研究者詳細 - 神﨑　亮

論文 - 神﨑　亮

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Kanzaki R., Uchida K., Song X., Umebayashi Y., Ishiguro S.I. . Acidity and basicity of aqueous mixtures of a protic ionic liquid, ethylammonium nitrate . Analytical Sciences24 ( 10 ) 1347 - 1349 2008年10月査読

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Analytical Sciences

Ethylammonium nitrate (EAN) is composed of C2H 5NH3+ and NO3- ions, which behave as an acid and a base, respectively. The ionic liquid thus involves small amounts of C2H5NH2 and HNO3 molecules owing to proton transfer from C2H5NH 3+ to NO3-. The equilibrium constant Ks (= [C2H5NH2][HNO3]), which corresponds to the autoprotolysis constant of water, was obtained to be ca. 10-10 mol2 dm-6 by potentiometry using an ion-selective field-effect transistor and hydrogen electrodes at 298 K. The value indicates that C2H5NH2 and HNO 3 molecules of ca. 10-5 mol dm-3 are involved in neat EAN. On the other hand, in an EAN-water mixture, a water molecule behaves as a base. The apparent pKs value was determined in EAN-water mixtures of various solvent compositions. Interestingly, the pKs value is remained at 10.5 in mixtures over the range of an EAN mole fraction of 0.05-0.9. The value is close to the pKa of C2H 5NH2, or the acid-dissociation constant of C 2H5NH3+, in aqueous solution. This implies that the reaction C2H5NH3+ + H2O → C2H5NH2 + H 3O+ is responsible for the pKs over a wide range of solvent composition. The pKs value in neat EAN is thus slightly smaller than that in the mixtures, implying that H3O + is a stronger acid than HNO3 in an EAN solution, unlike water. 2008 © The Japan Society for Analytical Chemistry.

DOI： 10.2116/analsci.24.1347

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Fukuda S., Takeuchi M., Fujii K., Kanzaki R., Takamuku T., Chiba K., Yamamoto H., Umebayashi Y., Ishiguro S.i. . Liquid structure of N-butyl-N-methylpyrrolidinium bis-(trifluoromethanesulfonyl) amide ionic liquid studied by large angle X-ray scattering and molecular dynamics simulations . Journal of Molecular Liquids143 ( 1 ) 2 - 7 2008年9月査読

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Molecular Liquids

Large angle X-ray scattering of the N-butyl-N-methylpyrrolidinium bis-(trifluoromethanesulfony) amide (P14+TFSA-) ionic liquid was measured at 298 K. The total interference function iLAXS(s) and the total pair correlation function GLAXS(r) were successfully obtained. The iLAXS(s) was analyzed in terms of the intra-molecular geometries of the conformational isomers of the P14+ and TFSA- ions based on the crystal structures, the inter-molecular correlation function GinterLAXS(r) and the inter-molecular radial distribution function as the form DinterLAXS(r) - 4πr2ρ0 were evaluated. With DinterLAXS(r) - 4πr2ρ0, the inter-molecular correlation peaks at 3.5, 4.5 and 5-6 Å evidently appeared as the short range interaction, while considerable long range interactions were found as the broad peaks at 10 and 15 Å. Molecular dynamics simulations of the ionic liquid based on the effective pairwise potentials were carried out. The X-ray total interference function derived from the MD simulations iMD(s) was in agreement with the experimental one. According to the inter-molecular partial atom-atom correlation functions from MD simulations, the observed peaks at 3.5, 4.5 and 5-6 Å can be predominantly ascribed to the closest atom-atom correlations between the P14+ and TFSA- ions such as C···O and C···F. In the inter-molecular partial atom-atom correlation function between terminal methyl carbons of the butyl chain in the P14+ ion, a peak at 4.0 Å was found as the inter-molecular correlation, suggesting that the ionic liquid shows an alkyl chain aggregation, which is similar to that observed for 1-alkyl-3-methylmidazolium ionic liquids. © 2008 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.molliq.2008.02.012

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Fujii K., Soejima Y., Kyosholin Y., Fukuda S., Kanzaki R., Umebayashi Y., Yamaguchi T., Ishiguro S.I., Takamuku T. . Liquid structure of room-temperature ionic liquid, 1-ethyl-3- methylimidazolium bis-(trifluoromethanesulfonyl) imide . Journal of Physical Chemistry B112 ( 14 ) 4329 - 4336 2008年4月査読

