| 摘要 |
The invention relates to fluorinated fluorene derivatives of negative DC anisotropy, of the formula I <?in-line-formulae description="In-line Formulae" end="lead"?>R<SUP>1</SUP>-(-A<SUP>1</SUP>-Z<SUP>1</SUP>-)<SUB>k1</SUB>-(-A<SUP>2</SUP>-Z<SUP>2</SUP>-)<SUB>k2</SUB>-W-(-Z<SUP>3</SUP>-A<SUP>3</SUP>-)<SUB>k3</SUB>-(-Z<SUP>4</SUP>-A<SUP>4</SUP>-)<SUB>k4</SUB>-R<SUP>2</SUP>I<?in-line-formulae description="In-line Formulae" end="tail"?> in which W denotes the sub-formula L<SUP>1 </SUP>and L<SUP>2</SUP>, independently of one another, are H, F, Cl, -CH<SUB>2</SUB>F, -CHF<SUB>2 </SUB>or -CF<SUB>3</SUB>, with the proviso that L<SUP>1 </SUP>and L<SUP>2 </SUP>are not both H, L<SUP>3 </SUP>and L<SUP>4</SUP>, independently of one another, are H or F, and R<SUP>1</SUP>, R<SUP>2</SUP>, A<SUP>1</SUP>, A<SUP>2</SUP>, A<SUP>3</SUP>, A<SUP>4</SUP>, Z<SUP>1</SUP>, Z<SUP>2</SUP>, Z<SUP>3</SUP>, Z<SUP>4</SUP>, k1, k2, k3 and k4 are as defined above. The invention furthermore relates to liquid-crystalline media and to optical and electro-optical display elements. |
