Anode electrolysis of sulfides.

Traditional sulfide metallurgy produces harmful sulfur dioxide and is energy intensive. To this end, we develop an anode electrolysis approach in molten salt by which sulfide is electrochemically split into sulfur gas at a graphite inert anode while releasing metal ions that diffuse toward and are deposited at the cathode. The anodic splitting dictates the "sulfide-to-metal ion and sulfur gas" conversion that makes the reaction recur continuously. Using this approach, Cu2S is converted to sulfur gas and Cu in molten LiCl-KCl at 500 °C with a current efficiency of 99% and energy consumption of 0.420 kWh/kg-Cu (only considering the electricity for electrolysis). Besides Cu2S, the anode electrolysis can extract Cu from Cu matte that is an intermediate product from the traditional sulfide smelting process. More broadly, Fe, Ni, Pb, and Sb are extracted from FeS, CuFeS2, NiS, PbS, and Sb2S3, providing a general electrochemical method for sulfide metallurgy.

Synthesis and Characterization of Ion Pairs between Alkaline Metal Ions and Anionic Anti-Aromatic and Aromatic Hydrocarbons with π-Conjugated Central Seven- and Eight-Membered Rings.

The synthesis, isolation and full characterization of ion pairs between alkaline metal ions (Li+, Na+, K+) and mono-anions and dianions obtained from 5H-dibenzo[a,d]cycloheptenyl (C15H11 = trop) is reported. According to Nuclear Magnetic Resonance (NMR) spectroscopy, single crystal X-ray analysis and Density Functional Theory (DFT) calculations, the trop‒ and trop2-• anions show anti-aromatic properties which are dependent on the counter cation M+ and solvent molecules serving as co-ligands. For comparison, the disodium and dipotassium salt of the dianion of dibenzo[a,e]cyclooctatetraene (C16H12 = dbcot) were prepared, which show classical aromatic character. A d8-Rh(I) complex of trop- was prepared and the structure shows a distortion of the C15H11 ligand into a conjugated 10π -benzo pentadienide unit-to which the Rh(I) center is coordinated-and an aromatic 6π electron benzo group which is non-coordinated. Electron transfer reactions between neutral and anionic trop and dbcot species show that the anti-aromatic compounds obtained from trop are significantly stronger reductants.

Synthesis and Dissolution of Metal Oxides in Ionic liquids and Deep Eutectic Solvents.

Ionic liquids (ILs) and deep eutectic solvents (DESs) have proven to be suitable solvents and reactants for low-temperature reactions. To date, several attempts were made to apply this promising class of materials to metal oxide chemistry, which, conventionally, is performed at high temperatures. This review gives an overview about the scientific approaches of the synthesis as well as the dissolution of metal oxides in ILs and DESs. A wide range of metal oxides along with numerous ILs and DESs are covered by this research. With ILs and DESs being involved, many metal oxide phases as well as different particle morphologies were obtained by means of relatively simple reactions paths. By the development of acidic task-specific ILs and DESs, even difficultly soluble metal oxides were dissolved and, hence, made accessible for downstream chemistry. Especially the role of ILs in these reactions is in the focus of discussion.

Advances in Synthesis and Measurement of Charge Transport in DNA-Based Derivatives.

Charge transport through molecular structures is interesting both scientifically and technologically. To date, DNA is the only type of polymer that transports significant currents over distances of more than a few nanometers in individual molecules. For molecular electronics, DNA derivatives are by far more promising than native DNA due to their improved charge-transport properties. Here, the synthesis of several unique DNA derivatives along with electrical characterization and theoretical models is surveyed. The derivatives include double stranded poly(G)-poly(C) DNA molecules, four stranded G4-DNA, metal-DNA hybrid molecular wires, and other DNA molecules that are modified either at the bases or at the backbone. The electrical characteristics of these nanostructures, studied experimentally by electrostatic force microscopy, conductive atomic force microscopy, and scanning tunneling microscopy and spectroscopy, are reviewed.

Biodegradable/biocompatible coated metal implants for orthopedic applications.

Biocompatible metals have been suggested as revolutionary biomaterials for bone-grafting therapies. Although metals and their alloys are widely and successfully used in producing biomedical implants due to their good mechanical properties and corrosion resistance, they have a lack in bioactivity. Therefore coating of the metal surface with calcium phosphates (CaP) is a benign way to achieve well bioactivity and get controlled corrosion properties. The biocompatibility and bioactivity calcium phosphates (CaP) in bone growth were guided them to biomedical treatment of bone defects and fractures. Many techniques have been used for fabrication of CaP coatings on metal substrates such as magnesium and titanium. The present review will focus on the synthesis of CaP and their relative forms using different techniques especially electrochemical techniques. The latter has always been known of its unique way of optimizing the process parameters that led to a control in the structure and characteristics of the produced materials.

