Dante Gatteschi

University of Florence, Florens, Tuscany, Italy

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Publications (595)1487.3 Total impact

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    ABSTRACT: The quest for efficient ways of modulating localized surface plasmon resonance is one of the frontiers in current research in plasmonics; the use of a magnetic field as a source of modulation is among the most promising candidates for active plasmonics. Here we report the observation of magnetoplasmonic modes on colloidal gold nanoparticles detected by means of magnetic circular dichroism (MCD) spectroscopy and provide a model that is able to rationalize and reproduce the experiment with unprecedented qualitative and quantitative accuracy. We believe that the steep slope observed at the plasmon resonance in the MCD spectrum can be very efficient in detecting changes in the refractive index of the surrounding medium, and we give a simple proof of principle of its possible implementation for magnetoplasmonic refractometric sensing.
    Nano Letters 09/2013; · 13.03 Impact Factor
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    Dante Gatteschi, Alessandro Vindigni
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    ABSTRACT: Single-chain magnets are molecular spin chains displaying slow relaxation of the magnetisation on a macroscopic time scale. To this similarity with single-molecule magnets they own their name. In this chapter the distinctive features of single-chain magnets as opposed to their precursors will be pinpointed. In particular, we will show how their behaviour is dictated by the physics of thermally-excited domain walls. The basic concepts needed to understand and model single-chain magnets will also be reviewed.
    03/2013;
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    ABSTRACT: BACKGROUND: The ferroxidase center of DNA-binding proteins from starved cells (Dps) is a major player in the iron oxidation/detoxification process that leads to a decreased reactive oxygen species production. The possible Mn(II) participation in this process has been studied in Dps from Kineococcus radiotolerans, a radiation-resistant bacterium with a high cytosolic Mn/Fe ratio and a high capacity to survive ionizing and stress conditions. METHODS: The X-ray structure of recombinant K. radiotolerans Dps loaded with Mn(II) has been solved at 2.0 Å resolution. Mn(II) binding to K. radiotolerans Dps and its effect on Fe(II) oxidation have been characterized in spectroscopic measurements. RESULTS: In K. radiotolerans Dps, the Fe-Fe ferroxidase center can have also a Mn-Fe composition. Mn(II) binds only at the high affinity, so-called A site, whereas Fe(II) binds also at the low affinity, so-called B site. The Mn-Fe and Fe-Fe centers behave distinctly upon iron oxidation by O(2). A site-bound Mn(II) or Fe(II) play a catalytic role, while B site-bound Fe(II) behaves like a substrate and can be replaced by another Fe(II) after oxidation. When H(2)O(2) is the Fe(II) oxidant, single electrons are transferred to aromatic residues near the ferroxidase center and give rise to intra-protein radicals thereby limiting OH(•) release in solution. The presence of the Mn-Fe center results in significant differences in the development of such intra-protein radicals. GENERAL SIGNIFICANCE: The results provide a likely molecular mechanism for the protective role of Mn(II) under oxidative stress conditions as it participates in redox cycling in the hetero-binuclear ferroxidase center.
    Biochimica et Biophysica Acta 02/2013; · 4.66 Impact Factor
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    ABSTRACT: Nitronyl nitroxides (NitR) are a family of persistent radicals widely used in molecular magnetism and recently suggested as potential candidates for spintronic applications. In this paper we characterize by X- and W- band Electron Paramagnetic Resonance (EPR) spectroscopy the new radical S-4-(nitronyl nitroxide) benzyl ethanethioate (NitSAc) designed for assembling on Au surfaces. We determined the radical magnetic tensors and studied by X-band pulse EPR its spin relaxation behaviour in fluid and glassy solutions of toluene. A comparison with the well known nitroxide 3-carbamoyl-2,2,5,5-tetramethyl-3-pyrrolin-1-oxyl (CTPO) is afforded. The advantages of using NitSAc in technological applications are discussed on the basis of the slow spin relaxation demonstrated by this study.
    Journal of Materials Chemistry 10/2012; 22(41):22272-22281. · 5.97 Impact Factor
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    ABSTRACT: Ein Vergleich der strukturellen und magnetischen Eigenschaften von molekularen Nanomagneten und magnetischen Nanopartikeln kann hilfreich sein, um ein tieferes Verständnis des magnetischen Verhaltens im Zwischenbereich zwischen molekularen und Bulkobjekten zu gewinnen. In dieser Hinsicht sind Eisen-Oxo-Cluster besonders interessant, weil hier eine Reihe von molekularen Systemen existiert, die der Größe von magnetischen Eisenoxid-Nanopartikeln nahekommen. In diesem Kurzaufsatz geben wir einen Überblick über Literaturdaten, mit dem Ziel, ein besseres Verständnis davon zu erlangen, wie die Eigenschaften molekularer Nanomagnete in magnetischen Nanopartikeln in Erscheinung treten und umgekehrt.
    Angewandte Chemie 05/2012; 124(20).
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    ABSTRACT: Highly versatile coordinating ligands are designed and synthesized with two β-diketonate groups linked at the carbon 3 through a phenyl ring. The rigid aromatic spacer is introduced in the molecules to orient the two acetylacetone units along different angles and coordination vectors. The resulting para, meta, and ortho bis-(3-acetylacetonate)benzene ligands show efficient chelating properties toward Cu(II) ions. In the presence of 2,2'-bipyridine, they promptly react and yield three dimers, 1, 2, and 3, with the bis-acetylacetonate unit in bridging position between two metal centers. X-ray single crystal diffraction shows that the compounds form supramolecular chains in the solid state because of intermolecular interactions. Each of the dinuclear complexes shows a magnetic behavior which is determined by the combination of structural parameters and spin polarization effects. Notably, the para derivative (1) displays a moderate antiferromagnetic coupling (J = -3.3 cm(-1)) along a remarkably long Cu···Cu distance (12.30 Å).
