Crystal structure of di-µ-chlorido-bis-{chlorido-[(-)-5,6-pinenebi-pyridine]-cobalt(II)} aqua-dichlorido[(-)-5,6-pinenebi-pyridine]cobalt(II).

The crystal structure of [Co2Cl4(C17H18N2)2][CoCl2(C17H18N2)(H2O)] or [Co(L)Cl(µ-Cl)]2[Co(L)(Cl)2(OH2)], where L is the enanti-opure bidentate ligand (-)-5,6-pinenebi-pyridine (C17H18N2), has been determined. Crystals suitable for X-ray structure analysis were obtained by slow evaporation of an ethano-lic solution containing equimolar amounts of L and CoCl2·6H2O. The CoII cations all have a coordination number of five, and in each case the coordination polyhedron is a trigonal bipyramid. The Co-N bonds lengths range from 2.037 (7) to 2.195 (7) Å, and Co-Cl bonds lengths range from 2.284 (2) to 2.509 (2) Å. The asymmetric unit contains two discrete complexes, one dinuclear and the other mononuclear. Between the two mol-ecules, two types of inter-molecular inter-actions have been evidenced: π-π stackings involving the bi-pyridine units, and O-H⋯Cl hydrogen bonds between the hydrogen atoms of the aqua ligand coordinating to the mononuclear complex and the non-bridging chlorido ligand coordinating to the dinuclear mol-ecule. These inter-actions lead to a two-dimensional supra-molecular arrangement parallel to the ab plane.

Jet Colliding and Mixing Efficiency.

Two experimental methods, the Nile Red dye extraction and the Williamson ether synthesis in biphasic conditions, were used to characterize the mixing performance of a new cheap impinging jet colliding mixer from Gjosa and to compare it to other commercial micromixers (Caterpillar CPMM-R300, T-mixer, LTF MR-MX and LTF MR-MS). The Nile Red method shows that the Caterpillar mixer is the best one. Excellent results are also achieved with two Gjosa mixers in series. These results are not reflected in the Williamson ether synthesis, where the best mixer is the Gjosa one.

Heptacoordinate CoII Complex: A New Architecture for Photochemical Hydrogen Production.

The first heptacoordinate cobalt catalyst for light-driven hydrogen production in water has been synthesized and characterized. Photochemical experiments using [Ru(bpy)3 ]2+ as photosensitizer gave a turnover number (TON) of 16300 mol H2 (mol cat.)-1 achieved in 2 hours of irradiation with visible (475 nm) light. This promising result provides a path forward in the development of new structures to improve the efficiency of the catalysis.

Synthesis of hydrophilic and hydrophobic carbon quantum dots from waste of wine fermentation.

Wine lees are one of the main residues formed in vast quantities during the fermentation of wine. While toxic when applied to plants and wetlands, it is a biodegradable material, and several alternatives have been proposed for its valorization as: dietary supplement in animal feed, source for various yeast extracts and bioconversion feedstock. The implementation of stricter environment protection regulations resulted in increasing costs for wineries as their treatment process constitutes an unavoidable and expensive step in wine production. We propose here an alternative method to reduce waste and add value to wine production by exploiting this rich carbon source and use it as a raw material for producing carbon quantum dots (CQDs). A complete synthetic pathway is discussed, comprising the carbonization of the starting material, the screening of the most suitable solvent for the extraction of CQDs from the carbonized mass and their hydrophobic or hydrophilic functionalization. CQDs synthesized with the reported procedure show a bright blue emission (λmax = 433 ± 13 nm) when irradiated at 366 nm, which is strongly shifted when the wavelength is increased (e.g. emission at around 515 nm when excited at 460 nm). Yields and luminescent properties of CQDs, obtained with two different methods, namely microwave and ultrasound-based extraction, are discussed and compared. This study shows how easy a residue can be converted into an added-value material, thus not only reducing waste and saving costs for the wine-manufacturing industry but also providing a reliable, affordable and sustainable source for valuable materials.

Sustainable Chemistry: From Wine Industry Waste (Wine Lees) to Luminescent Ink-jet Inks Containing Carbon Dots.

Carbon nanodots can be obtained in good yields by direct combustion of an abundant waste from the wine industry, wine lees. The extraction of these nanoparticles followed by their chemical functionalization lead to an ink-jettable material emitting in the visible region (blue) under specific UV irradiation.

Preventing Implant-Associated Infections by Silver Coating.

Implant-associated infections (IAIs) are a dreaded complication mainly caused by biofilm-forming staphylococci. Implant surfaces preventing microbial colonization would be desirable. We examined the preventive effect of a silver-coated titanium-aluminum-niobium (TiAlNb) alloy. The surface elicited a strong, inoculum-dependent activity againstStaphylococcus epidermidisandStaphylococcus aureusin an agar inhibition assay. Gamma sterilization and alcohol disinfection did not alter the effect. In a tissue cage mouse model, silver coating of TiAlNb cages prevented perioperative infections in an inoculum-dependent manner and led to a 100% prevention rate after challenge with 2 × 10(6)CFU ofS. epidermidisper cage. InS. aureusinfections, silver coating had only limited effect. Similarly, daptomycin or vancomycin prophylaxis alone did not preventS. aureusinfections. However, silver coating combined with daptomycin or vancomycin prophylaxis thwarted methicillin-resistantS. aureusinfections at a prevention rate of 100% or 33%, respectively. Moreover, silver release from the surface was independent of infection and occurred rapidly after implantation. On day 2, a peak of 82 µg Ag/ml was reached in the cage fluid, corresponding to almost 6× the MIC of the staphylococci. Cytotoxicity toward leukocytes in the cage was low and temporary. Surrounding tissue did not reveal histological signs of silver toxicity.In vitro, no emergence of silver resistance was observed in several clinical strains of staphylococci upon serial subinhibitory silver exposures. In conclusion, our data demonstrate that silver-coated TiAlNb is potent for prevention of IAIs and thus can be considered for clinical application.

New antimicrobial and biocompatible implant coating with synergic silver-vancomycin conjugate action.

Materials foreign to the body are used ever more frequently, as increasing numbers of patients require implants. As a consequence, the numbers of implant-related infections have grown as well, and with increasing resistance. Treatments often fail; thus, new antibacterial coating strategies are being developed by scientists to avoid, or at least strongly reduce, bacterial adhesion to implant surfaces. In this study, we focused on producing a self-protective coating combining silver(I) ions and a vancomycin-derived molecule, intelligent pyridinate vancomycin (IPV), with a synergetic and effective action against bacteria. These Ag(I) -IPV conjugate-coated surfaces are well characterized and exhibit strong bactericidal activity in vitro against Staphylococci strains. Furthermore, the released quantities of both drugs from the coated surfaces do not affect their biocompatibility and soft tissue integration. These newly developed Ag(I) -IPV conjugate coatings thus represent a possible and efficient protection method against bacterial adhesion and biofilm formation during and after implant surgery.