Cyclic Tribismuthide as a Piano Stool Complex Ligand - Synthesis and Crystal Structure of (η3 -Bi3 )M (CO)3 3- (M = Cr, Mo)

Insight into the formation of bismuth-tungsten carbonyl clusters

Multimetallic clusters play a key role as models to doped metals, as candidates to new types of superatomic catalysts and as precursors to new multimetallic solids. Understanding formation pathways is an essential and necessary step forward in the development of cluster synthesis and research, yet remains considerably lacking owing to difficulty in identification of intermediates and the ill-defined nature of common starting materials. Here we show progress in this regard by investigating the reactivity of an intermetallic solid of nominal composition 'K₅Ga₂Bi₄' with [W(cod)(CO)₄] upon extraction with ethane-1,2-diamine (en) and 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane (crypt-222). Several polybismuthide intermediates and by-products were identified along the reaction pathway, ultimately forming the new polybismuthide salt [K(crypt-222)]₃[µ:η³-Bi₃{W(CO)₃}₂]∙en∙tol. DFT calculations revealed plausible reaction schemes for the transformations taking place in the reaction mixture providing insight into the complex reactivity of 'K₅Ga₂Bi₄' on the basis of in situ generation of Bi₂^2-.

Infrared photodissociation spectroscopy of heteronuclear group 15 metal-iron carbonyl cluster anions AmFe(CO)n- (A = Sb, Bi; m, n = 2, 3)

Heteronuclear group 15 metal-iron carbonyl cluster complexes of A_mFe(CO)_n^- (A = Sb, Bi; m, n = 2-3) were generated in the gas phase and studied by infrared photodissociation spectroscopy in the carbonyl stretching region. Their structures were determined by comparing the experimental spectra with predicted spectra derived from DFT calculations at the B3LYP and BP86 levels. All of the A_mFe(CO)_n^- cluster anions were determined to have Fe(CO)_n^- fragments with all of the CO ligands terminally bonded to the iron center, and they can be regarded as being formed via the interactions of the neutral group 15 metal clusters with the Fe(CO)_n^- fragments. Bonding analyses indicated that each A₂Fe(CO)_n^- (n = 2, 3) cluster anion contained two A-Fe single bonds and one A-A double bond. Each A₃Fe(CO)_n^- (n = 2, 3) cluster anion involved three A-Fe single bonds and three A-A single bonds. There is an isolobal relationship between the Fe(CO)₃^- group and the group 15 atoms. The substitution of an Fe(CO)₃^- group in place of one A atom in the tetrahedral A₄ molecule resulted in an A₃Fe(CO)₃^- cluster anion with the closed-shell electronic configuration for all the group 15 metals and iron atoms.

Insights into Formation and Relationship of Multimetallic Clusters: On the Way toward Bi-Rich Nanostructures

Bismuth-rich polyanions show a unique potential in constructing nanostructured bismuth-based materials, but they are still poorly investigated. We use a ternary precursor of the nominal composition "K₅Ga₂Bi₄" for the formation of [K(crypt-222)]⁺ salts of novel Bi-rich polyanions [Bi@Ga₈(Bi₂)₆]^q- (q = 3, 5; in 1), (Ga₂Bi₁₆)^4- (in 2), and [{Ru(cod)}₄Bi₁₈]^4- (in 3). Their bismuth contents exceed that of the largest homoatomic polyanion, Bi₁₁^3-. The numbers of bismuth atoms in the anions in 2 and 3 furthermore surmount that of the Bi-richest binary main-group anion, (Ge₄Bi₁₄)^4-, and they equal (2) or surmount (3) that reported for the anion and the cations with the largest number of Bi atoms so far, [K₂Zn₂₀Bi₁₆]^6-, [(Bi₈)Ru(Bi₈)]⁶⁺, and [(Bi₈)Au(Bi₈)]⁵⁺. Compounds 1 and 2 were obtained from reaction mixtures that contain [La(C₅Me₄H)₃], apparently assisting in the network formation without being included in the products. In the presence of [Ru(cod)(H₂CC(Me)CH₂)₂], yet another reaction pathway leads to the formation of the anions in 3 (conformers 3a and 3b), which are Bi-Bi linked dimers of two "[{Ru(cod)}₂Bi₉]^2-" subunits. They comprise the largest connected assemblies of Bi atoms within one molecule and may be viewed as snapshots on the way toward even larger polybismuthide units and, ultimately, new bismuth modifications. Mass spectrometry allowed insight into the processes in solution that precede the cluster formation. In-depth quantum chemical studies were applied to explain structural peculiarities, stabilities of the observed isomers, and bonding characteristics of these bismuth-rich nanoarchitectures. The work demonstrates the high potential of the method for the access of new Bi-based materials.

[Bi6Mo3(CO)9]4-: a multiple local σ-aromatic cluster containing a distorted Bi6 triangular prism

The first Zintl cluster containing a distorted Bi₆ triangular prism, [Bi₆Mo₃(CO)₉]^4-, has been synthesized and structurally characterized. Quantum chemical calculations indicated that the distorted cage cluster features multiple local σ-aromaticity.

[(η3-Bi3)2(IrCO)6(μ4-Bi)3]3−: a new archetype of a 15-vertex deltahedral hybrid from Bixx−-coordination aggregation of cationic [IrCO]+ units

The first Zintl-deltahedral metal carbonyl hybrid [(η³-Bi₃)₂(IrCO)₆(μ₄-Bi)₃]³⁻ was obtained by a new synthetic methodology, namely the Bi_x^x−-coordination aggregation of [Ir(CO)]⁺ to trigonal prismatic [Ir(CO)]₆⁶⁺.