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| 1.
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論文
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Maruyama, Tatsuya ; Kikukawa, Yuji ; Sakiyama, Hiroshi ; Katayama, Misaki ; Inada, Yasuhiro ; Hayashi, Yoshihito ; 林, 宜仁
概要:
金沢大学理工研究域物質化学系<br />The structure transformation of multinuclear-metal-cores can change catalytic, optical, and magnetic
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properties. Cyclic decavanadate ligands exhibit versatility in the number and the direction of the coordination sites by changing the conformation to stabilize various multinuclear-metal-cores, while organic multinucleating ligands require specific design for each of the multimetal complexes due to their structure directing ability. The flexibility of cyclic decavanadate ligands is demonstrated here to achieve accommodation of dinuclear or trinuclear units by using the same ligand. The reaction of a dinuclear-cobalt-core-containing decavanadate [Co2(H2O)2V10O30]6- (Co2) with 1 equiv. of Co(OAc)2 (OAc = acetate) gave a trinuclear-cobalt-core-containing decavanadate [Co3(H2O)(OAc)V10O30]5- (Co3) in high yield. The central cobalt core exhibited an incomplete-cubane-type structure. The decavanadate ring contracts to accommodate a smaller dinuclear unit by taking a wavy conformation and expands to accommodate the larger trinuclear unit. The reverse reaction quantitatively proceeded by the addition of 5 equiv. of [VO3]- with respect to Co3. Although a trinuclear-manganese-core-containing decavanadate [Mn3(H2O)(OAc)V10O30]5- (Mn3) possesses the same structure as that of Co3, the addition of 5 equiv. of [VO3]- yielded a different structure of a dinuclear-manganese-core-containing decavanadate [Mn2V10O30]6- (Mn2) with two cyclic pentavanadate ligands sandwiching the manganese core. Thus, the conformations of the cyclic decavanadates are rearranged to respond to the central metal core structures. EXAFS study suggests both manganese complexes maintain the molecular structure in solution. The simultaneous analyses of the magnetic susceptibility data and the magnetization data revealed the switch of magnetic interaction modes from ferromagnetic in dinuclear complexes to mixed ferromagnetic and antiferromagnetic interactions in trinuclear complexes: the ferromagnetic interaction in dinuclear units of Co2 (J = 8.05 cm-1) and Mn2 (J = 0.76 cm-1) (Hex = -JS1S2), and the ferromagnetic and antiferromagnetic interactions in Co3 (J = -1.59 cm-1 and J′ = 13.6 cm-1) and Mn3 (J = -2.20 cm-1 and J′ = 0.07 cm-1) (Hex = -JSA1SA2 - J′[SA1SB + SA2SB]) were studied. © 2017 The Royal Society of Chemistry.
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| 2.
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2. Formation of vv lacunary polyoxovanadates and interconversion reactions of dodecavanadate species
Okaya, Kenji ; Kobayashi, Tetsuhiro ; Koyama, Yuki ; Hayashi, Yoshihito ; Isobe, Kiyoshi
概要:
金沢大学理工研究域物質化学系<br />Oxidation, reactions of the reduced decavanadate [VIV2Vv8O26]4- (1) with halide guest anions were in
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vestigated for the synthesis of Vv host molecules. The reaction with Cl- afforded a new dodecavanadate, [HVV12O32(C1)]4-(3), which incorporated the guest chloride anion. The polyoxovanadate framework of 3 is different from, the bowl-shaped dodecavanadate [VV12O 32(CH3CN)]4- (2). The structure of 3 is regarded as a trilacunary counterpart of the pentadecavanadate [V V9VIV8O36C1] 4-. Employment: of an F-template yielded the layered polyoxovanadate [HVV11O29F2] 4- (4). The framework of 4 is a monolacunary structure of the fluoride-incorporated dodecavanadate [H6VV2VIv10O30F2] 6-, in which one of the VO groups at the belt position is removed. The three vana-dium atoms in the capping units are connected, by (μ3-F bridges. Reaction with Br provided [HVv12O32(Br)]4- (5) with minor formation of [H3VV10O28]3- Interconversion reactions between 2, 3, and 4 proceeded as follows: the reaction of 2 with Cl- prompted, an isomerization reaction of the bowl-type framework, affording 3; the reaction of 3 with F- gave 4; the reaction of 4 with CH3CN reproduced acetonitrile-incorporated 2. Complexes 3 and 4 were characterized by X-ray analysis. Polyoxovanadates 3 and 4, with the highest oxidation cores, exhibited distinct signals in the 51V NMR spectra, corresponding to lacunary polyoxovanadate geometries. © Wiley-VCH Verlag GmbH & Co. KGaA.
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| 3.
