論文 - 神﨑　亮

Ishiguro S.I., Umebayashi Y., Kanzaki R. .  Characterization of Metal Ions in Coordinating Solvent Mixtures by Means of Raman Spectroscopy .  Analytical Sciences20 ( 3 ) 415 - 421   2004年3月

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記述言語：日本語   出版者・発行元：Analytical Sciences  

Titration Raman spectroscopy has been developed for studying the solvation structure of metal ions in solution. The method affords us the solvation number, and the value thus obtained in neat solvents is in good agreement with that determined by EXAFS. The method is then applied to solvent mixtures, and the individual solvation number for each solvent is extracted. In a solvent mixture of N,N-dimethylformamide (DMF) and N,N,N′,N′-tetramethylurea (TMU), the metal ion prefers DMF to TMU, which is ascribed to the solvation steric effect. The same applies also for the solvent mixture of N,N-dimethylpropionamide (DMPA) and DMF. However, unlike TMU, DMPA changes its conformation from the planar cis to non-planar staggered upon solvation to the metal ion. The enthalpy for the conformational change of DMPA is positive in the bulk, while it is significantly negative in the coordination sphere of the manganese(II) ion. Here, we briefly describe the procedure of measurements and analyses for the titration Raman spectroscopy, and review the solvation structure of the alkaline earth, first transition metal(II) and lanthanide(III) ions in some solvent mixtures in view of solvation steric effect.

DOI： 10.2116/analsci.20.415

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Maki T., Kanzaki R., Umebayashi Y., Ishiguro S.I. .  Hysteretic behavior on the heat of protonation of diethylenetriamine in aqueous solution .  Chemistry Letters33 ( 2 ) 186 - 187   2004年2月査読

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

Hysteretic behavior was found on the heat of protonation of diethylenetriamine (dien) in aqueous solution at 298 K. We propose the presence of two conformers for Hdien+, which have significantly different proton affinities. Mutual transformation between the conformers may be practically forbidden, but is strongly accelerated upon their protonation to form H2dien2+.

DOI： 10.1246/cl.2004.186

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Umebayashi Y., Shin M., Kanzaki R., Ishiguro S. .  Thermodynamics of [Co(NCS)<inf>4</inf>]^2- at poly(ethylene oxide) and octylphenyl moieties in micelles of nonionic surfactants .  Journal of Colloid and Interface Science237 ( 2 ) 167 - 173   2001年5月査読

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Colloid and Interface Science  

Formation of cobalt(II)-thiocyanato complexes in nonionic surfactant solutions of poly(ethylene oxide) type with varying poly(ethylene oxide) chain lengths of 7.5 (Triton X-114), 30 (Triton X-305), and 40 (Triton X-405) has been studied by titration spectrophotometry and calorimetry at 298 K. Data were analyzed by assuming formation of a series of ternary complexes Co(NCS)nYm(2-n)+ (Y = surfactant) with an overall formation constant βnm. In all the surfactant systems examined, data obtained can be explained well in terms of formation of Co(NCS)+ and Co(NCS)2 in an aqueous phase (aq), and Co(NCS)4Y2- in micelles, and their formation constants, enthalpies, and entropies have been determined. The β41/β20 ratio increases and the corresponding enthalpy becomes significantly less negative with an increasing number of ethylene oxide groups. This suggests that micelles of these nonionic surfactants have a heterogeneous inner structure consisting of ethylene oxide and octylphenyl moieties. Indeed, on the basis of molar volumes of ethylene oxide and octylphenyl groups, intrinsic thermodynamic parameters have been extracted for the reaction Co(NCS)2(aq) + 2NCS-(aq) = Co(NCS)4Y2- (ΔrG°, ΔrH°, and ΔrS°) at each moiety. The ΔrG°, ΔrH°, and ΔrS° values are -16 kJ mol-1, -15 kJ mol-1, and 3 J K-1 mol-1, respectively, for the ethylene oxide moiety, and -15 kJ mol-1, -70 kJ mol-1, and -183 J K-1 mol-1 for octylphenyl. Significantly less negative ΔrH° and ΔrS° values for ethylene oxide imply that the hydrogen-bonded network structure of water is extensively formed at the ethylene oxide moiety, and the structure is thus broken around the Co(NCS)42- complex with weak hydrogen-bonding ability. © 2001 Academic Press.

