Exploration of New Birefringent Crystals in Bismuth d0 Transition Metal Selenites

The first examples of bismuth fluoride selenites with d⁰-TM/Te^VI polyhedrons, namely, Bi₄TiO₂F₄(SeO₃)₄ ( 1 ), Bi₄NbO₃F₃(SeO₃)₄ ( 2 ), Bi₄TeO₄F₂(TeO₃)₂(SeO₃)₂ ( 3 ), Bi₂F₂(MoO₄)(SeO₃) ( 4 ) and Bi₂ZrO₂F₂(SeO₃)₂ ( 5 ) have been successfully synthesized under hydrothermal reactions by aliovalent substitution. The five new compounds feature three different types of structures. Compounds 1 – 3 , containing Ti^IV, Nb^V and Te^VI respectively, are isostructural, exhibiting a new 3D framework composed of a 3D bismuth oxyfluoride architecture, with intersecting tunnels occupied by d⁰-TM/Te^VI octahedrons and selenite/tellurite groups. Interestingly, compound Bi₄TeO₄F₂(TeO₃)₂(SeO₃)₂ ( 3 ) is the first structure containing Se^IV and mixed-valent Te^IV/Te^VI cations simultaneously. Compound 4 features a new 3D structure formed by a 3D bismuth oxyfluoride network with MoO₄ tetrahedrons and selenites groups imbedded in the 1D tunnels. Compound 5 displays a novel pillar-layered 3D open framework, consisting of 2D bismuth oxide layers bridged by the [ZrO₂F₂(SeO₃)₂]⁶⁻ polyanions. Theoretical calculations revealed that the five compounds displayed very strong birefringence. The birefringence values of compounds 1 – 3 , especially, are above 0.19 at 1064 nm, which are larger than the mineral calcite. Based on the structure and property analysis, it was found that the asymmetric SeO₃ groups (and TeO₃ in compound 3 ) displayed the largest anisotropy, compared with the bismuth cations and the d⁰-TM/Te polyhedra, which is beneficial to the birefringence.     

Peculiarities of Electrochemical Bismuth Film Formation in the Presence of Bromide and Heavy Metal Ions

Bi films were deposited on glassy carbon electrode from solutions with and without KBr. The morphology of both types of the films was characterized by scanning electron microscopy (SEM), and their electrochemical behavior was studied by square wave (SWV) and cyclic voltammetry (CV). Bi films were also co‐deposited with common analyte‐heavy‐metals in the presence of KBr and these films also were characterized by SEM, SWV and CV in order to understand the formation of the mixed metal films. All films studied had a different morphology. Bromide addition made the Bi films more compact and uniform, whereas Pb catalyzed Bi film deposition.     

Bismuth Compounds in Radical Catalysis: Transition Metal Bismuthanes Facilitate Thermally Induced Cycloisomerizations

The controlled radical chemistry of bismuth compounds is still in its infancy. Further developments are fueled by the properties of these complexes (e.g., low toxicity, high functional group tolerance, low homolytic bond dissociation energies, and reversible homolytic bond dissociations), which are highly attractive for applications in synthetic chemistry. Here we report the first catalytic application of transition metal bismuthanes (i.e. compounds with a Bi–TM bond; TM=transition metal). Using the catalyzed radical cyclo‐isomerization of δ‐iodo‐olefins as a model reaction, characteristics complementary or superior to known B, Mn, Cu, Zn, Sn, and alkali metal reagents are demonstrated (including a different crucial intermediate), establishing transition metal bismuthanes as a new class of (pre‐)catalysts for controlled radical reactions.     

铋单质及其复合材料在光催化中的应用

单质铋作为近年来报道的新型光催化材料受到了研究者的广泛关注,本文主要介绍了铋单质的光敏化、半导体光催化及等离子体共振光催化机理。阐述了以沉淀法、溶剂热法、电化学法为代表的铋单质光催化材料的主要制备方法,并探讨了制备方法中表面活性剂、反应温度以及pH对合成铋单质的影响。归纳了铋单质尺寸和形貌对其吸光性能的影响。在此基础上进一步综述了以铋-二氧化钛、铋-铋系氧化物、铋-氧化锌、铋-氮化碳（C₃N₄）为主要代表的铋-半导体复合光催化材料,并归纳了其光催化增强机理,最后阐述了铋单质及其复合光催化材料的发展趋势。     

Metal Halide Regulated Photophysical Tuning of Zero-Dimensional Organic Metal Halide Hybrids: From Efficient Phosphorescence to Ultralong Afterglow

The photophysical tuning is reported for a series of tetraphenylphosphonium (TPP) metal halide hybrids containing distinct metal halides, TPP₂MX_n (MX_n=SbCl₅, MnCl₄, ZnCl₄, ZnCl₂Br₂, ZnBr₄), from efficient phosphorescence to ultralong afterglow. The afterglow properties of TPP⁺ cations could be suspended for the hybrids containing low band gap emissive metal halide species, such as SbCl₅²⁻ and MnCl₄²⁻, but significantly enhanced for the hybrids containing wide band gap non-emissive ZnCl₄²⁻. Structural and photophysical studies reveal that the enhanced afterglow is attributed to stronger π–π stacking and intermolecular electronic coupling between TPP⁺ cations in TPP₂ZnCl₄ than in the pristine organic ionic compound TPPCl. Moreover, the afterglow in TPP₂ZnX₄ can be tuned by controlling the halide composition, with the change from Cl to Br resulting in a shorter afterglow due to the heavy atom effect.     

