Cluster structure of imidazolium salts in methanol controlled by the balance of interactions: cation-anion, cation-solvent, and anion-solvent.

We have studied the cluster structure of 1-butyl-3-methylimidazolium halide, bmimX (X = Cl, Br, I), in methanol solution by means of an electrospray mass spectrometer, which is specially designed for analysis of clusters isolated from solution. In positive ion mode experiments, the ratio of solvated bmim(+), bmim(+)(MeOH)(n) and ion-pair clusters, bmim(bmim(+)X(-))(m) was dependent on the counter anion. As for bmimCl solutions, few solvated bmim(+) clusters were observed, and the ion-pair clusters were clearly observed.

Solute-solvent interactions in imidazolium camphorsulfonate ionic liquids.

We directly observe the interaction between 1-butyl-3-methylimidazolium (bmim) or 1-butyl-2,3-dimethylimidazolium (bm(2)im) and the solute, ethyl acrylate (EA), which is the popular dienophile in the Diels-Alder reaction and an H-bonding acceptor, by using specially designed electrospray mass spectrometry. In imidazolium ionic liquids, cation-anion interactions are controlled by selecting the appropriate anion, and the naked C(2)-H of imidazolium, which loosely interacts with its counterion, can readily interact with an H-bonding acceptable solute. The ion-counterion (solvent-solvent) interaction affects the ion-solute (solvent-solute) interaction.

Camphor ionic liquid: correlation between stereoselectivity and cation-anion interaction.

[structure: see text] As a halogen-free anion for an imidazolium room temperature ionic liquid, the use of a camphorsulfonate causes an increase in the number of free (naked) imidazolium cations, which produces an effective endo/exo stereoselective Diels-Alder reaction.

The first utilization of acidic ionic liquid for preparation of tetraarylporphyrins.

A phase-separated acidic ionic liquid affords to catalyze a reaction of pyrrole with benzaldehyde in dichloromethane, forming porphyrins in a comparable yield to the Lindsey method and is reusable at least ten times without loss of catalytic activity.

In vitro selection of hairpin ribozymes activated with short oligonucleotides.

We have carried out an in vitro selection to obtain an allosteric hairpin ribozyme, which has cleavage activity in the presence of an exogenous short oligonucleotide as a regulator. Random sequences were inserted in a region corresponding to the hairpin loop of the ribozyme. After 12 rounds of selection, DNA templates were cloned.