DOI： 10.1006/jcis.2001.7457

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Kanzaki R., Umebayashi Y., Uemura K., Ishiguro S.I. .  Distribution thermodynamics of 1,10-phenanthroline in non-ionic surfactant triton X-100 micelles .  Physical Chemistry Chemical Physics3 ( 5 ) 824 - 828   2001年3月

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記述言語：日本語   出版者・発行元：Physical Chemistry Chemical Physics  

The distribution thermodynamics of 1,10-phenanthroline (phen) and 2,9-dimethyl-1,10-phenanthroline (dmphen) in micelles of the non-ionic surfactant Triton X-100 were studied by potentiometry and titration calorimetry at 298 K. Both of these ligands form HL+ and HL2+ (L = phen and dmphen) in acidic solution. Their formation constants were determined in aqueous solutions containing various concentrations of Triton X-100, and were found to decrease with increasing concentration of the surfactant. The decrease is explained in terms of accommodation of neutral phenanthrolines in micelles by taking into account the surfactant solution as a heterogeneous solvent mixture. The case in which the surfactant is treated as the third reactant was also examined, and thermodynamic parameters for the interaction between the surfactant and phenanthrolines, i.e. the Gibb's energies, enthalpies and entropies of transfer of phenanthrolines from aqueous solution to a micellar pseudo-phase, were obtained. The Gibb's energies of transfer of the neutral ligand L are -8.2 and -11.7 kJ mol-1 for L = phen and dmphen, respectively. The corresponding enthalpies of transfer are both small and negative, implying that these neutral 1,10-phenanthrolines are still strongly hydrated in micelles, as well as in water, through the hydrophilic nitrogen sites.

DOI： 10.1039/b009132o

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R Kanzaki, Y Umebayashi, K Uemura, S Ishiguro .  Distribution thermodynamics of 1,10-phenanthroline in non-ionic surfactant Triton X-100 micelles .  PHYSICAL CHEMISTRY CHEMICAL PHYSICS3 ( 5 ) 824 - 828   2001年査読

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

The distribution thermodynamics of 1,10-phenanthroline (phen) and 2,9-dimethyl-1,10-phenanthroline (dmphen) in micelles of the non-ionic surfactant Triton X-100 were studied by potentiometry and titration calorimetry at 298 K. Both of these ligands form HL+ and HL2+ (L = phen and dmphen) in acidic solution. Their formation constants were determined in aqueous solutions containing various concentrations of Triton X-100, and were found to decrease with increasing concentration of the surfactant. The decrease is explained in terms of accommodation of neutral phenanthrolines in micelles by taking into account the surfactant solution as a heterogeneous solvent mixture. The case in which the surfactant is treated as the third reactant was also examined, and thermodynamic parameters for the interaction between the surfactant and phenanthrolines, i.e. the Gibb's energies, enthalpies and entropies of transfer of phenanthrolines from aqueous solution to a micellar pseudo-phase, were obtained. The Gibb's energies of transfer of the neutral ligand L are -8.2 and -11.7 kJ mol(-1) for L = phen and dmphen, respectively. The corresponding enthalpies of transfer are both small and negative, implying that these neutral 1,10-phenanthrolines are still strongly hydrated in micelles, as well as in water, through the hydrophilic nitrogen sites.