Synthesis, spectral studies and biological evaluation of 2-aminonicotinic acid metal complexes.

We synthesized 2-aminonicotinic acid (2-ANA) complexes with metals such as Co(II), Fe(III), Ni(II), Mn(II), Zn(II), Ag(I),Cr(III), Cd(II) and Cu(II) in aqueous media. The complexes were characterized and elucidated using FT-IR, UV-Vis, a fluorescence spectrophotometer and thermo gravimetric analysis (TGA). TGA data showed that the stoichiometry of complexes was 1:2 metal/ligand except for Ag(I) and Mn(II) where the ratio was 1:1. The metal complexes showed varied antibacterial, fungicidal and nematicidal activities. The silver and zinc complexes showed highest activity against Bacillus subtilis and Bacillus licheniformis respectively. Fusarium oxysporum was highly susceptible to nickel and copper complexes whereas Macrophomina phaseolina was completely inert to the complexes. The silver and cadmium complexes were effective against the root-knot nematode Meloidogyne javanica.

Development and application of metal materials in terms of vascular stents.

BACKGROUND: With life pace accelerated, poor diet habits developed, psychological burden enhanced and many other factors, the incidence of coronary heart disease, atherosclerosis and other cardiovascular cerebrovascular diseases has been increased year by year, which are serious threat to human health. OBJECTIVE: Provide relational references for the similar researchers after metal stent materials were reviewed and prospected. METHODS: This paper reviews the development and application of metal materials in terms of vascular stents, focusing on the advantages and disadvantages of 316L stainless steel, nitinol super-elastic alloys, cobalt-based alloys (Co-Cr-Ni-Mo-Mn), magnesium-based alloy, iron-based alloys and tantalum metal stents as well as in clinical practice research and application. RESULTS: Recognize the advantages and disadvantages of different metal stent materials as well as in clinical practice research and application. CONCLUSIONS: Although metal stents have been widely used in clinical practice, there are still many problems to be solved, especially to improve mechanical properties and biological activity. Strong immune rejection is also a problem. Therefore, it will be a significant direction for future material research to treat surface modification, further improve the biocompatibility, reduce the thrombosis and completely eliminate the rejection and vascular restenosis. In addition, the stent materials should be developed toward controllable degradation and special features in the future.

ProPhenol-catalyzed asymmetric additions by spontaneously assembled dinuclear main group metal complexes.

The development of catalytic enantioselective transformations has been the focus of many research groups over the past half century and is of paramount importance to the pharmaceutical and agrochemical industries. Since the award of the Nobel Prize in 2001, the field of enantioselective transition metal catalysis has soared to new heights, with the development of more efficient catalysts and new catalytic transformations at increasing frequency. Furthermore, catalytic reactions that allow higher levels of redox- and step-economy are being developed. Thus, alternatives to asymmetric alkene dihydroxylation and the enantioselective reduction of α,ß-unsaturated ketones can invoke more strategic C-C bond forming reactions, such as asymmetric aldol reactions of an aldehyde with α-hydroxyketone donors or enantioselective alkynylation of an aldehyde, respectively. To facilitate catalytic enantioselective addition reactions, including the aforementioned aldol and alkynylation reactions, our lab has developed the ProPhenol ligand. In this Account, we describe the development and application of the ProPhenol ligand for asymmetric additions of both carbon- and heteroatom-based nucleophiles to various electrophiles. The ProPhenol ligand spontaneously forms chiral dinuclear metal complexes when treated with an alkyl metal reagent, such as Et2Zn or Bu2Mg. The resulting complex contains both a Lewis acidic site to activate an electrophile and a Brønsted basic site to deprotonate a pronucleophile. Initially, our research focused on the use of Zn-ProPhenol complexes to facilitate the direct aldol reaction. Fine tuning of the reaction through ligand modification and the use of additives enabled the direct aldol reaction to proceed in high yields and stereoselectivities with a broad range of donor substrates, including acetophenones, methyl ynones, methyl vinyl ketone, acetone, α-hydroxy carbonyl compounds, and glycine Schiff bases. Additionally, an analogous magnesium ProPhenol complex was used to facilitate enantioselective diazoacetate aldol reactions with aryl, α,ß-unsaturated, and aliphatic aldehydes. The utility of bimetallic ProPhenol catalysts was extended to asymmetric additions with a wide range of substrate combinations. Effective pronucleophiles include oxazolones, 2-furanone, nitroalkanes, pyrroles, 3-hydroxyoxindoles, alkynes, meso-1,3-diols, and dialkyl phosphine oxides. These substrates were found to be effective with a number of electrophiles, including aldehydes, imines, nitroalkenes, acyl silanes, vinyl benzoates, and α,ß-unsaturated carbonyls. A truly diverse range of enantioenriched compounds have been prepared using the ProPhenol ligand, and the commercial availability of both ligand enantiomers makes it ideally suited for the synthesis of complex molecules. To date, enantioselective ProPhenol-catalyzed reactions have been used in the synthesis of more than 20 natural products.

