59 research outputs found
Extending substrate sensing capabilities of zinc tris(2-pyridylmethyl)amine-based stereodynamic probe
No full textTripodal metal complexes have been widely used for catalysis and more recently also for molecular recognition applications. Their ability in recognition and signal amplification of chiral substrates is because of the setup of the ligand around the metal in a propeller shape. Within this subject, we have recently reported tris(2-pyridylmethyl)amine- and triphenolamine-based complexes for the determination of the enantiomeric excess of various substrates. Herein, we show the versatility of the zinc tris(2-pyridylmethyl)amine-based stereodynamic probe by performing a detailed study of the imine formation process, by the extension of the sensing capabilities to other chiral compounds. A principal component analysis study of the system together with TD-DFT studies highlights the molecular origin of the observed chiroptical properties
Magnetic interactions in spin-labeled Au nanoparticles
No full text© 2014 American Chemical Society. A series of gold nanoparticles functionalized with TEMPO-modified disulfide 2 have been prepared and studied by electron paramagnetic resonance (EPR) spectroscopy, UV-vis, transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), and thermogravimetric analysis (TGA). In order to increase the packing of spin labels on the particle surface, heat-induced size evolution and ligand exchange reactions were used. The optimized synthesis included a one-pot reaction at room temperature that led to gold nanoparticles with a controlled large size (ca. 7 nm) and high coverage of radicals. These nanoparticles showed a |Δms| = 2 transition at half-field, which gives direct evidence of the presence of a high-spin state and permits an EPR study of the nature of the magnetic coupling between the spins. The results showed dominant antiferromagnetic interactions between radicals, but at lower temperatures, a ferromagnetic contribution was observed.This work was supported by the University of York Research Visitor Scheme, the DGI grant CONSOLIDERC (CTQ2006-06333), CSIC-PIF RAPCAM (PIF-08-017-3), AGAUR (2009-SGR-00516), and DGI grant POMAs (CTQ2010-19501). CIBER-BBN is an initiative funded by the VI National R&D&i Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions, and financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund.Peer Reviewe
Tris(2-pyridylmethyl)amines as emerging scaffold in supramolecular chemistry
No full texttris-(2-Pyridylmethyl)amine (usually abbreviated as TPA or TPMA) are ligands which are emerging in many fields of chemistry because of their ability to form stable and catalytically active complexes with a wide variety of metals. While the applications in catalysis began soon after the synthesis of the first metal complexes, studies in supramolecular chemistry are more recent and they often take advantage from their stereodynamic nature. This review surveys TPMA applications as: i) anion sensors, ii) biochemical sensors, iii) molecular switches, iv) chiral probes and as v) building blocks in the synthesis of supramolecular cages
Screening sustainability assessment of innovative bio-based solutions for art restoration within the EC SSbD framework
No full textImplementing the EC Safe and Sustainable by Design (SSbD) framework from the early design phase of innovative solutions remains challenging. Although various methods to evaluate safety and sustainability exist, their integration throughout the innovation process, especially during the early stages at low Technology Readiness Levels (TRLs), is often hindered by time constraints, limited resources, the need for multidisciplinary expertise, and uncertainty in data availability and quality.
This study presents the Screening Sustainability Assessment (SSA), a screening-level method developed to support early-stage innovation by integrating functionality, safety, and sustainability aspects in product design. The SSA combines semi-quantitative scoring with targeted SSbD-oriented questions, enabling structured assessment across all life cycle stages. Each aspect is evaluated through specific criteria and questions, scored on a five-level scale, fostering informed stakeholder dialogue and supporting the early integration of SSbD objectives. The SSA was applied to assess two innovative bio-based protective coatings against a fossil-based benchmark. These products are intended for the preventive and remedial conservation of cultural heritage surfaces, a sector where traditional materials often present limitations in terms of durability, and sustainability performance. The application of the SSA method to the case study demonstrates its effectiveness in identifying SSbD performance and critical areas for improvement throughout the product life cycle. Although designed for the cultural heritage sector, the methodology is transferable to other fields facing similar challenges. It contributes to the broader goal of operationalizing the SSbD framework by offering a tool for embedding safety and sustainability considerations into innovation processes from the outset
Supporting the development of sustainable nano-based formulations for the restoration of modern and contemporary works of art
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Guiding the development of sustainable nano-enabled products for the conservation of works of art: proposal for a framework implementing the Safe by Design concept
