| 摘要 |
Chiral compounds of formula (I) where in R1, R2, R3, R4 = equal or unequal = H, F, Cl, R5, R6 or R7; R5 = CN, NCS, CF3, OCF3; R6 = chiral alkyl, alkenyl, alkynyl or fluoroalkyl with chain lengths up to 15 carbon atoms, with one or several asymmetric C atoms substituted with -CH3, -C2H5, -CN, halogen, -CF3, -CHF2, CH2F, -CCl3, -CF2Cl, -CFCl2, -OCF3, -OCHF2, -OCH2F in which one or several CH2 groups independently one to another can be replaced by -S-, -O-, cyclobutane, [1.1.1]bicyclopentane, cyclopropane, oxirane, thiirane, -CO-, -COO-, -OCO-, -OCOO-, -OOCO-; R7 = non chiral alkyl, alkenyl, alkynyl or fluoroalkyl with chain lengths up to 15 carbon atoms, in which one or several C atoms can be substituted with -CH3, -C2H5, -CN, halogen, -CF3, -CHF2, CH2F, -CCl3, -CF2Cl, -CFCl2, -OCF3, -OCHF2, -OCH2F, and in which one or several CH2 groups independently one to another can be replaced by -S-, -O-, cyclobutane, [1.1.1]bicyclopentane, cyclopropane, oxirane, thiirane, -CO-, -COO-, -OCO-, -OCOO-, -OOCO-; ring A1, A2, A3, A4 = independently substituted or unsubstituted 1,4-phenylene ring; X1, X2 = independently S, C(R8 R9); R8, R9 = H, F, Cl, R5, R6, R7; with the proviso that at least one of the groups R1, R2, R3, R4, R8, R9 is equal to R6, and not more than two of the groups R1, R2, R3, R4 are equal to R5. These compounds can be switched between two stable optical states and are suited for use in chirooptical displays. |
