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Your search keyword '"Suguru Murata"' showing total 4 results
Start Over Author "Suguru Murata" Topic inorganic chemistry
4 results on '"Suguru Murata"'

1. Molecular Structures and Redox Properties of Homoleptic Aluminum(III) Complexes with Azobisphenolate (azp) Ligands

Author

Kazuyuki Takahashi, Takumi Noguchi, Keiji Ueda, Atsuhiro Miyawaki, and Suguru Murata

Subjects
azobisphenolate ligand, aluminum complex, redox-active ligand, crystal structure, redox property, DFT calculation, Inorganic chemistry, QD146-197
Abstract

To elucidate the oxidation behavior of the 2,2′-azobisphenolate (azp) ligand, a series of homoleptic 1:2 AlIII complexes of four azp derivatives (L1) with 5,5′-dichloro-, 5,5′-dimethyl-, 5,5′-di-t-butyl-, 3,3′,5,5′-tetramethyl-substituents and of one imino derivative (L2) were synthesized and obtained as TPP[Al(L)2]·solvent (TPP = tetraphenylphosphonium ion). The X-ray crystal structure analyses showed that the two ONO-tridentate ligands were meridionally coordinated to a central AlIII ion in an almost perpendicular manner to give a homoleptic octahedral coordination structure in all the AlIII complexes. The proton nuclear magnetic resonance spectra suggested that all the AlIII complexes retained the homoleptic coordination structure in solution. From the cyclic voltammetry measurements in dichloromethane solutions, all the AlIII complexes with the azp ligands showed two partially reversible oxidation waves, and an additional reversible or partially reversible reduction wave. The substitution effects on the first oxidation and reduction peak potentials were revealed in the AlIII complexes with the azp ligands. On the other hand, the imino complex showed a partially reversible oxidation wave accompanying a film deposition. The density functional theory (DFT) calculations indicated that the molecular orbital (MO) coefficients of the frontier MOs in the AlIII complexes were present on the ligands and were absent on the AlIII ion. These results confirmed that the azp ligands are susceptible to oxidation and can give a relatively stable oxidation species depending upon substituent effects.

Published
2022
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2. Single-crystal-to-single-crystal transformation in hydrogen-bond-induced high-spin pseudopolymorphs from protonated cation salts with a π-extended spin crossover Fe(III) complex anion

Author

Takahiro Sakurai, Kazuyuki Takahashi, Hitoshi Ohta, and Suguru Murata

Subjects
Hydrogen bonding, 010405 organic chemistry, Hydrogen bond, Chemistry, Inorganic chemistry, Protonation, Single-crystal-to-single-crystal transformation, 010402 general chemistry, π-stacking interaction, 01 natural sciences, Magnetic susceptibility, Anionic spin-crossover complex, 0104 chemical sciences, Ion, Inorganic Chemistry, Crystal, Crystallography, Spin crossover, Materials Chemistry, Molecule, Protonated cation, Physical and Theoretical Chemistry, Single crystal
Abstract

Novel pseudopolymorphic Hdabco compounds with an Fe(III) complex anion, (Hdabco)[Fe(aznp)2]·CH2Cl2 1 and (Hdabco)[Fe(aznp)2]·0.5H2O 2 [dabco = 1,4-diazabicyclo[2.2.2]octane, H2aznp = (2′-hydroxyphenylazo)-2-hydroxynaphthalene], were prepared and characterized. The magnetic susceptibility for 1 and 2 revealed that both complexes were in a high-spin (HS) state in the whole temperature range and exhibited weak ferromagnetic interactions below 40 K. The crystal structural analyses suggested that strong N–H⋯O hydrogen bonding interactions between the Hdabco cation and [Fe(aznp)2] anion may induce the distortion of a coordination structure resulting in the HS complexes, whereas π-stacking interactions between the π-ligands in the [Fe(aznp)2] anion and additional C–H⋯N hydrogen bonding interactions between the Hdabco cation and [Fe(aznp)2] anion constructed a intermolecular interaction framework structure with one-dimensional channels. The thermogravimetry analysis for compound 1 indicated the adsorption of a water molecule took place after the desorption of a dichloromethane molecule. This transformation of 1 into 2 proved to proceed in a single-crystal-to-single-crystal way by powder X-ray diffractions and single crystal X-ray structural analysis.

Published
2017

3. Cooperative spin-crossover transition from three-dimensional purely pi-stacking interactions in a neutral heteroleptic azobisphenolate Fe-III complex with a N3O3 coordination sphere

Author

Yasuaki Einaga, Suguru Murata, Takahiro Sakurai, Tomoyuki Mochida, Kazuyuki Takahashi, Hitoshi Ohta, and Takashi Yamamoto

Subjects
Thermal hysteresis, Coordination sphere, 010405 organic chemistry, Chemistry, Stacking, Trapping, 010402 general chemistry, Photochemistry, 01 natural sciences, 0104 chemical sciences, Inorganic Chemistry, Chemical physics, Spin crossover, Excited state
Abstract

A novel neutral heteroleptic FeIII complex from two kinds of π-extended tridentate ligands was designed and prepared. The π-ligands formed a three-dimensional purely pi-stacking interaction network. The present complex proved to be the first neutral spin-crossover (SCO) FeIII complex with a N3O3 coordination sphere exhibiting an abrupt SCO transition with a thermal hysteresis of 10 K and the light-induced excited spin-state trapping effect.

Published
2017

4. The Role of Coulomb Interactions for Spin Crossover Behaviors and Crystal Structural Transformation in Novel Anionic Fe(III) Complexes from a π-Extended ONO Ligand

Author

Yasuaki Einaga, Takashi Yamamoto, Kazuyuki Takahashi, Takahiro Sakurai, Yoshihito Shiota, Hitoshi Ohta, Kazunari Yoshizawa, and Suguru Murata

Subjects
crystal structural transformation, Coordination sphere, General Chemical Engineering, 010402 general chemistry, 01 natural sciences, Inorganic Chemistry, Crystal, chemistry.chemical_compound, spin crossover, Computational chemistry, Spin crossover, Coulomb, lcsh:QD901-999, Molecule, General Materials Science, Coulomb interaction, π-stacking interaction, mononuclear Fe(III) complex, anionic complex, ONO tridentate ligand, Tetramethylammonium, 010405 organic chemistry, Ligand, Electric potential energy, Condensed Matter Physics, 0104 chemical sciences, Crystallography, chemistry, lcsh:Crystallography
Abstract

To investigate the π-extension effect on an unusual negative-charged spin crossover (SCO) FeIII complex with a weak N2O4 first coordination sphere, we designed and synthesized a series of anionic FeIII complexes from a π-extended naphthalene derivative ligand. Acetonitrile-solvate tetramethylammonium (TMA) salt 1 exhibited an SCO conversion, while acetone-solvate TMA salt 2 was in a high-spin state. The crystal structural analysis for 2 revealed that two-leg ladder-like cation-anion arrays derived from π-stacking interactions between π-ligands of the FeIII complex anion and Coulomb interactions were found and the solvated acetone molecules were in one-dimensional channels between the cation-anion arrays. A desolvation-induced single-crystal-to-single-crystal transformation to desolvate compound 2’ may be driven by Coulomb energy gain. Furthermore, the structural comparison between quasi-polymorphic compounds 1 and 2 revealed that the synergy between Coulomb and π-stacking interactions induces a significant distortion of coordination structure of 2.

Published
2016

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