    Inorganic Chemistry 04/2012; 51(9):5409-16. · 4.59 Impact Factor
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    ABSTRACT: The comparison of the structural and magnetic properties of molecular nanomagnets (MNM) and magnetic nanoparticles (MNP) can be instructive to get a deeper understanding of the magnetic behavior on the intermediate scale between molecular and bulk objects. In this respect iron oxo based clusters are particularly interesting, since they provide an increasing number of molecular systems with sizes close to that of iron oxide MNP. In this Minireview we report a survey of literature data aimed at improving our understanding of the emergence of MNP properties from MNM ones.
    Angewandte Chemie International Edition 04/2012; 51(20):4792-800. · 13.73 Impact Factor
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    ABSTRACT: In this paper we report on the characterization by continuous wave electron spin resonance spectroscopy (cw-ESR) of a nitronyl nitroxide radical in a nematic phase. A detailed analysis is performed by exploiting an innovative modeling strategy alternative to the usual spectral simulation approach: most of the molecular parameters needed to calculate the spectrum are evaluated a priori and the ESR spectrum is obtained by direct application of the stochastic Liouville equation. Allowing a limited set of fitting parameters it is possible to reproduce satisfactorily ESR spectra in the temperature range 260 K-340 K including the nematic-to-isotropic phase transition (325.1 K). Our results open the way to a more quantitative understanding of the ordering and mobility of nitronyl nitroxide radicals in nanostructured environments.
    Physical Chemistry Chemical Physics 02/2012; 14(9):3200-7. · 3.83 Impact Factor
  • The Journal of Physical Chemistry C 01/2012; 116:8261. · 4.81 Impact Factor
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    J. Mater. Chem. 01/2012; 22:1622.
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    Journal of Materials Chemistry 01/2012; 22:1662. · 5.97 Impact Factor
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    ABSTRACT: We present a simple and cost-effective method for rendering networks of cellulose fibers, such as paper, fabrics or membranes, superparamagnetic by impregnating the individual fibers with a reactive acrylic monomer. The cellulose fibers are wetted by a cyanoacrylate monomer solution containing superparamagnetic manganese ferrite colloidal nanoparticles. Upon moisture initiated polymerization of the monomer on the fiber surfaces, a thin nanocomposite shell forms around each fiber. The nanocomposite coating renders the cellulose fibers water repellent and magnetically responsive. Magnetic and microscopy studies prove that the amount of the entrapped nanoparticles in the nanocomposite shell is fully controllable, and that the magnetic response is directly proportional to this amount. A broad range of applications can be envisioned for waterproof magnetic cellulose materials (such as magnetic paper/tissues) obtained by such a simple yet highly efficient method.
    Journal of Materials Chemistry 01/2012; 22(4):1662-66. · 5.97 Impact Factor
  • Andrea Dei, Dante Gatteschi
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    ABSTRACT: A bitter pill? The dose of quantum concepts that chemists must digest is steadily increasing. The drug perhaps tastes bitter, but it produces good effects yielding novel systems to test the foundations of quantum mechanics. This point is considered in reference to molecular nanomagnets (see structure of a terbium phthalocyaninate complex), a class of materials that continues to show new facets requiring the exploration of new quantum effects.
    Angewandte Chemie International Edition 12/2011; 50(50):11852-8. · 13.73 Impact Factor
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    ChemPhysChem 06/2011; 12(12):2221-4. · 3.35 Impact Factor
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    ABSTRACT: Synthesis of functionalized magnetic nanoparticles (NPs) for biomedical applications represents a current challenge. In this paper we present the synthesis and characterization of water-dispersible sugar-coated iron oxide NPs specifically designed as magnetic fluid hyperthermia heat mediators and negative contrast agents for magnetic resonance imaging. In particular, the influence of the inorganic core size was investigated. To this end, iron oxide NPs with average size in the range of 4-35 nm were prepared by thermal decomposition of molecular precursors and then coated with organic ligands bearing a phosphonate group on one side and rhamnose, mannose, or ribose moieties on the other side. In this way a strong anchorage of the organic ligand on the inorganic surface was simply realized by ligand exchange, due to covalent bonding between the Fe(3+) atom and the phosphonate group. These synthesized nanoobjects can be fully dispersed in water forming colloids that are stable over very long periods. Mannose, ribose, and rhamnose were chosen to test the versatility of the method and also because these carbohydrates, in particular rhamnose, which is a substrate of skin lectin, confer targeting properties to the nanosystems. The magnetic, hyperthermal, and relaxometric properties of all the synthesized samples were investigated. Iron oxide NPs of ca. 16-18 nm were found to represent an efficient bifunctional targeting system for theranostic applications, as they have very good transverse relaxivity (three times larger than the best currently available commercial products) and large heat release upon application of radio frequency (RF) electromagnetic radiation with amplitude and frequency close to the human tolerance limit. The results have been rationalized on the basis of the magnetic properties of the investigated samples.
