Papers - NAKAYA Manabu
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Post-synthetic Modification of a Dinuclear Spin Crossover Iron(III) Complex Reviewed
Yuki Komatsumaru, Manabu Nakaya, Fumiya Kobayashi, Ryo Ohtani, Masaaki Nakamura, Leonard F. Lindoy, Shinya Hayami
Zeitschrift fur Anorganische und Allgemeine Chemie 644 ( 14 ) 729 - 734 2018.08
Language：English Publishing type：Research paper (scientific journal)
© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim The dinuclear iron(III) complex [Fe(salten)2(bipytz)](BPh4)2·EtOH (1) was synthesized and its post-synthesis modification yielded [Fe(salten)2(bipydz)](BPh4)2·EtOH (2). The crystal structures and magnetic behaviors of 1 and 2 were investigated by variable temperature XRD, magnetic susceptibility, and Mössbauer spectra measurements, with each of these dinuclear iron(III) complexes exhibiting gradual spin crossover behavior.
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Intermolecular Interaction Tuning of Spin-Crossover Iron(III) Complexes with Aromatic Counteranions Reviewed
Asami Tsukiashi, Manabu Nakaya, Fumiya Kobayashi, Ryo Ohtani, Masaaki Nakamura, Jack M. Harrowfield, Yang Kim, Shinya Hayami
Inorganic Chemistry 57 ( 5 ) 2834 - 2842 2018.02
Language：English Publishing type：Research paper (scientific journal) Publisher：American Chemical Society
© 2018 American Chemical Society. Iron(III) spin-crossover (SCO) complexes [Fe(qsal)2]BS·MeOH·H2O (1), [Fe(qsal)2](NS)·MeOH (2), [Fe(qnal)2](NS) (3), and [Fe(qnal)2]PS·MeOH·CH2Cl2 (4) (Hqsal, N-(8-quinolinyl)salicylaldimine; Hqnal, N-(8-quinolinyl)-2-hydroxy-1-naphthaldimine; BS, benzenesulfonate; NS, 1-naphthalenesulfonate; PS, 1-pyrenesulfonate) have been synthesized and characterized by X-ray structure determinations and temperature-dependent magnetic susceptibility measurements. The aromatic counteranions BS, NS, and PS can be used for the tuning of intermolecular coupling through a variety of weak interactions. All of the complexes show temperature-dependent SCO behavior. but the light-induced excited spin-state trapping (LIESST) effect was observed only for 1, 3, and 4 when the samples were illuminated (λ 808 nm) for 1 h at 5 K. In particular, 59% of the LS form of 1 was converted to the metastable HS state by illumination, equal to the highest degree of conversion yet known for LIESST in [Fe(qsal)2]+ derivatives. The lack of a LIESST effect for 2 may be due to the relatively limited degree of interaction between the cations and anions in the lattice, reflected in a much longer minimum Fe···Fe separation in this complex in comparison to the others.
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Supramolecular architectures self-assembled using long chain alkylated spin crossover cobalt(II) compounds Reviewed International journal
Ryohei Akiyoshi, Keita Kuroiwa, Saliu Alao Amolegbe, Manabu Nakaya, Ryo Ohtani, Masaaki Nakamura, Leonard F. Lindoy, Shinya Hayami
Chemical Communications 53 ( 34 ) 4685 - 4687 2017.03
Language：English Publishing type：Research paper (scientific journal)
© 2017 The Royal Society of Chemistry. Self-assembled hybrid supramolecular architectures formed between amphiphilic anions and long alkylated cationic cobalt(ii) complexes of type [Co(Cn-terpy)2](C12-Glu)2 (n = 15-20) have been synthesized and characterized by TEM, PXRD and magnetic susceptibility measurements. The hybrids display wire or rolled sheet supramolecular arrangements with odd and even alkyl chain dependence, with the cobalt(ii) centres exhibiting gradual spin-crossover behaviours.
