We studied the interaction of water-soluble cationic metalloporphyrins, [Formula: see text]Py and TMPyP, with the DNA double helix in ionic liquid solutions using CD and absorption spectra. The dispersibility of their porphyrin complexes was improved by electrostatic interactions of the anions of the ionic liquid. In the case of Cu(II) and Zn(II) complexes, the [Formula: see text]Py complexes with pyridinium cations attached to the meso-phenyl groups via methylene groups intercalated into the DNA double helix, while the compact TMPyP complexes with pyridinium cations at the meso-position could not interact with DNA. Thus, it was suggested that the solvation behavior by ionic liquids depends on the structure of the porphyrin and also affects its interaction with DNA. Neither Mn(III) complexes with axial ligands could interact with DNA, regardless of the presence of the ionic liquids, due to their steric hindrance.

Chiral ionic liquids, starting from (S)-proline, have been prepared and evaluated the ability of a chiral catalyst. In Michael reaction of trans-β-nitrostyrene and cyclohexanone, all the reactions were carried out under homogeneous conditions without any solvent except for excess cyclohexanone. The chiral ionic liquid catalyst with the positive charge delocalized bulky pyrrolidinium cation shows excellent yields (up to 92%), diastereoselectivities (syn/anti = 96/4), and enantioselectivities (up to 95% ee) and could be reused at least three times without any loss of its catalytic activity. Such results demonstrated a promising new approach for green and economic chiral synthesis by using the chiral ionic liquids as a chiral catalyst and a chiral medium.

「化学工業」(化学工業社発行)の第59巻,第3号(2008) 9-14ページに掲載

We synthesized the novel chiral ionic liquid based on L-proline which is an excellent chiral catalyst for various asymmetric reactions. The proline type ionic liquid showed very low melting point and viscosity, and an effective catalytic activity for asymmetric Michael addition reactions of cyclohexanone to nitrostyrenes to afford the corresponding Michael adducts in high yields (up to 96 %), diastereoselectivities (syn/anti ratio up to 96/4), and enantioselectivities (up to 95 % ee). The proline type chiral ionic liquid could be easily recovered and the recovered ionic liquid could be reused for at least three times without significant loss of diastereoselectivities and enantioselectivities. We report the synthesis and properties of the proline type chiral ionic liquid and several asymmetric reactions catalyzed by the ionic liquid.

The pressure effect on the rate of thermal fading of open form chromene photochemically generated from close form chromene was measured in multiple ionic liquids. The activation volumes of the thermal cyclezation of chromene were equivalent in almost ionic liquids. Exceptionally, the activation volume was negatively small only in [bmim][CS]. It seemed the desolvation around chromene was promoted, because CS anion was too bulky. To prove the desolvation from the chromene in [bmim][CS], the dilution effect of [bmim][CS] by [bmim][TFSI] was investigated.

In recent years, ionic liquids have received a considerable upsurge of interest as electrolytes for various electrochemical devices, such as Li-ion batteries, dye-sensitized solar cells. This is mainly attributable to their superior properties, such as non-flammability, non-volatility and intrinsic ion conductivity. High ionic conductivity and fast ion mobility (including the doped ions such as Li⁺ for Li batteries) are the requirements for ionic liquids as supporting electrolytes in high-energy devices. This means that the viscosity of ionic liquids must be as low as possible. Therefore, we synthesized multiple low-viscosity ionic liquids. We report the viscosity, ion conductivity and the melting point of these ionic liquids.

In the Diels-Alder reaction using imidazolium ionic liquids with charge delocalized anions, high stereoselectivity is shown. These ionic liquids show weaker anion- cation interaction. This situation allows hydrogen bonding between the C² hydrogen of the imidazolium and the carbonyl oxygen of the dienophile and act like a Lewis acid catalyst. In this study, we report that the effect of ionic liquid with charge delocalized anion as a Diels-Alder reation media in various conditions and Lewis acid catalyst in various reactions.

In general, rearrangement of solvent molecules is more rapid than movement of a reactant solute. However, this relation can be inverted when viscosity of the used solvent drastically increase by applying high pressure. Here we firstly report this phenomenon, known as the dynamic solvent effect, could be observable even in imidazolium ionic liquids. Pressure effect (0.1 M-600 Mpa) on a photoisomerization reaction in an ionic liquid was monitored from the viewpoint of the molecular structure of the salt medium. We would discuss the relation between the dynamic solvent effect and the salt design (side chain structure of the imidazolium cation and anion size).

Utilizing an imidazolium ionic liquid possessing -OH moiety for 5 μm Fe3O4 without any surfactants such as an oleic acid results in a MR fluid. The obtained Fe3O4 fluid supported by the ionic liquid maintained the dispersion state for at least two weeks at room temperature.

Functional composite base on dsDNA and functional molecules with ILs has attracted great interest in the material science. The hydrophilic porphyrins as well as the hydrophobic porphyrins could interact with dsDNA, and the THPP-Cu(II) complex-dsDNA composites show good catalytic ability for chiral Diels-Alder reaction. In addition, we could observe a formation of Z-DNA in the ILs.

When cellulose is heated in hydrochloric acid, 5-(chloromethyl)furfiiral which is easily converted to the biofuel is obtained. We report the conversion of cellulose into 5-(chloromethyl)furfural utilizing acidic ionic liquids. Macrocrystalline cellulose was added to [Hmim][Cl]-HCl(1:1)solution to give a homogeneous mixture, which was introduced into a flask containing 1,2-dichloroethane. The solvent was kept at 65 ℃ with continuous stirring and extracted for 42 h. 5-(chloromethyl)furfural(33%) was isolated.

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