Koordinationschemische Stabilisierung „nackter”︁ Elemente der V. Hauptgruppe (außer Stickstoff) - Synthese, Struktur und Bindung

Reactivity of E4 (E4 =P4 , As4 , AsP3 ) towards Low-Valent Al(I) and Ga(I) Compounds

The reactivity of yellow arsenic and the interpnictogen compound AsP₃ towards low-valent group 13 compounds was investigated. The reactions of [LAl] (1, L=[{N(C₆ H₃ ⁱ Pr₂ -2,6)C(Me)}₂ CH]^- ) with As₄ and AsP₃ lead to [(LAl)₂ (μ,η^1:1:1:1 -E₄ )] (E₄ =As₄ (3 b), AsP₃ (3 c)) by insertion of two fragments [LAl] into two of the six E-E edges of the E₄ tetrahedra. Furthermore, the reaction of [LGa] (2) with E₄ afforded [LGa(η^1:1 -E₄ )] (E₄ =As₄ (4 b), AsP₃ (4 c)). In these compounds, only one E-E bond of the E₄ tetrahedra was cleaved. These compounds represent the first examples of the conversion of yellow arsenic and AsP₃ , respectively, with group 13 compounds. Furthermore, the reactivity of the gallium complexes towards unsaturated transition metal units or polypnictogen (E_n ) ligand complexes was investigated. This leads to the heterobimetallic compounds [(LGa)(μ,η^2:1:1 -P₄ )(LNi)] (5 a), [(Cp'''Co)(μ,η^4:1:1 -E₄ )(LGa)] (E=P (6 a), As (6 b), Cp'''=η⁵ -C₅ H₂ ^t Bu₃ ) and [(Cp'''Ni)(η^3:1:1 -E₃ )(LGa)] (E=P (7 a), As (7 b)), which combine two different ligand systems in one complex (nacnac and Cp) as well as two different types of metals (main group and transition metals). The products were characterized by crystallographic and spectroscopic methods.

The Influence of β-diiminato Ligands on As4 Activation by Cobalt Complexes

In a systematic study of the activation of As₄, three [LCo(tol)] (L=β‐diiminato) complexes have revealed different steric and electronic influences. 2,6‐Diisopropylphenyl (Dipp) and 2,6‐dimethylphenyl (dmp) flanking groups were used, one of the ligands with H backbone substituents (β‐dialdiminate L⁰) and two with Me substituents (β‐diketiminates L³ and L¹). In the reaction with As₄, different dinuclear products [(LCo)₂As₄] (LM=L⁰ (1), L¹ (2), L³ (3)) were isolated, with all showing differently shaped [Co₂As₄] cores in the solid state: octahedral in 1, prismatic in 2, and asterane‐like in 3. Thermal treatment of 3 leads to the abstraction of one arsenic atom to yield [(L³Co)₂As₃] (4). All products were comprehensively characterized by single‐crystal X‐ray diffraction, FD‐MS, and ¹H NMR spectroscopy. A rational explanation for the different reactivity is also proposed and DFT calculations shed light on the nature of the highly flexible [Co₂As₄] cores.

An electron-poor di-molybdenum triple-decker with a puckered [B4Ru2] bridging ring is an oblato-closo cluster

An unprecedented, 22-valence-electron triple-decker sandwich complex [(Cp*Mo)2{μ-η(6):η(6)-B4H4Ru2(CO)6}], 2, has been prepared. In an effort to generate analogous triple-deckers with group 6 metal carbonyl fragments in the middle deck, we have isolated [(Cp*MoCO)2(μ-H)2B4H4], 3, that provides the first direct evidence for the missing link between [(Cp*MoCl)2B3H7] and [(Cp*Mo)2B5H9] clusters.

Halide Ion Addition to Bismuth-Containing Iron Carbonyl Compounds: Synthesis and Characterization of the Two Bridged-Butterfly Cluster Compounds [Et(4)N][(&mgr;-H)Fe(2)(CO)(6)Bi(2){&mgr;-Fe(CO)(4)}] and [{PhCH(2)NMe(3)}{(&mgr;-H)Fe(2)(CO)(6)Bi(2)(&mgr;-Cl)(2)}](infinity) and Stabilization of Reduced-Hypervalent Bismuth Centers by Coordination to a Metal Center in [PhCH(2)NMe(3)](3)[Bi(3)Cl(4)(&mgr;-Cl)(4){Fe(CO)(3)}]

The reaction of [Q](2)[Bi(4)Fe(4)(CO)(13)] ([Q](2)[1]; [Q] = [Et(4)N](+), [PhCH(2)NMe(3)](+)) with MePCl(2) in MeCN is a complicated reaction which gives different results depending upon the stoichiometry of the reaction. At a ratio of 1:1.33 (cluster:phosphine), the reaction yields a mixture of the new bismuth-iron carbonyl compounds [Q][(&mgr;-H)Fe(2)(CO)(6)Bi(2){Fe(CO)(4)}] ([Q][2]), which has a tetrahedral Fe(2)Bi(2) core edge-bridged across the bismuth centers by an [Fe(CO)(4)](2)(-) fragment, and [Q](3)[Bi(3)Cl(4)(&mgr;-Cl)(4){Fe(CO)(3)}] ([Q](3)[3]), containing a reduced complex ion [Bi(3)Cl(8)](-) stabilized by coordination to an iron tricarbonyl fragment. Extended Hückel molecular orbital calculations on this unusual anion are consistent with each bismuth atom possessing the same reduced oxidation state of +2.33. The compound [Et(4)N][2] crystallizes in the triclinic space group P&onemacr; (No. 2) with a = 10.246(2) Å, b = 11.859(2) Å, c = 12.474(2) Å, alpha = 71.11(3) degrees, beta = 79.60(3) degrees, gamma = 76.37(3) degrees, V = 1384.7(4) Å(3), and Z = 2, while [PhCH(2)NMe(3)](3)[3].0.87Et(2)O was characterized in the orthorhombic space group Pbca (No. 61) with a = 20.801(4) Å, b = 19.937(4) Å, c = 25.480(5) Å, V = 10566.8(36) Å(3), and Z = 8. When the reaction is carried out at a ratio of 1:2, the novel hydride [{Q}{(&mgr;-H)Fe(2)(CO)(6)Bi(2){&mgr;-Cl}(2)}](infinity) ([{Q}{4}](infinity)) is isolated. This cluster also has a "tetrahedral" core, with the Bi-Bi vector bridged by a chloride ligand and the molecules joined into infinite polymeric chains in the solid state by the second intermolecularly-bridging chloride ligand. [{PhCH(2)NMe(3)}{4}](infinity) crystallizes in the monoclinic space group P2(1)/n (No. 14) with a = 7.864(2) Å, b = 22.465(4) Å, c = 13.797(3) Å, beta = 105.96(3) degrees, V = 2343.5(9) Å(3), and Z = 4. The metal framework of [4](-) is similar to that of [2](-) with the notable exception that the Bi-Bi bond present in [2](-) is missing in [4](-) because of the additional electrons provided by the chloride ions. At stoichiometries greater than 2:1, the previously reported [Fe(CO)(4)Bi(2)Cl(6)](2)(-) ion is formed.