formally ternary intermetallic compounds was analyzed for their true components with a combination of powder and single crystal X-ray diffraction measurements. Two influences on the product formation were taken into account: the choice of alkaline metal and the initial stoichiometry. The extraction of all obtained materials led to the formation of a series of novel binary Zintl anions that were subsequently crystallized and characterized. “K2TlBi3” was shown to be a very good starting material for the synthesis of (TlBi3)2– , affording the product in high yield and purity. However, it was shown to actually be a mixture of two intermetallic compounds, KTlBi and KBi2. The reactivity of (TlBi3)2– was studied in a series of reactions with transition metal complexes. Reactions with lanthanide complexes [Ln(cpMe4H)3] afford intermetalloid 13 atom cages [Ln@Tl2Bi11]4– (Ln = La, Ce, Nd, Sm), as observed for the lighter homologues Ga and In. Utilization of actinide complexes [U(cpMe4H)3] or [An(cpMe4H)3Cl] (An = U, Th) again affords intermetalloid 13 atom cages, this time however containing M4+ ions instead of M3+ ions. This oxidation was observed for a series of different starting materials (GaBi3)2– and (Pb2Bi2)2– in cooperation with my colleagues Armin Eulenstein und Dr. Robert J. Wilson, leading to the formation of further intermetalloid clusters [An@Bi12]q– (An/q = U/3, Th/4), [U@Pb7Bi7]3– and [An@Pb4Bi9]3– (An = U, Th). Quantum chemical investigations hint towards a strong interaction between the cluster shell and the central atoms in [An@Bi12]q– (An/q = U/3, Th/4). These studies are the first reports of intermetalloid clusters containing endohedral actinide ions. Reactions of (TlBi3)2– with [Ru(cod)(Me−Allyl)2] afford the cluster anions [Bi9{Ru(cod)}2]3– and [Tl2Bi6{Ru(cod)}]2– . The cluster [Bi9{Ru(cod)}2]3– comprises the novel polybismuthide fragment Bi97- and its electronic structure combines localized and multi-center bonding. The anion [Tl2Bi6{Ru(cod)}]2– was the first ternary cluster anion with group 13 atoms that also contains a d-block transition metal atom. Even though the cluster is formally in accordance with the Wade-Mingos rules for a nido cluster the structural parameters show abnormalities that required a more detailed investigation with quantum chemical methods. These showed that 2e-3c multi-center bonds exist within the (Tl2Bi6)-fragment while all bonds to the Ru atom are mainly covalent. The potential of the (TlBi3)2– anion to form novel polybismuthide ions was tested in a reaction series with MPh2 complexes (M = Zn, Cd, Hg). Reactions with CdPh2 afford the coordination compound [(Bi7)Cd(Bi7)]4– , which is the first report of the Bi73-7 anion acting as a ligand. The stabilities of [(Pn7)M(Pn7)]4– compounds (Pn = P - Bi, M = Zn - Hg, Hg22+) were investigated with quantum chemical methods. Equivalent reactions of (TlBi3)2– with ZnPh2 and HgPh2 afford (Tl4Bi5)3– as the main product. However, in the case of ZnPh2 a reaction intermediate could be crystallized. This salt contains the anion [(Bi6)Zn3(TlBi5)]4– , which was again studied with quantum chemical methods. Its electronic structure is comparable to that of [Bi9{Ru(cod)}2]3– in terms of bonding, as it again combines localized with multi-center bonds. The anion comprises an almost complete Bi7 nortricyclane fragment in which only the apical atom was replaced by three Zn2+ ions and can, in that aspect, be regarded as an intermediate of the Bi73- formation. The presented studies only provide a glimpse into the large research topics of intermetallic compounds for the syntheses of binary Zintl anions as well as their reactivities. This work will hopefully spark further research and serve as a foundation for these studies.