Specific Decoration of a Discrete Bismuth Oxido Cluster by Selected Peptides towards the Design of Metal Tags

Metal tags find application in a multitude of biomedical systems and the combination with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) offers an opportunity for multiplexing. To lay the foundation for an increase of the signal intensities in such processes, we herein present a general approach for efficient functionalization of a well-defined metal oxido cluster [Bi₆O₄(OH)₄(SO₃CF₃)₆(CH₃CN)₆]⋅2 CH₃CN ( 1 ), which can be realized by selecting 7mer peptide sequences via combinatorial means from large one-bead one-compound peptide libraries. Selective cluster-binding peptide sequences ( CBS ) for 1 were discriminated from non-binders by treatment with H₂S gas to form the reduction product Bi₂S₃, clearly visible to the naked eye. Interactions were further confirmed by NMR experiments. Extension of a binding peptide with a maleimide linker ( Mal ) introduces the possibility to covalently attach thiol-bearing moieties such as biological probes and for their analysis the presence of the cluster instead of mononuclear entities should lead to an increase of signal intensities in LA-ICP-MS measurements. To prove this, CBS - Mal was covalently bound onto thiol-presenting glass substrates, which then captured 1 effectively, so that LA-ICP-MS measurements demonstrated drastic signal amplification compared to single lanthanide tags.     

铋、氧化铋、硫化铋在醋酸-硫脲中的溶解性研究

通过研究铋(Ⅲ)与硫脲络合染色,测得络合物最大吸收峰位于460nm波长处,Bi(Ⅲ)含量在0.059～5.7μg/mL范围内符合比尔定律,回归方程Y=0.0117+0.17319 X;相关系数R=0.9999;相对标准偏差RSD为2.66%;检出限为0.013μg/mL;摩尔吸光系数为3.72×104 L.mol-1.cm-1。实验结果表明,铋、氧化铋和硫化铋在醋酸-硫脲中的溶解度分别是0.077、1.347、1.245μg/mL。经比较发现铋、氧化铋和硫化铋在醋酸-硫脲中的溶解性大小是:氧化铋>硫化铋>铋。铋、氧化铋和硫化铋的回收率分别是97.4%、98.1%、96.6%。     

Fifty Years of Inorganic Biomimetic Chemistry: From the Complexation of Single Metal Cations to Polynuclear Metal Complexes by Multidentate Thiolate Ligands

This article covers 50 years of coordination chemistry of transition metal complexes and metal-sulfur aggregates involving thiolate-incorporating ligands by reviewing selected examples. The studies in the coordination chemistry of sulfur-rich ligands have been undoubtedly triggered and fed by the concomitant development of bioinorganic chemistry, particularly of iron-sulfur enzymes. The review is broken down in five sections, which examine complexes of increasing nuclearity, including binuclear complexes based on compartmental macrocyclic ligands. We show also how ligand engineering has allowed the researchers in the field to control the nuclearity of the complexes, which was a particularly difficult task for sulfur-based ligands, as thiolates show a strong tendency to coordinate to more than one metal cation at once.     

Metal–Organic Frameworks: From Molecules/Metal Ions to Crystals to Superstructures

Metal–organic frameworks (MOFs) are among the most attractive porous materials known today, exhibiting very high surface areas, tuneable pore sizes and shapes, adjustable surface functionality, and flexible structures. Advances in the formation of MOF crystals, and in their subsequent assembly into more complex and/or composite superstructures, should expand the scope of these materials in many applications (e.g., drug delivery, chemical sensors, selective reactors and removal devices, etc.) and facilitate their integration onto surfaces and into devices. This Concept article aims to showcase recently developed synthetic strategies to control the one‐, two‐ and three‐dimensional (1‐, 2‐ and 3D) organisation of MOF crystals.     

New Forms and Functions of Tellurium: From Polycations to Metal Halide Tellurides

Metal chalcogenides and metal chalcogenide halides are distinguished by their structural diversity and by their very different physical properties. Therefore, the synthesis of novel compounds from this class is always a rewarding goal for the preparatively oriented solid-state chemist. Over the past few years, many syntheses and structural investigations have stimulated the field. The emphasis of the research has been placed on selenium-rich and tellurium-rich compounds, which are characterized by directed covalent bonds between the chalcogen atoms. Compounds with novel chalcogen polycations have also become accessible during the past few years by reacting the chalcogen elements with transition metal halides, or from chemical vapor deposition in the sense of chemical transport reactions. In these compounds, tellurium differs from its lighter homologues by a pronounced tendency towards greater covalence. This article attmepts to provide an overview of new developments in the field of compounds with chalcogen polycations and of metal chalcogenide halides, with an emphasis on compounds containing molybdenum and tungsten as the transition metals and tellurium as the chalcogen.     

