Influence of SPION Surface Coating on Magnetic Properties and Theranostic Profile.

This study aimed to develop multifunctional nanoplatforms for both cancer imaging and therapy using superparamagnetic iron oxide nanoparticles (SPIONs). Two distinct synthetic methods, reduction-precipitation (M) and co-precipitation at controlled pH (M), were explored, including the assessment of the coating's influence, namely dextran and gold, on their magnetic properties. These SPIONs were further functionalized with gadolinium to act as dual T1/T2 contrast agents for magnetic resonance imaging (MRI).

Implementing Mesoporosity in Zeolitic Imidazolate Frameworks through Clip-Off Chemistry in Heterometallic Iron-Zinc ZIF-8.

Bond breaking has emerged as a new tool to postsynthetically modify the pore structure in metal-organic frameworks since it allows us to obtain pore environments in structures that are inaccessible by other techniques. Here, we extend the concept of clip-off chemistry to archetypical ZIF-8, taking advantage of the different stabilities of the bonds between imidazolate and Zn and Fe metal atoms in heterometallic Fe-Zn-ZIF-8. We demonstrate that Fe centers can be removed selectively without affecting the backbone of the structure that is supported by the Zn atoms.

The influence of strontium deficiency on thermodynamics of defect formation, structural stability and electrical transport of SrFeTaO-based solid solutions with an excess tantalum content.

The crystalline and electronic band structures, thermodynamic stability, oxygen non-stoichiometry and high-temperature transport properties of perovskite-like solid solutions with a general formula SrFeTaO, where , ≥ 0, are thoroughly studied using a combination of experimental and theoretical methods. It is argued that the basic compound SrFeTaO possesses an orthorhombic lattice symmetry, while its tantalum-doped derivatives belong to a tetragonal space group. Importantly, the purposeful addition of a certain deficiency in a strontium sublattice is shown to be a valid method for stabilizing the SrFeTaO oxides with an excess tantalum content.

Redox and guest tunable spin-crossover properties in a polymeric polyoxometalate.

A bifunctionalized polyoxometalate (POM), [VO(CHNO)], which contains a redox active hexavanadate moiety covalently linked to two tridentate 2,6-bis(pyrazol-1-yl)pyridine (1-bpp) ligands, has been prepared and characterized. Reaction of this hybrid molecule with Fe(ii) or Zn(ii) ions produces crystalline neutral 1D networks of formula Fe[VO(CHNO)]·solv (2) and Zn[VO(CHNO)]·solv (3) (solv = solvent molecules). Magnetic properties of 2 show an abrupt spin-crossover (SCO) with the temperature, which can be induced by light irradiation at 10 K (Light-Induced Excited Spin-State Trapping, LIESST effect).

Ultramicroporous iron-isonicotinate MOFs combining size-exclusion kinetics and thermodynamics for efficient CO/N gas separation.

Two ultramicroporous 2D and 3D iron-based Metal-Organic Frameworks (MOFs) have been obtained by solvothermal synthesis using different ratios and concentrations of precursors. Their reduced pore space decorated with pendant pyridine from tangling isonicotinic ligands enables the combination of size-exclusion kinetic gas separation, due to their small pores, with thermodynamic separation, resulting from the interaction of the linker with CO molecules. This combined separation results in efficient materials for dynamic breakthrough gas separation with virtually infinite CO/N selectivity in a wide operando range and with complete renewability at room temperature and ambient pressure.

Metal mobility and bioaccessibility from cyanide leaching heaps in a historical mine site.

Unlike acidic sulfide mine wastes, where metal/loid mobility and bioaccessibility has been widely studied, less attention has been paid to alkaline cyanide heap leaching wastes. Thus, the main goal of this study is to evaluate the mobility and bioaccessibility of metal/loids in Fe-rich (up to 55%) mine wastes resulting from historical cyanide leaching activities. Wastes are mainly composed of oxides/oxyhydroxides (i.

Controlled modulation of the dynamics of the Deinococcus grandis Dps N-terminal tails by divalent metals.

DNA-binding proteins from starved cells (Dps) are small multifunctional nanocages expressed by prokaryotes in acute oxidative stress conditions or during the starvation-induced stationary phase, as a bacterial defense mechanism. Dps proteins protect bacterial DNA from damage by either direct binding or by removing precursors of reactive oxygen species from solution. The DNA-binding properties of most Dps proteins studied so far are related to their unordered, flexible, N- and C-terminal extensions.

Two-dimensional magnetic behaviour in hybrid NiFe-layered double hydroxides by molecular engineering.

Layered double hydroxides (LDHs) are a class of two-dimensional (2D) anionic materials that exhibit remarkable chemical versatility, making them ideal building blocks in the design of complex multifunctional materials. In this line, a NiFe-LDH is probably one of the most important LDHs due to its interesting electrochemical and magnetic properties. However, no direct magnetic measurements of exfoliated NiFe-LDH nanosheets have been reported so far.

The Conformation of the N-Terminal Tails of Dps Is Modulated by the Ionic Strength.

