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[摘要]：The fluorescent properties of a series of H8BINOL-amine compounds are investigated. It is revealed that the intramolecular hydrogen bonds of these compounds contribute I to the shift of the emission of their H8BINOL unit to a much longer wavelength. That is, the emission of H8BINOL is at lambda = 323 nm, but that of the H8BINOL-amino alcohol (S)-5 is at lambda = 390 nm. Binding of (3)-5 with mandelic acid suppresses its intramolecular hydrogen bonding and restores the short wavelength emission of the H8BINOL unit. When (S)-s (1.0 x 10(-4) in CH2Cl2) was treated with (R)-mandelic acid (4.0 x 10(-3)), a large fluorescence enhancement at the short wavelength (lambda(emi) = 330 nm) was observed with I-R/I-0 = 11.7. When (S)-MA was used under the same conditions, the enhancement at the short wavelength emission was much smaller. Thus, a good enantioselective fluorescent response was observed with ef =3.5 [ef: enantioselective fluorescence enhancement ratio = (I-R - I-0)/(I-S - I-0)]. This study demonstrates that the H8BINOL-based molecules are promising as a new class of enantioselective fluorescent sensors. |
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