DOI： 10.1039/C7CC01501A
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Molecular Assemblies of Metal Complexes via Base-Pairing of Nucleic Acids in the Crystalline State Reviewed
Manabu Nakaya, Ryo Ohtani, Kunihisa Sugimoto, Masaaki Nakamura, Leonard F. Lindoy, Shinya Hayami
Chemistry - A European Journal 23 ( 30 ) 7232 - 7237 2017.03
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：Wiley-VCH Verlag
© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim The nature of the molecular assemblies formed in the crystalline state by cobalt(II) terpyridine (terpy) complexes incorporating appended adenine (A) or thymine (T) bases was found to be controlled by which bases are present. Single-crystals of the cobalt(II) complexes [Co(A-C6-terpy)2](BF4)2 (1) and [Co(T-C6-terpy)2](BF4)2 (2) have needle and block habits, respectively. Subsequent mixing of 1 and 2 in MeOH resulted in isolation of [Co(A-C6-terpy)1.5(T-C6-terpy)0.5](BF4)2 (3) as plate-like crystals. A 3D network structure is present in 1 that incorporates 1D chains, whereas 2 adopts a 2D stacked structure constructed from ladder-type assemblies. For 3, “dimer-rings” consisting of [Co(A-C6-terpy)2]2+ and [Co(A-C6-terpy)(T-C6-terpy)]2+ units are generated by means of base-pairing between A and T. Notably, 3 displays the first crystal structure of a heteroleptic cobalt(II) complex of [Co(A-C6-terpy)(T-C6-terpy)](BF4)2. These assembly differences involving the terpyridine cobalt(II) complex units in 1–3 affect the cooperativities influencing their spin crossover (SCO) behavior. The influence of the terminal nucleobases on the resulting assembly has been probed by investigating the co-crystallization of [Co(terpy)2](BF4)2 (4) with [Co(C6-terpy)2](BF4)2 (5) and 1 with 5.
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Risa Nakahara, Manabu Nakaya, Jong Won Shin, Ryo Ohtani, Masaaki Nakamura, Shinya Hayami
Australian Journal of Chemistry 70 ( 5 ) 494 - 498 2016.11
Language：English Publishing type：Research paper (scientific journal) Publisher：CSIRO
© 2017 CSIRO. Cobalt(ii) complexes with terpyridine-type ligands, [Co(n-pyterpy)2](ClO4)2 (n=3 (1), 4 (2)), were prepared and characterised. Different positions of the nitrogen atom in the terpyridine ligands influenced their assembly properties in the crystal structures. Complex 1 showed a 2D network structure consisting of 1D chains connected by intermolecular NHC interactions. On the other hand, complex 2 consisted of two different cobalt ion sites (Co1 and Co2) with slightly different coordination environments. Complex 2 showed 1D chains with no interchain interactions. Such differences are discussed with the cooperativities estimated by their spin crossover behaviours.
DOI： 10.1071/CH16556
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Water-dependent charge-transfer-induced spin transition of Prussian blue analogues Reviewed
Hitomi Ohmagari, Ryo Ohtani, Manabu Nakaya, Masaaki Ohba, Masaaki Nakamura, Leonard F. Lindoy, Osamu Sato, Shinya Hayami
Dalton Transactions 45 ( 42 ) 16784 - 16788 2016.09
Language：English Publishing type：Research paper (scientific journal) Publisher：Royal Society of Chemistry
© 2016 The Royal Society of Chemistry. Cobalt-iron Prussian blue analogues are magnetic functional compounds that exhibit charge-transfer-induced spin transition (CTIST), however, the role of guest species such as water in influencing the magnetic behaviour has remained unclear. Here, we report the water-dependent CTIST behaviour of Na0.46Co[Fe(CN)6]0.78(H2O)1.31 together with its single crystal X-ray structural analysis, for the first time.
DOI： 10.1039/C6DT03474H
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Ryo Ohtani, Saki Egawa, Manabu Nakaya, Hitomi Ohmagari, Masaaki Nakamura, Leonard F. Lindoy, Shinya Hayami
Inorganic Chemistry 55 ( 7 ) 3332 - 3337 2016.03
Language：English Publishing type：Research paper (scientific journal) Publisher：American Chemical Society
© 2016 American Chemical Society. Metal dilution effects on reverse spin transition (rST) in mixed crystals of type [Co1-xZnx(C16-terpy)2](BF4)2 (x = 0.1-0.7) were investigated by comparison with behavior of [Co1-xFex(C16-terpy)2](BF4)2 (x = 0.1-0.4). In the mixed crystals, the Zn complexes increased rST temperatures linearly with increasing values of x, without changing the hysteresis width, while the Fe complexes decreased rST temperatures. Moreover, the strength of the metal dilution effects in the CoZn mixed crystals is weaker than what occurs in the CoFe mixed crystals.
