Liquid-crystalline medium and liquid-crystal display comprising the same

Abstract

The invention relates to a liquid-crystalline medium, preferably having a nematic phase and dielectric anisotropy of 0.5 or more, which comprises one or more compounds of formula YXin whichthe parameters have the meanings given in the text,to the use thereof in an electro-optical display, particularly in an active-matrix display based on the IPS or FFS effect, to displays of this type which contain a liquid-crystalline medium of this type, and to the use of the compounds of formula YX for the improvement of the transmission and/or response times of a liquid-crystalline medium which comprises one or more additional mesogenic compounds.

1 - 17 . (canceled) 
     
     
         18 . A compound of formula YX 
       
         
           
           
               
               
           
         
         in which 
       
       
         
           
           
               
               
           
         
       
       denote independently of each other denote 
       
         
           
           
               
               
           
         
         n denotes 0 or 1, 
         R Y  denotes alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms, 
         X Y  denotes F, Cl, NCS, fluorinated alkyl, fluorinated alkenyl, fluorinated alkoxy or fluorinated alkenyloxy, the latter four groups having 1 to 4 C atoms, preferably F, CF 3  or OCF 3 , and 
         Z Y  denotes a single bond, —CH═CH—, —C≡C—, —CH 2 —CH 2 —, —CF 2 —O—, CH 2 —O— or —CO—O—; 
         except that compounds wherein 
         n denotes 1, 
         Z Y  denotes a single bond, 
       
       
         
           
           
               
               
           
         
       
       A denotes 
       
         
           
           
               
               
           
         
       
       denotes 
       
         
           
           
               
               
           
         
       
       and
 X Y  denotes F, 
 or 
 n denotes 1, 
 Z Y  denotes a single bond, 
 
       
         
           
           
               
               
           
         
       
       denotes 
       
         
           
           
               
               
           
         
       
       denotes 
       
         
           
           
               
               
           
         
       
       and
 X Y  denotes OCF 3 , 
 or 
 n denotes 0, 
 Z Y  denotes a single bond, 
 
       
         
           
           
               
               
           
         
       
       denotes 
       
         
           
           
               
               
           
         
       
       and
 X Y  denotes F or OCF 3 , 
 are excluded. 
 
     
     
         19 . The compound of  claim 18 , wherein the compound is selected from the group of compounds of formulae YX-1, YX-2, YX-3, YX-4 and YX-5: 
       
         
           
           
               
               
           
         
       
       in which
 R Y  denotes alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms or alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms, and 
 X Y  denotes F, Cl, CN, NCS, fluorinated alkyl, fluorinated alkenyl, fluorinated alkoxy or fluorinated alkenyloxy, the latter four groups preferably having 1 to 4 C atoms, preferably F, CF 3  or OCF 3 . 
 
     
     
         20 . The compound according to  claim 18 , wherein the compound is selected from the group consisting of: 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
       
       wherein n is an integer from 1 to 6. 
     
     
         21 . A process for the preparation of a liquid-crystalline medium comprising one or more compounds of formula YX according to  claim 18 , wherein one or more compounds of formula YX are mixed with one or more additional mesogenic compounds. 
     
     
         22 . A process for the preparation of a compound of formula YX according to  claim 18 , comprising:
 nucleophilic addition of a metallated aryl derivative resulting in a corresponding tertiary alcohol,   dehydration of the tertiary alcohol to give a cyclohexylene-cyclohexenylenephenylene compound, and   hydrogenation of the cyclohexylene-cyclohexenylene-phenylene compound to the respective bicyclohexylene-phenylene compound.   
     
     
         23 . The process of  claim 18  wherein the nucleophilic addition of a metallated aryl derivative resulting in the corresponding tertiary alcohol is a Grignard reagent to a bicyclohexyl ketone.