A strategy for the generation of arsenium dication equivalents from readily available and easy-to-handle phenylarsine oxide and Tf2O has been developed. The in situ-generated dication equivalent can react with biarylborates to directly produce the corresponding dibenzoarsoles, which are difficult to prepare by other means, via the successive formation of inter- and intramolecular C-As bonds. Furthermore, the unique oxygen atom insertion into the C-As bond in the dibenzoarsole is developed to form the corresponding [1,2]oxarsinine derivative.

Although it marks a cornerstone of pnictogenium ion [R2Pn][+] reactivity, the insertion of arsenium ions [R2As][+] into non-polar bonds remains highly challenging. Herein, a synthetic approach is developed, which circumvents the limitations of insertion reactivity of [R2As][+] (e.g., formal redox state of +V at As) via alleviation of ring strain in the substrate. Thus, unlocking arsenium ion bond insertion delivers the ring-expanded complexes [{LnM}(η[3]-Pn3AsCy2][TEF] ({LnM} = Cp[‴]Ni, Pn = P (1); {LnM} = {CpMo(CO)2}, Pn = P (2), As (5); Cp[‴] = 1,2,4-[t]Bu3C5H2, [TEF][-] = [Al{OC(CF3)3}4][-]). Computational analysis of the reaction mechanism and quantum crystallographic investigation of 1 highlight the release of ring strain as the crucial driving force for this reactivity. This rational is corroborated by the isolation of the arsenium ion coordinated [{CpMo(CO)2}2(μ,η[2:2]-P2AsCy2)][TEF] (3) as well as the phosphenium ion inserted [{CpMo(CO)2}(η[3]-As3PPh2)][TEF] (4).

The synthesis and structural characterization of a slightly distorted square pyramidal arsenium cation is reported. Spectroscopic, crystallographic, and computational evidence indicate that coordination of typical Lewis bases to the As(III)-center induces its oxidation to As(V) with concomitant reduction of the supporting, redox-active bis(amidophenolate) ligand. That reaction is reversible and represents a well-defined example of base-induced electromerism in an As-complex. Single electron reduction of the same As(III) species initially generates a ligand-centered radical, which is persistent enough to be observed by EPR but slowly decays to a heterodimer. Preliminary experiments demonstrate the utility of the As(III)-cation as initiator for transfer hydrogenation reactions.

This article explores recent advancements and innovative strategies in biosorption technology, with a particular focus on the removal of heavy metals, such as Cu(II), Pb(II), Cr(III), Cr(VI), Zn(II), and Ni(II), and a metalloid, As(V), from various sources. Detailed information on biosorbents, including their composition, structure, and performance metrics in heavy metal sorption, is presented. Specific attention is given to the numerical values of the adsorption capacities for each metal, showcasing the efficacy of biosorbents in removing Cu (up to 96.4%), Pb (up to 95%), Cr (up to 99.9%), Zn (up to 99%), Ni (up to 93.8%), and As (up to 92.9%) from wastewater and industrial effluents. In addition, the issue of biosorbent deactivation and failure over time is highlighted as it is crucial for the successful implementation of adsorption in practical applications. Such phenomena as blockage by other cations or chemical decomposition are reported, and chemical, thermal, and microwave treatments are indicated as effective regeneration techniques. Ongoing research should focus on the development of more resilient biosorbent materials, optimizing regeneration techniques, and exploring innovative approaches to improve the long-term performance and sustainability of biosorption technologies. The analysis showed that biosorption emerges as a promising strategy for alleviating pollutants in wastewater and industrial effluents, offering a sustainable and environmentally friendly approach to addressing water pollution challenges.

A systematic study on the reactivity of the cyclo-P4 complexes [Cp[R]Ta(CO)2(η[4]-P4)] towards pnictogenium cations results in the formation of functionalised interpnictogen cations. Phosphenium ions insert into one of the P-P bonds to give ring-expanded cyclo-P5R2 products. In contrast, an arsenium-functionalised P4AsCy2 ligand displays an interesting borderline case between ring expansion and coordination, while stibenium cations afford addition products. Tuning of the steric and electronic properties of the stibenium ion shows a drastic influence on the reaction outcome.