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Molecular Designs for Enhancement of Polarity in Ferroelectric Soft Materials Reviewed
Ryo Ohtani, Manabu Nakaya, Hitomi Ohmagari, Masaaki Nakamura, Kazuchika Ohta, Leonard F. Lindoy, Shinya Hayami
Scientific Reports 5 2015.11
Language：English Publishing type：Research paper (scientific journal) Publisher：Nature Publishing Group
© 2015, Nature Publishing Group. All rights reserved. The racemic oxovanadium(IV) salmmen complexes, [VO((rac)-(4-X-salmmen))] (X=C12C10C5 (1), C16 (2), and C18 (3); salmmen=N,N′-monomethylenebis-salicylideneimine) with "banana shaped" molecular structures were synthesized, and their ferroelectric properties were investigated. These complexes exhibit well-defined hysteresis loops in their viscous phases, moreover, 1 also displays liquid crystal behaviour. We observed a synergetic effect influenced by three structural aspects; the methyl substituents on the ethylene backbone, the banana shaped structure and the square pyramidal metal cores all play an important role in generating the observed ferroelectricity, pointing the way to a useful strategy for the creation of advanced ferroelectric soft materials.
DOI： 10.1038/srep16606
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Hitomi Ohmagari, Manabu Nakaya, Ryo Ohtani, Masaaki Nakamura, Shinya Hayami
Acta Crystallographica Section E: Crystallographic Communications 71 ( Pt 8 ) 997 - 999 2015.07
Language：English Publishing type：Research paper (scientific journal) Publisher：International Union of Crystallography
In the title compound, [Co(C25H30N4O4)2](ClO4)3·CH3OH·H2O, the metal atom is coordinated by two tridentate crown ether terpyridine ligands, forming a distorted CoN6 octahedron. The three pyridine rings in each crown-terpyridine ligand are approximately coplanar [maximum deviations = 0.088 (12) and 0.102 (15) Å] and the mean planes through the three pyridine rings are perpendicular to each other, making a dihedral angle of 89.95 (17)°. An intramolecular C-H···π interaction is observed between the two terpyridine ligands. In the crystal, O-H···O and C-H···O hydrogen bonds, a π-π stacking interaction [centroid-centroid distance = 3.923 (7) Å] and a C-H···π interaction connect the complex cation, the perchlorate anions and the two types of solvent molecules, forming a three-dimensional network.
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Photoswitching of the dielectric property of salicylideneaniline Reviewed
Kodai Shimayama, Mohammad Razaul Karim, Saliu Alao Amolegbe, Manabu Nakaya, Masaaki Nakamura, Ryo Ohtani, Leonard F. Lndoy, Shinya Hayami
Journal of Inclusion Phenomena and Macrocyclic Chemistry 82 ( 1-2 ) 219 - 223 2015.03
Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Netherlands
© 2015 Springer Science+Business Media. Temperature dependent dielectric constant changes for salicylideneaniline (SA) were observed before and after light irradiation. The dielectric constant for a non-illuminated sample is higher than that for an illuminated one. It was considered that this fascinating observation might reflect dynamic chromophoric structural changes within the tautomers of SA.
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Manabu Nakaya
Journal of Inclusion Phenomena and Macrocyclic Chemistry 82 ( 1-2 ) 213 - 218 2015.03
Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Netherlands
© 2015 Springer Science+Business Media. Manganese(III) complexes [MnL 21 ]BPh4 (1) and [MnL 22 (MeOH)2]BPh4 (2) were synthesized (HL1 = 2-{N-[2-(2-pyridyl)ethyl]iminomethyl}-6-methoxyphenol and HL2 = 2-{N-[2-(2-pyridyl)ethyl]iminomethyl}-4-methylphenol) and characterized. The crystal structures were determined by single crystal X-ray crystallography for 1 and 2 and magnetic properties were characterized by magnetic susceptibility. Compounds 1 and 2 crystallized in the triclinic system with space groups P-1. The crystal structure of 1 showed that the central manganese(III) ions were coordinated by four nitrogen and two oxygen atoms of two ligands in trans positions, exhibiting a pseudo-octahedral geometry. On the other hand, the crystal structure of 2 showed that the manganese(III) ions were coordinated by the two nitrogen and two oxygen atoms of two ligands and two methanol solvent molecules. The variable temperature-dependence magnetic susceptibilities have shown that the compounds 1 and 2 manganese(III) oxidation state; there is no magnetic interaction between complexes.
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Direct observation of low-temperature bistability in an iron(III) LIESST compound Reviewed
Naoto Saigo, Yusuke Sekimoto, Manabu Nakaya, Ryo Ohtani, Msaaki Nakamura, Shinya Hayami
Journal of Inclusion Phenomena and Macrocyclic Chemistry 82 ( 1-2 ) 225 - 228 2015.03
Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Netherlands
© 2015 Springer Science+Business Media. Iron(III) Schiff base compound [Fe(pap)2]ClO4·H2O (1, and Hpap = (2-(2-pyridylmethyleneamino)phenol)) shows abrupt spin crossover (SCO) with a hysteresis (T1/2↓ = 165 K, T1/2↑ = 180 K) and anomalous light induced excited spin state trapping. In the complex 1, the existence of the interaction between molecules by π electrons is suggested from single crystal structure. An anomalous LS → HS conversion, aberrant increase of HS molar fraction, was observed at low-temperature (50 K) in 1 after rapid cooling, and interpreted in terms of bistability resulted from strong cooperative interactions.
