0000000001312959
AUTHOR
Corine Mathonière
Room-Temperature Magnetic Bistability in a Salt of Organic Radical Ions
International audience; Cocrystallization of 7,7′,8,8′-tetracyanoquinodimethane radical anion (TCNQ −•) and 3-methylpyridinium-1,2,3,5dithiadiazolyl radical cation (3-MepyDTDA +•) afforded isostructural acetonitrile (MeCN) or propionitrile (EtCN) solvates containing cofacial π dimers of homologous components. Loss of lattice solvent from the diamagnetic solvates above 366 K affords a high-temperature paramagnetic phase containing discrete TCNQ −• and weakly bound π dimers of 3-MepyDTDA +• , as evidenced by X-ray diffraction methods and magnetic susceptibility measurements. Below 268 K, a first-order phase transition occurs, leading to a low-temperature diamagnetic phase with TCNQ −• σ dimer…
Photoswitching of the antiferromagnetic coupling in an oxamato-based dicopper(ii) anthracenophane
Thermally reversible photomagnetic (ON/OFF) switching behavior has been observed in a dinuclear oxamatocopper(ii) anthracenophane upon UV light irradiation and heating; the two CuII ions (SCu = 1/2) that are antiferromagnetically coupled in the dicopper(ii) metallacyclic precursor (ON state) become uncoupled in the corresponding [4+4] photocycloaddition product (OFF state), as substantiated from both experimental and theoretical studies. © 2011 The Royal Society of Chemistry.
Dimensionality Switching Through a Thermally Induced Reversible Single-Crystal-to-Single-Crystal Phase Transition in a Cyanide Complex
International audience; The heterometallic hexanuclear cyanide-bridged complex {[Mn(bpym)(H(2)O)](2)[Fe(HB(pz)(3))(CN)(3)](4)} (1), its C(15)N and D(2)O enriched forms {[Mn(bpym)(H(2)O)](2)[Fe(HB(pz)(3))(C(15)N)(3)](4)} (2) and {[Mn(bpym)(D(2)O)](2)[Fe(HB(pz)(3))(CN)(3)](4)} (3), and the hexanuclear derivative complex {[Mn(bpym)(H(2)O)](2)[Fe(B(pz)(4))(CN)(3)](4)}*4H(2)O (4) [bpym = 2,2'-bipyrimidine, HB(pz)(3)(-) = hydrotris(1-pyrazolyl)borate, B(pz)(4)(-) = tetra(1-pyrazolyl)borate] have been synthesized. Their structures have been determined through single-crystal X-ray crystallography at different temperatures. Whereas 3 and 4 maintain a discrete hexanuclear motif during the entire temp…
Synthesis, structural and magnetic characterizations of new complexes of di-2,6-(2-pyridylcarbonyl)pyridine (pyCOpyCOpy) ligand
International audience; Using the di-2,6-(2-pyridylcarbonyl)pyridine ligand (L1) as starting framework, five new mononuclear complexes were obtained: [Cu(L1)(MeCN)(ClO4)2] (1) [Co(L1)(MeCN)(Br)2]*MeCN (2), [Fe(L1)2](BF4)2*MeOH*H2O (3), [Cr(L2a)Cl2]*2MeOH (where HL2a is (6-(hydroxyl(methoxy)(pyridin-2-yl)methyl)pyridin-2-yl)(pyridin-2-yl)methanone) (4) and one trinuclear [NiII3] complex, [Ni3(L2b)2(Bz)2(EtOH)2](ClO4)2*2EtOH (where HL2b is (6-(hydroxyl(ethoxy)(pyridin-2-yl)methyl)pyridin-2-yl)(pyridin-2-yl)methanone; Bz = benzoato) (5). Their structural and magnetic characterizations are herein reported. All the metal ions show octahedral coordination geometry, which is slightly unusual for t…
Metal-organic magnets with large coercivity and ordering temperatures up to 242°C.
International audience; Magnets derived from inorganic materials (e.g., oxides, rare-earth–based, and intermetallic compounds) are key components of modern technological applications. Despite considerable success in a broad range of applications, these inorganic magnets suffer several drawbacks, including energetically expensive fabrication, limited availability of certain constituent elements, high density, and poor scope for chemical tunability. A promising design strategy for next-generation magnets relies on the versatile coordination chemistry of abundant metal ions and inexpensive organic ligands. Following this approach, we report the general, simple, and efficient synthesis of light…
Photo-induced magnetic bistability in a controlled assembly of anisotropic coordination nanoparticles.
International audience; Anisotropic coordination nanoparticles of the photomagnetic network Cs(I)(2)Cu(II)(7)[Mo(IV)(CN)(8)](4) are obtained through a surfactant-free high-yield synthetic procedure in water. These particles are organised as Langmuir-Blodgett films with a preferential orientation of the nano-objects within the film that exhibit a magnetic bistability below 20 K with a very large coercivity due to an efficient photo-transformation.
Photoinduced effects on the magnetic properties of the (Fe0.2Cr0.8)1.5[Cr(CN)6] Prussian blue analogue
International audience; One of the most attractive characteristics of some Prussian blue derivatives is the sensitivity of their magnetic properties to the irradiation with light. In this work photoinduced effects in the (Fe0.2Cr0.8)1.5[Cr(CN)6]·15H2O PBA have been studied by means of X-ray-based spectroscopies and magnetometry. It is found that the photosensitivity of this compound is mostly centred on the Fe cations: the exposure to green light induces a transfer of electrons from them to the Cr that provokes a reversal of the previously existing linkage isomerization and increases the elastic strain caused by the misfit of the unit cells of the Fe–NC–Cr and Cr–NC–Cr sublattices. The gree…
CCDC 1983877: Experimental Crystal Structure Determination
Related Article: Panagiota Perlepe, Itziar Oyarzabal, Aaron Mailman, Morgane Yquel, Mikhail Platunov, Iurii Dovgaliuk, Mathieu Rouzières, Philippe Négrier, Denise Mondieig, Elizaveta A. Suturina, Marie-Anne Dourges, Sébastien Bonhommeau, Rebecca A. Musgrave, Kasper S. Pedersen, Dmitry Chernyshov, Fabrice Wilhelm, Andrei Rogalev, Corine Mathonière, Rodolphe Clérac|2020|Science|6516|587|doi:10.1126/science.abb3861
CCDC 2007863: Experimental Crystal Structure Determination
Related Article: Panagiota Perlepe, Itziar Oyarzabal, Aaron Mailman, Morgane Yquel, Mikhail Platunov, Iurii Dovgaliuk, Mathieu Rouzières, Philippe Négrier, Denise Mondieig, Elizaveta A. Suturina, Marie-Anne Dourges, Sébastien Bonhommeau, Rebecca A. Musgrave, Kasper S. Pedersen, Dmitry Chernyshov, Fabrice Wilhelm, Andrei Rogalev, Corine Mathonière, Rodolphe Clérac|2020|Science|6516|587|doi:10.1126/science.abb3861