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991.
Alberto Privitera Emilio Macaluso Alessandro Chiesa Alessio Gabbani Davide Faccio Demetra Giuri Matteo Briganti Niccol Giaconi Fabio Santanni Nabila Jarmouni Lorenzo Poggini Matteo Mannini Mario Chiesa Claudia Tomasini Francesco Pineider Enrico Salvadori Stefano Carretta Roberta Sessoli 《Chemical science》2022,13(41):12208
It is well assessed that the charge transport through a chiral potential barrier can result in spin-polarized charges. The possibility of driving this process through visible photons holds tremendous potential for several aspects of quantum information science, e.g., the optical control and readout of qubits. In this context, the direct observation of this phenomenon via spin-sensitive spectroscopies is of utmost importance to establish future guidelines to control photo-driven spin selectivity in chiral structures. Here, we provide direct proof that time-resolved electron paramagnetic resonance (EPR) can be used to detect long-lived spin polarization generated by photoinduced charge transfer through a chiral bridge. We propose a system comprising CdSe quantum dots (QDs), as a donor, and C60, as an acceptor, covalently linked through a saturated oligopeptide helical bridge (χ) with a rigid structure of ∼10 Å. Time-resolved EPR spectroscopy shows that the charge transfer in our system results in a C60 radical anion, whose spin polarization maximum is observed at longer times with respect to that of the photogenerated C60 triplet state. Notably, the theoretical modelling of the EPR spectra reveals that the observed features may be compatible with chirality-induced spin selectivity, but the electronic features of the QD do not allow the unambiguous identification of the CISS effect. Nevertheless, we identify which parameters need optimization for unambiguous detection and quantification of the phenomenon. This work lays the basis for the optical generation and direct manipulation of spin polarization induced by chirality.Our work provides a first attempt to directly detect the spin polarisation of Chiral-Induced Spin Selectivity (CISS) effect by studying the photoinduced electron transfer in a CdSe Quantum Dot-chiral bridge-fullerene derivative (QD–χ–C60) system. 相似文献
992.
Devis Montroni Matteo Di Giosia Matteo Calvaresi Giuseppe Falini 《Molecules (Basel, Switzerland)》2022,27(17)
The chemical functionalization of polysaccharides to obtain functional materials has been of great interest in the last decades. This traditional synthetic approach has drawbacks, such as changing the crystallinity of the material or altering its morphology or texture. These modifications are crucial when a biogenic matrix is exploited for its hierarchical structure. In this work, the use of lectins and carbohydrate-binding proteins as supramolecular linkers for polysaccharide functionalization is proposed. As proof of concept, a deproteinized squid pen, a hierarchically-organized β-chitin matrix, was functionalized using a dye (FITC) labeled lectin; the lectin used was the wheat germ agglutinin (WGA). It has been observed that the binding of this functionalized protein homogenously introduces a new property (fluorescence) into the β-chitin matrix without altering its crystallographic and hierarchical structure. The supramolecular functionalization of polysaccharides with protein/lectin molecules opens up new routes for the chemical modification of polysaccharides. This novel approach can be of interest in various scientific fields, overcoming the synthetic limits that have hitherto hindered the technological exploitation of polysaccharides-based materials. 相似文献
993.
Osmane Camara Anamul H. Mir Krzysztof Dzieciol Graeme Greaves Shibabrata Basak Hans Kungl Matteo Bosi Luca Seravalli Steve E. Donnelly Rüdiger A. Eichel Jonathan A. Hinks 《Particle & Particle Systems Characterization》2021,38(12):2100154
Once nanomaterials have been synthesized, inducing further structural modifications is challenging. However, being able to do so in a controlled manner is crucial. In this context, germanium nanowires are irradiated in situ within a transmission electron microscope (TEM) by a 300 keV xenon ion beam at temperatures ranging from room temperature (RT) to 500 °C. The ion irradiation is performed in situ and the evolution of nanowires during irradiation is monitored. At 300 °C and below, where the temperature is low enough to allow amorphization, the ion beam causes the formation of nanostructures within the nanowires. Formation of nanopores and swelling of nanowires is observed for a very low fluence of 2.2 × 1014 and up to 4.2 × 1015 ions cm−2. At higher fluences, the thickness of the nanowires decreases, the nanowires lose their wire-like cylindrical shape and the nanostructuring caused by the ion beam becomes more complex. The nanostructures are observed to be stable upon crystallization when the nanowires are annealed at 530 °C. Furthermore, in situ imaging allows the growth of nanopores during irradiation to be followed at RT and at 300 °C providing valuable insights into the mechanism responsible for the nanostructuring. 相似文献
994.