DNA-binding proteins from starved cells (Dps) are homododecameric nanocages, with N- and C-terminal tail extensions of variable length and amino acid composition. They accumulate iron in the form of a ferrihydrite mineral core and are capable of binding to and compacting DNA, forming low- and high-order condensates. This dual activity is designed to protect DNA from oxidative stress, resulting from Fenton chemistry or radiation exposure.

Exploiting the Redox Activity of MIL-100(Fe) Carrier Enables Prolonged Carvacrol Antimicrobial Activity.

The design of efficient food contact materials that maintain optimal levels of food safety is of paramount relevance to reduce the increasing number of foodborne illnesses. In this work, we develop a smart composite metal-organic framework (MOF)-based material that fosters a unique prolonged antibacterial activity. The composite is obtained by entrapping a natural food preserving molecule, carvacrol, into a mesoporous MIL-100(Fe) material following a direct and biocompatible impregnation method, and obtaining particularly high payloads.

Structural features and stability of apo- and holo-forms of a simple iron-sulfur protein.

Iron-sulfur centers are widespread in living organisms, mostly performing electron transfer functions, either in electron transfer chains or as part of multi-enzymatic complexes, while being also present in enzyme active sites, handling substrate catalysis. Rubredoxin is the simplest iron-sulfur containing protein constituted by a single polypeptide chain of 50 to 60 amino acids, of which four cysteine residues are responsible for metal binding in a tetrahedral coordination sphere. In this manuscript we explore the structure and stability of both apo- and holo-forms of a Rubredoxin from Marinobacter hydrocarbonoclasticus using Synchrotron Radiation Circular Dichroism (SRCD) in combination with other biochemical and spectroscopic techniques.

Temperature dependence of desolvation effects in hydrogen-bonded spin crossover complexes.

The synthesis, crystal structure and (photo)magnetic properties of the anhydrous spin crossover salt of formula [Fe(bpp)](CHO) (1) (bpp = 2,6-bis(pyrazol-3-yl)pyridine; CHO = adipate dianion), obtained by desolvation at 400 K of the original tetrahydrate in a single-crystal-to-single-crystal (SC-SC) transformation, are reported. This work offers a comparison between this compound and the previously reported hydrated material ([Fe(bpp)](CHO)·4HO, 1·4HO), highlighting the significance of the thermal conditions used in the dehydration-rehydration processes. In both compounds, a hydrogen-bonded network between iron(ii) complexes and adipate anions is observed.

3D-printed platform multi-loaded with bioactive, magnetic nanoparticles and an antibiotic for re-growing bone tissue.

Polymeric platforms obtained by three-dimensional (3D) printing are becoming increasingly important as multifunctional therapeutic systems for bone treatment applications. In particularly, researchers aim to control bacterial biofilm on these 3D-platforms and enhance re-growing bone tissue, at the same time. This study aimed to fabricate a 3D-printed polylactic acid platform loaded with hydroxyapatite (HA), iron oxide nanoparticles (IONPs) and an antibiotic (minocycline) with tuneable properties and multistimuli response.

[Co/Fe(α-Alkyl-tpdt)]: Alkyl-Substituted Cobalt and Iron Bis-dithiolenethiophenic Complexes.

Tetraphenylphosphonium salts of Co and Fe complexes with alkyl-substituted, -butyl (), and isopropyl () 2,3-thiophenedithiolate (α-tpdt) ligands, namely, TPP[Co(α--tpdt)] (), TPP[Fe(α--tpdt)] (-), TPP[Co(α--tpdt)] (), and TPP[Fe(α--tpdt)] () were prepared and characterized by cyclic voltammetry, single crystal X-ray diffraction, magnetic susceptibility measurements, and Fe Mössbauer spectroscopy. Compound and are isostructural with their Au and Ni analogues with a square-planar coordination geometry. Compound presents two polymorphs (-) both showing a Fe(III) bisdithiolene dimerization.

Fundamental Insights into the Covalent Silane Functionalization of NiFe Layered Double Hydroxides.

Layered double hydroxides (LDHs) are a class of 2D anionic materials exhibiting wide chemical versatility and promising applications in different fields, ranging from catalysis to energy storage and conversion. However, the covalent chemistry of this kind of 2D materials is still barely explored. Herein, the covalent functionalization with silanes of a magnetic NiFe-LDH is reported.

SPIONs Prepared in Air through Improved Synthesis Methodology: The Influence of γ-FeO/FeO Ratio and Coating Composition on Magnetic Properties.

Superparamagnetic iron oxide nanoparticles (SPIONs) have shown great potential in biomedicine due to their high intrinsic magnetization behaviour. These are small particles of magnetite or maghemite, and when coated, their surface oxidation is prevented, their aggregation tendency is reduced, their dispersity is improved, and the stability and blood circulation time are increased, which are mandatory requirements in biomedical applications. In this work, SPIONs were synthesized in air through a reduction-precipitation method and coated with four different polymers (Polyethylene glycol(PEG) 1000/6000 and dextran T10/T70).

Role of Structure and Composition on the Performances of P-Type Tin Oxide Thin-Film Transistors Processed at Low-Temperatures.