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Physical Chemistry B

The liquid structure of 1-ethyl-3-methylimidazolium bis- (trifluoromethanesulfonyl) imide (EMI+TFSI-) has been studied by means of large-angle X-ray scattering (LAXS), 1H, 13C, and 19F NMR, and molecular dynamics (MD) simulations. LAXS measurements show that the ionic liquid is highly structured with intermolecular interactions at around 6, 9, and 15 Å. The intermolecular interactions at around 6, 9, and 15 Å are ascribed, on the basis of the MD simulation, to the nearest neighbor EMI+⋯TFSI- interaction, the EMI+⋯EMI+ and TFSI -⋯TFSI- interactions, and the second neighbor EMI+⋯TFSI- interaction, respectively. The ionic liquid involves two conformers, C1 (cis) and C2 (trans), for TFSI-, and two conformers, planar cis and nonplanar staggered, for EMI+, and thus the system involves four types of the EMI +⋯TFSI- interactions in the liquid state by taking into account the conformers. However, the EMI+⋯TFSI - interaction is not largely different for all combinations of the conformers. The same applies also to the EMI+⋯EMI+ and TFSI-⋯TFSI- interactions. It is suggested from the 13C NMR that the imidazolium C2 proton of EMI+ strongly interacts with the O atom of the -SO2(CF3) group of TFSI-. The interaction is not ascribed to hydrogen-bonding, according to the MD simulation. It is shown that the liquid structure is significantly different from the layered crystal structure that involves only the nonplanar staggered EMI+ and C1 TFSI- conformers. © 2008 American Chemical Society.

DOI： 10.1021/jp7105499

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Fujil K., Seki S., Fukuda S., Kanzaki R., Takamuku T., Umebayashi Y., Ishiguro S. . Anion conformation of low-viscosity room-temperature ionic liquid 1-ethyl-3-methylimidazolium bis(fluorosulfonyl) imide . Journal of Physical Chemistry B111 ( 44 ) 12829 - 12833 2007年11月査読

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Physical Chemistry B

Anion conformation of a low-viscosity room-temperature ionic liquid 1-ethyl-3-methylimidazolium bis(fluorosulfonyl) imide (EMI+FSI -) has been studied by Raman spectra and theoretical DFT calculations. Three strong Raman bands were found at 293, 328, and 360 cm -1, which are ascribed to the FSI- ion. These Raman bands show significant temperature dependence, implying that two FSI- conformers coexist in equilibrium. This is supported by theoretical calculations that the FSI- ion is present as either C2 (trans) or C1 (cis) conformer; the former gives the global minimum, and the latter has a higher SCF energy of about 4 kJ mol-1. Full geometry optimizations followed by normal frequency analyses show that die observed bands at 293, 328, and 360 cm-1 are ascribed to the C2 conformer. The corresponding vibrations at 305, 320, and 353 cm-1 were extracted according to deconvolution of the observed Raman bands in the range280-400 cm-1 and are ascribed to the C1 conformer. The enthalpy ΔHo of conformational change from C2 to C1 was experimentally evaluated to be ca. 4.5 kJ mol-1, which is in good agreement with the predicted value by theoretical calculations. The bis(trifluoromethanesulfonyl) imide anion (TFSI-) shows a conformational equilibrium between C1 and C2 analogues (ΔHo = 3.5 kJ mol-1). However, the profile of the potential energy surface of the conformational change for FSI- (the F-S-N-S dihedral angle) is significantly different from that for TFSI - (the C-S-N-S dihedral angle). © 2007 American Chemical Society.

DOI： 10.1021/jp074325e

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Asada M., Mitsugi T., Fujii K., Kanzaki R., Umebayashi Y., Ishiguro S.i. . Vibrational spectroscopy and molecular orbital calculations of N,N-dimethylacrylamide and N,N-dimethylpropionamide - Conformational equilibrium in the liquid state - . Journal of Molecular Liquids136 ( 1-2 ) 138 - 146 2007年11月査読

