Pnictogen (As,Sb, Bi) Nanosheets for Electrochemical Applications Are Produced by Shear Exfoliation Using Kitchen Blenders

Layered materials are of high importance because of their anisotropy and as a source of 2D materials. Whilst there is a plethora of multi‐elemental 2D materials, the number mono‐elemental 2D materials is rather limited. Herein, we demonstrate that aqueous shear exfoliation can be used to obtain As, Sb, and Bi exfoliated nanosheets. Morphological and chemical characterization of the exfoliated materials shows a decrease in thickness, sheet‐to‐nanosheet scale, and partial oxidation owing to a higher surface area. The electrochemical performance is tested in terms of inherent electrochemistry, electron transfer, and sensing applications as demonstrated with ascorbic acid. Potential energy‐related applications are evaluated in the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR), with shear‐exfoliated Sb having the best electrochemical performance overall. These findings will have a profound impact on the preparation and application of 2D mono‐elemental materials.     

Cytotoxicity of Shear Exfoliated Pnictogen (As,Sb, Bi) Nanosheets

The experimental achievement of phosphorene, which exhibits superior electronic, physical, and optical properties has spurred recent interest in other Group 15 elemental 2D nanomaterials such as arsenene, antimonene, and bismuthene. These unique and superior properties of the pnictogen nanosheets have spurred intensive research efforts and led to the discovery of their diversified potential applications; for instance, optical Kerr material, photonic devices, pnictogen-decorated microfibers, high-speed transistors, and flexible 2D electronics. Previous studies have mainly been dedicated to study the synthesis, properties, and applications of the heavy pnictogens nanosheets; however, the toxicological behaviour of these nanosheets has yet to be established. Herein, the cytotoxicity study of pnictogen nanosheets (As, Sb, and Bi) was conducted over 24 h of incubation with various concentrations of test materials and adenocarcinoma human lung epithelial A549 cells. After the treatment period, the remaining cell viabilities were obtained through absorbance measurements with WST-8 and MTT assays. These findings demonstrate that the toxicity of pnictogen nanosheets decreases down Group 15, whereby arsenic nanosheets are considered to be the most toxic, whereas bismuth nanosheets induce low cytotoxicity. The findings of this study constitute an important initial step towards enhancing our understanding of the toxicological effects of pnictogen nanosheets in light of their prospective commercial applications.     

Studies of cluster anions C n X− (X=N,P, As,Sb, Bi) produced by laser ablation

A series of cluster anions C _n X^? are produced from laser ablation of appropriate samples, where X is selected as a group-VB element. The recorded mass spectra of these cluster anions display a drastic even/odd alternation on ion intensities: For C _n N^?, only anions with oddn can be observed; For C _n P^? and C _n As^?, cluster anions with evenn are produced but with lower signal intensities; For C _n Sb^?, the signal intensity of clusters does not show even/odd alternation; Finally, for C _n Bi^?, the intensities of cluster anions with evenn are higher than those with oddn. This parity effect can be attributed to the linear structure of the cluster anions, and the parity reversal of C _n X^? from C _n N^? to C _n Bi^? can be explained from the electronegativity decreasing of the heteroatom X as it descends in the group. The Hückel model was applied to account the structural feature of these clusters.     

Dicationic E4 Chains (E=P,As, Sb,Bi) Embedded in the Coordination Sphere of Transition Metals

The oxidation chemistry of the complexes [{CpMo(CO)₂}₂(μ,η²:η²‐E₂)] (E=P ( A ), As ( B ), Sb ( C ), Bi ( D )) is compared. The oxidation of A – D with [Thia]⁺ (=[C₁₂H₈S₂]⁺) results in the selective formation of the dicationic E₄ complexes [{CpMo(CO)₂}₄(μ₄,η²:η²:η²:η²‐E₄)]²⁺ (E=P ( 1 ), As ( 2 ), Sb ( 3 ), Bi ( 4 )), stabilized by four [CpMo(CO)₂] fragments. The formation of the corresponding monocations [ A ]⁺, [ C ]⁺, and [ D ]⁺ could not be detected by cyclic voltammetry, EPR, or NMR spectroscopy. This finding suggests that dimerization is fast and that there is no dissociation in solution, which was also predicted by DFT calculations. However, EPR measurements of 2 confirmed the presence of small amounts of the radical cation [ B ]⁺ in solution. Single‐crystal X‐ray diffraction revealed that the products 1 and 2 feature a zigzag E₄ chain in the solid state while 3 and 4 bear a central E₄ cage with a distorted “butterfly‐like” geometry. Additionally, 1 can be easily and reversibly converted into a symmetric and an unsymmetric form.     

