Kyushu University · Materials Science
Professor Masaaki Ohba's research lab specializes in the design and synthesis of functional coordination materials, with a primary focus on metal-organic frameworks, cyanide-bridged bimetallic assemblies, and spin-crossover systems. The lab explores stimuli-responsive magnetic and optical properties, particularly in porous frameworks that exhibit reversible structural and electronic changes upon guest molecule adsorption or redox stimulation. Key research directions include the development of smart materials for magnetic chemo-switching, spin-transition control, and the integration of redox and coordination chemistry for advanced functional materials.
Figures are computed from collected data and may differ slightly.
The ins and outs of spin: Using the microporous coordination polymer {Fe(pz)[Pt(CN)(4)]} (1, pz=pyrazine), incorporating spin-crossover subunits, two-directional magnetic chemo-switching is achieved at room temperature. In situ magnetic measurements following guest vapor injection show that most guest molecules transform 1 from the low-spin (LS) state to the high-spin (HS) state, whereas CS(2) uniquely causes the reverse HS-to-LS transition.
TGF-beta 1 controls the expression of numerous genes, including early response and cellular matrix genes. However, the signal-transducing mechanism underlying this regulation of gene expression is not fully understood. In this study, we investigated whether redox regulation plays a role in the TGF-beta 1 signal transduction in the mouse osteoblastic cell line (MC3T3-E1). The overall intracellular oxidized state of the cells, when measured using 2',7'-dichlorofluorescin diacetate by laser-scannin
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA New Bimetallic Ferromagnet, [Ni(en)2]3[Fe(CN)6]2.cntdot.2H2O, with a Rare Rope-Ladder Chain StructureMasaaki Ohba, Naomi Maruono, Hisashi Okawa, Toshiaki Enoki, and Jean-Marc LatourCite this: J. Am. Chem. Soc. 1994, 116, 25, 11566–11567Publication Date (Print):December 1, 1994Publication History Published online1 May 2002Published inissue 1 December 1994https://pubs.acs.org/doi/10.1021/ja00104a046https://doi.org/10.1021/ja00104a046research-articleACS
Cyanide-bridged bimetallic assemblies [Ni(pn)2]2[Fe(CN)6]X·catnH2O (X = ClO4- and n = 2 (1); X = BF4- and n = 2 (2); X = PF6- and n = 2 (3)) and [Ni(1,1-dmen)2]2[Fe(CN)6]X·nH2O (X = ClO4- and n = 2 (4); X = BF4- and n = 3 (5); X = PF6- and n = 2 (6); X = CF3SO3- and n = 2 (7); X = BzO- and n = 6 (8); X = I- and n = 4 (9); X = N3- and n = 4 (10); X = NCS- and n = 1 (11); X = NO3- and n = 4 (12)) have been prepared (pn = 1,2-propanediamine, 1,1-dmen = 1,1-dimethylethylenediamine). 7 crystallizes i
Mixing with the guests: Exposure of the porous spin-crossover framework {Fe(pz)[PtII(CN)4]} to X2 (pz=pyrazine; X2=Cl2, Br2, and I2) leads to incorporation of the halides in the coordinatively unsaturated [PtII(CN)4]2− moieties through oxidative addition, thus affording the mixed-valence series {Fe(pz)[PtII/IV(CN)4(X)]}, which features quite distinct cooperative spin-transition properties.
The first modified analogue of the A<sup>II</sup><sub>3</sub> [B<sup>III</sup> (CN)<sub>6</sub> ]<sub>2</sub> ⋅x H<sub>2</sub> O type of Prussian-Blue, the title compound, has a three-dimensional network structure extended by Cr<sup>III</sup> -CN-Mn<sup>II</sup> linkages, which is based on a defective cubane unit comprising three Cr and four Mn ions (see structure), and shows ferrimagnetic ordering below 69 K.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOxalate-bridged dinuclear chromium(III)-M(II) (M = copper, nickel, cobalt, iron, manganese) complexes: synthesis, structure, and magnetismMasaaki Ohba, Hiroko Tamaki, Naohide Matsumoto, and Hisashi OkawaCite this: Inorg. Chem. 1993, 32, 23, 5385–5390Publication Date (Print):November 1, 1993Publication History Published online1 May 2002Published inissue 1 November 1993https://pubs.acs.org/doi/10.1021/ic00075a069https://doi.org/10.1021/ic00075a069researc
Three bimetallic assemblies, PPh4[Ni(pn)2][M(CN)6]·H2O (M = Fe (1), Cr (2), Co (3); pn = rac-1,2-diaminopropane), have been prepared and structurally and magnetically characterized. Assembly 2 crystallizes in the monoclinic system of the space group P2/c (No. 13) with a = 12.927(2) Å, b = 8.454(2) Å, c = 17.564(2) Å, β = 100.15(1)°, V = 1889.5(6) Å3, and Z = 2, and 3 crystallizes in the same space group with a = 12.971(1) Å, b = 8.437(1) Å, c = 17.118(1) Å, β = 99.84(1)°, V = 1845.7(3) Å3, and Z
Abstract Gasteinschluss und Spin : Das mikroporöse Koordinationspolymer {Fe(pz)[Pt(CN) 4 ]} ( 1 , pz=Pyrazin) enthält Spin‐Crossover‐Untereinheiten und kann als chemischer Schalter verwendet werden, der bei Raumtemperatur zwischen zwei magnetischen Zuständen wechselt. Magnetische Messungen unter Bedampfung belegen, dass die Einlagerung der meisten Gastspezies 1 aus dem Low‐Spin(LS)‐Zustand in den High‐Spin(HS)‐Zustand überführt; allein CS 2 bewirkt den umgekehrten Übergang von HS nach LS. magnif
Effects of pressure on the structures and magnetic properties of three types of 3-D cyanide-bridged bimetallic coordination polymer magnets, MnIICrIII ferrimagnet [Mn(en)]3[Cr(CN)6]2.4H2O (1; en = ethylenediamine), NiIICrIII ferromagnet [Ni(dipn)]3[Cr(CN)6]2.3H2O (2; dipn = N,N-di(3-aminopropyl)amine), and NiIIFeIII ferromagnet [Ni(dipn)]2[Ni(dipn)(H2O)][Fe(CN)6]2.11H2O (3), were systematically examined under hydrostatic pressure up to 19.8 GPa using a piston-cylinder-type pressure cell and a di
M. Ohba, H. Ōkawa, T. Ito and A. Ohto, J. Chem. Soc., Chem. Commun., 1995, 1545 DOI: 10.1039/C39950001545
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