Stepwise Bi–Bi Bond Formation: From a Bi-centered Radical to Bi₄ Butterfly and Bi₈ Cuneane-Type Clusters

Abstract

In contrast to their lighter homologues (P, As, Sb), the synthesis of polybismuthane clusters is still restricted to classical solid-state approaches. We herein report on systematic reduction reactions of different bismuth precursors with Ga­(I) and Mg­(I) complexes. This study not only yielded the first metal-coordinated tetrabismuthane ([{L1(Cl)­Ga}2-μ,η1:1-Bi4] 3, L1 = HC­[C­(Me)­N­(2,6-i-Pr2C6H3)]2) and realgar-type bismuth cluster ([(L2Mg)4(μ4,η2:2:2:2-Bi8)] 4, L2 = HC­[C­(Me)­N­(2,4,6-Me3C6H2)]2) in addition to the bismuth-centered radical [L1Ga­(Cl)]2Bi• 1 and dibismuthene [L1(Cl)­GaBi]2 2, but clearly demonstrates the crucial role of the substituents and the oxidation state of the bismuth precursor as well as the specific reduction potential of the main group metal reductants on the product formation. Compounds 3 and 4 were spectroscopically characterized (1H, 13C NMR, IR), and the structures of 1–4 were determined by single-crystal X-ray diffraction. Computational calculations gave deeper insights into the electronic structures of 1′, 3′, and 4′.

Structural diversity of mixed polypnictogen complexes: dicationic E2E′2 (E ≠ E′ = P, As, Sb, Bi) chains, cycles and cages stabilized by transition metals

“…So far, only similar metal-coordinated Sb 4 and Bi 4 complexes have been reported either as dicationic ( VIII and IX ) 11 or as neutral species. 26 In contrast, 3a and 4a exhibit central cage-like As 2 Sb 2 and As 2 Bi 2 cores, respectively, which differ from the hitherto discussed structures. The structure in 3a reveals to be a very remarkable intermediate stage between the zigzag E 4 and E 2 E′ 2 chains in 1 , 2 , VI and VII on the one hand, and the distorted “butterfly-like” E 4 and Sb 2 Bi 2 cages in 5 , VIII and IX on the other hand.…”

Synthesis, structure and bonding nature of heavy dipnictene radical anions

“…carbon-based ligands, 4 amides, 5 boryles, 6 ferrocenyls, 7 and phosphanides. 8 In addition, carbene-coordinated homonuclear π-bonded diatomic p-block elements compounds 9 and L(X)Ga-substituted dipnictenes [L(X)GaE] 2 were structurally characterized, 10 and their electronic nature was analysed by quantum chemical calculations. 11 The LUMO of dipnictenes containing σ-bonded ligands is typically represented by low-lying π* orbitals, whereas the level of the molecular orbitals of the π orbitals are somewhat indistinct since their energy levels are close to those of n + orbital or high lying σ bonds (in phase integration of lone pairs).…”

Long‐Lived Radicals of the Heavier Group 15 Elements Arsenic, Antimony, and Bismuth

“…When employing Cp Ar AsCl 2 (Cp Ar = C 5 (4‐ t BuC 6 H 4 ) 5 ) as a more weakly bound and sterically more demanding Cp Ar ligand‐containing compound, the isolation of arsanyl radical [L(Cl)Ga] 2 As · ( 39 ) was achieved (Scheme ) . Moreover, bismuthanyl radical [L(Cl)Ga] 2 Bi · ( 40 ) was formed as a side product in reactions of LGa with Cp* 2 BiCl or BiCl 3 , and was also structurally characterized in the solid‐state …”