    Journal of the American Chemical Society 06/2011; 133(27):10459-72. · 10.68 Impact Factor
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    ABSTRACT: Synthesis of functionalized magnetic nanoparticles (NPs) for biomedical applications represents a current challenge. In this paper we present the synthesis and characterization of water-dispersible sugar-coated iron oxide NPs specifically designed as magnetic fluid hyperthermia heat mediators and negative contrast agents for magnetic resonance imaging. In particular, the influence of the inorganic core size was investigated. To this end, iron oxide NPs with average size in the range of 4–35 nm were prepared by thermal decomposition of molecular precursors and then coated with organic ligands bearing a phosphonate group on one side and rhamnose, mannose, or ribose moieties on the other side. In this way a strong anchorage of the organic ligand on the inorganic surface was simply realized by ligand exchange, due to covalent bonding between the Fe3+ atom and the phosphonate group. These synthesized nanoobjects can be fully dispersed in water forming colloids that are stable over very long periods. Mannose, ribose, and rhamnose were chosen to test the versatility of the method and also because these carbohydrates, in particular rhamnose, which is a substrate of skin lectin, confer targeting properties to the nanosystems. The magnetic, hyperthermal, and relaxometric properties of all the synthesized samples were investigated. Iron oxide NPs of ca. 16–18 nm were found to represent an efficient bifunctional targeting system for theranostic applications, as they have very good transverse relaxivity (three times larger than the best currently available commercial products) and large heat release upon application of radio frequency (RF) electromagnetic radiation with amplitude and frequency close to the human tolerance limit. The results have been rationalized on the basis of the magnetic properties of the investigated samples.
    06/2011;
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    ABSTRACT: A W-band single-crystal EPR study has been performed on a molecular cluster comprising 19 iron(III) ions bridged by oxo- hydroxide ions, Fe(19), in order to investigate magnetic nanosystems with a behavior in between the one of Magnetic NanoParticles (MNP) and that of Single Molecule Magnets (SMM). The Fe(19) has a disk-like shape: a planar Fe(7) core with a brucite (Mg(OH)(2)) structure enclosed in a "shell" of 12 Fe(III) ions. EPR and magnetic measurements revealed an S = 35/2 ground state with an S = 33/2 excited state lying ∼ 8 K above. The presence of other low-lying excited states was also envisaged. Rhombic Zero Field Splitting (ZFS) tensors were determined, the easy axes lying in the Fe(19) plane for both the multiplets. At particular temperatures and orientations, a partially resolved fine structure could be observed which could not be distinguished in powder spectra, due to orientation disorder. The similarities of the EPR behavior of Fe(19) and MNP, together with the accuracy of single crystal analysis, helped to shed light on spectral features observed in MNP spectra, that is a sharp line at g = 2 and a low intensity transition at g = 4. Moreover, a theoretical analysis has been used to estimate the contribution to the total magnetic anisotropy of core and surface; this latter is crucial in determining the easy axis-type anisotropy, alike that of MNP surface.
    Dalton Transactions 06/2011; 40(32):8145-55. · 3.81 Impact Factor
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    ABSTRACT: In an effort to build a unitary view of the properties of magnetic nanoparticles (MNPs) and molecular nanomagnets (MNMs), we investigated with different techniques MNPs of spinel-type iron oxide of approximately 3.5 and 8 nm mineralized in the internal cavity of ferritin-type proteins. In particular, we used electron magnetic resonance (EMR) and static and dynamic magnetic measurements and took advantage of the capacity of the protein shells to control the size of the MNPs. A signal at half-field in the EMR spectrum is observed for MNPs as big as 8 nm mineralized in protein cavities. This feature has been interpreted as the signature of the discrete structure of the energy levels and, therefore, of the quantum nature of the system. The EMR behavior of the MNPs is compared with that of two large MNMs: one containing 19 Fe(III) and a second containing 19 Mn(II) centers. The ideal structure of the latter is used as a model to show the structuring of the energy levels. In particular, the analysis of MNP behavior based on the MNM approach helps to shed light on the role of the different energy terms that govern the MNP properties.
    Physical review. B, Condensed matter 03/2011; 83(10).
  • Lorenzo Sorace, Cristiano Benelli, Dante Gatteschi
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    ABSTRACT: In this tutorial review we discuss some basic aspects concerning the magnetic properties of rare-earth ions, which are currently the subject of a renovated interest in the field of molecular magnetism, after the discovery that slow relaxation of the magnetization at liquid nitrogen temperature can occur in mononuclear complexes of these ions. Focusing on Dy(III) derivatives a tutorial discussion is given of the relation of the crystal field parameters, which determine the anisotropy of these systems and consequently their interesting magnetic properties, with the geometry of the coordination sphere around the lanthanide centre and with the pattern of f orbitals. The problem of systems of low point symmetry is also addressed by showing how detailed single crystal investigation, coupled to more sophisticated calculation procedures, is an absolute necessity to obtain meaningful structure-property relationships in these systems.
    Chemical Society Reviews 03/2011; 40(6):3092-104. · 24.89 Impact Factor