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Hayashi, Yoshihito
概要:
Many synthetic methods for heteropolyoxovanadates and lacunary polyoxovanadates have been developed in recent years. We
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outline various approaches used to produce new polyoxovanadate species, including heterometal-incorporated complexes of tetravanadates, hexavanadates, decavanadates and dodecavanadates. In particular, three types of synthetic routes are explored; based on (i) coordination of metavanadate species to transition metal cations, (ii) oxidation of reduced polyoxovanadates, and (iii) template synthesis. Metavanadate species can coordinate to metal cations as inorganic macrocyclic ligands to form heteropolyoxovanadates. The incorporation of a heterometal cation into decavanadates has also been reported. The oxidation reaction of reduced polyoxovanadates provides a new route to the formation of the lacunary polyoxovanadates, which can serve as inorganic host molecules. Dodecavanadates are bowl-type molecules of particular structural interest; a chloride anion can be incorporated into the bowl through a template synthesis. Structural transformations between these dodecavanadate species and alkoxopolyoxovanadates are also described. © 2011 Elsevier B.V.
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| 4.
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Kayatani, Takayuki ; Hayashi, Yoshihito ; Suzuki, Masatatsu ; Inomata, Katsuhiko ; Uehara, Akira
概要:
A dicopper(II) complex with a novel unsymmetric dinucleating ligand, H2L-1, which can provide donor atom, coordination n
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umber, and geometric asymmetries at metal centers, [Cu2(L-1)(CH3COO)]ClO4·H2O·0.5NaClO4 (1), was synthesized, where H2L-1 is a racemic 1-bis(2-pyridylmethyl)amino-3-salicylideneaminopropan-2-ol. The ligand is a hybrid one of 1,3-bis[bis(2-pyridylmethyl)amino]propan-2-ol (Htpdp) and 1,3-bis(salicylideneamino)propan-2-ol (H3L-2). Crystal structure of 1 was determined by X-ray crystallography. Complex 1 crystallizes in monoclinic space group C2/c with a = 42.704(8), b = 12.689(6), c = 29.008(9) Å, β = 128.28(1)°, and Z = 16. The crystal structure showed that two stereoisomers (1a and 1b) are present in solid state. This is attributable to the presence of an enantiomeric pair of L-1. Dinuclear cations consist of one square-planar site with a NO3 donor set and one five-coordinate site with a N3O2 donor set, which are linked by an endogenous alkoxide bridge of L-1 and an exogenous acetate bridge. A powdered sample of 1 shows weak antiferromagnetic interaction (2.60 B.M./Cu2 at 300 and 1.81 B.M./Cu2 at 5 K). Cryomagnetic data is analyzed using two exchange coupling constants, J1 = −0.18 cm−1 and J2 = −9.05 cm−1. EHMO calculations revealed that the observed weak antiferromagnetic interaction(s) compared with that found for [Cu2(L-2)(CH3COO)] (3) (J = −85 cm−1) is reasonably interpreted in terms of the energy gap and the nature of HOMO and LUMO. Some other physicochemical properties of the complex are discussed in comparison with those of the parent complexes, [Cu2(tpdp)(CH3COO)]2+ (2) and [Cu2(L-2)(CH3COO)] (3).
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| 5.
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Kobayashi, Tetsuhiro ; Kuwajima, Sho ; Kurata, Taisei ; Hayashi, Yoshihito
概要:
A spherical tetradecavanadate, [V14O38(Cl)] 7-, was synthesized from a chloride-incorporated bowl-type dodecavanadate. © 2014 Elsevier B.V. All rights reserved.
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| 6.
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Kikukawa, Yuji ; Yokoyama, Taiga ; Kashio, Sanae ; Hayashi, Yoshihito
概要:
The speciation studies of oxovanadates are essential to clarify their biological activities. We surveyed the distributio
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n of oxovanadate species in the presence of halide anions with various acid concentrations in an aqueous mixed-solvent system. The presence of chloride, bromide, and iodide anions has no effects on the appearance of polyoxovanadate species observed in 51V NMR. Those are the precedent formation of metavanadate species and decavanadates. The presence of fluoride anion during the addition of acids exhibits strong intervention in the polyoxovanadate equilibria and we found the subsequent formation of two polyoxovanadate species by 51V NMR observation. From the estimated experimental condition, we isolated fluoride-incorporated polyoxovanadates {Et<inf>4</inf>N}<inf>4</inf>[V<inf>7</inf>O<inf>19</inf>F] and {Et<inf>4</inf>N}<inf>4</inf>[HV<inf>11</inf>O<inf>29</inf>F<inf>2</inf>], successfully. Polyanion [V<inf>7</inf>O<inf>19</inf>F]4 - is the fluoride-incorporated all V(V) state polyoxovanadate which has two different coordination environments of tetrahedral and square pyramidal vanadium units within the one anionic structural integrity. The structural gap between tetrahedral-unit-based metavanadate and octahedral-unit-based decavanadate structures may be linked by this hybrid complex. © 2015 Elsevier Inc. All rights reserved.<br />Embargo Period 24 months
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| 7.
