| abstract |
Liquid-crystalline allenes of the formula I <IMAGE> I where M is a mesogenic group, R1 and R2 are hydrogen or a C-organic radical having 1-8 carbon atoms, R3 is a C-organic radical having 1-30 carbon atoms, X1 is -(CH2)q-O-(CH2)p-, -(CH2)q-NR4-(CH2)p-, -(CH2)q-CO-O-(CH2)p-, -(CH2)q-O-CO-(CH2)p-, -(CH2)q-CO-NR4-(CH2)p- or -(CH2)q-NR4-CO-(CH2)p-, R4 is hydrogen or an alkyl radical having 1-4 carbon atoms, p is from 1 to 20, and q is from 0 to 20, where the definitions of R2 and R3 can also be interchanged, are used in optical display elements. |