Isolation of an organometallic yttrium bismuth cluster and elucidation of its electronic structure

Effect of La3+ on the Formation of Endohedral Zintl Clusters Featuring In/Bi Shells

Investigating the interactions of f-block metal ions with p-block polyanions in multinary cluster compounds is becoming increasingly attractive but remains a challenge in terms of both the synthetic approach and the control of the structures that are formed during the syntheses. So far, two types of reactions were dominant for the formation of corresponding clusters: the reaction of binary anions of p-block elements in 1,2-diamino-ethane (en) solutions or the reaction of organobismuth compounds with corresponding f-block metal complexes in THF. Herein, we report the synthesis of [La@In2Bi11]4- (1) and its doubly μ-Bi-bridged analogue in the doubly [K(crypt-222)]+-coordinated {[K(crypt-222)]2[La@In2Bi11](μ-Bi)2[La@In2Bi11]}4- (2) as their [K(crypt-222)]+ salts [K(crypt-222)]41 and [K(crypt-222)]42, respectively, achieved by reactions of [InMes3] and [La(C5Me4H)3] (Mes = mesityl, C5Me4H = tetramethylcyclopentadienyl) with K10Ga3Bi6.65/crypt-222 (crypt-222 = 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane) in en. In the absence of [La(C5Me4H)3], the otherwise unchanged reactions afford the anions [Bi6(InMes)(InMes2)]3- (3) and [Mes3In-InMes3]2- (4) instead, which can be isolated as their [K(crypt-222)]+ salts [K(crypt-222)]33 and [K(crypt-222)]24·tol (tol = toluene), respectively. The {Bi6} fragment observed in anion 3 is assumed to be one of the key intermediates not only toward the formation of 1 and 2 but also on the way to more general bismuth rich compounds.

A defect-enriched PdMo bimetallene for ethanol oxidation reaction and 4-nitrophenol reduction

A defect-enriched PdMo bimetallene (d-PdMo) was prepared by a one-pot wet chemical reaction followed by post-treatment of oxidative etching. The introduction of defects can tailor the electronic structure of PdMo bimetallene and the prepared d-PdMo bimetallene exhibited excellent performance in the ethanol oxidation reaction (EOR) and 4-nitrophenol (4-NP) reduction reaction.

Stabilizing Monoatomic Two-Coordinate Bismuth(I) and Bismuth(II) Using a Redox Noninnocent Bis(germylene) Ligand

The formation of isolable monatomic BiI complexes and BiII radical species is challenging due to the pronounced reducing nature of metallic bismuth. Here, we report a convenient strategy to tame BiI and BiII atoms by taking advantage of the redox noninnocent character of a new chelating bis(germylene) ligand. The remarkably stable novel BiI cation complex 4, supported by the new bis(iminophosphonamido-germylene)xanthene ligand [(P)GeII(Xant)GeII(P)] 1, [(P)GeII(Xant)GeII(P) = Ph2P(NtBu)2GeII(Xant)GeII(NtBu)2PPh2, Xant = 9,9-dimethyl-xanthene-4,5-diyl], was synthesized by a two-electron reduction of the cationic BiIIII2 precursor complex 3 with cobaltocene (Cp2Co) in a molar ratio of 1:2. Notably, owing to the redox noninnocent character of the germylene moieties, the positive charge of BiI cation 4 migrates to one of the Ge atoms in the bis(germylene) ligand, giving rise to a germylium(germylene) BiI complex as suggested by DFT calculations and X-ray photoelectron spectroscopy (XPS). Likewise, migration of the positive charge of the BiIIII2 cation of 3 results in a bis(germylium)BiIIII2 complex. The delocalization of the positive charge in the ligand engenders a much higher stability of the BiI cation 4 in comparison to an isoelectronic two-coordinate Pb0 analogue (plumbylone; decomposition below -30 °C). Interestingly, 4[BArF] undergoes a reversible single-electron transfer (SET) reaction (oxidation) to afford the isolable BiII radical complex 5 in 5[BArF]2. According to electron paramagnetic resonance (EPR) spectroscopy, the unpaired electron predominantly resides at the BiII atom. Extending the redox reactivity of 4[OTf] employing AgOTf and MeOTf affords BiIII(OTf)2 complex 7 and BiIIIMe complex 8, respectively, demonstrating the high nucleophilic character of BiI cation 4.

f-Element heavy pnictogen chemistry

The coordination and organometallic chemistry of the f-elements, that is group 3, lanthanide, and actinide ions, supported by nitrogen ligands, e.g. amides, imides, and nitrides, has become well developed over many decades. In contrast, the corresponding f-element chemisty with the heavier pnictogen analogues phosphorus, arsenic, antimony, and bismuth has remained significantly underdeveloped, due largely to a lack of suitable synthetic methodologies and also the inherent hard(f-element)-soft(heavier pnictogen) acid-base mismatch, but has begun to flourish in recent years. Here, we review complexes containing chemical bonds between the f-elements and heavy pnictogens from phosphorus to bismuth that spans five decades of endeavour. We focus on complexes whose identity has been unambiguously established by structural authentication by single-crystal X-ray diffraction with respect to their synthesis, characterisation, bonding, and reactivity, in order to provide a representative overview of this burgeoning area. By highlighting that much has been achieved but that there is still much to do this review aims to inspire, focus and guide future efforts in this area.