Author: Ryo Ohtani

Enhanced bistability by guest inclusion in Fe(ii) spin crossover porous coordination polymers

2012

Inclusion of thiourea guest molecules in the tridimensional spin crossover porous coordination polymers {[Fe(pyrazine)[M(CN)(4)]} (M = Pd, Pt) leads to novel clathrates exhibiting unprecedented large thermal hysteresis loops of ca. 60 K wide centered near room temperature.

Materials sciencePyrazineStereochemistryMetals and Alloyschemistry.chemical_elementGeneral ChemistryCatalysisSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsHysteresischemistry.chemical_compoundCrystallographychemistryThioureaSpin crossoverMaterials ChemistryCeramics and CompositesMoleculePlatinumThermal analysisPalladiumChemical Communications

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Precise Control and Consecutive Modulation of Spin Transition Temperature Using Chemical Migration in Porous Coordination Polymers

2011

Precise control of spin transition temperature (T(c)) is one of the most important challenges in molecular magnetism. A Hofmann-type porous coordination polymer {Fe(pz)[Pt(II)(CN)(4)]} (1; pz = pyrazine) exhibited cooperative spin transition near room temperature (T(c)(up) = 304 K and T(c)(down) = 284 K) and its iodine adduct {Fe(pz)[Pt(II/IV)(CN)(4)(I)]} (1-I), prepared by oxidative addition of iodine to the open metal sites of Pt(II), raised the T(c) by 100 K. DSC and microscopic Raman spectra of a solid mixture of 1-I and 1 revealed that iodine migrated from 1-I to 1 through the grain boundary after heating above 398 K. We have succeeded in precisely controlling the iodine content of {Fe…

PyrazineMagnetismCoordination polymerInorganic chemistrySpin transitionGeneral ChemistryBiochemistryOxidative additionCatalysisAdductMetalsymbols.namesakechemistry.chemical_compoundCrystallographyColloid and Surface Chemistrychemistryvisual_artsymbolsvisual_art.visual_art_mediumRaman spectroscopyJournal of the American Chemical Society

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Oxidative Addition of Halogens on Open Metal Sites in a Microporous Spin-Crossover Coordination Polymer

2009

PolymersCoordination polymeroxidative additionMolecular ConformationchemisorptionPhotochemistryCatalysisMetalchemistry.chemical_compoundHalogensX-Ray Diffractionspin crossoverSpin crossoverPlatinumporous compoundsBinding SitesGeneral ChemistryMicroporous materialGeneral MedicineOxidative additioncoordination polymerschemistryMetalsChemisorptionvisual_artX-ray crystallographyHalogenvisual_art.visual_art_mediumOxidation-ReductionAngewandte Chemie

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A Switchable Molecular Rotator: Neutron Spectroscopy Study on a Polymeric Spin-Crossover Compound

2012

A quasielastic neutron scattering and solid-state 2H NMR spectroscopy study of the polymeric spin-crossover compound {Fe(pyrazine)[Pt(CN) 4]} shows that the switching of the rotation of a molecular fragment-the pyrazine ligand-occurs in association with the change of spin state. The rotation switching was examined on a wide time scale (10 -13-10 -3 s) by both techniques, which clearly demonstrated the combination between molecular rotation and spin-crossover transition under external stimuli (temperature and chemical). The pyrazine rings are seen to perform a 4-fold jump motion about the coordinating nitrogen axis in the high-spin state. In the low-spin state, however, the motion is suppres…

Spin statesPyrazineFrameworkNanotechnologyBiochemistryCrystalsCatalysischemistry.chemical_compoundColloid and Surface ChemistrySpin crossoverPorous Coordination PolymersMoleculeSpectroscopyChemistryGeneral ChemistryNeutron spectroscopyDynamicsCrystallographyRotorsFISICA APLICADAQuasielastic neutron scatteringTransitionProton NMRMachinesCondensed Matter::Strongly Correlated ElectronsRoom-TemperatureState

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Guest Modulation of Spin-Crossover Transition Temperature in a Porous Iron(II) Metal Organic Framework: Experimental and Periodic DFT Studies

2014

The synthesis, structure, and magnetic properties of three clathrate derivatives of the spin-crossover porous coordination polymer {Fe(pyrazine)[Pt(CN)(4)]} (1) with five-membered aromatic molecules furan, pyrrole, and thiophene is reported. The three derivatives have a cooperative spin-crossover transition with hysteresis loops 14-29 K wide and average critical temperatures T-c=201 K (1.fur), 167 K (1.pyr), and 114.6 K (1.thio) well below that of the parent compound 1 (T-c=295 K), confirming stabilization of the HS state. The transition is complete and takes place in two steps for 1.fur, while 1.pyr and 1.thio show 50% spin transition. For 1.fur the transformation between the HS and IS (mi…

Phase transitionPyrazineMetal–organic frameworksTransition temperatureOrganic ChemistrySpin transitionSpace groupGeneral ChemistryCatalysisSpin-crossover compoundsCrystallographychemistry.chemical_compoundTetragonal crystal systemDensity functional calculationsHofmann clathrateschemistryComputational chemistrySpin crossoverFISICA APLICADAMagnetic propertiesOrthorhombic crystal system

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