Aikawa, Yoshihide;Shimada, Tetsuya;Tachibana, Hiroshi;Inoue, Haruo
165
Asymmetric recognition of chiral alcohol by fluorenone derivatives with chiral substituents through intermolecular hydrogen bonding interaction in the singlet excited state was attempted. 1-((1S, 2R, 5S)-(+)-Menthyloxycarbonyl)aminofluoren-9-one (1-MAF) and 1-((1S, 2R, 5S)-(+)-menthyloxycarbonyl)oxyfluoren-9-one (1-MOF) were synthesized and their photophysical behaviors were characterized by the measurement of absorption and fluorescence spectra, as well as the quantum yield and the lifetime of fluorescence. The excited singlet states of 1-MAF and 1-MOF were revealed to have characteristics similar to those of fluorenone, though the intramolecular CT nature was fairly suppressed as compared with 3- and 4-substituted aminofluorenones. Fluorescences of 1-MAF and 1-MOF in acetonitrile were quenched by the addition of alcohols. Differences in fluorescence quenching efficiency were hardly observe for rather small chiral alcohols such as (R)-(-)- or (S)-(+)-2-butanol, while bulky alcohols such as menthol and isopinocampheol showed chiral recognition effects in their fluorescence quenching of 1-MAF in either acetonitrile or butyronitrile.