76
|
Deka S, Falqui A, Bertoni G, Sangregorio C, Poneti G, Morello G, De Giorgi M, Giannini C, Cingolani R, Manna L, Cozzoli PD. Fluorescent asymmetrically cobalt-tipped CdSe@CdS core@shell nanorod heterostructures exhibiting room-temperature ferromagnetic behavior. J Am Chem Soc 2009; 131:12817-28. [PMID: 19722722 DOI: 10.1021/ja904493c] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A colloidal two-step seeded-growth approach has been devised to selectively synthesize three-component magnetic/semiconductor hybrid nanocrystals (HNCs) with a matchstick-like profile and tunable geometric parameters. The newly developed heterostructures individually comprise a single metallic Co head connected to either apexes of one rod-shaped section made of a CdSe core eccentrically embedded in a CdS shell. The specific topological arrangement realized arises from the peculiar anisotropic reactivity of the noncentrosymmetric CdSe@CdS core@shell nanorods that have been used as substrates to seed heterogeneous nucleation of Co in a surfactant-free environment from an organometallic precursor. The HNCs retain appreciable fluorescent emission in spite of photoexcited charge transfer from the semiconductor to the metal domain and exhibit unusual ferromagnetic-like behavior at room temperature.
Collapse
|
77
|
Souza DA, Florencio AS, Soriano S, Calvo R, Sartoris RP, Walkimar de M Carneiro J, Sangregorio C, Novak MA, Vaz MGF. New copper(II)-radical one dimensional chain: Synthesis, crystal structure, EPR, magnetic properties and DFT calculations. Dalton Trans 2009:6816-24. [PMID: 19690694 DOI: 10.1039/b902967b] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The novel chain compound [Cu(Phtfac)(2)(NITpPy)](n) (where NITpPy = 4-pyridyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide and Phtfac = 4,4,4-trifluoro-1-phenylbutane-1,3-dione) was synthesized and characterized structurally, magnetically and by EPR. The compound contains two non equivalent Cu(II) ions, Cu1 and Cu2, located at inversion centers and bridged by a NITpPy ligand coordinating Cu1 through the pyridine donor atom, and Cu2 through a N-O group, resulting in a head-to-head chain structure. The chain exhibits an unusual spin topology with two alternating pairs of magnetic coupling constants. The magnetic behavior was modeled considering a 16-membered ring with alternating exchange couplings. The best fit parameters indicate a ferromagnetic (J(1) = 29.4 cm(-1)), and antiferromagnetic (J(2) = -4.6 cm(-1)) couplings and an average g = 2.05, corresponding to a ground state with three parallel and one anti-parallel spin for each Cu(2)NITpPy(2) unit. DFT calculations allowed assigning the ferromagnetic coupling to Cu-O-NITpPy and the antiferromagnetic coupling to Cu-N(Py)-NITpPy. Single crystal EPR spectra display only one resonance for most field orientations, as a consequence of the collapse of the signals of the different spins produced by the exchange interactions. The observed g-tensor of this resonance is related to those expected for the Cu(II) and radical ions. Comparison of this compound with other Cu-NIT radicals chains bearing different substituents in the organic radicals, highlights that the beta-diketonate ligand plays an important role in determining the final architecture. Moreover, we show how a knowledge of the spin density distribution in the initial building blocks is essential to rationalize the magnetic behavior of the resulting product.
Collapse
|
78
|
Fittipaldi M, Sorace L, Barra AL, Sangregorio C, Sessoli R, Gatteschi D. Molecular nanomagnets and magnetic nanoparticles: the EMR contribution to a common approach. Phys Chem Chem Phys 2009; 11:6555-68. [PMID: 19639130 DOI: 10.1039/b905880j] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The current status and future developments of the use of electron magnetic resonance (EMR) for the investigation of magnetic nano-systems is here reviewed. The aim is to stimulate efforts to provide a unified view of the properties of magnetic nanoparticles (MNP) comprising a few hundred magnetic centres, and molecular nanomagnets which contain up to ca. one hundred magnetic centres (MNM). The size of the systems is becoming the same but the approaches to the interpretation of their properties are still different, being bottom up for the latter and top down for the former. We make the point here of the need for a common viewpoint, highlighting the status of the two fields and giving some hints for the future developments. EMR has been a powerful tool for the investigation of magnetic nano-objects and it can provide a tool of fundamental importance for the development of a unified view.