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Spin-crossover behaviors in solvated cobalt(ii) compounds Reviewed
Shinya Hayami, Manabu Nakaya, Hitomi Ohmagari, Amolegbe Saliu Alao, Masaaki Nakamura, Ryo Ohtani, Ryotaro Yamaguchi, Takayoshi Kuroda-Sowa, Jack K. Clegg
Dalton Transactions 44 ( 20 ) 9345 - 9348 2015.01
Language：English Publishing type：Research paper (scientific journal) Publisher：Royal Society of Chemistry
© The Royal Society of Chemistry 2015. Two solvated cobalt(ii) terpyridine complexes, [Co(MeO-terpy)<inf>2</inf>](BF<inf>4</inf>)<inf>2</inf>·H<inf>2</inf>O (1·H<inf>2</inf>O) and [Co(MeO-terpy)<inf>2</inf>](BF<inf>4</inf>)<inf>2</inf>·acetone (1·acetone) were prepared. Annealing each of these complexes resulted in the formation of two desolvated species, 1 and 1′, respectively. 1·H<inf>2</inf>O and 1 exhibited two-step and gradual SCO. The compound 1·acetone has high-spin at all temperatures and 1′ undergoes a reverse spin transition due to a phase change.
DOI： 10.1039/C4DT03743J
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Structures and magnetic properties of iron(III) complexes with long alkyl chains Reviewed
Manabu Nakaya, Kodai Shimayama, Kohei Takami, Kazuya Hirata, Saliu Alao Amolegbe, Masaaki Nakamura, Leonald F. Lindoy, Shinya Hayami
Crystals 4 ( 2 ) 104 - 112 2014.05
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：MDPI AG
Iron(III) compounds with long alkyl chains, [Fe(Cn-pap)2]ClO4 (Cn-pap: alkoxy-2-(2-pyridylmethyleneamino)phenol, n = 8 (1), 10 (2), 12 (3), 14 (4), 16 (5)) have been synthesized. The compounds were characterized by single crystal X-ray structure analysis and temperature dependent magnetic susceptibility in order to research the relationship between magnetic properties and the presence of long alkyl chains in soft molecules of the present type. The compounds 1, 2, 3 and 4 are in the high-spin (HS) state over the temperature range of 5 to 400 K. On the other hand, compound 5 is low-spin (LS) showing that the difference in magnetic properties depends on the length of the alkyl chain in the respective compounds. © 2011 by the authors; licensee MDPI, Basel, Switzerland.
DOI： 10.3390/cryst4020104
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Manabu Nakaya, Kodai Shimayama, Kohei Takami, Kazuya Hirata, Amolegbe Saliu Alao, Masaaki Nakamura, Leonard F. Lindoy, Shinya Hayami
Chemistry Letters 43 ( 7 ) 1058 - 1060 2014.04
Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：Chemical Society of Japan
Spin-crossover (SCO) iron(III) compounds, [Fe(qnal- OMe) 2]PF6•acetone (1) and [Fe(qnal-OMe) 2]BPh4•2MeOH (2) (qnal-OMe: 7-methoxy-1-[(8-quinolinylimino) methyl]-2-naphthalenol), were prepared and characterized by X-ray singlecrystal structure analysis, temperature-dependent magnetic susceptibility, and Mössbauer spectroscopy measurements. The compounds exhibited SCO behavior with thermal hysteresis loop (T1/2↑ = 202 K, T 1/2↓ = 194K for 1 and T1/2↑ = 304 K, T 1/2↓ = 194K for 2). Moreover, the light-induced excited spin-state trapping (LIESST) effect was observed for the compounds when the samples were illuminated (1000 nm) at 5K. We suggest that the introduction of a strong intermolecular interaction, such as π-π stacking, can play an important role in the observed dynamic phase transition. © 2014 The Chemical Society of Japan.
DOI： 10.1246/cl.140255
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Crystal structure and Spin-Crossover behavior of iron(3) complex with nitroprusside Reviewed
Takahiro Togo, Manabu Nakaya, Kodai Shimayama, Masaaki Nakamura, Saliu Alao Amolegbe, Shinya Hayami, Ryotaro Yamaguchi, Takayoshi Kuroda-Sowa
Chemistry Letters 42 ( 12 ) 1542 - 1544 2013.09
Language：English Publishing type：Research paper (scientific journal)
DOI： 10.1246/cl.130759