# US 4,400,061 A · Liquid crystal ester compounds exhibiting a low or negative dielectric anisotropy and liquid crystal materials and devices incorporating such compounds

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- Number: US 4,400,061 A
- Document ID: US4400061A
- Status: Granted
- Kind: A
- Application number: 06/229,876
- Filed: 1981-01-30
- Granted: 1983-08-23
- Earliest claimed: 1980-01-30
- Assignees: Her Majesty's Government of the UK.
- Inventors: Neil Carr; George W. Gray; Stephen M. Kelly
- Web page: https://patentgrep.com/patent/US4400061A

## CPC

- C07C 29/00: Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C 29/145: with hydrogen or hydrogen-containing gases
- C07C 37/055: the substituted group being bound to oxygen, e.g. ether group
- C07C 59/347: containing keto groups
- C07C 61/15: Saturated compounds containing halogen
- C07C 255/00: Carboxylic acid nitriles (cyanogen or compounds thereof C01C3/00)
- C09K 19/321: {Compounds containing a bicyclo [2,2,2] octane ring}
- C09K 19/42: Mixtures of liquid crystal compounds covered by two or more of the preceding groups C09K19/06 - C09K19/40
- C07C 2601/14: The ring being saturated
- C07C 2602/44: the bicyclo ring system containing eight carbon atoms
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE

## Abstract

Novel liquid crystal ester compounds exhibiting a low or negative dielectric anisotropy have a structural formula: ##STR1## where R.sub.1 is an alkyl group, R.sub.2 is an alkyl or alkoxy group, ##STR2## is a 1,4-disubstituted bicyclo(2,2,2) octane ring and ##STR3## is a 1,4-disubstituted ring selected from the following: (i) a 1,4-disubstituted bicyclo(2,2,2) octane ring; (ii) a trans-1,4-disubstituted cyclohexane ring; (iii) a laterally substituted benzene ring ##STR4## where of the two groups Y and Z one is a halogen or a cyano group and the other is hydrogen or a halogen or a cyano group such that Y is the same as Z. These esters may be used in a number of known applications including liquid crystal materials for multiplexed twisted nematic devices. The esters may be made by preparative methods involving known steps.

## Claims

### Claim 1

A liquid crystal ester compound exhibiting a negative dielectric anisotropy having the structural formula: ##STR58## where R.sub.1 is an alkyl group; R.sub.2 is an alkyl or alkoxy group; ##STR59## is a 1,4-disubstituted bicyclo(2.2.2) octane ring; ##STR60## is a 1,4-disubstituted benzene ring; Y is a group selected from the class consisting of halogen and cyano; and
Z is a group selected from the class consisting of hydrogen, halogen and cyano;
provided that where Z is other than hydrogen it is the same as Y.

### Claim 2 (depends on 1)

A compound as claimed in claim 1 and wherein the groups R.sub.1 and R.sub.2 are n-alkyl groups having between 1 and 12 carbon atoms inclusive.

### Claim 3 (depends on 2)

A compound as claimed in claim 2 and wherein Z is the same as Y.

### Claim 4 (depends on 1)

A compound as claimed in claim 1 and wherein the group ##STR61##

### Claim 5 (depends on 1)

A compound as claimed in claim 1 and wherein the group ##STR62##

### Claim 6 (depends on 1)

A compound as claimed in claim 1 and wherein the group ##STR63##

### Claim 7 (depends on 1)

A compound as claimed in claim 1 and wherein the group R.sub.1 is an n-alkyl group having between 1 and 12 carbon atoms inclusive and the group R.sub.2 is (+)-2 methylbutyl.

### Claim 8 (depends on 1)

A liquid crystal composition comprising a mixture of liquid crystal compounds and wherein the improvement comprises at least one of said compounds being a compound as claimed in claim 1.

### Claim 9 (depends on 8)

A liquid crystal electro-optic display comprising two dielectric substrates at least one of which is optically transparent, a layer of liquid crystal material sandwiched between the substrates and electrodes on the inner surfaces of the substrates to enable an electric field to be applied across the layer of liquid crystal material to provide an electro-optic effect therein, and wherein the improvement comprises said liquid crystal material being a liquid crystal composition as claimed in claim 8.