Web of Science

Kanzaki R., Egashira T., Nakazato T., Umebayashi Y., Ishiguro S.I. .  Influence of charge on adduct formation of [M(phen)<inf>3</inf>](z+) (M = Ru²⁺, Co³⁺, Si⁴⁺) with 1,10-phenanthroline in aqueous solution .  Physical Chemistry Chemical Physics2 ( 17 ) 3825 - 3830   2000年9月査読

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Physical Chemistry Chemical Physics  

Adduct formation of the inert complexes Ru(phen)32+, Co(phen)33+ and Si(phen)34+ with 1,10-phenanthroline (phen) has been studied by potentiometry and calorimetry in aqueous solution containing 0.1 mol dm-3 NaCl as an ionic medium at 298 K. Formation of a 1 : 1 adduct, in which planar 1,10-phenanthroline molecules are stacked, has been found for all the inert complexes and their formation constants, enthalpies and entropies were obtained. Adduct formation constants are hardly influenced by the ionic charges of the metal center. The enthalpy values are all negative, indicating that a specific π-π interaction operates between stacked 1,10-phenanthroline molecules. The corresponding entropy values are positive for Ru(phen)32+ and Co(phen)33+, while it is negative for Si(phen)34+. The positive entropies indicate that reduction of hydrophobic hydration upon stacking also plays a key role in the adduct formation. Both enthalpy and entropy values significantly decrease with increasing charge, and they strongly compensate to give similar formation constants. This implies that hydrophobic hydration around aromatic rings within the inert complexes is reduced to a greater extent with increasing charge, Ru(phen)32+ < Co(phen)33+ < Si(phen)34+. 1,10-Phenanthroline forms protonated H(phen)+ and H(phen)2+ species in an acidic solution, and 1,10-phenanthroline molecules are stacked in the latter. The enthalpy and entropy of formation of H(phen)2+ are significantly negative, also indicating that π-π interaction play an essential role in the formation of H(phen)2+. On the other hand, both the enthalpy and entropy of solution of 1,10-phenanthroline remain unchanged in solution containing NaCl over the range 0.05-1 mol dm-3, suggesting that hydrophobic hydration shells are restricted at the vicinity of 1,10-phenanthroline.

DOI： 10.1039/b003854g

Web of Science

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Shin M., Umebayashi Y., Kanzaki R., Ishiguro S. .  Formation of copper(II) thiocyanato and cadmium(II) iodo complexes in micelles of nonionic surfactants with varying poly(ethylene oxide) chain lengths .  Journal of Colloid and Interface Science225 ( 1 ) 112 - 118   2000年5月査読

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Colloid and Interface Science  

Formation of copper(II) thiocyanato and cadminum(II) iodo complexes in micelles of poly(ethylene oxide) (PEO)-type nonionic surfactants with varying PEO chain lengths of 9.5 (Triton X-100), 30 (Triton X-305), and 40 (Triton X- 405) has been studied by titration spectrophotometry and calorimetry at 298 K. In a given surfactant solution, all data obtained were analyzed by assuming formation of ternary complexes MX(n)Y(m)/(2-n)+ (M = Cu(II), Cd(II); X = SCN-, I-; Y = surfactant), and the complexes thus form in aqueous phase (m = 0) or in micelles (m = 1). In the Cu(II)-SCN- system, spectrophotometric data obtained by varying concentrations of the surfactant can be explained well in terms of formation of Cu(NCS)2Y in micelles and Cu(NCS)+ and Cu(NCS)2 in an aqueous phase, and it turned out that formation constant of Cu(NCS)2Y increases with increasing PEO chain length. In the Cd(II)-I- system, the formation of CdI3Y- and CdI4Y2- is concluded in micelles, and that of CdI+, CdI-3, and CdI2-4 in an aqueous phase. Interestingly, formation enthalpies of CdI3Y- and CdI4Y2- become significantly less negative with increasing PEO chain length. This suggests that transfer of the complexes from aqueous solution to a hydrophobic octylphenyl (OP) moiety in micelles is significantly more exothermic than that to a hydrophilic PEO one. Thermodynamic parameters of transfer of CdI-3 and CdI2-4 from aqueous solution to the OP and PEO moieties of micelles have been evaluated. (C) 2000 Academic Press.

DOI： 10.1006/jcis.2000.6722

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