Liquid-crystalline medium

• US 6,689,291 B1
• Filed: 04/08/1994
• Issued: 02/10/2004
• Est. Priority Date: 04/09/1993
• Status: Active Grant

• Current Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Original Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Inventors: Pauluth, Detlet, Reiffenrath, Volker, Plach, Herbert
• Primary Examiner(s): KELLY, CYNTHIA HARRIS
• Application Number:
  US08/225,267
• Time in Patent Office: 3,595 Days
• Field of Search: 252/299.63, 252/299.66
• US Class Current: 252/299.63
• CPC Class Codes: C07C 25/18 Polycyclic aromatic halogenated hydrocarbons
• CPC Class Codes: C07C 25/24 Halogenated aromatic hydrocarbons with unsaturated side chains
• CPC Class Codes: C07C 255/50 to carbon atoms of non-condensed six-membered aromatic rings
• CPC Class Codes: C07C 2601/14 The ring being saturated
• CPC Class Codes: C07C 2601/16 the ring being unsaturated
• CPC Class Codes: C07C 43/215 having unsaturation outside the six-membered aromatic rings
• CPC Class Codes: C07C 43/225 containing halogen
• CPC Class Codes: C07D 213/26 Radicals substituted by halogen atoms or nitro radicals
• CPC Class Codes: C07D 213/30 Oxygen atoms
• CPC Class Codes: C07D 213/84 Nitriles
• CPC Class Codes: C07D 239/26 with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to ring carbon atoms
• CPC Class Codes: C07D 239/28 with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, directly attached to ring carbon atoms
• CPC Class Codes: C09K 19/3098 Unsaturated non-aromatic rings, e.g. cyclohexene rings
• CPC Class Codes: C09K 19/3444 the heterocyclic ring being a six-membered aromatic ring containing one nitrogen atom, e.g. pyridine
• CPC Class Codes: C09K 19/3469 Pyrimidine with a specific end-group other than alkyl, alkoxy or -C*-

Abstract

A liquid-crystalline medium based on a mixture of polar compound shaving positive dielectric anisotropy, characterized in that it contains one or more fluorophenylcyclohexene derivatives of the formula I

in which

R is H, an unsubstituted alkyl or alkenyl radical having up to 18 carbon atoms, in which one or more non-adjacent CH₂ groups are optionally replaced by —O—, —S—, —CO—, —O—CO—, —CO—O— or —C≡C—,

X is CN or Q—Y,

Y is H, F or Cl,

Q is —CF₂—, —CHF—, —OCF₂—, —OCHF—, —OCH₂CF₂—, —CH═CF—, —CF═CH—, —CF═CF—, —O—CF═CF—, —O—CH═CF— or a single bond,

m is 0 or 1, and

n is 0, 1 or 2.

Claims

1. A liquid-crystalline medium based on a mixture of polar compounds having positive dielectric anisotropy, comprising at least one fluorophenylcyclohexene derivative of formula I

wherein

R is H, an unsubstituted alkyl or alkenyl radical having up to 18 carbon atoms, in which one or more non-adjacent CH₂ groups are optionally replaced by —

O—

, —

S—

, —

CO—

, —

O—

CO—

, —

CO—

O—

or —

C≡

C—

,

X is CN or Q—

Y,

Y is H, F or Cl,

Q is —

CF₂—

, —

CHF—

, —

OCF₂—

, —

OCHF—

, —

OCH₂CF₂—

, —

CH═

CF—

, —

CF═

CH—

, —

CF═

CF—

, —

O—

CF═

CF—

, —

O—

CH═

CF—

or a single bond,

m is 0 or 1, and

n is 0, 1 or 2.

2. A medium according to claim 1, further comprising at least one compound of formulae II, III or IV:

wherein

R⁰ is alkyl, oxaalkyl, fluoroalkyl or alkenyl, in each case having up to 7 carbon atoms,

X⁰ is F, Cl, CF₃, OCF₃, OCHF₂ or CN,

Y¹ and Y² are each, independently of one another, H or F, and

r is 0 or 1.

3. A medium according to claim 1, further comprising at least one compound of general formula V to VIII:

wherein

R⁰ is alkyl, oxaalkyl, fluoroalkyl or alkenyl, in each case having up to 7 carbon atoms,

X⁰ is F, Cl, CF₃, OCF₃, OCHF₂ or CN,

Y¹ and Y² are each, independently of one another, H or F, and

r is 0 or 1.

4. A medium according to claim 1, further comprising at least one compound of formulae IX to XII:

wherein

R⁰ is alkyl, oxaalkyl, fluoroalkyl or alkenyl, in each case having up to 7 carbon atoms,

X⁰ is F, Cl, CF₃, OCF₃, OCHF₂ or CN, and

Y¹ and Y² are each, independently of one another, H or F.

5. A medium according to claim 1, further comprising at least one compound of formulae XIII to XV:

R⁰ is alkyl, oxaalkyl, fluoroalkyl or alkenyl, in each case having up to 7 carbon atoms, and

X⁰ is F, Cl, CF₃, OCF₃, OCHF₂ or CN.

6. A medium according to claim 2, wherein the proportion of compounds of the formulae I to IV together in the total mixture is at least 50% by weight.

7. A medium according to claim 1, wherein the proportion of compounds of the formula I in the total mixture is 10 to 50% by weight.

8. A medium according to claim 2, wherein the proportion of compounds of formulae II to IV in the total mixture is 30 to 70% by weight.

10. A liquid-crystalline medium according to claim 1, comprising a fluorophenylcyclohexene derivative of the formula

wherein

L is H or F.

11. A liquid-crystalline medium according to claim 1, comprising a fluorophenylcyclohexene derivative of formula I2

12. An electro-optical liquid-crystal display containing a liquid-crystalline medium according to claim 1.

13. A medium according to claim 1, wherein

is

X is Q—

Y, Y is F and Q is a single bond.

9. A liquid-crystalline medium, consisting essentially of at least one compound of formula I

wherein

R is H, an unsubstituted alkyl or alkenyl radical having up to 18 carbon atoms, in which one or more non-adjacent CH₂ groups are optionally replaced b —

O—

, —

S—

, —

CO—

, —

O—

CO—

, —

CO—

O—

, or —

C≡

C,

X is CN or Q—

Y,

Y is H, F or Cl,

Q is —

CF₂—

, —

CHF—

, —

OCF₂—

, —

OCHF—

, —

OCH₂CF₂—

, —

CH═

CF—

, —

CF═

CH—

, —

CF═

CF—

, —

O—

CF═

CF—

, —

O—

CH═

CF—

or a single bond,

m is 0 or 1, and

n is 0, 1 or 2,

and at least one compound of formulae II to XV;

 

wherein

R⁰ is alkyl, oxaalkyl, fluoroalkyl or alkenyl, in each case having up to 7 carbon atoms,

X⁰ is F, Cl, CF₃, OCF₃, OCHF₂ or CN,

Y¹ and Y² are each, independently of one another, H or F, an

r is 0 or 1.