| abstract |
The present invention provides a novel and stable liquid crystal or mesogenic compound, liquid crystal medium, and optical and electro-optical display elements having a highly negative DC anisotropy and suitable as a component of a liquid crystal medium. SOLUTION: R 1 -(-A 1 -Z 1- ) k 1- (A 2 -Z 2- ) k 2 -W-(-Z 3 -A 3- ) k 3 (-Z 4 -A 4 -) k4 -R 2, in the formula, W = sub-formula (2) L 1 and L 2 are independently ═H, F, Cl, —CH 2 F, —CHF 2 or —CF 3 , provided that L 1 and L 2 are not both H, L 3, L 4, independently, = H or F, R 1, R 2, a 1, a 2, a 3, a 4, Z 1, Z 2, Z 3, Z 4, k1, k2, k3 and k4 are novel fluorinated fluorene derivatives having a negative anisotropy of dielectric constant represented by the following meanings, liquid crystal media, optical and electro-optical display elements. [Selection figure] None |