Published Papers - HASHIMOTO Masato

Synthesis, structure, and characterization of an alpha-Dawson-type [S2W18O62](4-) complex

S Himeno, H Tatewaki, M Hashimoto

BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN ( CHEMICAL SOC JAPAN )  74 ( 9 ) 1623 - 1628   2001.09  [Refereed]

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A yellow sulfatotungstate complex was formed by heating a 50 mM W(Vl)-2 M H2SO4-40% (v/v) CH3CN system at 70 degreesC for 14 days, being isolated as the tetrapropylammonium (n-Pr4N+) salt. An X-ray structural analysis (orthorhombic, Pca2(1) (No. 29) a = 27.181(1), b = 14.1428(6), c = 27.7292(9) Angstrom, and Z = 4) revealed that the structure consists of an alpha -Dawson-type [S2W18O62](4-) anion. The alpha-[S2W18O62](4-) complex underwent a four-step reversible one-electron reduction in CH3CN, and the presence of acid caused the one-electron waves to be converted into three two-electron waves. The formation conditions were elucidated by a combined Raman and voltammetric study.

DOI

A P-31-NMR study of peroxo species formed during oxidation of cyclohexene with hydrogen peroxide in tri-n-butylphosphate catalyzed by heteropolyacids

M Hashimoto, K Itoh, KY Lee, M Misono

TOPICS IN CATALYSIS ( KLUWER ACADEMIC/PLENUM PUBL )  15 ( 2-4 ) 265 - 271   2001  [Refereed]

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In the oxidation of cyclohexene with H2O2 in monophasic tri-n-butylphosphate (TBP) solution catalyzed by Keggin-type 12-heteropolyacids, i.e., H3PMo12-xWxO40 (x = 0-12), several peroxo species were observed by P-31-NMR spectroscopy in lower field than the original heteropolyacids. Their composition varied regularly with that of the starting catalyst. The P-containing peroxo species formed was deduced as [PM4O8(O-2)(8)](3-) (M = Mo, W). The peroxo species formed more easily with a decrease in the W content, x of H3PMo12-xWxO40. It was further indicated from the reactivity with cyclohexene and the comparison with catalytic performance that W-rich peroxo species were catalytically more active than Mo-rich peroxo species for the oxidation of cyclohexene in this reaction system.

Facile formation and dissociation behaviour of C-C bond resulted from the nucleophilic attack of carbanions on a carbonyl carbon in [Pt(hfac)(2)]

S Okeya, M Hashimoto, F Nakamura, Y Kusuyama, M Kobayashi, R Arakawa

CHEMISTRY LETTERS ( CHEMICAL SOC JAPAN )  ( 10 ) 1130 - 1131   2000.10  [Refereed]

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[Pt(hfac)(2)] (hfac: hexafluoroacetylacetonate) reacts with MeNH2 in CH2Cl2/MeOH to give an -NHMe adduct complex on one of the carbonyl carbons, (MeNH3) [Pt(hfac)(hfac-NHMe)] 1 which is a tetrahedral intermediate of a Schiff base complex, [Pt(CF3COCHC(NMe)CF3)(2)] 2. Complex 1 activates H2O, MeOH, MeNO2 or acetone in solution to form the corresponding conjugate base adducts. The C-C bond in -CH2NO2 adduct 6, easily cleaves and generates nitromethane in solution.

Reactivity of organometallic molybdate toward lanthanide cations. Synthesis and structure of polynuclear lanthanide-molybdate complexes

M Hashimoto, M Takata, A Yagasaki

INORGANIC CHEMISTRY ( AMER CHEMICAL SOC )  39 ( 16 ) 3712 - +   2000.08  [Refereed]

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Novel polynuclear rare earth compounds [La-3(OH2)(7)-(Cp*MoO3)(2)(NO3)(7)] and [La-3(OH2)(5)(THF)(Cp*MoO3)(2)-(NO3)(6)](2)(NO3)(2) were synthesized by reacting [(n-C4H9)(4)N][CP*MoO3] With La(NO3)(3). 6H(2)O in THF. X-ray crystal structural analyses revealed that both these compounds are composed of a La3Mo2O6 unit in which the metal atoms arrange themselves into a trigonal bipyramid. The Ce analogues were also obtained.
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DOI

[NH₄]₃[VO₂(SO₄)₂(OH₂)₂].1.5H₂O

Masato Hashimoto, Michiru Kubata, Atsushi Yagasaki

Acta Crystallogr., Sect. C   C56   1411 - 1412   2000  [Refereed]