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Molecular Liquids

Molecular vibrations of N,N-dimethylacrylamide (DMAA) and N,N-dimethylpropionamide (DMPA) in the liquid state were studied by means of Raman and IR spectra over the wide frequency range. It has been established in our previous work that DMPA involves two rotational isomers within its propionyl CH3-CH2-C({double bond, long}O)- group. In the present work, it is revealed that, like DMPA, DMAA also involves two rotational isomers, the planar cis and nonplanar staggered ones, within its acryl CH2{double bond, long}CH-C({double bond, long}O)- group. The terminal methylene carbon of the acryl group locates cis to the O atom within the amide O{double bond, long}C-N plane (the planar cis conformer) or above the amide plane (the nonplanar staggered conformer). This is well supported by theoretical MO calculations. Torsion potential energy surfaces (PES) for the C-C-C-O dihedral angle θ of the acryl group show that a global minimum appears at ca. θ = 0° (the planar cis conformer) and a local minimum at ca. θ = 130° (the nonplanar staggered conformer). The geometry optimization followed by normal frequency analyses showed that theoretical Raman and IR bands for the conformers satisfactorily reproduce the observed ones. The enthalpy for the conformational change from the planar cis conformer to the nonplanar staggered one was experimentally evaluated by analyzing the integrated intensity changes of the bands in the range 700-800 cm- 1. The value thus obtained for the acryl group of DMAA is ca. 9 kJ mol- 1, which is significantly higher than the corresponding value for the propionyl group of DMPA (5 kJ mol- 1). © 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.molliq.2007.02.007

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Umebayashi Y., Mitsugi T., Fukuda S., Fujimori T., Fujii K., Kanzaki R., Takeuchi M., Ishiguro S.I. . Lithium ion solvation in room-temperature ionic liquids involving bis(trifluoromethanesulfonyl) imide anion studied by Raman spectroscopy and DFT calculations . Journal of Physical Chemistry B111 ( 45 ) 13028 - 13032 2007年11月査読

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Physical Chemistry B

The solvation structure of the lithium ion in room-temperature ionic liquids 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide (EMI+TFSI-) and N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide (BMP+TFSI-) has been studied by Raman spectroscopy and DFT calculations. Raman spectra of EMI +TFSI- and BMP+TFSI- containing Li+TFSI- over the range 0.144-0.589 and 0.076-0.633 mol dm-3, respectively, were measured at 298 K. A strong 744 cm -1 band of the free TFSI- ion in the bulk weakens with increasing concentration of the lithium ion, and it revealed by analyzing the intensity decrease that the two TFSI- ions bind to the metal ion. The lithium ion may be four-coordinated through the O atoms of two bidentate TFSI- ions. It has been established in our previous work that the TFSI- ion involves two conformers of C1 (cis) and C 2 (trans) symmetries in equilibrium, and the dipole moment of the C1 conformer is significantly larger than that of the C2 conformer. On the basis of these facts, the geometries and SCF energies of possible solvate ion clusters [Li(C1-TFSI-) 2]-, [Li(Ci-TFSI-)(C2-TFSI -)]-, and [Li(C2-TFSI-) 2]- were examined using the theoretical DFT calculations. It is concluded that the C1 conformer is more preferred to the C 2 conformer in the vicinity of the lithium ion. © 2007 American Chemical Society.

DOI： 10.1021/jp076869m

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Sukizaki T., Fukuda S., Yamaguchi T., Fujii K., Kanzaki R., Chiba K., Yamamoto H., Umebayashi Y., Ishiguro S.I. . Raman spectroscopic study and DFT calculations on the conformation of 5-azonia-spiro[4.4]nonane cation in crystal and dimethyl carbonate solution . Electrochemistry75 ( 8 ) 628 - 634 2007年8月査読

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Electrochemistry

5-Azonia-spiro[4.4]nonane tetrafluoroborate [(CH2) 4N(CH2)4]+ BF4- is dissolved in dimethyl carbonate (DMC) to yield two liquid phases, DMC and salt-rich DMC solutions. The molecular structure of the [(CH2)4N(CH2)4] ion in the crystalline state and in the salt-rich DMC solution was studied by means of Raman spectroscopy at 298 K and theoretical DFT calculations. The [(CH 2)4N(CH2)4]+ ion involves two pyrrolidinium (CH2)4N rings bridged through the N atom, and each pyrrolidinium ring involves various types of conformation. Theoretical DFT calculations for the [(CH2)4N(CH 2)4]+ ion show that the distorted envelope-envelope conformers of the type E1-E1 and E1-E3 give relatively small energies. Observed Raman spectra of [(CH2)4N(CH 2)4]+BF4- crystals and the salt-rich DMC solution were satisfactorily explained in terms of the favorable presence of the sole envelope-envelope conformer of the type E1-E1.