Metal complex-assisted activation of small molecules. From NO to superoxide and peroxides

Transition metal centres are one of the primary targets for nitric oxide (NO), superoxide (O2(-)) and hydrogen peroxide (H2O2), which are small molecules present in a biological milieu, and of industrial and environmental interest. Coordination to a metal centre modulates their redox behaviour in such a way that they become activated for an inner-sphere oxidation or reduction, depending on the electronic and redox properties of a particular transition metal ion. Since the related redox reactions play multiple roles in physiological and pathophysiological processes, as well as in chemical catalysis in terms of synthetic applications and exhaust gas purification, the elucidation of the mechanisms of the elementary reaction steps behind these complex processes is of fundamental importance. This review concentrates on our work in this area, where by applying low temperature and high pressure kinetic and thermodynamic techniques we shed more light on the mechanisms of the particular reaction steps involved in the activation of NO, O2(-) and various peroxides. The studies include work on solvent exchange reactions that control the binding of small molecules to the metal centre and subsequent electron-transfer processes. We paid special attention to different iron and manganese complexes with heme and non-heme ligand systems.     

From CsKTaF7 to CsNaTaF7: Alkali Metal Cations Regulation to Generate SHG Activity**

Inorganic metal halides play important roles in wide range of areas including fluorescence, X-ray detection, and nonlinear-optics. Herein, two new mixed alkali metal tantalum fluorides, CsKTaF₇ and CsNaTaF₇, have been obtained based on the strategy of cations regulation in A₂MF₇ (A represents monovalent cations and M is d⁰ transition-metal cation) system by a conventional hydrothermal route. CsKTaF₇ crystallizes in the centric Pnma space group, while CsNaTaF₇ crystallizes in the polar Cmc2₁ space group and exhibits moderate and phase-matchable NLO activity. Both halides possess large optical band gaps above 5.0 eV. The crystal structure evolution, optical properties, and detailed theory calculations of these two halides were elucidated in this work.     

Application of Ion Exchange Techniques to Industrial Process of Metal Ions Removal From Wine

In this article, the application of selective ion exchange resins to the industrial metals removal of wine has been studied as an alternative to the "blue clarification" technique. In this sense, under the perspective of using this technology in the metals removal of sherry wines, a set of experiments at laboratory and pilot plant scale have been carried out. The study shows the behavior of several alkaline ions, metal ions and other parameters (pH, colour, protein index, etc.) during the process. Moreover, using the general theoretical model for continuous multistage processes, this study contemplates also the engineering design and the economic balance of the industrial process based on ion exchange columns. The experimental results demonstrates that ion exchange techniques are more effective and economic than "blue clarification" for metals removal of sherry wines. The proposed practice does not produce alterations in the qualities of the products; it achieves stability enough and also permits an important decrease of the contents of heavy metals.     

Metal Phosphorous Trichalcogenides (MPCh3): From Synthesis to Contemporary Energy Challenges

Owing to their unique physical and chemical properties, layered two‐dimensional (2D) materials have been established as the most significant topic in materials science for the current decade. This includes layers comprising mono‐element (graphene, phosphorene), di‐element (metal dichalcogenides), and even multi‐element. A distinctive class of 2D layered materials is the metal phosphorous trichalcogenides (MPCh₃, Ch=S, Se), first synthesized in the late 1800s. Having an unusual intercalation behavior, MPCh₃ were intensively studied in the 1970s for their magnetic properties and as secondary electrodes in lithium batteries, but fell from scrutiny until very recently, being 2D nanomaterials. Based on their synthesis and most significant properties, the present surge of reports related to water‐splitting catalysis and energy storage are discussed in detail. This Minireview is intended as a baseline for the anticipated new wave of researchers who aim to explore these 2D layered materials for their electrochemical energy applications.     

Bismuth(III) based Metal Organic Frameworks: Luminescence,Gas Adsorption,and Antibacterial Studies

Bi^III‐MOFs 1 – 4 were prepared via solvothermal method using four organic linkers; 2‐mercapto‐3‐methyl‐4‐thiazoleacetic acid (H₂MMTA), 2,6‐naphthalenedicarboxylic acid (2,6‐NDA), 4,6‐dihydroxy‐2‐mercaptopyrimidine (H₂DMP), and 4‐mercaptobenzoic acid (H₂MBA), respectively. The resulting MOFs were structurally/morphologically characterized by UV/Vis, AAS/ICP‐MS, Fourier transform infrared spectroscopy (FT‐IR), ¹H NMR, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and powder X‐ray diffraction technique. All these MOFs showed good luminescence properties exhibiting blue luminescence. N₂ gas adsorption isotherms of 1 – 4 confirmed the porosity of these frameworks. In order to evaluate the effect of metal ion upon chelation, the free organic linkers and respective MOFs were screened for their antibacterial potential against some pathogenic bacteria and appreciable activity was observed.