Triple Bonds Between Iron and Heavier Group 15 Elements in AFe(CO)3− (A=As,Sb, Bi) Complexes

Heteronuclear transition‐metal–main‐group‐element carbonyl complexes of AsFe(CO)₃^?, SbFe(CO)₃^?, and BiFe(CO)₃^? were produced by a laser vaporization supersonic ion source in the gas phase, and were studied by mass‐selected IR photodissociation spectroscopy and advanced quantum chemistry methods. These complexes have C_3v structures with all of the carbonyl ligands bonded on the iron center, and feature covalent triple bonds between bare Group 15 elements and Fe(CO)₃^?. Chemical bonding analyses on the whole series of AFe(CO)₃^? (A=N, P, As, Sb, Bi, Mc) complexes indicate that the valence orbitals involved in the triple bonds are hybridized 3d and 4p atomic orbitals of iron, leading to an unusual (dp–p) type of transition‐metal–main‐group‐element multiple bonding. The σ‐type three‐orbital interaction between Fe 3d/4p and Group 15 np valence orbitals plays an important role in the bonding and stability of the heavier AFe(CO)₃^? (A=As, Sb, Bi) complexes.     

Triple Bonds Between Iron and Heavier Group 15 Elements in AFe(CO)3− (A=As,Sb, Bi) Complexes

Heteronuclear transition‐metal–main‐group‐element carbonyl complexes of AsFe(CO)₃⁻, SbFe(CO)₃⁻, and BiFe(CO)₃⁻ were produced by a laser vaporization supersonic ion source in the gas phase, and were studied by mass‐selected IR photodissociation spectroscopy and advanced quantum chemistry methods. These complexes have C_3v structures with all of the carbonyl ligands bonded on the iron center, and feature covalent triple bonds between bare Group 15 elements and Fe(CO)₃⁻. Chemical bonding analyses on the whole series of AFe(CO)₃⁻ (A=N, P, As, Sb, Bi, Mc) complexes indicate that the valence orbitals involved in the triple bonds are hybridized 3d and 4p atomic orbitals of iron, leading to an unusual (dp–p) type of transition‐metal–main‐group‐element multiple bonding. The σ‐type three‐orbital interaction between Fe 3d/4p and Group 15 np valence orbitals plays an important role in the bonding and stability of the heavier AFe(CO)₃⁻ (A=As, Sb, Bi) complexes.     

Possibilities and limits of the simultaneous determination of As, Bi, Ge, Sb, Se, and Sn by flow injection-hydride generation-inductively coupled plasma-time-of-flight mass spectrometry (FI-HG-ICP-TOFMS)

A simultaneous multi-elemental measurement of As, Bi, Ge, Sb, Se, and Sn was performed in this study by flow injection-hydride generation-inductively coupled plasma-time-of-flight mass spectrometry (FI-HG-ICP-TOFMS). An off-line pre-reduction treatment using a solution of 5% (m/v) KI and ascorbic acid for 15 min at 80 °C is described by presenting its advantages and disadvantages and compared with the results achieved without pre-reduction. Using optimised conditions the following figures of merit were achieved: limits of detection in the 0.08-0.54 ng ml⁻¹ range and relative standard deviations (RSD) of 1.7-6.7%, respectively. Applying the presented method, two certified reference materials (NIST 1643d freshwater and PACS-2 marine sediment) were analysed to demonstrate the suitability of the method for analysis of real samples. Results obtained from treated samples showed good agreement with certified values while the untreated ones considerably departed from them.     

Phase composition and phase transformation in Bi(Sb,Nb,Ta)O4 system

In this work Bi(Sb_xNb_yTa_z)O₄ (x + y + z = 1) samples are prepared using mixed-oxide method. A pseudo-ternary phase diagram of Bi(Sb,Nb,Ta)O₄ system is given below the melting point. It is composed of a monoclinic phase region, an orthorhombic phase region and a monoclinic–orthorhombic co-existing phase region. In the orthorhombic phase region, the transformation from orthorhombic to triclinic phase is found to be sensitive to the composition and sintering temperature. Both the transformation from monoclinic to orthorhombic structure and the transformation from orthorhombic to triclinic structure have been studied by the cell parameters.     

Binary Pnictogen Azides—An Experimental and Theoretical Study: [As(N3)4]−, [Sb(N3)4]−, and [Bi(N3)5(dmso)]2−

[PPh₄][EI₄] (E=As, Sb, Bi) salts were reacted with four and five equivalents of AgN₃ to form tetraazidopnictates and pentaazidopnictates of the type [PPh₄][E(N₃)₄] and [PPh₄]₂[E(N₃)₅], respectively. The synthesis of [PPh₄][P(N₃)₄] was also attempted from the reaction of P(N₃)₃ with [PPh₄]N₃, but it yielded only the starting materials. Herein, we report the synthesis and structure elucidation of [PPh₄][E(N₃)]₄ (E=As, Sb) and pentaazidobismuthate, stabilized as the dimethyl sulfoxide (DMSO) anion adduct, [PPh₄]₂[Bi(N₃)₅(dmso)]. Successive anion formation along the series E(N₃)₃+nN₃^? (n=1–3) and E(N₃)₅+N₃^? was studied by density functional theory.