DOI： 10.5796/electrochemistry.75.628

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Kanzaki R., Uchida K., Hara S., Umebayashi Y., Ishiguro S., Nomura S. . Acid-base property of ethylammonium nitrate ionic liquid directly obtained using ion-selective field effect transistor electrode . Chemistry Letters36 ( 5 ) 684 - 685 2007年5月査読

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Chemistry Letters

Ethylammonium nitrate (EAN) is a protic room-temperature ionic liquid and classified into an amphoteric solvent. The equilibrium constant KS = [EtNH2][HNO3] has directly been obtained for the first time by using an ion-selective field effect transistor (ISFET) electrode. The obtained KS value is of 10-10.0 mol2 dm -6, indicating that the neutral EAN involves HNO3 and EtNH2 molecules as much as 1.0 × 10-5 mol dm -3, or the pH (= -log[HNO3]) is 5 at 298 K. Copyright © 2007 The Chemical Society of Japan.

DOI： 10.1246/cl.2007.684

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Asada M., Fujimori T., Fujii K., Kanzaki R., Umebayashi Y., Ishiguro S.I. . Solvation structure of magnesium, zinc, and alkaline earth metal ions in N,N-dimethylformamide, N,N-dimethylacetamide, and their mixtures studied by means of Raman spectroscopy and DFT calculations - Ionic size and electronic effects on steric congestion . Journal of Raman Spectroscopy38 ( 4 ) 417 - 426 2007年4月査読

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Raman Spectroscopy

The solvation structure of magnesium, zinc(II), and alkaline earth metal ions in N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA), and their mixtures has been studied by means of Raman spectroscopy and DFT calculations. The solvation number is revealed to be 6, 7, 8, and 8 for Mg2+, Ca2+, Sr2+, and Ba2+, respectively, in both DMF and DMA. The δ (O-C-N) vibration of DMF shifts to a higher wavenumber upon binding to the metal ions and the shift Δν (= νbound - νfree) becomes larger, when the ionic radius of the metal ion becomes smaller. The ν (N-CH3) vibration of DMA also shifts to a higher wavenumber upon binding to the metal ions. However, the shift Δν saturates for small ions, as well as the transition-metal (II) ions, implying that steric congestion among solvent molecules takes place in the coordination sphere. It is also indicated that, despite the magnesium ion having practically the same ionic radius as the zinc(II) ion of six-coordination, their solvation numbers in DMA are significantly different. DFT calculations for these metalsolvate clusters of varying solvation numbers revealed that not only solvent-solvent interaction through space but also the bonding nature of the metal ion plays an essential role in the steric congestion. The individual solvation number and the Raman shift Δν in DMF-DMA mixtures indicate that steric congestion is significant for the magnesium ion, but not appreciable for calcium, strontium, and barium ions, despite the solvation number of these metal ions being large. Copyright © 2006 John Wiley & Sons, Ltd.

DOI： 10.1002/jrs.1662

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神崎亮, 梅林泰宏, 竹内宗孝, 藤井健太 . 分子シミュレーションおよびX線回折法によるイオン液体の構造とダイナミクス . アンサンブル9 ( 3 ) 18 - 21 2007年4月

梅林泰宏, 福田周平, 竹内宗孝, 神崎亮, 石黒慎一, 藤井健太, 高椋利幸 . 広角X線散乱実験および分子動力学計算によるイオン液体の液体構造 . 溶融塩および高温化学50 ( 3 ) 117 - 125 2007年4月招待査読

Fujimori T., Fujii K., Kanzaki R., Chiba K., Yamamoto H., Umebayashi Y., Ishiguro S.i. . Conformational structure of room temperature ionic liquid N-butyl-N-methyl-pyrrolidinium bis(trifluoromethanesulfonyl) imide - Raman spectroscopic study and DFT calculations . Journal of Molecular Liquids131 ( SPEC. ISS. ) 216 - 224 2007年3月査読