The newly prepared and fully characterized stibenium and bismuthenium ions [Rind MesE]+ (E=Sb, Bi; Rind =dispiro[fluorene-9,3'-(1',1',7',7'-tetramethyl-s-hydrindacen-4'-yl)-5',9''-fluorene) were rigorously compared to the previously communicated phosphenium and arsenium ions (E=P, As) as well as the bis(m-terphenyl) pnictogenium ions [(2,6-Mes2 C6 H3)2 E]+ (E=Sb, Bi). It is demonstrated that the choice of the aryl substituents dramatically effects the molecular structures (e. g. the primary E-C bond lengths) and the electronic structures (e. g. the energy of the LUMOs).

This contribution aims to demonstrate the scope of new hybrids between biomass and metal-organic frameworks (MOF@biomass) used in the adsorption process of pollutants. After a brief presentation of the use of the main series of MOFs as efficient adsorbents for different types of pollutants, the limitations of these structures related to particle size and hydrodynamic problems during their application are highlighted. Lignocellulosic biomasses are also recognized as an alternative adsorbent, mainly due to their high natural abundance and their low environmental impact during and after their application. The limited capacity of bioadsorbents becomes important in this research. Consequently, the largest amount of information existing in the last ten years on MOF-Biomass functionalization as a hybrid and improvement technology for adsorption processes is compiled, analyzed, compared and contrasted. So far, there is no evidence of works that exploit the concept of functionalization of adsorbents of different nature to give rise to new hybrid materials. Through this review it was found that the hybrids obtained show a higher adsorption capacity (Qe) compared to their precursors, due to the increase of organic functional groups provided by the biomass. Thus, for heavy metals, dyes, Arsenium anions and other organic and pharmaceutical compounds, there are increases in Qe of about 100 mg g-1. The possibility of the new hybrid being studied for desorption and reuse processes is also raised, resulting in a new line of research that is attractive for the industry from an economic and environmental point of view. The functionalization methods and techniques used in the studies cited in this article are outlined. In conclusion, this research brings a new horizon of study in the field of adsorption and mentions the main future challenges related to new sustainable applications.

Carbenes and their analogues have constantly enthralled chemists with their intriguing reactivity of ambiphilic character stemming from their electronic structures. Phosphenium and arsenium ions are fiercely reactive cationic species, the stabilization of which has been so far achieved in the condensed phase by dispersing the positive charge through electromeric conjugation with at least one electron-rich substituent (frequently amido groups). Although observed in the gas phase, the isolation of dicoordinate phosphenium and arsenium ions lacking such stabilizing ligands has eluded chemists for decades. Herein we show that by judicious choice of aromatic substituents, dicoordinate, donor-free, Lewis-superacidic phosphenium and arsenium ions can be kinetically stabilized. They feature singlet electronic ground states possessing a vacant p-orbital and an electron lone pair with predominantly s-character.

By reacting [{Cp‴Fe(CO)2}2(µ,η1:1-P4)] (1) with in situ generated phosphenium ions [Ph2P][A] ([A]- = [OTf]- = [O3SCF3]-, [PF6]-), a mixture of two main products of the composition [{Cp‴Fe(CO)2}2(µ,η1:1-P5(C6H5)2)][PF6] (2a and 3a) could be identified by extensive 31P NMR spectroscopic studies at 193 K. Compound 3a was also characterized by X-ray diffraction analysis, showing the rarely observed bicyclo[2.1.0]pentaphosphapentane unit. At room temperature, the novel compound [{Cp‴Fe}(µ,η4:1-P5Ph2){Cp‴(CO)2Fe}][PF6] (4) is formed by decarbonylation. Reacting 1 with in situ generated diphenyl arsenium ions gives short-lived intermediates at 193 K which disproportionate at room temperature into tetraphenyldiarsine and [{Cp‴Fe(CO)2}4(µ4,η1:1:1:1-P8)][OTf]2 (5) containing a tetracyclo[3.3.0.02,7.03,6]octaphosphaoctane ligand.

Transient phosphenium and arsenium ions, generated by fluoride abstraction from bis(m-terphenyl)fluoropnictogens, underwent intramolecular electrophilic attack prior to methyl group migration and gave rise to isolable 9-phospha- and 9-arsena-fluorenium ions.