Multicomponent polyanions. 52. Crystal structure of hexacaesium monohydrogen decamolybdo(VI)divanado(IV)phosphate(7-) dihydrate

M Hashimoto, A Selling, M Hakansson, L Pettersson

ACTA CHEMICA SCANDINAVICA ( MUNKSGAARD INT PUBL LTD )  53 ( 5 ) 305 - 313   1999.05  [Refereed]

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The structure of the title compound, (Cs6HPMo10V2O40)-V-VI-O-IV. 2H(2)O has been determined by a single-crystal X-ray diffraction method. The compound crystallises in two different space groups. Crystal A: monoclinic P2(1), a = 10.988(3), b = 10.615(3), c = 17.472(2) Angstrom, beta = 91.55(1)degrees, V = 2037(7) Angstrom(3) and Z = 2. Crystal B: monoclinic, Pn, a = 10.982(2), b = 10.614(3), c = 17.487(3) Angstrom, beta = 91.64(1)degrees, V = 2037(7) Angstrom(3) and Z = 2. The R-values based on F were 0.0487 for A and 0.0485 for B for 4491 (A) and 4464 (B) reflections with F-o > 4.0 sigma (F-o) and 353 parameters, and S = 1.048 (A) and 1.026 (B). The polyanion has a so-called alpha-Keggin structure in each crystal. The two vanadium atoms are delocalised in the 12 addenda atom positions in the anion.

Formation and conversion of molybdophosphate and -arsenate complexes in aqueous solution

S Himeno, M Hashimoto, T Ueda

INORGANICA CHIMICA ACTA ( ELSEVIER SCIENCE SA )  284 ( 2 ) 237 - 245   1999.01  [Refereed]

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The difference between the formation and conversion processes of molybdophosphate and -arsenate complexes was elucidated in a 100 mM Mo(VI)-0.5 M HCl system as a function of the P(V) or As(V) concentration. In the Mo(VI)-P(V) system, the Keggin-type [PMo12O40](3-) complex was stable only at P(V) concentrations <7 mM; further addition of P(V) caused the [PMo12O40](3-) complex to decompose mainly into the A-[PMo9O34H6](3-) complex at an ambient temperature. The latter was subsequently converted into the Dawson-type [P2Mo18O62](6-) complex at an elevated temperature; the Dawson complex was kinetically stable even in the presence of excess of P(V). At As(V) concentrations <10 mM, in contrast, the corresponding Mo(VI)-As(V) system did not produce the Keggin-type [AsMo12O40](3-) complex but the previously unknown complex (tentatively formulated as [AsMo10O37H5](4-)) at an ambient temperature; with further addition of As(V), the [AsMo10O37H5](4-) complex was transformed directly into the [As2Mo6O26H2](4-) complex. The Dawson-type [As2Mo18O62](6-) complex, which was formed upon heating the system at 80 degrees C for 5 h, also underwent subsequent transformation into the [As2Mo6O26H2](4-) complex at As(V) concentrations >20 mM. (C) 1999 Elsevier Science S.A. All rights reserved.

Multicomponent polyanions. 53. Structure of tetrakis(trimethylammonium) tetra-mu-oxo-bis(triaquahexadecaoxo(trioxophenylphosphato)hexamolybdate) dihydrate, [NH(CH3)(3)](4)[{(C6H5P)Mo6O21(H2O)(3)}(2)].2H(2)O

DG Lyxell, D Bostrom, M Hashimoto, L Pettersson

ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE ( MUNKSGAARD INT PUBL LTD )  54   424 - 430   1998.08  [Refereed]

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The title compound crystallized in the monoclinic space group P2(1)/n (No. 14) [a = 11.211 (5), b = 12.862 (3), c = 23.05 (1) Angstrom, beta = 94.37 (3)degrees, V = 3314 (2) Angstrom(3), Z = 2]. The polyanion can be regarded as a dimer of a phenylphosphonatohexamolybdate, (C6H5P)Mo6O23(H2O)(3), Linked by four O atoms. In this monomeric unit the six molybdenum octahedra are grouped into two parts consisting of four and two edge-sharing octahedra, respectively. These two parts are connected by two corner-sharing O atoms to form a bent Mo-6 ring. The phenylphosphonate group coordinates to the Mo-6 ring from the narrow side as a tripodal Ligand. The {(C6H5P)Mo6O21 (H2O)(3)}(2) units form layers parallel to (001) and the structure is stabilized by hydrogen bonds between water and neighboring anions. The monomeric unit has been shown to be a key structure in the process of deducing the aqueous solution structures of the (C6H5P)Mo-6(2-) and (C6H5P)Mo-7(4-) species found in a previous equilibrium study of the H+-MoO42-(C6H5P)O-3(2-) system.