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Molecular Liquids

Conformational structure of the N-butyl-N-methyl-pyrrolidinium (P14+) ion within its bis(trifluoromethanesulfonyl) imide (TFSI-) and bromide salts has been studied by means of DFT calculations and Raman spectroscopy. The P14+ ion gives various types of conformations with respect to the pyrrolidinium ring and N-butyl group. DFT calculations indicate that, among others, the eq- and ax-envelope conformers with the N-butyl group at equatorial and axial positions, respectively, against planar C4 atoms of the envelope pyrrolidinium ring (-NCH2CH2CH2CH2-) are relatively stable, and the former gives the global minimum. It revealed by comparing observed and calculated Raman spectra that the P14+ ion is present mainly as the ax-envelope conformer in the P14+Br- crystal, whilst the eq- and ax-envelope conformers are present in equilibrium in the P14+TFSI- ionic liquid. The presence of conformational equilibrium is further supported by Raman spectra measured by varying temperature. It is also established that conformation of the N-butyl group is restricted to the trans-TT, in which the butyl group locates trans against its nearest carbon atom in the pyrrolidinium ring, and all carbon atoms in the butyl chain are located trans each other. © 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.molliq.2006.08.054

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Kanzaki R., Umebayashi Y., Asada M., Ishiguro S.I., Matsumoto T., Wakisaka A. . Binuclear μ-perchlorato complexes of alkaline earth metal ions studied by electrospray ionization mass spectrometry and DFT calculations . Chemistry Letters35 ( 10 ) 1118 - 1119 2006年10月査読

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Chemistry Letters

Metal-ion clusters involving alkaline earth metal and perchlorate ions, and N,N-dimethylformamide (DMF) have been studied by electrospray ionization mass spectrometry (ESI-MS). Three types of metal-ion clusters. [M(DMF n)]2+, [M(ClO4)-(DMF)n]+, and [M2(ClO4)3(DMF)n]+ (M = Mg, Ca, and Sr) are found. It is proposed on the basis of DFT calculations that the metal ion in the [M2(ClO4)3(DMF) 6]+ clusters is six-coordinated with three μ-ClO 4- ions and three DMF molecules. Copyright © 2006 The Chemical Society of Japan.

DOI： 10.1246/cl.2006.1118

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Ishiguro S., Umebayashi Y., Fujii K., Kanzaki R. . Solvent conformation and ion solvation: From molecular to ionic liquids . Pure and Applied Chemistry78 ( 8 ) 1595 - 1609 2006年8月査読

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Pure and Applied Chemistry

Metal ions are solvated in solution, and, in a sterically congested organic solvent, those solvent molecules that are simultaneously bound to the metal ion will be subject to consequential steric interactions through space. The molecular structure of a solvent, particularly that of any functional groups in the vicinity of the coordinating atom to the metal ion, plays a key role in the solvation steric effect. Weak solvation steric effects lead to a distorted octahedral structure for six-coordinate transition-metal(II) ions, whereas strong steric effects lead to a decreased solvation number. In particular cases, the conformation of a solvent may undergo a change in response to coordination to the metal ion. Solvation steric effects play a decisive role in reaction thermodynamics and kinetics of the metal ion. Here, we show our recent results on solvation steric effects in terms of structure and thermodynamics, particularly, the conformational change of solvent and its effect on the metal-ion complexation. © 2006 IUPAC.

DOI： 10.1351/pac200678081595

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Fujii K., Fujimori T., Takamuku T., Kanzaki R., Umebayashi Y., Ishiguro S. . Conformational equilibrium of bis(trifluoromethanesulfonyl) imide anion of a room-temperature ionic liquid: Raman spectroscopic study and DFT calculations . Journal of Physical Chemistry B110 ( 16 ) 8179 - 8183 2006年4月査読

記述言語：日本語出版者・発行元：Journal of Physical Chemistry B

The structure of bis(trifluoromethanesulfonyl) imide (TFSI) in the liquid state has been studied by means of Raman spectroscopy and DFT calculations. Raman spectra of 1-ethyl-3-methylimidazolium (EMI+) TFSI- show relatively strong bands arising from TFSI- at about 398 and 407 cm-. Interestingly, the 407 cm-1 band, relative to the 398 cm-1 one, is appreciably intensified with raising temperature, suggesting that an equilibrium is established between TFSI- conformers in the liquid state. According to DFT calculations followed by normal frequency analyses, two conformers of C2 and C1 symmetry, respectively, constitute global and local minima, with an energy difference 2.2-3.3 kJ mol-1. The wagging ω-SO2 vibration appears at 396 and 430 cm-1 for the C1 conformer and at 387 and 402 cm-1 for the C2 one. Observed Raman spectra over the range 380-440 cm-1 were deconvoluted to extract intrinsic bands of TFSI- conformers, and the enthalpy of conformational change from C2 to C1 was evaluated. The enthalpy value is in good agreement with that obtained by theoretical calculations. We thus conclude that a conformational equilibrium is established between the C1 and C2 conformers of TFSI- in the liquid EMI +TFSI-, and the C2 conformer is more favorable than the C1 one. © 2006 American Chemical Society.