Asymmetric conjugate additions and allylic alkylations using nucleophiles generated by hydro- or carbometallation.

This Minireview discusses catalytic asymmetric conjugate addition and allylic alkylation reactions where the nucleophiles were generated in situ by hydrometallation or carbometallation. This exciting recent trend in asymmetric catalysis promises to expand the range of transformations available for the rapid and selective assembly of complex, functional molecules for both academic and industrial research. This Minireview aims to serve as a reference for studies reported to date and discusses the current state-of-the-art, scope and limitations of these processes.

Nanorods of a new metal-biomolecule coordination polymer showing novel bidirectional electrocatalytic activity and excellent performance in electrochemical sensing.

Metal organic coordination polymers (CPs), as most attractive multifunctional materials, have been studied extensively in many fields. However, metal-biomolecule CPs and CPs' electrochemical properties and applications were studied much less. We focus on this topic aiming at electrochemical biosensors with excellent performance and high biocompatibility. A new nanoscaled metal-biomolecule CP, Mn-tyr, containing manganese and tyrosine, was synthesized hydrothermally and characterized by various techniques, including XRD, TEM, EDS, EDX mapping, elemental analysis, XPS, and IR. Electrode modified with Mn-tyr showed novel bidirectional electrocatalytic ability toward both reduction and oxidation of H2O2, which might be due to Mn. With the assistance of CNTs, the sensing performance of Mn-tyr/CNTs/GCE was improved to a much higher level, with high sensitivity of 543 mA mol(-1) L cm(-2) in linear range of 1.00×10(-6)-1.02×10(-4) mol L(-1), and detection limit of 3.8×10(-7) mol L(-1). Mn-tyr/CNTs/GCE also showed fast response, high selectivity, high steadiness and reproducibility. The excellent performance implies that the metal-biomolecule CPs are promising candidates for using in enzyme-free electrochemical biosensing.

Water-only hydrothermal method: a generalized route for environmentally-benign and cost-effective construction of superhydrophilic surfaces with biomimetic micronanostructures on metals and alloys.

The present work demonstrates a generalized strategy using water-only hydrothermal oxidation to construct complex biomimetic micronanostructures on a series of metals and alloys, resulting in superhydrophilic surfaces. This general approach is environmentally-benign and cost-effective, which offers a unique clue for the rational fabrication of micronanoscale architectures and superhydrophilic surfaces.

State of the art of Lewis acid-containing zeolites: lessons from fine chemistry to new biomass transformation processes.

The former synthesis of TS-1 opened new catalytic opportunities for zeolites, especially for their application as selective redox catalysts in several fine chemistry processes. Interestingly, isolated Ti species in the framework positions of hydrophobic zeolites, such as high silica zeolites, offer unique Lewis acid sites even in the presence of protic polar solvents (such as water). Following this discovery, other transition metals (such as Sn, Zr, V, Nb, among others) have been introduced in the framework positions of different hydrophobic zeolitic structures, allowing their application in new fine chemistry processes as very active and selective redox catalysts. Recently, these hydrophobic metallozeolites have been successfully applied as efficient catalysts for several biomass-transformation processes in bulk water. The acquired knowledge from the former catalytic descriptions in fine chemistry processes using hydrophobic Lewis acid-containing zeolites has been essential for their application in these novel biomass transformations. In the present review, I will describe the recent advances in the synthesis of new transition metal-containing zeolites presenting Lewis acid character, and their unique catalytic applications in both fine chemistry and novel biomass-transformations.

Structure-function relationship of the foam-like pomelo peel (Citrus maxima)-an inspiration for the development of biomimetic damping materials with high energy dissipation.