Voltammetric determination of vanadium(V) and vanadium(IV) through the formation of a 12-molybdovanadate(V) complex

S Himeno, K Kusuyama, M Hashimoto, N Ishio

ANALYTICAL SCIENCES ( JAPAN SOC ANALYTICAL CHEM )  14 ( 4 ) 681 - 685   1998.08  [Refereed]

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A simple voltammetric method has been developed for the determination of V(V) and V(IV). When a mixture of V(V) and V(IV) is added last of all to a 50 mM Mo(VI)-0.3 M HCl-70%(v/v) CH3CN system, only V(V) reacts with Mo(VI) to form a 12-molybdovanadate(V) complex which undergoes a two-step reduction at the glassy carbon (GC) electrode; the reduction current is directly proportional to the V(V) concentration in the mixture. On the other hand, when HCl is added last after heating the Mo(VI)-CH3CN system containing a mixture of V(V) and V(IV) at 60 degrees C for 10 min, V(IV) is completely oxidized to V(V), and the total concentration of vanadium is determined. The V(IV) concentration is determined by subtracting the V(V) concentration before oxidation from the total concentration of vanadium. Interferences from foreign ions are also discussed.

Syntheses, structures and solution dynamics of anionic 5-coordinate Pt(II) complexes with halide

S Okeya, M Hashimoto, T Matsuo, K Yamanaka, T Sumino, H Hashimoto, N Kanehisa, Y Kai

CHEMISTRY LETTERS ( CHEMICAL SOC JAPAN )  ( 6 ) 541 - 542   1998.06  [Refereed]

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Five-coordinate anionic complexes, [Pt(hfac)(2)X](-) (X = Cl, Pr, I), were prepared by reaction of [Pt(hfac)(2)] and [PPh4]X in CH2Cl2. A distorted square pyramidal structure was revealed by the X-ray analysis. The variable-temperature H-1 and F-19 NMR spectra of these complexes were explained by two independent dynamic motions in solution, which were considered good models for the ligand exchange and cis-trans isomerization reactions.

Multicomponent polyanions. 54. Crystal structure of tetracaesium monohydrogen phosphato(phosphito)pentamolybdate dihydrate, Cs-4[H(HP)PMo5O22]center dot 2H(2)O

DG Lyxell, D Bostrom, M Hashimoto, L Pettersson

ACTA CHEMICA SCANDINAVICA ( MUNKSGAARD INT PUBL LTD )  52 ( 4 ) 425 - 430   1998.04  [Refereed]

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The crystal structure of tetracaesium monohydrogen phosphato (phosphito)pentamolybdate dihydrate was determined by single-crystal X-ray diffraction. The compound crystallises in the triclinic space group P (1) over bar, a=10.284(2), b= 10.791(2) and c=13.047(3) Angstrom, alpha=109.34(2), beta=99.92(2) and gamma=102.85(2)degrees, V=1283.4(5) Angstrom(3) and Z=2. The final R-values are R=0.066, wR=0.039 and S=1.3667. The H(HP)PMo5O224- anion has common features with the Strandberg X2M5-type heteropolyanion. The five MoO6 octahedra form a five-membered ring by one corner-sharing and four edge-sharing connections, and the tripodal phosphate and phosphite ligands protrude from each side of this ring in opposite directions. This is the first example of the structure of the heteropolyoxometalate having both P-III and P-V as heteroatoms.