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Tong, Thu Minh Thi ; Soeta, Takahiro ; Suga, Takuya ; Kawamoto, Keisuke ; Hayashi, Yoshihito ; Ukaji, Yutaka
概要:
An enantioselective formal total synthesis of (+)-manzacidin C is described. A key feature of the synthesis is the const
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ruction of two chiral centers via the asymmetric 1,3-dipolar cycloaddition of an azomethine imine to methallyl alcohol by the use of (S,S)-DIPT as a chiral auxiliary. © 2017 American Chemical Society.<br />Embargo Period 12 months
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| 8.
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論文
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Inoue, Yoshitaka ; Kikukawa, Yuji ; Kuwajima, Sho ; Hayashi, Yoshihito
概要:
Chloride-incorporated dodecavanadates show two distinct structures of the monoprotonated-form [HV12O32(Cl)]4- (closed-V1
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2) with a spherical closed-structure and the opened-form [V12O32(Cl)]5- (opened-V12). The reaction of closed-V12 with a stoichiometric amount of ethylenediamine drives the structure transformation reaction to opened-V12, quantitatively. From time dependent observations of 51V NMR, a tube-type intermediate [V12O32(Cl)]5- (tube-V12) was observed in the transformation process. Isolation of the intermediate was achieved by the deprotonation reaction of closed-V12 with diethylamine, and the structure transformation was confirmed by using the isolated intermediate. The reverse transformation from opened-V12 to closed-V12 was also achieved by addition of trifluoroacetic acid. The geometrical difference between closed-V12 and opened-V12 is reflected in the reactivity difference to the external reagents, and this was demonstrated by examining the chloride removal reaction by using a silver cation. The incorporated chloride was preserved in the closed-V12 cage even in the presence of a silver cation. In contrast, the chloride in opened-V12 was removed as AgCl by the silver cation. In addition, by the reaction of chloride-free opened-V12 with a quantitative amount of {Et4N}Cl retrieved opened-V12, showing the capability of opened-V12 to recapture a guest chloride in the cavity. This transformation between two isomeric dodecavanadate structures is regarded as the movement of a molecular mitt to catch a ball and secure it. © 2016 The Royal Society of Chemistry.<br />Embargo Period 12 months
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| 9.
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Inami, Shinnosuke ; Nishio, Masaki ; Hayashi, Yoshihito ; Isobe, Kiyoshi ; Kameda, Hiroyuki ; Shimoda, Tatsuya
概要:
金沢大学理工研究域物質化学系<br />An all-inorganic complex, [Mn2{(CVO3) 5}2]6- (1), was synthesized, and the structure determination r
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eveals a dinuclear manganese complex coordinated by two cyclic pentavanadate ligands. The cyclic pentavanadate units sandwich the edge-sharing octahedral dimanganese core through, coordination of the oxido group of the pentavanadate. A. dinuclear cobalt complex with, a cyclic decavanadate, [Co 2(OH2)2(VO3)10]6- (2), was also synthesized. The structure analysis reveals a dinuclear cobalt complex with a macrocyclic decavanadate, which is composed of 10 VO4 units joined by the vertex. Sharings. The CoO6 octahedrons are edge-shared, with each cobalt octahedron coordinated to five oxido groups from the decavanadate. The remaining site is occupied by - water. The coordinated water molecules are supported with hydrogen bonds in two directions. Complex 2 in acetonitrile shows no reactivity with dioxygen even at low temperature, and the cyclic voltammogram of 2 shows no redox chemistry in acetonitrile. Complex 2 exhibits chromism by water exposure both, in the solid state and. in acetonitrile. Complex 2 is green-yellow in color, and. the addition of water causes the complex to turn brown. After heating the sample, it returns to its original color in a reversible manner. The EXAFS data in acetonitrile is also reported, and is consistent with the solid-state structure. © Wiley-VCH Verlag GmbH & Co. KGaA.
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| 10.
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Domae, Kyosuke ; Uchimura, Daisuke ; Koyama, Yuuki ; Inami, Shinnosuke ; Hayashi, Yoshihito ; Isobe, Kiyoshi ; Kameda, Hiroyuki ; Shimoda, Tatsuya
概要:
金沢大学理工研究域物質化学系<br />A new route to an alkoxohexavanadate species leads to the isolation of a bowl-type dodecavanadate wi
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thout a guest molecule in the cavity. The 1D tetravanadate, [V4O11]2-, is a good precursor for the alkoxohexavanadate, [V6O13(OCH3)6]2-, which is then utilized for the [V6 + V6] coupling reaction to form the dodecavanadate, [V12O42]4-, with a capped dichloromethane molecule at the cavity entrance. We also obtained structural information on a newly discovered octadecavanadate, [V18O46(NO3)]5-, in both the solid and solution states through extended X-ray absorption fine structure (EXAFS) studies. The existence of the chiral inorganic species in acetonitrile with double-stranded V8 chains was confirmed through EXAFS oscillations. © 2009 IUPAC.
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