No full textNanotechnology provides innovative and promising solutions for the conservation of cultural heritage, but the development and application of new nano-enabled products pose concerns regarding their human health and environmental risks. To address these issues, we propose a sustainability framework implementing the Safe by Design concept to support product developers in the early steps of product development, with the aim to provide safer nano-formulations for conservation, while retaining their functionality. In addition, this framework can support the assessment of sustainability of new products and their comparison to their conventional chemical counterparts if any. The goal is to promote the selection and use of safer and more sustainable nano-based products in different conservation contexts. The application of the proposed framework is illustrated through a hypothetical case which provides a realistic example of the methodological steps to be followed, tailored and iterated along the decision-making process
Calcium aluminate cement as an alternative to ordinary Portland cement for the remediation of heavy metals contaminated soil: mechanisms and performance
No full textPurpose: This work deals with the application of a solidification/stabilization process with the aim to obtain safe and reusable granular materials from a polluted soil and to elucidate the mechanisms involved in the retention of several heavy metals. Materials and methods: The High Performance Solidification/Stabilization (HPSS®) process was applied to the selected contaminated soil by using both ordinary Portland cement and calcium aluminate cement, as well as several binders prepared by combining these two types of cement in different proportions. Leaching and mechanical tests were carried out to evaluate the performances of the proposed binders in the pellets produced by the HPSS® process, while XRD analysis and SEM/EDX imaging were used to investigate the phase composition and internal microstructure of the treated samples. Result and discussion: The examination of the obtained granular materials revealed that the immobilization of Sb was mainly related to its inclusion within calcium silicate hydrates’ structure; the immobilization of Cr, Pb, Ni, Co, Zn and Tl was associated with the eluate pH and their incorporation within ettringite structure, while for Se, Cu, Ba and V, the main retention mechanism was physical encapsulation. In addition, the application of a wet conditioning process improved the materials’ performance, leading to granules always satisfying the Italian regulatory requirements for reuse. Conclusions: The findings obtained in this study were useful to better elucidate the mechanisms involved in the retention of heavy metals by several binders, contributing to the development of sustainable management strategies for contaminated soils and sediments through their transformation into reusable materials. Graphical abstract: [Figure not available: see fulltext.
A multitechnique approach for the identification of multiple contamination sources near a polluted industrial site
No full textDegraded land requires rapid and suitable remedial actions, thus appropriate and fast methodological approaches for estimating the spatial distribution of contaminants are needed. In this context, a methodological approach combining isotopic measurements, heavy metals concentrations mapping, X-ray diffraction, and cluster analysis, was applied to characterize a polluted industrial site where the contamination due to improper waste disposal could have spread also into the surrounding fields. This approach was applied to a set of representative topsoil (from 15 to 30 cm depth) and subsoil (from 130 to 150 cm depth) samples, selected either inside or outside the contaminated site. The X-ray diffraction analysis highlighted that only the mineralogy of the subsoil below the buried waste was noticeably altered, while the concentration mapping highlighted that the levels of several heavy metals on the edge of the contaminated site, at both depths, were very similar to those found in the samples from the outside. Based on these findings, Pb was used as a tracer for heavy metal pollution by its stable isotopes' analysis. The cluster analysis of the isotopic measurements revealed that only the contamination detected inside the industrial site could be attributed to the pollutants migration from the buried waste. Conversely, the contaminants concentrations found in the topsoil samples taken outside the site could be ascribed to contamination sources other than the polluted waste present inside the site
Interaction between Copper Oxide Nanoparticles and Amino Acids: Influence on the Antibacterial Activity
No full textThe increasing concern about antibiotic-resistance has led to the search for alternative antimicrobial agents. In this effort, different metal oxide nanomaterials are currently under investigation, in order to assess their effectiveness, safety and mode of action. This study focused on CuO nanoparticles (CuO NPs) and was aimed at evaluating how the properties and the antimicrobial activity of these nanomaterials may be affected by the interaction with ligands present in biological and environmental media. Ligands can attach to the surface of particles and/or contribute to their dissolution through ligand-assisted ion release and the formation of complexes with copper ions. Eight natural amino acids (L-Arg, L-Asp, L-Glu, L-Cys, L-Val, L-Leu, L-Phe, L-Tyr) were chosen as model molecules to investigate these interactions and the toxicity of the obtained materials against the Gram-positive bacterium Staphylococcus epidermidis ATCC 35984. A different behavior from pristine CuO NPs was observed, depending on the aminoacidic side chain. These results were supported by physico-chemical and colloidal characterization carried out by means of Fourier-Transform Infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Thermo-Gravimetric Analysis (TGA), Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and light scattering techniques (Dynamic Light Scattering (DLS), Electrophoretic Light Scattering (ELS) and Centrifugal Separation Analysis (CSA)
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