The chiroptical properties of N-(2-hydroxy-1-naphthyl)methylidene-(S)--phenylethylamine (s-1) were studied as a model of chiral molecular switches.The Schiff base exhibited a pH-responsive chiroptical inversion behavior as a result of breaking and forming of the intramolecular hydrogen bonding and accompanying CC single bond rotation far away from the chiral center.DFT computation results showed that both two preferred conformers of s- 1 and its deprotonated species are stereochemically quasi-enantiotropic.On the basis of these findings we designed a chiral styrene-type monomer (VNP) containing imine linkage and synthesized corresponding polymers through RAFT technique.It was found that the chiroptical properties of PVNPs are highly sensitive to acid/base stimulus.The addition of acid produced an intensive Cotton effect at 382 nm for the THF solution of polymer

which is probably derived from the dissymmetric spatial arrangement of interacting chromophores in adjacent pendent groups due to the protonation of imine moiety.Furthermore

the CD signal can be totally reversed with addition of base.Chiroptical signals remained consistent after five acid-base reaction cycles

proving that a robust polymer-based chiroptical switch was established.This promising new type of chiroptical switches is relatively unique as it does not involve any covalent bond formation/breakage or conformational transition of polymer main chains and thus possess distinct advantages

such as fast switching rate

high reversibility and fatigue resistance as well as the nondestructive readout.Using such a reversible and reproducible chiral switching system

we designed the IHIBIT molecular logic gate that might have potential uses in information processing at molecular level.