Chiral azetidinone derivatives, and their use as dopes in liquid-crystal mixtures

摘要

Azetidinones of the formula I <IMAGE> (I) in which, for example, R1 is an alkyl or alkenyl radical, R2 and R3 are hydrogen or an alkyl or alkenyl radical, Z is hydrogen or (pseudo)halogen, A1, A2 and A3 are a ring system, and M is a spacer group, can be added to liquid-crystal mixtures. Even when admixed in small amounts, they cause considerable twist in the cholesteric and smectic C* phase, which can compensate the pitch of another dope or produce a short SC* pitch.