Collapse
|
79
|
Lartigue L, Oumzil K, Guari Y, Larionova J, Guérin C, Montero JL, Barragan-Montero V, Sangregorio C, Caneschi A, Innocenti C, Kalaivani T, Arosio P, Lascialfari A. Water-Soluble Rhamnose-Coated Fe3O4 Nanoparticles. Org Lett 2009; 11:2992-5. [DOI: 10.1021/ol900949y] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
80
|
Bernot K, Luzon J, Bogani L, Etienne M, Sangregorio C, Shanmugam M, Caneschi A, Sessoli R, Gatteschi D. Magnetic Anisotropy of Dysprosium(III) in a Low-Symmetry Environment: A Theoretical and Experimental Investigation. J Am Chem Soc 2009; 131:5573-9. [DOI: 10.1021/ja8100038] [Citation(s) in RCA: 231] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
81
|
Bräuer B, Vaynzof Y, Zhao W, Kahn A, Li W, Zahn DRT, Fernández CDJ, Sangregorio C, Salvan G. Electronic and Magnetic Properties of Ni Nanoparticles Embedded in Various Organic Semiconductor Matrices. J Phys Chem B 2009; 113:4565-70. [DOI: 10.1021/jp809777z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
82
|
Sorace L, Sangregorio C, Figuerola A, Benelli C, Gatteschi D. Magnetic Interactions and Magnetic Anisotropy in Exchange Coupled 4f-3d Systems: A Case Study of a Heterodinuclear Ce3+-Fe3+Cyanide-Bridged Complex. Chemistry 2009; 15:1377-88. [DOI: 10.1002/chem.200801638] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
83
|
Larionova J, Guari Y, Sangregorio C, Guérin C. Cyano-bridged coordination polymer nanoparticles. NEW J CHEM 2009. [DOI: 10.1039/b900918c] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
84
|
Bartoli S, Bazzicalupi C, Biagini S, Borsari L, Bencini A, Faggi E, Giorgi C, Sangregorio C, Valtancoli B. Cu(ii) complexation with an acridine-containing macrocycle. Assembly of water cluster chains within the cavity of tetranuclear metallomacrocycles. Dalton Trans 2009:1223-30. [DOI: 10.1039/b815040k] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
85
|
Larionova J, Guari Y, Tokarev A, Chelebaeva E, Luna C, Sangregorio C, Caneschi A, Guérin C. Coordination polymer nano-objects into ionic liquids: Nanoparticles and superstructures. Inorganica Chim Acta 2008. [DOI: 10.1016/j.ica.2008.03.038] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
86
|
Pineider F, Mannini M, Sangregorio C, Gorini L, Sessoli R. Insertion of a functionalised single molecule magnet into preformed self-assembled monolayers. Inorganica Chim Acta 2008. [DOI: 10.1016/j.ica.2008.03.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
87
|
Bogani L, Bernot K, Sessoli R, Sangregorio C, Gatteschi D. Slow relaxation of the magnetization in rationally designed single-chain magnets. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308086650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
88
|
Folch B, Guari Y, Larionova J, Luna C, Sangregorio C, Innocenti C, Caneschi A, Guérin C. Synthesis and behaviour of size controlled cyano-bridged coordination polymernanoparticles within hybrid mesoporous silica. NEW J CHEM 2008. [DOI: 10.1039/b709490f] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
89
|
Casu A, Casula MF, Corrias A, Falqui A, Loche D, Marras S, Sangregorio C. The influence of composition and porosity on the magnetic properties of FeCo–SiO2nanocomposite aerogels. Phys Chem Chem Phys 2008; 10:1043-52. [DOI: 10.1039/b712719g] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
90
|
Gillon B, Sangregorio C, Caneschi A, Gatteschi D, Sessoli R, Ressouche E, Pontillon Y. Experimental spin density in the high spin ground state of the Fe8pcl cluster. Inorganica Chim Acta 2007. [DOI: 10.1016/j.ica.2007.01.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
91
|
Carbonera C, Dei A, Létard JF, Sangregorio C, Sorace L. Relaxation dynamics of a photoinduced di-cobalt-tetraoxolene valence tautomer. Inorganica Chim Acta 2007. [DOI: 10.1016/j.ica.2007.01.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
92
|
