Hexaazide octahedral molybdenum cluster complexes: synthesis, properties and the evidence of hydrolysis

This article reports the synthesis, crystal structure of new molybdenum hexaazide cluster complex (ⁿBu₄N)₂[{Mo₆I₈}(N₃)₆] (3) and comparison of its photophysical and electrochemical properties to those of earlier reported analogues (ⁿBu₄N)₂[{M₆X₈}(N₃)₆] (X = Cl, Br). Additionally, the dimerisation of 3 as a result of hydrolysis was revealed by mass spectrometry and single crystal X-Ray diffraction. Indeed, the structurally characterised compound (ⁿBu₄N)₄[{Mo₆I₈}(N₃)₅)₂O] represents the first example of oxo-bridged dimer of octahedral molybdenum clusters complexes

From photoinduced to dark cytotoxicity via an octahedral cluster hydrolysis

Octahedral molybdenum and tungsten clusters have potential biological applications in photodynamic therapy and bioimaging. However, poor solubility and hydrolysis stability of these compounds hinder their application. The first water-soluble photoluminescent octahedral tungsten cluster [{W6I8}(DMSO)6](NO3)4 was synthesised and demonstrated to be at least one order of magnitude more stable towards hydrolysis than its molybdenum analogue. Biological studies of the compound on larynx carcinoma cells suggest that it has a significant photoinduced toxicity, while the dark toxicity increases with the increase of the degree of hydrolysis. The increase of the dark toxicity is associated with the in situ generation of nanoparticles that clog up the cisternae of rough endoplasmic reticulum

Ovothiol A is the Main Antioxidant in Fish Lens

Tissue protection from oxidative stress by antioxidants is of vital importance for cellular metabolism. The lens mostly consists of fiber cells lacking nuclei and organelles, having minimal metabolic activity; therefore, the defense of the lens tissue from the oxidative stress strongly relies on metabolites. Protein-free extracts from lenses and gills of freshwater fish, Sander lucioperca and Rutilus rutilus lacustris, were subjected to analysis using high-field 1H NMR spectroscopy and HPLC with optical and high-resolution mass spectrometric detection. It was found that the eye lenses of freshwater fish contain high concentrations of ovothiol A (OSH), i.e., one of the most powerful antioxidants exciting in nature. OSH was identified and quantified in millimolar concentrations. The concentration of OSH in the lens and gills depends on the fish genus and on the season. A possible mechanism of the reactive oxygen species deactivation in fish lenses is discussed. This work is the first to report on the presence of OSH in vertebrates. The presence of ovothiol in the fish tissue implies that it may be a significantly more common antioxidant in freshwater and marine animals than was previously thought

The Application of Quantitative Metabolomics for the Taxonomic Differentiation of Birds

In the current pilot study, we propose the use of quantitative metabolomics to reconstruct the phylogeny of vertebrates, namely birds. We determined the concentrations of the 67 most abundant metabolites in the eye lenses of the following 14 species from 6 orders of the class Aves (Birds): the Black kite (Milvus migrans), Eurasian magpie (Pica pica), Northern raven (Corvus corax), Eurasian coot (Fulica atra), Godlewski’s bunting (Emberiza godlewskii), Great crested grebe (Podiceps cristatus), Great tit (Parus major), Hawfinch (Coccothraustes coccothraustes), Hooded crow (Corvus cornix), House sparrow (Passer domesticus), Rock dove (Columba livia), Rook (Corvus frugilegus), Short-eared owl (Asio flammeus) and Ural owl (Strix uralensis). Further analysis shows that the statistical approaches generally used in metabolomics can be applied for differentiation between species, and the most fruitful results were obtained with hierarchical clustering analysis (HCA). We observed the grouping of conspecific samples independently of the sampling place and date. The HCA tree structure supports the key role of genomics in the formation of the lens metabolome, but it also indicates the influence of the species lifestyle. A combination of genomics-based and metabolomics-based phylogeny could potentially resolve arising issues and yield a more reliable tree of life

Evidences of the non-stoichiometry and control of the composition of the cluster-based solid solution K6[Re6-xMoxS8(CN)5] (x=2.75-3.63)

International audienceIn this work, we investigated a high-temperature reaction between ReS2, MoS2 and KCN resulting in the formation of the cluster-based K6[Re6-xMoxS8(CN)5] solid solution. The crystal structure is based on chains of [Re6-xMoxS8(CN)6] cluster units. It was found that both the sintering temperature of starting sulfides and the reaction temperature with KCN have an influence on the composition of the product allowing x to be varied within the range x = 2.75-3.63. The molar ration of ReS2:MoS2:KCN loaded composition is fixed to 3:3:14 in all experiments. Energy dispersive spectroscopy (EDS), powder X-ray diffraction (PXRD) and high-resolution electrospray (ESI) mass spectrometry were used to characterize the solid solution K6[Re6-xMoxS8(CN)5]. It was shown by mass spectrometry that the solid solution with fractional x contains anions based on the {Re4Mo2S8}, {Re3Mo3S8} and {Re2Mo4S8} cluster cores in different proportions depending on the above-mentioned factors. Particularly, the rise of the temperature of the synthesis or temperature of sintering of metal sulfides led to increase of the rhenium content in the solid solution

Seasonal Variations and Interspecific Differences in Metabolomes of Freshwater Fish Tissues: Quantitative Metabolomic Profiles of Lenses and Gills

