Thermodynamics of spin crossover in a bis(terpyridine) cobalt(II) complex featuring a thioether functionality.

In this contribution, a terpyridine-based ligand bearing a thioether functionality is used to prepare a new cobalt(II) spin crossover complex: [Co(TerpyPhSMe)](PF) (1), where TerpyPhSMe is 4'-(4-methylthiophenyl)-2,2':6',2''-terpyridine. Its structure, determined by single crystal X-ray diffraction, reveals a coordination of the tridentate terpyridine ligands, leading to a tetragonally compressed octahedron. Intermolecular interactions in the crystal lattice freeze the complex in the high spin state in the solid state at all temperatures, as indicated by magnetometry and Electron Paramagnetic Resonance (EPR) spectra.

Undecanoic Acid and L-Phenylalanine in Vermiculite: Detection, Characterization, and UV Degradation Studies for Biosignature Identification on Mars.

Solar radiation that arrives on the surface of Mars interacts with organic molecules present in the soil. The radiation can degrade or transform the organic matter and make the search for biosignatures on the planet's surface difficult. Therefore, samples to be analyzed by instruments on board Mars probes for molecular content should be selectively chosen to have the highest organic preservation content.

New heterometallic Co/Zn, Ag/Co, and Ag/Zn imidazolates: structural characterization and catalytic activity in the oxidation of organic compounds.

Nanocrystalline powders of monometallic and bimetallic imidazolates of Co, Zn and Ag were produced by a reaction carried out in water. The powders were characterized by powder X-ray diffraction and the crystal structures of the new compounds AgZnIm and AgCoIm (Im = imidazolate) were solved. Heterometallic Co/Zn imidazolates showed the known Zn- crystal structure while Ag/Zn and Ag/Co systems were isostructural to the copper analogs.

Activation of RSK by phosphomimetic substitution in the activation loop is prevented by structural constraints.

The activation of the majority of AGC kinases is regulated by two phosphorylation events on two conserved serine/threonine residues located on the activation loop and on the hydrophobic motif, respectively. In AGC kinase family, phosphomimetic substitutions with aspartate or glutamate, leading to constitutive activation, have frequently occurred at the hydrophobic motif site. On the contrary, phosphomimetic substitutions in the activation loop are absent across the evolution of AGC kinases.

Bridging Solution and Solid-State Chemistry of Dicyanoaurate: The Case Study of Zn-Au Nucleation Units.

The behavior in solution of the dicyanoaurate anion in the presence of other metal centers has so far been little explored, despite its importance in material science. The design and synthesis of systems with controlled coordination behavior, using chelating ligands and Zn, has allowed us to detect self-assembly and oligomerization in solution. This phenomenon has been studied with C and H NMR, absorption and emission UV-vis spectroscopy, ESI-MS, and XAS at both the Au L-edge and Zn K-edge: all of these techniques confirm the presence of Au-Zn aggregation products.

Paracetamol-Galactose Conjugate: A Novel Prodrug for an Old Analgesic Drug.

Paracetamol has been one of the most commonly used and prescribed analgesic drugs for more than a hundred years. Despite being generally well tolerated, it can result in high liver toxicity when administered in specific conditions, such as overdose, or in vulnerable individuals. We have synthesized and characterized a paracetamol galactosylated prodrug (PARgal) with the aim of improving both the pharmacodynamic and pharmacological profile of paracetamol.

Crystal structure of bacterial CYP116B5 heme domain: New insights on class VII P450s structural flexibility and peroxygenase activity.

Class VII cytochromes P450 are self-sufficient enzymes carrying a phthalate family oxygenase-like reductase domain and a P450 domain fused in a single polypeptide chain. The biocatalytic applications of CYP116B members are limited by the need of the NADPH cofactor and the lack of crystal structures as a starting point for protein engineering. Nevertheless, we demonstrated that the heme domain of CYP116B5 can use hydrogen peroxide as electron donor bypassing the need of NADPH.

Ti-Based Catalysts and Photocatalysts: Characterization and Modeling.

This perspective article aims to underline how cutting-edge synchrotron radiation spectroscopies such as extended X-ray absorption spectroscopy (EXAFS), X-ray absorption near edge structure (XANES), high resolution fluorescence detected (HRFD) XANES, X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS) have played a key role in the structural and electronic characterization of Ti-based catalysts and photocatalysts, representing an important additional value to the outcomes of conventional laboratory spectroscopies (UV-Vis, IR, Raman, EPR, NMR etc.). Selected examples are taken from the authors research activity in the last two decades, covering both band-gap and shape engineered TiO materials and microporous titanosilicates (ETS-10, TS-1 and Ti-AlPO-5).

Autoluminescent Metal-Organic Frameworks (MOFs): Self-Photoemission of a Highly Stable Thorium MOF.

A novel thorium(IV) metal-organic framework (MOF), Th(2,6-naphtalenedicarboxylate), has been synthesized via solvothermal reaction of thorium nitrate and 2,6-naphtalendicarboxilyc acid. This compound shows a new structural arrangement with an interesting topology and an excellent thermal resistance, as the framework is stable in air up to 450 °C. Most notably, this MOF, combining the radioactivity of its metal center and the scintillation property of the ligand, has been proven capable of spontaneous photon emission.

Novel Ligand and Device Designs for Stable Light-Emitting Electrochemical Cells Based on Heteroleptic Copper(I) Complexes.