The mechanical properties of artificial foams are mainly determined by the choice of bulk materials and relative density. In natural foams, in contrast, variation to optimize properties is achieved by structural optimization rather than by conscious substitution of bulk materials. Pomelos (Citrus maxima) have a thick foam-like peel which is capable of dissipating considerable amounts of kinetic energy and thus this fruit represents an ideal role model for the development of biomimetic impact damping structures. This paper focuses on the analysis of the biomechanics of the pomelo peel and on its structure-function relationship. It deals with the determination of the onset strain of densification of this foam-like tissue and on how this property is influenced by the arrangement of vascular bundles. It was found here that the vascular bundles branch in a very regular manner-every 16.5% of the radial peel thickness-and that the surrounding peel tissue (pericarp) attains its exceptional thickness mainly by the expansion of existing interconnected cells causing an increasing volume of the intercellular space, rather than by cell division. These findings lead to the discussion of the pomelo peel as an inspiration for fibre-reinforced cast metallic foams with the capacity for excellent energy dissipation.

An alternative pathway for the synthesis of isocyanato- and urea-functionalised metal-organic frameworks.

We have developed a generic two-step post-functionalisation technique for transforming amino-functionalised MOFs into their isocyanate analogues. The first part of the synthetic pathway consists in the conversion of the amino moieties into azido groups. Next, the thermal activation of these azido groups leads to nitrene species that can react with carbon monoxide to yield the desired products. As a proof of concept, this method was applied to the highly stable Al-MIL-53-NH2 and to the acid-sensitive In-MIL-68-NH2. The resulting nitrene species were highly reactive, with side reactions dominating initially. This issue was overcome through the use of a mixed-linker strategy applied during the MOF synthesis that decreased the nitrene radical density within the pore, thereby permitting In-MIL-68-NH2 to be converted into its isocyanate analogue with 100% selectivity. To illustrate the potential of this method for grafting a wide library of potentially active organic groups inside MOFs, amines were condensed onto isocyanato MOFs to form urea analogues.

Shape assisted fabrication of fluorescent cages of squarate based metal-organic coordination frameworks.

Micronic cage structures of squarate based metal-organic coordination frameworks (MOCFs) have been fabricated for the first time by specific anion selective etching of metal squarate cubes. Time and stoichiometry dependent synthesis and the corresponding microscopic studies have provided mechanistic insight into the cage formation. Furthermore, a non-covalent post-synthetic strategy has been adopted to functionalize the micronic cubes or cages with chromophores rendering the resulting hybrids green fluorescent.

Surface engineering of inorganic nanoparticles for imaging and therapy.

Many kinds of inorganic nanoparticles (NPs) including semiconductor, metal, metal oxide, and lanthanide-doped NPs have been developed for imaging and therapy applications. Their unique optical, magnetic, and electronic properties can be tailored by controlling the composition, size, shape, and structure. Interaction of such NPs with cells and/or in vivo compartments is critically determined by the surface properties, and sophisticated control over the NP surface is essential to control their fate in biological environments. We review NP surface coating strategies using the categories of small surface ligand, polymer, and lipid. Use of small ligand molecules has the advantage of maintaining the minimal hydrodynamic (HD) size. Polymers can be advantageous in NP anchoring by combining multiple affinity groups. Encapsulation of NPs in polymers, lipids or surfactants can preserve the as-synthesized NPs. NP surface properties and reaction conditions should be carefully considered to obtain a bioconjugate that maintains the physicochemical properties of NP and functionalities of the conjugated biomolecules. We highlight how the surface properties of NPs impact their interactions with cells and in vivo compartments, especially focused on the important surface design parameters such as HD size, surface charge, and targeting. Typically, maximal cellular uptake can take place in the intermediate NP size range of 40-60nm. Clearance of NPs from blood circulation is largely dependent on the degree of uptake by reticuloendothelial system when they are larger than 10nm. When the HD size is below 10nm, NPs show broad distribution over many organs. Reduction of HD size below the limit of renal barrier can achieve fast clearance of NPs. For maximal tumor accumulation, NPs should have long blood circulation time and should be large enough to prevent rapid penetration. NPs are also desired to rapidly clear out from the body after the mission before they cause toxic side effects. However, efficient clearance from the body to avoid side effects may result in the reduction in residence time required for accumulation in target tissues. Smart design of NP surface coating that can meet the conflicting demands can open a new avenue of NP applications. Surface charge and hydrophobicity need to be carefully considered for NP surface design. Positively charged NPs more adsorb on cell membranes and consequently show higher level of internalizations when compared with negatively charged or neutral NPs. NPs encounter a large variety of biomolecules in vivo, where non-specific adsorptions can potentially alter the physicochemical properties of the NPs. For optimal performance, NPs are suggested to have neutral surface charge at physiological conditions, small HD size, and minimal non-specific adsorption levels. Zwitterionic NP surface coating by small surface ligands can be a promising approach. Toxicity is one of most critical issues, where proper control of the NP surface can significantly reduce the toxicities.