Buonsanti R, Grillo V, Carlino E, Giannini C, Curri ML, Innocenti C, Sangregorio C, Achterhold K, Parak FG, Agostiano A, Cozzoli PD. Seeded Growth of Asymmetric Binary Nanocrystals Made of a Semiconductor TiO2 Rodlike Section and a Magnetic γ-Fe2O3 Spherical Domain. J Am Chem Soc 2006; 128:16953-70. [PMID: 17177447 DOI: 10.1021/ja066557h] [Citation(s) in RCA: 153] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Asymmetric binary nanocrystals (BNCs), comprising one c-axis elongated anatase TiO2 section and one gamma-Fe2O3 spherical domain attached together, are synthesized by heterogeneous nucleation of iron oxide onto the longitudinal facets of TiO2 nanorods in a ternary surfactant mixture. The topologically controlled composition of the BNCs is ascertained by a combination of powder X-ray diffraction, Raman and Mössbauer spectroscopy, high-angle annular dark-field imaging, and high-resolution transmission electron microscopy lattice fringe mapping, while their size-dependent magnetic behavior is demonstrated by ac susceptibility measurements. The heteroepitaxial growth proceeds through a mechanism never observed before for colloidal nanoheterostructures: the two domains share a restricted and locally curved junction region, which accommodates efficiently the interfacial strain and retards the formation of misfit dislocations. It is believed that these BNCs, which combine the properties of two technologically relevant oxide materials, can pave the way to reinforced applications in several fields of nanoscience, such as in photocatalysis, in malignant cell treatments, and in nanocrystal assembly.
Collapse
|
93
|
Beni A, Carbonera C, Dei A, Létard JF, Righini R, Sangregorio C, Sorace L. Optically induced valence tautomeric interconversion in cobalt dioxolene complexes. J BRAZIL CHEM SOC 2006. [DOI: 10.1590/s0103-50532006000800007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
94
|
O'connor CJ, Seip C, Sangregorio C, Carpenter E, Li S, Irvin G, John VT. Nanophase Magnetic Materials: Synthesis and Properties. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/10587259908028885] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
95
|
Carpenter EE, Sangregorio C, O'connor CJ. Synthesis of Antiferromagnetic Macromolecular Particles. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/10587259908023358] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
96
|
Armelao L, Barreca D, Bottaro G, Maragno C, Tondello E, Caneschi A, Sangregorio C, Gialanella S. Structural and magnetic properties of pure and Ca-doped LaCoO3 nanopowders obtained by a sol-gel route. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2006; 6:1060-7. [PMID: 16736767 DOI: 10.1166/jnn.2006.147] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Pure and Ca-doped LaCoO3 nanopowders were prepared by a non-alkoxidic sol-gel route using cobalt(II) acetate, lanthanum(III) nitrate and calcium(II) acetate as oxide precursors. The structural evolution and magnetic properties of the samples were studied as a function of thermal treatments in air up to 1273 K. In particular, the microstructure and composition of the systems were analyzed by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and X-ray Photoelectron Spectroscopy (XPS). Both pure and calcium-doped samples annealing at 973 K resulted in the formation of cubic LaCoO3 (average crystallite size <30 nm). This phase was fully retained in the calcium-doped materials even after annealing at higher temperatures, whereas a transition to the rhomboedral polymorph was detected in the pure samples at 1073 K. The magnetic behavior of the nanopowders was investigated as a function of temperature and applied field using both dynamic and static susceptibility measurements. Pure lanthanum cobaltite samples underwent a transition to an ordered state at 88 K, and their magnetic properties changed as a function of thermal treatments. As concerns calcium-doped samples, they ordered ferromagnetically at 171 and 185 K depending on the annealing temperature and displayed open hysteresis loops with coercive fields as large as 1.75 T at low temperatures.