This work represents the first comprehensive report on quantitative metabolomic composition of tissues of pike-perch (Sander lucioperca) and Siberian roach (Rutilus rutilus lacustris). The total of 68 most abundant metabolites are identified and quantified in the fish lenses and gills by the combination of LC-MS and NMR. It is shown that the concentrations of some compounds in the lens are much higher than that in the gills; that indicates the importance of these metabolites for the adaptation to the specific living conditions and maintaining the homeostasis of the fish lens. The lens metabolome undergoes significant seasonal changes due to the variations of dissolved oxygen level and fish feeding activity. The most season-affected metabolites are osmolytes and antioxidants, and the most affected metabolic pathway is the histidine pathway. In late autumn, the major lens osmolytes are N-acetyl-histidine and threonine phosphoethanolamine (Thr-PETA), while in winter the highest concentrations were observed for serine phosphoethanolamine (Ser-PETA) and myo-inositol. The presence of Thr-PETA and Ser-PETA in fish tissues and their role in cell osmotic protection are reported for the first time. The obtained concentrations can be used as baseline levels for studying the influence of environmental factors on fish health

Quantitative Metabolomic Dataset of Avian Eye Lenses

Metabolomics is a powerful set of methods that uses analytical techniques to identify and quantify metabolites in biological samples, providing a snapshot of the metabolic state of a biological system. In medicine, metabolomics may help to reveal the molecular basis of a disease, make a diagnosis, and monitor treatment responses, while in agriculture, it can improve crop yields and plant breeding. However, animal metabolomics faces several challenges due to the complexity and diversity of animal metabolomes, the lack of standardized protocols, and the difficulty in interpreting metabolomic data. The current dataset includes quantitative metabolomic profiles of eye lenses from 26 bird species (111 specimens) that can aid researchers in developing new experiments, mathematical models, and integrating with other “-omics” data. The dataset includes raw 1H NMR spectra, protocols for sample preparation, and data preprocessing, with the final table containing information on the abundance of 89 reliably identified and quantified metabolites. The dataset is quantitative, making it relevant for supplementing with new specimens or comparison groups, followed by data mining and expected new interpretations. The data were obtained using the bird specimens collected in compliance with ethical standards and revealed potential differences in metabolic pathways due to phylogenetic differences or environmental exposure

Easy Ligand Activation in the Coordination Sphere of Ru inside the [PW11O39]7– Backbone

Irradiation of the Keggin-type [PW11O39{Ru(NO)}]4− (Ru-NO) polyoxometalate in CH3CN results in rapid NO ligand elimination with the formation of [PW11O39{RuIII(CH3CN)}]4− (Ru-CH3CN). This complex offers an easy entry into the Ru-based chemistry of the {PW11Ru} complex. Attempts to substitute N3− for CH3CN in the presence of an NaN3 excess lead a variety of products: (i) [PW11O39{RuIII(N3)}]4− (Ru-N3); (ii) [PW11O39{RuIII(N4HC-CH3)}]4− (Ru-Tz) as a click-reaction product; and (iii) [PW11O39{RuII(N2)}]5− (Ru-N2). UV-VIS, CV, and HR-ESI-MS techniques were used for the reaction monitoring and characterization of the products

Molecular heterometallic clusters [Re6−xMoxS8L6] (x = 2–3, L = py, etpy, tbp): negligible influence of the x value on the crystal structures

International audienceThe influence of the metal ratio on the geometric characteristics and crystal structures of heterometallic clusters with {Re6−xMoxQ8} cores was studied. For this purpose, nine new molecular cluster complexes of the type [Re6−xMoxS8L6] (x = 2, 3 or non-integer value between 2 and 3; L = pyridine, 4-ethylpyridine or 4-tert-butylpyridine) were synthesized. The compounds were obtained by one-step replacement of the cyanide apical ligands of [Re6−xMoxS8(CN)6]5−/4− cluster complexes with the corresponding organic compounds under solvothermal conditions. The crystal structures of all the obtained compounds were investigated by single-crystal X-ray diffraction analysis. Analysis of the crystal structures showed that clusters with the same apical ligands and different x values have similar geometries and form isostructural packings, demonstrating the formation of solid solutions

Coordination capacity of Keggin anions as polytopic ligands: case study of [VNb 12 O 40 ] 15

International audienceReaction of Na9H4[VNb12O40{NbO(CO3)}2] with [(C6H6)RuCl2]2 (molar ratio {VNb12}:{(C6H6)Ru} = 1:4) in aqueous solution gives a mixture of [α-{(C6H6)Ru}4VNb12O40] 7and [α-{(C6H6)Ru}3VNb12O40] 9-. Direct acetone diffusion into mother liquor leads to crystallization of Na6H[α-{(C6H6)Ru}4VNb12O40]•41.25H2O (1), characterized by single crystal x-ray diffraction (SCXRD). This anion has four organometallic fragments asymmetrically coordinated to the α-Keggin type [VNb12O40] 15backbone. Three {(C6H6)Ru} 2+ groups cap triangular faces and one group a rectangular face of [VNb12O40] 15-. Equilibrated mixture of [α-{(C6H6)Ru}4VNb12O40] 7and [α-{(C6H6)Ru}3VNb12O40] 9was studied by 1 H DOSY NMR, HPLC-ICP-AES and HPLC-ESI-MS combined techniques. Direct chromatographic separation of these complexes results in unexpected transformation of both species into [α-{(C6H6)Ru}5VNb12O40] 5-, isolated and characterized as Na5[α-{(C6H6)Ru}5VNb12O40]•16H2O (2). This anion contains five symmetrically coordinated organometallic groups occupying both triangular and rectangular faces