The First Naked Bismuth–Chalcogen Metal Carbonyl Clusters: Extraordinary Nucleophilicity of the Bi Atom and Semiconducting Characteristics

Abstract

Mixed bismuth–chalcogen–iron clusters [{EFe3(CO)9}­Bi]− [E = Te (1a) or Se (1b)] were produced via the reduction of BiCl3 with [EFe3(CO)9]2– under mild conditions. X-ray analysis showed that both clusters 1a and 1b had a square-pyramidal geometry, where the naked Bi and chalcogen both adopted a distorted trigonal-pyramidal configuration with a stereoactive lone pair. Complexes 1a and 1b can be further functionalized by methylation and metalation, which permits the nucleophilicity of the 6s/5s and 6s/4s lone pairs to be compared. In the metalation, the 6s pair of the Bi atom in 1a and 1b had an extraordinary nucleophilicity toward the unsaturated Cr­(CO)5 fragment, even in the presence of the more chemically active 5s or 4s pair, whereas in the case of methylation, only the 4s pair of Se could be selectively alkylated. Upon oxidation of 1a and 1b with suitable oxidizing agents, NaBiO3 or K2SeO3, Bi–E bonded tetrahedral complexes [{EFe2(CO)6}­Bi]− [E = Te (4a) or Se (4b)] were formed by the elimination of one Fe­(CO)3 vertex. X-ray photoelectron spectroscopy, X-ray absorption near-edge structure, and density functional theory (DFT) calculations showed that all of the Bi atoms in these complexes had oxidation states close to +1. Due to the electropositive character of the Bi atom, pronounced induced Bi···E inter- and intramolecular interactions were evident in 1a (1b), 4a (4b), and the metalated 3a (3b), where their linear-like ···Bi···E··· or zigzag-like ···Bi–E··· (E = Te or Se) chain or the Bi···E···E···Bi (E = Te or Se) dimeric chain can further expand into the two-dimensional network via nonclassical C–H···O­(carbonyl) interactions, supported by noncovalent interaction index and DFT calculations. These positively charged Bi-induced Bi···E (E = Te or Se) and carbonyl-aided weak interactions can facilitate efficient electron transport within these ternary Bi–E–Fe or quaternary Bi–E–Fe–Cr cluster-based frameworks, resulting in semiconducting behavior with surprising ultranarrow energy gaps of 1.01–1.21 eV.

Carbonyl Chalcogenide Cluster-based Polymers

“…These square pyramidal complexes also can be demetalated to give tetrahedral anionic complexes [{EFe 2 (CO) 6 }Bi] À (E ¼ Te, Se), in which the reactive sites can be understood by their corresponding HOMO orbitals. 18 Importantly, these square pyramidal, tetrahedral, and Cr(CO) 5 -decorated complexes were found to have intra-and intermolecular BiÁ Á ÁE interactions to give Á Á ÁBiÁ Á ÁEÁ Á Á chains or BiÁ Á ÁEÁ Á ÁEÁ Á ÁBi (E ¼ Te or Se) dimers. These chains or dimeric units were further connected to their counterions through C-HÁ Á ÁO(carbonyl) hydrogen bonds to give 2D supramolecular networks (Figure 1.6).…”

“…Recently, a new series of small-to medium-to large-sized manganese telluride carbonyl clusters have been synthesized. 18 ] compounds (Scheme 1.1). 8 It was worth noting that two large-sized, electron-precise clusters [Mn 6 Te 6 (CO) 18 ] 4À and [Mn 6 Te 10 (CO) 18 ] 4À possessed unusual paramagnetic properties with S ¼ 1, derived from the presence of two types of Mn atoms in different oxidation states in the compounds.…”

“…Recently, a rare class of mixed pnictogen (Bi and Sb) and chalcogen (Te, Se, or S) iron carbonyl clusters were systematically synthesized. 18,19 In the case of the Bi system, when A Te or A Se was treated with BiCl 3 , square pyramidal anionic complexes [EBiFe 3 (CO) 9 ] À (E ¼ Te, Se) were obtained (Scheme 1.4). 18 Complexes [EBiFe 3 (CO) 9 ] À (E ¼ Te, Se) displayed a BiEFe 2 basal plane with an apical Fe(CO) 3 fragment, in which both the Bi and chalcogen atom possessed an outward stereoactive lone pair.…”

“…18,19 In the case of the Bi system, when A Te or A Se was treated with BiCl 3 , square pyramidal anionic complexes [EBiFe 3 (CO) 9 ] À (E ¼ Te, Se) were obtained (Scheme 1.4). 18 Complexes [EBiFe 3 (CO) 9 ] À (E ¼ Te, Se) displayed a BiEFe 2 basal plane with an apical Fe(CO) 3 fragment, in which both the Bi and chalcogen atom possessed an outward stereoactive lone pair. These square pyramidal complexes can undergo methylation and metalation via competitive 6s/5s and 6s/4s lone pairs selectivity, to give a 4s-methylated compound {(Me)SeFe 3 (CO) 9 }Bi, 6s-Cr(CO) 5 -decorated complexes [BiEFe 3 (CO) 9 {Cr(CO) 5 }] À (E ¼ Te, Se) (Scheme 1.4).…”

A Survey of Supramolecular Aggregation Based on Main Group Element⋯Selenium Secondary Bonding Interactions—A Survey of the Crystallographic Literature

“…The three remaining crystals feature one-dimensional chains. In 39 [61], of interest owing to a semi-conducting character and where a Bi-Se atom pair caps a Fe2(CO)6 unit, the presence of Bi … Se interactions lead to a helical, supramolecular chain; Figure 11c. A helical chain is also observed in 40 [62], Figure 11d, again sustained by, on average one Bi … Se interaction per repeat unit.…”