This work reports on the role of structure and composition on the determination of the performances of p-type SnO TFTs with a bottom gate configuration deposited by rf magnetron sputtering at room temperature, followed by a post-annealed step up to 200 °C at different oxygen partial pressures (O) between 0% and 20% but where the p-type conduction was only observed between in a narrow window, from 2.8% to 3.8%.

Naturally occurring radioactive material and risk assessment of tailings of polymetallic and Ra/U mines from legacy sites.

Old mine tailings from Northern and Central Portugal were studied in order to perform a radiological and chemical characterization. The evaluation of massic activity of natural radionuclides and concentrations in tailings of polymetallic and Ra/U mines was performed by gamma spectrometry and neutron activation analysis. Iron speciation was carried out by Mössbauer spectroscopy.

Variable Dimensionality, Valence, and Magnetism in Fluoride-Rich Iron Phosphates Ba Fe (PO)F (1 ≤ x ≤ 3, 2 ≤ y ≤ 12).

We report the synthesis and characterization of three fluoride-rich barium iron phosphates Ba Fe (PO)F (1 ≤ x ≤ 3, 2 ≤ y ≤ 12), which exhibited abundant structural chemistry, exhibiting diverse frameworks and connecting modes between [FeO F] octahedra surrounding Fe or Fe ions. BaFe(PO)F (I) consisted of two-dimensional [Fe(PO)F] sheets built from linear [FeOF] moieties formed by fluorine corner-sharing FeOF and FeOF octahedra with linking PO tetrahedra. Mixed-valence BaFe(PO)F (II) possessed a three-dimensional framework containing FeOF tetramers formed by the edge-sharing oxygen or fluorine atoms of cis-FeFO octahedra.

Conducting Anilate-Based Mixed-Valence Fe(II)Fe(III) Coordination Polymer: Small-Polaron Hopping Model for Oxalate-Type Fe(II)Fe(III) 2D Networks.

The mixed-valence FeFe 2D coordination polymer formulated as [TAG][FeFe(ClCNAn)]·(solvate) 1 (TAG = tris(amino)-guanidinium, ClCNAn = chlorocyanoanilate dianionic ligand) crystallized in the polar trigonal space group P3. In the solid-state structure, determined both at 150 and at 10 K, anionic 2D honeycomb layers [FeFe(ClCNAn)] establish in the ab plane, with an intralayer metal-metal distance of 7.860 Å, alternating with cationic layers of TAG.

Isoreticular two-dimensional magnetic coordination polymers prepared through pre-synthetic ligand functionalization.

Chemical functionalization is a powerful approach to tailor the physical and chemical properties of two-dimensional (2D) materials, increase their processability and stability, tune their functionalities and, even, create new 2D materials. This is typically achieved through post-synthetic functionalization by anchoring molecules on the surface of an exfoliated 2D crystal, but it inevitably alters the long-range structural order of the material. Here we present a pre-synthetic approach that allows the isolation of crystalline, robust and magnetic functionalized monolayers of coordination polymers.

Iron(ii) complexes of tris(2-pyridylmethyl)amine (TPMA) and neutral bidentate ligands showing thermal- and photo-induced spin crossover.

Three new mononuclear Fe(ii) complexes have been prepared and characterized by the combination of tetradentate tris(2-pyridylmethyl)amine (TPMA) with three neutral bidentate ligands, such as ethylenediamine (en), 1,2-diaminopropane (pn) and 2-picolylamine (2-pic), in compounds [FeII(TPMA)(en)](ClO4)2 (1), [FeII(TPMA)(2-pic)](ClO4)2 (2) and [FeII(TPMA)(pn)](ClO4)2 (3). Structural and magnetic characterization demonstrates that the three compounds present a complete SCO behavior. The absence of strong intermolecular interactions and solvent molecules leads to reversible and gradual spin transitions.

A highly stable and hierarchical tetrathiafulvalene-based metal-organic framework with improved performance as a solid catalyst.

Herein we report the synthesis of a tetrathiafulvalene (TTF)-based MOF, namely , which shows a non-interpenetrated hierarchical crystal structure with mesoporous one-dimensional channels of 3 nm and orthogonal microporous channels of 1 nm. This highly stable MOF (aqueous solution with pH values ranging from 2 to 11 and different organic solvents), which possesses the well-known [Fe(μ-O)(COO)] secondary building unit, has proven to be an efficient catalyst for the aerobic oxidation of dibenzothiophenes.

Light-induced decarboxylation in a photo-responsive iron-containing complex based on polyoxometalate and oxalato ligands.

A new photoresponsive molecular polyanion in which two Fe(iii) ions are simultaneously coordinated by two [A-α-PWO] polyoxometalate units and two oxalato ligands has been obtained. When irradiated with UV light its potassium salt, , exhibits a remarkable photocoloration effect, attributable to the partial reduction of the POM units to give rise to a mixed-valence species. The photoinduced process is intramolecular and involves electron transfer from the oxalato ligands, which partially decompose releasing CO, towards the Fe(iii) and the POM.