DOI： 10.1021/jp0612477

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梅林泰宏, 藤森崇夫, 藤井健太, 神崎亮, 石黒慎一 . DFT計算およびMDシミュレーションによるイオン液体中の金属イオン溶媒和 . 九州大学情報基盤センター広報 2006年4月

Umebayashi Y., Fujimori T., Sukizaki T., Asada M., Fujii K., Kanzaki R., Ishiguro S.I. . Evidence of conformational equilibrium of 1-ethyl-3-methylimidazolium in its ionic liquid salts: Raman spectroscopic study and quantum chemical calculations . Journal of Physical Chemistry A109 ( 40 ) 8976 - 8982 2005年10月査読

記述言語：日本語出版者・発行元：Journal of Physical Chemistry A

Raman spectra of liquid 1-ethyl-3-methylimidazolium (EMI+) salts, EMI+BF4-, EMI+PF6, EMI+CF3SO3-, and EMI +N(CF3SO2)2-, were measured over the frequency range 200-1600 cm-1. In the range 200-500 cm-1, we found five bands originating from the EMI+ ion at 241, 297, 387, 430, and 448 cm-1. However, the 448 cm-1 band could hardly be reproduced by theoretical calculations in terms of a given EMI+ conformer, implying that the band originates from another conformer. This is expected because the EMI+ involves an ethyl group bound to the N atom of the imidazolium ring, and the ethyl group can rotate along the C-N bond to yield conformers. The torsion energy for the rotation was then theoretically calculated. Two local minima with an energy difference of ca. 2 kJ mol-1 were found, suggesting that two conformers are present in equilibrium. Full geometry optimizations followed by normal frequency analyses indicate that the two conformers are those with planar and nonplanar ethyl groups against the imidazolium ring plane, and the nonplanar conformer is favorable. It elucidates that bands at 241, 297, 387, and 430 cm-1 mainly originate from the nonplanar conformer, whereas the 448 cm-1 band does originate from the planar conformer. Indeed, the enthalpy for conformational change from nonplanar to planar EMI+ experimentally obtained by analyzing band intensities of the conformers at varying temperatures is practically the same as that evaluated by theoretical calculations. We thus conclude that the EMI + ion exists as either a nonplanar or planar conformer in equilibrium in its liquid salts. © 2005 American Chemical Society.

DOI： 10.1021/jp053476j

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Fujii K., Umebayashi Y., Kanzaki R., Kobayashi D., Matsuura R., Ishiguro S.I. . Thermodynamic aspects of metal-ion complexation in the structured solvent, N-methylformamide . Journal of Solution Chemistry34 ( 7 ) 739 - 753 2005年7月査読

記述言語：日本語出版者・発行元：Journal of Solution Chemistry

Chloride complexation of cobalt(II), nickel(II) and zinc(II) ions has been studied by calorimetry and spectrophotometry in N-methylformamide (NMF) containing 1.0 mol-dm-3 (n-C4H9) 4NClO4 as an ionic medium at 298 K. A series of mononuclear complexes, MCln(2 -n)+ (M=Co, Ni and Zn) with n = 1, 3 and 4 for cobalt(II), n = 1 for nickel(II), and n = 1-4 for zinc(II), are formed and their formation constants, enthalpies and entropies were obtained. It revealed that complexation is suppressed significantly in NMF relative to that in N,N-dimethylformamide (DMF) in all metal systems examined. The suppressed complexation in NMF is mainly ascribed to the smaller formation entropies in NMF reflecting that the solvent-solvent interaction or solvent structure in the bulk NMF is much stronger than that in the bulk DMF. Formation entropies, ΔS1o, of the monochloro complex in DMF, dimethyl sulfoxide and NMF are well correlated with the Marcus' solvent parameter, ΔΔvSo/R, according to ΔS 1o/R = aΔΔvSo/R+b. The a value is negative and similar in all metal systems examined, whereas the b value depends on the metal system. When a gaseous ion is introduced into a solvent, the ionic process of solvation is divided into two stages: the ion destroys the bulk solvent structure to isolate solvent molecules at the first stage and the ion then coordinates a part of isolated solvent molecules around it at the second stage. We propose that the a and b values may reflect the changes in the freedom of motion of solvent molecules at the first and second stages, respectively, of the ionic process of solvation. © 2005 Springer Science+Business Media, Inc.

