@article{Watarai2006, 
author = {Hitoshi Watarai and Sayaka Wada and Kazuhiko Fujiwara},
title = {Spectroscopic Detection of Chiral Aggregation at Liquid-Liquid Interfaces},
year = {2006},
journal = {Tsinghua Science and Technology},
volume = {11},
number = {2},
pages = {228-232},
keywords = {chiral aggregation, liquid-liquid interface, spectroscopic detection, centrifugal liquid membrane, second harmonic generation circular dichroism},
url = {https://www.sciopen.com/article/10.1016/S1007-0214(06)70181-X},
doi = {10.1016/S1007-0214(06)70181-X},
abstract = {Two new spectroscopic methods to detect the optical activity of liquid-liquid interfaces have been developed. The first one is the centrifugal liquid membrane (CLM) method combined with a conventional circular dichroism (CD) spectropolarimetry and the second one is a more interfacial specific second harmonic generation CD (SHG-CD) spectrometry. In the CLM-CD method, a cylindrical glass cell containing small amounts of organic and aqueous phases was rotated at about 7000 r/min in a sample chamber of a CD spectropolarimeter to generate an interface with a high specific interfacial area between the two-phase liquid membranes. The CD spectra of the J-aggregate of protonated 5,10,15, 20-tetraphenylporphyrin formed at the toluene-sulfuric acid interface have been measured. As for the SHG-CD, a circularly polarized wavelength-variable fs-laser system was constructed to measure the interfacial SHG spectra of a flat liquid-liquid interface. The ion-associated aggregation of a water-soluble anionic porphyrin promoted with a cationic amphiphile at the heptane-water interface was observed by this technique and the observed SHG-CD spectra proved the generation of a characteristic optical activity accompanied by the formation of the interfacial aggregate of inherently achiral porphyrin molecules. These methods will pioneer a new field of interfacial chiral chemistry in the studies of solvent extraction mechanisms.}
}