均一沈殿法による12-タングストリン酸アンモニウム酸性塩触媒の調製とその構造

犬丸 啓, 中島 仁, 橋本 正人, 御園生 誠

日本化学会誌     390 - 397   1998  [Refereed]

Heteropoly compounds .30. Alkane oxidation with mixed addenda heteropoly catalysts containing Ru(III) and Rh(III)

Y Matsumoto, M Asami, M Hashimoto, M Misono

JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL ( ELSEVIER SCIENCE BV )  114 ( 1-3 ) 161 - 168   1996.12  [Refereed]

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Oxidation of alkanes, mainly of cyclohexane, with t-butyl hydroperoxide (TBHP) catalyzed by alkylammonium salts of mixed addenda heteropoly compounds having Keggin-type polyanions were studied in benzene solutions, with regard to the relative catalytic activity, reaction orders and the stability of catalysts. Tetra-n-hexylammonium salts of SiRu(H2O)W11O395- and SiRh(H2O)W11O395- showed higher catalytic activities than the corresponding Fe- and Go-substituted catalysts for the selective oxidation of cyclohexane to cyclohexanol and cyclohexanone. Although the Ru catalyst was possibly a mixture, it consisted mainly of SiRu(H2O)W11O395- and gave reproducible catalytic performance for repeated preparations. The initial rates were approximately proportional to the concentrations of cyclohexane, TBHP and the catalyst. Although the rate decreased with the consumption of TBHP, the initial rate was resumed by the addition of TBHP, indicating the absence of the deterioration of catalytic activity. Similarly alcohols and ketones were selectively formed from n-decane and ethylbenzene.

DOI

Multicomponent polyanions .48. The crystal structure of trihydrogen dodecamolybdophosphate-benzene(1/3)

DG Lyxell, D Bostrom, M Hashimoto, L Pettersson

ACTA CHEMICA SCANDINAVICA ( MUNKSGAARD INT PUBL LTD )  50 ( 11 ) 985 - 990   1996.11  [Refereed]

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A novel organic solvated heteropoly compound, H3Mo12PO40. 3(C6H6), crystallised in the monoclinic form, P2(1)/n (No. 14), with a = 12.189(2), b = 13.981(2), c = 12.978(1) Angstrom and beta = 98.59(1)degrees. The refinement of 340 parameters with 3705 reflections [I > 3.0 sigma(I)] gave a final R-value of 0.061 (R(w) = 0.067). The polyanion, having a so-called alpha-Keggin structure, is disordered around an inversion centre. One of three benzene molecules is sandwiched between polyanions, and the other two are accommodated in a cavity surrounded by polyanions. The links between polyanions and benzene rings are mainly due to hydrogen bonds. The phosphate and benzene in the compound were formed by hydrolysis of phenylphosphonate. (C) Acta Chemica Scandinavica 1996.

Preparation and structure of tetramethylammonium hydrogen triperoxotrimolybdodisulfate trihydrate, [N(CH3)4]3[H(SO4) 2-(MoO2(O2))3]·3H 2O

Masato Hashimoto, Hikaru Ichida, Yukiyoshi Sasaki

Journal of Coordination Chemistry ( Taylor and Francis Ltd. )  37 ( 1-4 ) 349 - 359   1996  [Refereed]

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A novel peroxopolyoxomolybdate compound, [N(CH3)4]3 [H(SO4)2 (MoO2(O2))3]·3H2O, has been obtained from a strongly acidic aqueous solution of a molybdate-sulfate system as the monoclinic crystal of P21/n, a = 13.497(3), b = 15.231 (4), c = 32.603(2) Å, β= 103.113(9)°, and V = 6577(2) Å3. The final R-value was 0.0986 for 395 parameters using 7162 reflections. Each of the two crystallographically independent polyanions contains three molybdenum atoms with five O2-, one O2 2-, and two sulfate groups, one of which is a tripod ligand apical to the molybdenum plane, and the other is a bipod ligand equatorial to the Mo plane. © 1996 OPA (Overseas Publishers Association) Amsterdam B.V. Published in The Netherlands under license by Gordon and Breach Science Publishers SA.

DOI

SYNTHESIS AND CHARACTERIZATION OF A BIDENTATE CHELATING DIISONITRILE LIGAND WITH 2 THIOETHEREAL SULFURS IN A BRIDGING GROUP AND ITS COPPER(I), RHODIUM(I) AND PALLADIUM(II) COMPLEXES

K SAKATA, K MATSUMOTO, M HASHIMOTO

INORGANICA CHIMICA ACTA ( ELSEVIER SCIENCE SA LAUSANNE )  227 ( 1 ) 113 - 118   1994.12  [Refereed]