Concentración de metales séricos (titanio, cromo y cobalto) en el seguimiento de las artroplastias totales de cadera / Serum metal (titanium, chromium and cobalt) concentrations in the follow-up of total hip arthroplasty

Objetivo: Analizar la degradación de los productos metálicos que constituyen las aleaciones de las prótesis de cadera. Pacientes y método: Se midió, mediante absorción atómica, el titanio, el cromo y el cobalto en la sangre de 58 pacientes con prótesis totales de cadera, compuestas por aleaciones de cromo y cobalto y de titanio, con o sin cementar. Se analizó la evolución de las concentraciones séricas preoperatorias, a los seis y a los 12 meses. Resultados: Encontramos una elevación significativa tras el inicio de la movilización de la articulación, pero sin afectación clínica. Los percentiles 95 de la distribución de concentraciones fueron para el Ti 27 mg/L, Cr 1 mg/L y Co 1,7 mg/L. Conclusión: La elevación de estas concentraciones podría ser indicativa de mal funcionamiento del implante o de desgaste excesivo que podría conducir a toxicidades locales o remotas (AU)

Objective: To analyze the degradation of the metal products contained in hip prosthesis alloys. Patients and method: Atomic absorption measurements were made of the titanium, chromium and cobalt concentrations in the blood of 58 patients with total hip replacement implants made of titanium, chromium and cobalt alloys with or without cementing. The evolution of the serum metal concentrations was assessed based on measurements obtained preoperatively and 6 and 12 months after surgery. Results: A significant increase in serum levels was noted after the start of joint mobilization, though without clinical repercussions. The percentile 95 values of the metal concentration distributions were 27 mg/l for titanium, 1 mg/l in the case of chromium, and 1.7 mg/l for cobalt. Conclusion: The rise in serum metal concentrations could be indicative of poor implant function or excessive wear that in turn could lead to local or disseminated toxicity (AU)

Synthesis and photophysical properties of metallophthalocyanines substituted with a benzofuran based fluoroprobe.

The synthesis, characterization and photophysical properties of the tetra- {6-(-benzofuran-2-carboxylate)-hexylthio} substituted copper(II), cobalt(II), manganese(III) and zinc (II) phthalocyanines, {M[Pc(ß-S(CH(2))(6)OCOBz-Furan)(4)], which were derived from 6-(3,4-dicyanophenylthio)-hexyl-2-benzofuranate (BzF) (1-4) are reported for the first time. The new compounds have been synthesized and fully characterized by elemental analysis, FTIR, UV-vis, (1)H- and (13)C NMR, MS (Maldi-TOF). In this work, we also report the effects of peripherally bound BzF substituent on the photophysical properties of metallo phthalocyanine derivatives. The effects of changing the central metal ions on quantum yield are discussed. It was found that the substitution of BzF groups on the framework of phthalocyanines diminished the fluorescence quantum yield of these complexes depending on paramagnetic behavior of central metal atoms. In addition, central metal atoms like Co and Cu also caused to decrease in quantum yield of phthalocyanine backbone.

Urea metal-organic frameworks as effective and size-selective hydrogen-bond catalysts.

A new urea-containing metal-organic framework (MOF) was synthesized to act as a heterogeneous catalyst. Ureas are well-known for self-recognition and aggregation behavior, resulting in loss of catalytic competency. The catalyst spatial isolation achievable in a porous MOF environment suggests a potentially general solution. The combination of a symmetrical urea tetracarboxylate strut, 4,4'-bipyridine, and Zn(NO(3))(2)·6H(2)O under solvothermal conditions afforded a new microporous MOF (NU-601). This material is indeed an effective hydrogen-bond-donor catalyst for Friedel-Crafts reactions between pyrroles and nitroalkenes, whereas a homogeneous urea is much less competent. The higher rates of reaction of small substrates relative to larger ones with NU-601 strongly suggest that catalysis primarily occurs within the pores of this new material rather than on its exterior. To the best of our knowledge, this approach is the first example of specific engineering of successful hydrogen-bonding catalysis into a MOF material.