995.
Dr. Stefano Marchesi Dr. Matteo Guidotti Prof. Leonardo Marchese Claudio Evangelisti Prof. Fabio Carniato Prof. Chiara Bisio 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(14):4723-4730
For the first time, the co-presence in the saponite structure of luminescent EuIII and catalytic NbV metal sites was exploited for the simultaneous detection and catalytic abatement of sulfur-containing blister chemical warfare agents. Metal centers were introduced in structural positions of the saponite (in the interlayer space or inside the inorganic framework) following two different synthetic methodologies. The functionalized saponites were able to reveal the presence of a sulfur mustard simulant (2-chloroethyl)ethyl sulfide (CEES) after few seconds of contact time and more than 80 % of the substrate was catalytically decomposed after 24 h in the presence of aqueous hydrogen peroxide. 相似文献
996.
997.
Giorgio Brida Maria Bondani Ivo P. Degiovanni Marco Genovese Matteo G. A. Paris Ivano Ruo Berchera Valentina Schettini 《Foundations of Physics》2011,41(3):305-316
With the purpose of introducing a useful tool for researches concerning foundations of quantum mechanics and applications
to quantum technologies, here we address three quantumness quantifiers for bipartite optical systems: one is based on sub-shot-noise
correlations, one is related to antibunching and one springs from entanglement determination. The specific cases of parametric
downconversion seeded by thermal, coherent and squeezed states are discussed in detail. 相似文献
998.
Matteo Signorile Luca Braglia Valentina Crocell Piero Torelli Elena Groppo Gabriele Ricchiardi Silvia Bordiga Francesca Bonino 《Angewandte Chemie (International ed. in English)》2020,59(41):18145-18150
Ti silicates, and in particular, titanium silicalite‐1 (TS‐1), are nowadays important catalysts for several partial oxidation reactions in the presence of aqueous H2O2 as an oxidant. Despite the numerous studies dealing with this material, some fundamental aspects are still unclear. In particular, the structure and the catalytic role of defective Ti sites, other than perfect tetrahedral sites recognized as the main active species, has not been quantitatively discussed in the literature. We assess the structural features of defective Ti sites on the basis of outcomes of electronic spectroscopies, as interpreted through quantum mechanical simulation. Strong evidence is disclosed to support the fact that the most common defective Ti sites, often reported in the TS‐1 literature, are monomeric Ti centers that are embedded in the zeolite framework, and which have a distorted octahedral local symmetry. 相似文献
999.
Dr. Filippo Doria Dr. Erica Salvati Luca Pompili Dr. Valentina Pirota Carmen D'Angelo Francesco Manoli Dr. Matteo Nadai Prof. Sara N. Richter Dr. Annamaria Biroccio Dr. Ilse Manet Prof. Mauro Freccero 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(47):11085-11097
Naphthalene diimide (NDI) dyads exhibiting a different substitution pattern and linker length have been synthesised and evaluated as G-quadruplex (G4) ligands, by investigating their cytotoxicity in selected cell lines. The dyads with the long C7 linker exhibit extremely low IC50 values, below 10 nm , on different cancer cell lines. Contrary, the dyads with the shorter C4 linker were much less effective, with IC values increasing up to 1 μm . Among the three dyads with the longest linker, small differences in the IC50 values emerge, suggesting that the linker length plays a more important role than the substitution pattern. We have further shown that the dyads are able to induce cellular DNA damage response, which is not limited to the telomeric regions and is likely the origin of their cytotoxicity. Both absorption titration and dynamic light scattering of the most cytotoxic dyads in the presence of hTel22 highlight their ability to induce effective G4 aggregation, acting as non-covalent cross-linking agents. 相似文献
1000.
Morozova Ksenia Armani Mariachiara Scampicchio Matteo 《Journal of Thermal Analysis and Calorimetry》2020,139(1):375-382
Journal of Thermal Analysis and Calorimetry - Isothermal microcalorimetry is often used to monitor microbiological activity and growth in various types of biological samples. Usually, it is useful... 相似文献