DOI： 10.1007/s10953-005-5114-9

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Kanzaki R., Umebayashi Y., Maki T., Ishiguro S.I. . Thermodynamics and fluorescence spectra of 1,10-phenanthroline in micelles of poly (ethylene oxide)-type nonionic surfactant . Journal of Solution Chemistry33 ( 6-7 ) 699 - 709 2004年6月

記述言語：日本語出版者・発行元：Journal of Solution Chemistry

The distribution of 1,10-phenanthroline (phen) in micellar solutions of the nonionic surfactants Triton X and C 12E n with varying poly (ethylene oxide) chain lengths has been studied by potentiometry, calorimetry, and fluorometry at 298 K. Micelles accommodate 1,10-phenanthroline according to the reaction, phen + Y m = Y m(phen), where Y m denotes a surfactant molecule aggregated in micelles. The constant K m for the reaction of Triton X increases as a linear function of n*, the number of ethylene oxide (EO) groups, as K m = K EOn* + K c. Nonzero K EO and K c values suggest a heterogeneous inner structure of the micelle, i.e., the hydrophobic core surrounded by a hydrophilic poly (ethylene oxide) (PEO) shell. On the basis of molar volumes, the intrinsic thermodynamic parameters of transfer of 1,10-phenantholine were extracted. The enthalpy and entropy of transfer of 1,10-phenanthroline from the PEO shell to the core are found to be small and negative. By using K EO and K c values for C 12E n obtained by fluorometry, individual fluorescence spectra of 1,10-phenanthroline in the PEO shell and core were extracted. The fluorescence intensity of 1,10-phenathroline accommodated in the core, like in organic solvents, is significantly reduced relative to that in water. These facts indicate that the aromatic rings of 1,10-phenanthroline penetrate into the hydrophobic core, while its hydrophilic N site is still hydrated in the PEO shell.

DOI： 10.1023/B:JOSL.0000043634.09653.cb

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R Kanzaki, Y Umebayashi, T Maki, S Ishiguro . Thermodynamics and fluorescence spectra of 1,10-phenanthroline in micelles of poly (ethylene oxide)-type nonionic surfactant . JOURNAL OF SOLUTION CHEMISTRY33 ( 6-7 ) 699 - 709 2004年6月査読

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：KLUWER ACADEMIC/PLENUM PUBL

The distribution of 1,10-phenanthroline (phen) in micellar solutions of the nonionic surfactants Triton X and C12En with varying poly (ethylene oxide) chain lengths has been studied by potentiometry, calorimetry, and fluorometry at 298 K. Micelles accommodate 1,10-phenanthroline according to the reaction, phen + Y-m = Y-m(phen), where Ym denotes a surfactant molecule aggregated in micelles. The constant Km for the reaction of Triton X increases as a linear function of n*, the number of ethylene oxide (EO) groups, as K-m = K(EO)n* + K-c. Nonzero K-EO and K-c values suggest a heterogeneous inner structure of the micelle, i.e., the hydrophobic core surrounded by a hydrophilic poly (ethylene oxide) (PEO) shell. On the basis of molar volumes, the intrinsic thermodynamic parameters of transfer of 1,10-phenantholine were extracted. The enthalpy and entropy of transfer of 1,10-phenanthroline from the PEO shell to the core are found to be small and negative. By using KEO and Kc values for C12En obtained by fluorometry, individual fluorescence spectra of 1,10-phenanthroline in the PEO shell and core were extracted. The fluorescence intensity of 1,10-phenathroline accommodated in the core, like in organic solvents, is significantly reduced relative to that in water. These facts indicate that the aromatic rings of 1,10-phenanthroline penetrate into the hydrophobic core, while its hydrophilic N site is still hydrated in the PEO shell.

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