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The diisonitrile ligand (L) has been synthesized in five reaction steps from t-butylbenzene with an overall yield of 7.3%. The reaction of palladium(II) chloride with L leads to the palladium(II) complex, PdLCl(2), whereas the rhodium(I) complexes, RhL(2)Cl and RhL(2)BF(4), and the copper(I) complex, CuL(2)BF(4), are prepared by ligand exchange reactions. These complexes were investigated by means of mass, infrared, nuclear magnetic resonance (NMR) and electronic spectra, as well as molar conductances. Judging from the molar conductances of the RhL(2)Cl, RhL(2)BF(4), and CuL(2)BF(4), complexes, tetrafluoroborate and chloride anions are ionized in acetonitrile. This is also supported by mass spectral data. The strong band at 2100 cm(-1) is assigned to the N drop C stretching mode. This band shifts to higher frequency upon metal coordination because of the inductive effect produced by the positive charge of the metal ions. This shift increases with increasing charge on the complex. The methy]ene proton signals of the benzy] group and the bridging group in the ligand are shifted slightly downfield on formation of the complexes. Since the magnitude of the shift is approximately proportional to the oxidation number in the metal complexes, the oxidation number could be distinguished by proton NMR studies of the methy]ene groups. These results indicate that the N drop C group in the ligand serves as a sigma-donor and the thioethereal sulfur in the bridging group is not coordinated to the metal atoms. It is surprising that L does not coordinate through the sulfur atoms rather than the isonitriles, because the S-coordinated form would have a stable five-membered-ring structure and the isonitrile coordination gives a fifteen-membered-ring structure.

CD(2,2'-BIPYRIDINE-N,N')NI(CN)4, A HIGHLY BENT CLOSE 2-DIMENSIONAL NETWORK OF [CD-((NC)NI1/4)4]N

M HASHIMOTO, T IWAMOTO

ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS ( MUNKSGAARD INT PUBL LTD )  50   496 - 498   1994.04  [Refereed]

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The crystal structure of poly[(2,2'-bipyridine-N,N')cadmium(II) tetra-mu-cyanonickelate(II)], [Cd(CoH8N2)][Ni(CN)4], has been determined. The tetracyanonickelate(II) ion, Ni(CN)42-, bridges four Cd+ ions to form an infinite two-dimensional folded network stacking along the b axis. The 2,2'-bipyridine ligands chelate to the Cd atoms alternately above and below the folded network. The distortion about the octahedrally coordinated Cd atom is so large, as a result of the unusual coordination behaviour of the Ni(CN)4 in the network formation, that one of the Cd-N-C angles is markedly bent [143.1 (3)-degrees].

ACID STRENGTH OF HETEROPOLYACIDS AND ITS CORRELATION WITH CATALYTIC ACTIVITY

T OKUHARA, CW HU, M HASHIMOTO, M MISONO

BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN ( CHEMICAL SOC JAPAN )  67 ( 4 ) 1186 - 1188   1994.04  [Refereed]

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UV spectrophotometry of a Hammett indicator revealed that the acid strength of the Keggin-type heteropolyacids having W as addenda atoms increased as the valency of the central atom increased (Co < B < Si, Ge < P). The catalytic activity for the decomposition of isobutyl propionate in a homogeneous system was correlated well with the acid strength.

[(C5H5N)2H]3[PW12O40]

M HASHIMOTO, M MISONO

ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS ( MUNKSGAARD INT PUBL LTD )  50   231 - 233   1994.02  [Refereed]

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The crystal structure of tris(dipyridinium) dodecatung-stophosphate has been determined. The [PW12O40]3- heteropolyanion, having T(d) symmetry, is disordered by the 3 symmetry. The pyridine molecules are paired around H+ forming (C5H5N)-H+-(NC5H5) cations with their molecular planes almost parallel to the ab plane of the crystal.

DOI

SELECTIVE OXIDATION OF CYCLOPENTENE AND CYCLOHEXENE BY HYDROGEN-PEROXIDE CATALYZED BY HETEROPOLYACIDS

KY LEE, K ITOH, M HASHIMOTO, N MIZUNO, M MISONO

NEW DEVELOPMENTS IN SELECTIVE OXIDATION II ( ELSEVIER SCIENCE PUBL B V )  82   583 - 591   1994  [Refereed]

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Oxidation of cycloolefins by hydrogen peroxide catalyzed by various Keggin-type heteropolyacids, H3PMo12-xWxO40, x=0-12, were studied in homogeneous tri-n-butyl phosphate solution, placing stress on the effects of the constituent elements of heteropoly anion. Remarkable synergistic effect of mixed addenda atoms, Mo and W, was observed and high yields of dialdehyde were obtained. A reaction scheme was proposed based on the time course and stoichiometry of reaction, and the reactivity of products.