Cyclic Hydrocarbon Frameworks Containing Two Bismuth Atoms: Towards 9,10-Dibismaanthracene

When bismuth atoms are incorporated into cyclic organic systems, this commonly goes along with strained or distorted molecular geometries, which can be exploited to modulate the physical and chemical properties of these compounds. In six-membered heterocycles, bismuth atoms are often accompanied by oxygen, sulfur or nitrogen as a second hetero-element. In this work, we present the first examples of six-membered rings, in which two CH units are replaced by BiX moieties (X=Cl, Br, I), resulting in dihydro-anthracene analogs. Their behavior in chemically reversible reduction reactions is explored, aiming at the generation of dibisma-anthracene (bismanthrene). Heterometallic compounds (Bi/Fe, Bi/Mn) are introduced as potential bismanthrene surrogates, as supported by bismanthrene-transfer to selenium. Analytical techniques used to investigate the reported compounds include NMR spectroscopy, high-resolution mass spectrometry, single-crystal X-ray diffraction analyses, and DFT calculations.

Dimetalloylene (M-E-M) Complexes of Heavier Main Group Elements Ge, Sn, Pb, Bi via Cleavage of E-X Bonds (X=N(SiMe3 )2 , OtBu) with an Iridium Hydride

Reactions of the IrV hydride [Me BDIDipp ]IrH4 {BDI=(Dipp)NC(Me)CH(Me)CN(Dipp); Dipp=2,6-iPr2 C6 H3 } with E[N(SiMe3 )2 ]2 (E=Sn, Pb) afforded the unusual dimeric dimetallotetrylenes ([Me BDIDipp ]IrH)2 (μ2 -E)2 in good yields. Moreover, ([Me BDIDipp ]IrH)2 (μ2 -Ge)2 was formed in situ from thermal decomposition of [Me BDIDipp ]Ir(H)2 Ge[N(SiMe3 )2 ]2 . These reactions are accompanied by liberation of HN(SiMe3 )2 and H2 through the apparent cleavage of an E-N(SiMe3 )2 bond by Ir-H. In a reversal of this process, ([Me BDIDipp ]IrH)2 (μ2 -E)2 reacted with excess H2 to regenerate [Me BDIDipp ]IrH4 . Varying the concentrations of reactants led to formation of the trimeric ([Me BDIDipp ]IrH2 )3 (μ2 -E)3 . The further scope of this synthetic route was investigated with group 15 amides, and ([Me BDIDipp ]IrH)2 (μ2 -Bi)2 was prepared by the reaction of [Me BDIDipp ]IrH4 with Bi(NMe2 )3 or Bi(OtBu)3 to afford the first example of a "naked" two-coordinate Bi atom bound exclusively to transition metals. A viable mechanism that accounts for the formation of these products is proposed. Computational investigations of the Ir2 E2 (E=Sn, Pb) compounds characterized them as open-shell singlets with confined nonbonding lone pairs at the E centers. In contrast, Ir2 Bi2 is characterized as having a closed-shell singlet ground state.

Bismuth species in the coordination sphere of transition metals: synthesis, bonding, coordination chemistry, and reactivity of molecular complexes

This contribution is focused on bismuth species in the coordination sphere of transition metals. In molecular transition metal complexes, three types of Bi-M bonding are considered, namely dative Bi→M interactions (with Bi acting as a donor), dative Bi←M interactions (with Bi acting as an acceptor) and covalent Bi-M interactions (M = transition metal). Synthetic routes to all three classes of compounds are outlined, the Bi-M bonding situation is discussed, trends in the geometric parameters and in the coordination chemistry of the compounds are addressed, and common spectroscopic properties are summarized. As an important part of this contribution, the reactivity of bismuth species in the coordination sphere of transition metal complexes in stoichiometric and catalytic reactions is highlighted.