Hitoshi Watarai

Chiral Recognition of 2-Alkylalcohols with Magnetic Circular Dichroism Measurement of Porphyrin J-Aggregate on Silica Gel Plate

Simple chiral recognition method of 2-alkylalcohols on a silica gel plate was proposed by using the induced circular dichroism (ICD) of J-aggregates of diprotonated tetraphenylporphyrin and magnetic circular dichroism (MCD) spectrometry. To the silica gel on a glass slide including a chiral 2-alkylalcohol and 4 M sulfuric acid, the porphyrin in toluene was added and mixed. Then, the glass slide was used for in situ MCD measurement. The observed ICD spectra could recognize well the chirality of the alcohols and the ICD intensity normalized by the MCD intensity of the J-aggregate correlated linearly to the amount of the chiral alcohols in the silica gel.

SERS Measurement of Cysteamine Molecules Stretched by the Electromagnetophoretic Force

The role of an external force on chemical equilibria is an important subject in mechanobiochemistry. The effect of an electromagnetophoretic force for the stretching of cysteamine molecules was examined by using SERS spectrometry. Polystyrene particles modified with cysteamine were bound to silver nanoparticles adsorbed on the wall of a silica capillary cell. Under a constant magnetic field, when an electric current was applied to the conductive medium in the capillary, the shift of SERS bands and the increase of the trans/gauche ratio of cysteamine were observed, suggesting a molecular conformation change of cysteamine due to the stretching force.