Clarification of a misconception in the BINOL-based fluorescent sensors: synthesis and study of major-groove BINOL-amino alcohols.

The major-groove BINOL-amino alcohol (S)-6 shows greatly enhanced fluorescence over the minor-groove one (S)-3. The study of a series of the major-groove BINOL-amino alcohol compounds demonstrates that the commonly accepted acid inhibition of the PET fluorescence quenching of aryl-amine compounds is not involved in the BINOL-amine sensors.