Publication Stats

4k Citations
1,487.30 Total Impact Points

Institutions

  • 1978–2013
    • University of Florence
      • Dipartimento di Chimica "Ugo Schiff"
      Florens, Tuscany, Italy
  • 2012
    • University of Padova
      • Department of Chemical Sciences
      Padova, Veneto, Italy
  • 2011
    • Institut Charles Gerhardt
      Montpelhièr, Languedoc-Roussillon, France
  • 2010
    • Universität Stuttgart
      Stuttgart, Baden-Württemberg, Germany
  • 2009
    • Sapienza University of Rome
      • Department of Biochemical Sciences "Alessandro Rossi Fanelli
      Roma, Latium, Italy
  • 2007
    • University of Milan
      • Department of Inorganic, Organometallic and Analytical Chemistry "Lamberto Malatesta" CIMA
      Milano, Lombardy, Italy
    • Ben-Gurion University of the Negev
      • Department of Physics
      Beersheba, Southern District, Israel
    • National High Magnetic Field Laboratory
      Tallahassee, Florida, United States
  • 2004–2006
    • University of Catania
      • Department of Chemical Sciences
      Catania, Sicily, Italy
  • 2005
    • Georg-August-Universität Göttingen
      • Institute of Inorganic Chemistry
      Göttingen, Lower Saxony, Germany
    • French National Centre for Scientific Research
      • Laboratoire National des Champs Magnétiques Intenses
      Lutetia Parisorum, Île-de-France, France
  • 1999–2005
    • Università degli Studi di Modena e Reggio Emilia
      • Department of Chemical and Geological Sciences
      Modène, Emilia-Romagna, Italy
  • 2001–2003
    • Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali
      Florens, Tuscany, Italy
    • University of Utah
      Salt Lake City, Utah, United States
    • Université Paris-Sud 11
      • Laboratoire de Physique des Solides
      Paris, Ile-de-France, France
  • 2002
    • University of Naples Federico II
      Napoli, Campania, Italy
  • 2000
    • Iowa State University
      • Department of Physics and Astronomy
      Ames, IA, United States
    • University of Pavia
      • Department of Physics
      Pavia, Lombardy, Italy
  • 1996
    • Academy of Sciences of Moldova
      Kischinew, Chişinău, Moldova
    • Università della Calabria
      Rende, Calabria, Italy
  • 1991
    • Università degli Studi del Sannio
      Benevento, Campania, Italy