This work reports on the positive impact of (i) attaching methoxy groups at the ortho position of the bipyridine ligand (6,6'-dimethoxy-2,2'-bipyridine) in heteroleptic copper(I) complexes belonging to the [Cu(bpy)(POP)] family, and (ii) a new device design comprising a multilayered architecture to decouple hole/electron injection and transport processes on the performance of light-emitting electrochemical cells (LECs). In short, the substituted complex showed enhanced thermal- and photostability, photoluminescence, and ionic conductivity features in thin films compared to those of the archetypal complex without substitution. These beneficial features led to LECs outperforming reference devices in terms of luminance, stability, and efficacy.

Aceclofenac-Galactose Conjugate: Design, Synthesis, Characterization, and Pharmacological and Toxicological Evaluations.

Aceclofenac is a popular analgesic, antipyretic, and nonsteroidal anti-inflammatory drug (NSAID) used for prolonged treatment (at least three months) in musculoskeletal disorders. It is characterized by several limitations such as poor water solubility and low oral bioavailability. The main side-effect of aceclofenac, as well as all NSAIDs, is the gastrotoxicity; among other adverse effects, there is the risk of bleeding since aceclofenac reversibly inhibits platelet aggregation.

Working at the membrane interface: Ligand-induced changes in dynamic conformation and oligomeric structure in human aromatase.

Aromatase catalyzes the biosynthesis of estrogens from androgens. Owing to the physiological importance of this conversion of lipophilic substrates, the interaction with the lipid bilayer for this cytochrome P450 is crucial for its dynamics that must allow an easy access to substrates and inhibitors. Here, the aromatase-anastrozole interaction is studied by combining computational methods to identify possible access/egress routes with the protein inserted in the membrane and experimental tools aimed at the investigation of the effect of the inhibitor on the protein conformation.

Maskless X-Ray Writing of Electrical Devices on a Superconducting Oxide with Nanometer Resolution and Online Process Monitoring.

X-ray nanofabrication has so far been usually limited to mask methods involving photoresist impression and subsequent etching. Herein we show that an innovative maskless X-ray nanopatterning approach allows writing electrical devices with nanometer feature size. In particular we fabricated a Josephson device on a BiSrCaCuO (Bi-2212) superconducting oxide micro-crystal by drawing two single lines of only 50 nm in width using a 17.

Impact of R264C and R264H polymorphisms in human aromatase function.

The cytochrome P450 aromatase is involved in the last step of sex hormones biosynthesis by converting androgens into estrogens. The human enzyme is highly polymorphic and literature data correlate aromatase single nucleotide polymorphisms to the onset of pathologies such as breast cancer and neurodegenerative diseases. The aims of this study were i) to study the influence of the mutations R264C and R264H on the structure-function of the enzyme also upon phosphorylation by selected kinases and ii) to compare the activity of the variants to that of aromatase wild type in two different cell lines.

Effect of Al and Ca co-doping, in the presence of Te, in superconducting YBCO whiskers growth.

High-T superconducting cuprates (HTSC) such as YBaCuO (YBCO) are promising candidates for solid-state THz applications based on stacks of intrinsic Josephson junctions (IJJs) with atomic thickness. In view of future exploitation of IJJs, high-quality superconducting YBCO tape-like single crystals (whiskers) have been synthesized from Ca-Al-doped precursors in the presence of Te. The main aim of this paper is to determine the importance of the simultaneous use of Al, Te and Ca in promoting YBCO whiskers growth with good superconducting properties (T = 79-84 K).

Effect of sildenafil on human aromatase activity: From in vitro structural analysis to catalysis and inhibition in cells.

Aromatase catalyses the conversion of androgens into estrogens and is a well-known target for breast cancer therapy. As it has been suggested that its activity is affected by inhibitors of phosphodiesterase-5, this work investigates the potential interaction of sildenafil with aromatase. This is carried out both at molecular level through structural and kinetics assays applied to the purified enzyme, and at cellular level using neuronal and breast cancer cell lines.

High-Throughput Preparation of New Photoactive Nanocomposites.

New low-cost photoactive hybrid materials based on organic luminescent molecules inserted into hydrotalcite (layered double hydroxides; LDH) were produced, which exploit the high-throughput liquid-assisted grinding (LAG) method. These materials are conceived for applications in dye-sensitized solar cells (DSSCs) as a co-absorbers and in silicon photovoltaic (PV) panels to improve their efficiency as they are able to emit where PV modules show the maximum efficiency. A molecule that shows a large Stokes' shift was designed, synthesized, and intercalated into LDH.

Subtle structural changes in the Asp251Gly/Gln307His P450 BM3 mutant responsible for new activity toward diclofenac, tolbutamide and ibuprofen.

This paper reports the structure of the double mutant Asp251Gly/Gln307His (named A2) generated by random mutagenesis, able to produce 4'-hydroxydiclofenac, 2-hydroxyibuprofen and 4-hydroxytolbutamide from diclofenac, ibuprofen and tolbutamide, respectively. The 3D structure of the substrate-free mutant shows a conformation similar to the closed one found in the substrate-bound wild type enzyme, but with a higher degree of disorder in the region of the G-helix and F-G loop. This is due to the mutation Asp251Gly that breaks the salt bridge between Aps251 on I-helix and Lys224 on G-helix, allowing the G-helix to move away from I-helix and conferring a higher degree of flexibility to this element.

Synthesis of bench-stable diarylmethylium tetrafluoroborates.

A representative number of bench-stable nonsymmetric diarylcarbenium tetrafluoroborates have been isolated via the direct coupling of aryl (or heteroaryl) aldehydes and N-heteroarenes and fully characterized. They have proven to be highly stable in the presence of both EDG and EWG substituents. An (E)-iminium vinylogous substructure has been shown as the common cation scaffold by X-ray analysis and by NOE determination.