Bimesogenic Compounds And Flexoelectric Devices

• US 20080142758A1
• Filed: 11/28/2005
• Published: 06/19/2008
• Est. Priority Date: 12/23/2004
• Status: Active Grant

• Current Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Original Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Inventors: Golding, Kevin, Saxton, Patricia Eileen, Duffy, Warren, Aldem, Kevin
• Granted Patent: US 7,544,400 B2
• Time in Patent Office: Days
• US Class Current: 252/299.63
• CPC Class Codes: C09K 19/0258 Flexoelectric
• CPC Class Codes: C09K 19/04 characterised by the chemical structure of the liquid crystal components , e.g. by a specific unit
• CPC Class Codes: C09K 19/20 linked by a chain containing carbon and oxygen atoms as chain links, e.g. esters or ethers
• CPC Class Codes: C09K 19/3066 in which the rings are linked by a chain containing carbon and oxygen atoms, e.g. esters or ethers
• CPC Class Codes: C09K 19/42 Mixtures of liquid crystal compounds covered by two or more of the preceding groups C09K19/06 - C09K19/40
• CPC Class Codes: C09K 2019/0444 characterized by a linking chain between rings or ring systems, a bridging chain between extensive mesogenic moieties or an end chain group
• CPC Class Codes: C09K 2019/0466 the linking chain being a -CF2O- chain
• CPC Class Codes: C09K 2323/00 Functional layers of liquid crystal optical display excluding electroactive liquid crystal layer characterised by chemical composition

Abstract

The invention relates to bimesogenic compounds of formula (I): R¹-MG-X-Sp-X²-MG-R² wherein R¹, R², MG¹, MG², X¹, X² and Sp have the meaning given in claim 1, to the use of bimesogenic compounds of formula (I) in liquid crystal media and devices, in particular in flexoelectric liquid crystal devices, to liquid crystal media and devices, in particular flexoelectric devices, comprising bimesogenic compounds of formula (I) and to improvements in flexoelectric devices.

Claims

1. Bimesogenic compounds of formula I

R¹-MG¹-X¹-Sp-X²-MG²-R²

wherein

R¹ and R² are each independently F, Cl, CN, NCS or a straight-chain or branched alkyl group with 1 to 25 C atoms which may be unsubstituted, mono- or polysubstituted by halogen or CN, it being also possible for one or more non-adjacent CH₂ groups to be replaced, in each case independently from one another, by —

O—

, —

S—

, —

NH—

, —

N(CH₃)—

, —

CO—

, —

COO—

, —

OCO—

, —

O—

CO—

O—

, —

S—

CO—

, —

CO—

S—

, —

CH═

CH—

, —

CH═

CF—

, —

CF═

CF—

or —

C≡

C—

in such a manner that oxygen atoms are not linked directly to one another,

MG¹ and MG² are each independently a mesogenic group,

Sp is a spacer group comprising 4 to 40 C atoms, wherein one or more non-adjacent CH₂ groups may also be replaced by —

O—

, —

S—

, —

NH—

, —

N(CH₃)—

, —

CO—

, —

O—

CO—

, —

S—

CO—

, —

O—

COO—

, —

CO—

S—

, —

CO—

O—

, —

CH(halogen)—

, —

CH(CN)—

, —

CH═

CH- or —

C≡

C—

,

X¹ and X² are each independently —

O—

, —

S—

, —

CO—

, —

COO—

, —

OCO—

, —

O—

CO—

O—

, —

CO—

NH—

, —

NH—

CO—

, —

CH₂CH₂—

, —

OCH₂—

, —

CH₂O—

, —

SCH₂—

, —

CH₂S—

, —

CH═

CH—

, —

CH═

CH—

COO—

, —

OCO—

CH═

CH—

, —

C≡

C—

or a single bond, characterised in that

at least one of the mesogenic groups MG¹ and MG² comprises one or more linking groups selected from —

CF₂O— and

—

OCF₂—

.

2. Bimesogenic compounds according to claim 1, characterized in that MG¹ and MG² are selected of formula II

-A¹-(Z¹-A²)_m- 

 

II

wherein

in at least in one of MG¹ and MG² at least one of

Z¹ —

CF₂O—

, or —

OCF₂— and

the other

Z¹ are, in each case independently, —

COO—

, —

OCO—

, —

O—

CO—

O—

, —

OCH₂—

, —

CH₂O—

, —

CH₂CH₂—

, —

(CH₂)₄—

, —

CF₂CF₂—

, —

CH₂CF₂—

, —

CF₂CH₂—

, —

CH═

CH—

, —

CF═

CF—

, —

CH═

CH—

COO—

, —

OCO—

CH═

CH—

, —

C≡

C—

, —

CF₂O—

, —

OCF₂—

or a single bond,

A¹ and A² are each independently 1,4-phenylene, wherein in addition one or more CH groups may be replaced by N, trans-1,4-cyclohexylene in which, in addition, one or two non-adjacent CH₂ groups may be replaced by O and/or S, 1,4-cyclohexenylene, 1,4-bicyclo-(2,2,2)-octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydro-naphthalene-2,6-diyl, 1,2,3,4-tetrahydro-naphthalene-2,6-diyl, cyclobutane-1,3-diyl, spiro[3,3]heptane-2,6-diyl or dispiro[3,1,3,1] decane-2,8-diyl, it being possible for all these groups to be unsubstituted, mono-, di-, tri- or tetrasubstituted with F, Cl, CN or alkyl, alkoxy, alkylcarbonyl or alkoxycarbonyl groups with 1 to 7 C atoms, wherein one or more H atoms may be substituted by F or Cl,

m is 0, 1, 2 or 3.

3. Bimesogenic compounds according claim 1, characterized in that one of MG¹ and MG² is or both of them are selected independently of each other from the group of the following formulae II a to II j and their respective mirror images

4. Bimesogenic compounds according to claim 1, characterized in that R¹ and R² are selected from F, Cl, CN, NO₂, OCH₃, COCH₃, COC₂H₅, COOCH₃, COOC₂H₅, CF₃, C₂F₅, OCF₃, OCHF₂, and OC₂F₅.

5. Bimesogenic compounds according to claim 1, characterized in that Sp is —

(CH₂)_o— and

o is an integer from 5 to 15.

6. Use of bimesogenic compounds according to claim 1 in liquid crystalline media and liquid crystal devices.

7. Liquid crystalline medium comprising at least two components, at least one of which is a bimesogenic compound according to claim 1.

8. Liquid crystal device with a liquid crystalline medium comprising at least two components, at least one of which is a bimesogenic compound according to claim 1.

9. Liquid crystal device according to claim 8, characterized in that it is a flexoelectric device.

10. Liquid crystal device according to claim 8, characterized in comprises two plane parallel electrodes the inner surfaces of which exhibit hybrid alignment conditions.