Fluoride abstraction from bis-m-terphenylelement fluorides (2,6-Mes2 C6 H3)2 EF (E=P, As) generated the highly reactive phosphenium ion [(2,6-Mes2 C6 H3)2 P][+] and the arsenium ion [(2,6-Mes2 C6 H3)2 As][+] , which immediately underwent intramolecular electrophilic substitution and formation of an 1,2,4-trimethyl-6-mesityl-5-m-terphenyl-benzo[b]phospholium ion and an 1,2,4-trimethyl-6-mesityl-5-m-terphenyl-benzo[b]arsolium ion, respectively. The formation of the latter involved a methyl group migration from the ortho-position of a flanking mesityl group to the meta-position. This reactivity of [(2,6-Mes2 C6 H3)2 E][+] (E=P, As) is in sharp contrast to the related stibenium ion [(2,6-Mes2 C6 H3)2 Sb][+] and bismuthenium ion [(2,6-Mes2 C6 H3)2 Bi][+] , which have been recently isolated and fully characterized (Angew. Chem. Int. Ed. 2018, 57, 10080-10084). On the basis of DFT calculations, a mechanism for the rearrangement of the phosphenium and arsenium ions into the phospholium and arsolium ions is proposed, which is not feasible for the stibenium and bismuthenium ions.

Stable acyclic arsenium cations R2 As+ , isoelectronic analogues of germylenes, are rare in comparison to the corresponding phosphenium cations. The first example of a diphosphaarsenium salt, [{(Dipp)2 P}2 As][Al{OC(CF3)3 }4 ]⋅1 1 / 2 PhMe, is described. This salt exhibits remarkable stability due to the delocalisation of a lone pair from a planar phosphorus centre into the vacant p-orbital at arsenic; the bonding in 2 has been probed by DFT calculations. An attempt to synthesise an analogous diphosphaphosphenium salt unexpectedly generated the cyclic phosphonium salt [cyclo-{(Mes)P}2 P(Mes)2 ][BArF 4 ]⋅CyMe through the cyclisation of a putative phosphine-substituted diphosphene cation intermediate.

This study aimed to investigate the effects of gallium-aluminum-arsenium (GaAlAs) (670 nm) laser therapy on neoangiogenesis and fibroplasia during tissue remodelling. Forty male Wistar rats underwent cutaneous surgery and were divided into 2 experimental groups: the Control and Laser group (9 mW, 670 nm, 0.031 W/cm2 , 4 J/cm2). After 14, 21, 28, and 35 days, the animals were euthanised. Descriptive and quantitative analyses were performed in sections stained with haematoxylin-eosin and Sirius Red, respectively. The amounts of VEGF+ and CD31+ cells were evaluated by immunohistochemistry and histomorphometric analysis, respectively. Statistical analysis was performed using the Mann-Whitney, Friedman, and Spearman correlation test, P < 0.05. The collagen expression was significantly higher in the laser group compared with the control group on days 14 and 21 after the creation of the skin wound (P = 0.008; P = 0.016) and in the control group between 14 and 28 and 14 and 35 days (P = 0.001; P = 0.007). There were more blood vessels in three periods of the study only in the (Laser) treated group, with statistical significance at day 14 (P = 0.016). There was no statistically significant difference in VEGF+ cell count in the different experimental groups throughout the study, although a positive correlation was shown with the area of collagen on days 14 and 28 (P = 0.037). Laser treatment had a positive effect in the late course of healing, particularly with regards to collagen expression and the number of newly formed vessels. VEGF+ cells were present in both experimental groups, and VEGF appeared to influence fibroplasia in the treated group.

Most luminescent biosensors for heavy metals are fluorescent and rely on intensity measurements, whereas a few are ratiometric and rely on spectral changes. Bioluminescent biosensors for heavy metals are less common. Firefly luciferases have been coupled to responsive promoters for mercury and arsenium, and used as light on biosensors. Firefly luciferase bioluminescence spectrum is naturally sensitive to heavy metal cations such as zinc and mercury and to pH. Although pH sensitivity of firefly luciferases was shown to be useful for ratiometric estimation of intracellular pH, its potential use for ratiometric estimation of heavy metals was never considered. Using the yellow-emitting Macrolampis sp2 firefly luciferase and site-directed mutagenesis, we show that the residues H310 and E354 constitute two critical sites for metal sensitivity that can be engineered to increase sensitivity to zinc, nickel, and mercury. A linear relationship between cation concentration and the ratio of bioluminescence intensities at 550 and 610 nm allowed, for the first time, the ratiometric estimation of heavy metals concentrations down to 0.10 mM, demonstrating the potential applicability of firefly luciferases as enzymatic and intracellular ratiometric metal biosensors.