Collapse
|
97
|
Mahé N, Guillou O, Daiguebonne C, Gérault Y, Caneschi A, Sangregorio C, Chane-Ching JY, Car PE, Roisnel T. Polynuclear Lanthanide Hydroxo Complexes: New Chemical Precursors for Coordination Polymers. Inorg Chem 2005; 44:7743-50. [PMID: 16241123 DOI: 10.1021/ic0401086] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The synthesis of hexanuclear lanthanide hydroxo complexes by controlled hydrolysis led to polymorphic compounds. The hexanuclear entities crystallize in four different ways that depend on the extent of their hydration. The four structures can be described as hexanuclear lanthanide entities with formula [Ln(6)(mu(6)-O)(mu(3)-OH)(8)(NO(3))(6)(H(2)O)(12)](2+). Two additional NO(3)(-) ions intercalate between the hexanuclear entities in order to ensure the electroneutrality of the crystal structure. Some crystallization water molecules fill the intermolecular space. The three first families of compounds (1-3) exhibit crystal structures that have previously been reported. The fourth family of compounds (4) is described here for the first time. Its chemical formula is [Ln(6)(mu(6)-O)(mu(3)-OH)(8)(NO(3))(6)(H(2)O)(12)](NO(3))(2).2H(2)O (Ln = Gd, Er, and Y). In this paper, the chemical and thermal stabilities of the hexanuclear lanthanide compounds are reported together with the magnetic properties of the Gd(III)-containing species. To use these entities as precursors for new materials, the substitution of the nitrato groups by chloride ions has been studied. Two byproduct compounds have so been obtained: The first (compound 5) is a nitrato/chloride hexanuclear compound of chemical formula [Er(6)(mu(6)-O)(mu(3)-OH)(8)(NO(3))(6)(H(2)O)(12)](NO(3))Cl.2H(2)O. The second one (compound 6) is a polymeric compound in which the hexanuclear entities are linked by an unexpected and original N(2)O(4) bridge. Its chemical formula is [Er(6)(mu(6)-O)(mu(3)-OH)(8)(NO(3))(4)(H(2)O)(11)(OH)(ONONO(2))]Cl(3).2H(2)O. Its crystal structure can be described as the juxtaposition of chainlike molecular motifs. To the best of our knowledge, this is the first example of a coordination polymer synthesized from an isolated polylanthanide hydroxo complex.
Collapse
|
98
|
Bogani L, Sangregorio C, Sessoli R, Gatteschi D. Molecular Engineering for Single-Chain-Magnet Behavior in a One-Dimensional Dysprosium-Nitronyl Nitroxide Compound. Angew Chem Int Ed Engl 2005; 44:5817-21. [PMID: 16080226 DOI: 10.1002/anie.200500464] [Citation(s) in RCA: 409] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
99
|
Vázquez M, Bermejo MR, Licchelli M, González-Noya AM, Pedrido RM, Sangregorio C, Sorace L, García-Deibe AM, Sanmartín J. Non-Covalent Aggregation of Discrete Metallo-Supramolecular Helicates into Higher Assemblies by Aromatic Pathways: Structural and Chemical Studies of New Aniline-Based Neutral Metal(II) Dihelicates. Eur J Inorg Chem 2005. [DOI: 10.1002/ejic.200500142] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
100
|
Carbonera C, Dei A, Létard JF, Sangregorio C, Sorace L. Thermally and light-induced valence tautomeric transition in a dinuclear cobalt-tetraoxolene complex. Angew Chem Int Ed Engl 2005; 43:3136-8. [PMID: 15199559 DOI: 10.1002/anie.200453944] [Citation(s) in RCA: 172] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|