Dopants

{
  "publication_number": "US6056893A",
  "country": "US",
  "kind": "A",
  "title": "Dopants",
  "abstract": "A dopant compound of the formula I R.sup.1 -(A.sup.1 -Z.sup.1).sub.n -A.sup.2 -W I in which ##STR1## and R 1, A 1, A 2, Z 1 n, X and R a are as defined in claim 1, and to the use thereof as chiral dopants in liquid-crystalline media for electro-optical displays, and to electro-optical displays containing such media.",
  "claims": [
    "1. A dopant compound of the formula I R.sup.1 -(A.sup.1 -Z.sup.1).sub.n -A.sup.2 -W I in which W is ##STR259## X is --C═C--Y or --CH═CH--Y, Y is a) H or an alkyl or alkenyl radical having 1-15 carbon atoms which are unsubstituted, monosubstituted by CN or CF 3 or monosubstituted to perhalo-substituted by halogen, where one or more CH 2 groups in these radicals are optionally replaced, in each case independently of one another, by --O--, --CO-- or --CO--O-- in such a way that heteroatoms are not linked directly to one another, or b) a phenylene radical in which one or two CH groups are optionally replaced by N and which is unsubstituted or substituted one or more times by CN, Cl or F or by an alkyl, alkenyl or alkoxy radical having 1 to 8 carbon atoms, in which one or more H atoms are optionally replaced by F atoms, R a is a straight-chain alkyl radical having 1-15 carbon atoms R 1 is H or an alkyl or alkenyl radical having 1-15 carbon atoms which is unsubstituted, monosubstituted by CN or CF 3 or monosubstituted to perhalosubstituted by halogen, where one or more CH 2 groups in these radicals may optionally replaced, in each case independently of one another by --O--, --S--, --CO--, --CO--O--, --O--CO-- or --O--CO-- --O-- in such a way that heteroatoms are not linked directly to one another, A 1 and A 2, in each case independently of one another, are a a) trans-1,4-cyclohexylene radical, in which one or more nonadjacent CH 2 groups are optionally replaced by --O-- and/or --S--, b) 1,4-cyclohexenylene radical, c) 1,4-phenylene radical, in which one or two CH groups are optionally replaced by N, d) radical from the group consisting of 1,4-bicyclo[2.2.2]octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl and 1,2,3,4-tetrahydronaphthalene-2,6-diyl, where the radicals a), b) and c) are optionally substituted by CN, Cl, F or an alkyl or alkenyl radical having 1 to 5 carbon atoms, Z 1 is --CO--O--, --O--CO--, --CH 2 O--, --O--CH 2 --, --CH 2 CH 2, --CH═CH--, --C--C-- or a single bond, and n is 0, 1, 2 or 3, with the proviso that, in the case where A 2 is unsubstituted 1,4-phenylene and X is C.tbd.CH, Alis not 1,4-phenylene in which one or two CH groups are optionally replaced by N.",
    "2. A dopant compound according to claim 1 of the formula I2 ##STR260## in which R 1 and W are as defined, and L 1, L 2, L 3 and L 4 are independently H, Cl or F.",
    "3. A dopant according to claim 1 of the formula 16 ##STR261## in which R 1 and W are as defined, and L 1, L 2, L 3 and L 4 are independently H, Cl or F.",
    "4. A dopant compound according to claim 1, in which X is --C.tbd.C--H, --CH═CH 2 or ##STR262##.",
    "5. A dopant compound according to claim 1, in which W is of the formula (1) ##STR263## and p is 3, 4, 5, 6 or 7.",
    "6. A dopant compound according to claim 1, in which W is of the formula (2) ##STR264## and p is 3, 4, 5, 6 or 7.",
    "7. A dopant compound according to claim 1, in which W is of the formula (3) ##STR265## and p is 3, 4, 5, 6 or 7.",
    "8. A liquid-crystalline medium, which comprises at least one dopant compound according to claim 1.",
    "9. A liquid-crystalline medium according to claim 8, wherein the medium has a chiral tilted smectic phase.",
    "10. A liquid-crystalline medium according to claim 8, wherein the dopant concentration is from 0.001% by weight to 40-- by weight.",
    "11. A liquid-crystalline medium according to claim 9, wherein the dopant concentratio is from 0.1% by weight to 40% by weight.",
    "12. A liquid-crystalline medium according to claim 10, wherein the dopant concentration is from 0.001% by weight to 15% by weight.",
    "13. An electro-optical display, which contains a liquid-crystalline medium according to claim 8.",
    "14. A liquid crystalline medium according to claim 11, wherein, within the range of from 0° C. to 50° C., the cholesteric pitch of the medium has a temperature dependence of from 0.1% to 10% per °C.",
    "15. A liquid crystalline medium according to claim 12, wherein, within the range of from 0° C to 50° C., the cholesteric pitch of the medium has a temperature dependence of from 0.1% to 10% per °C.",
    "16. A liquid crystalline medium according to claim 8, wherein the medium has a temperature dependence of the threshold voltage of less than 0.1%/°C.",
    "17. A liquid crystalline medium according to claim 8, wherein the medium has a temperature dependence of the threshold voltage of from 0.01%/°C. to 0.05%/°C."
  ],
  "cpc": [
    "C09K 19/46",
    "C07C 255/54",
    "C07C 255/55",
    "C07C 2601/14",
    "C07C 43/225",
    "C09K 19/3001",
    "C09K 19/3003",
    "C09K 19/586",
    "C09K 2019/3021"
  ],
  "assignees": [
    "MERCK PATENT GMBH"
  ],
  "filing_date": "1997-10-30",
  "publication_date": "2000-05-02",
  "grant_date": "2000-05-02",
  "priority_date": "1996-10-31",
  "application_number": "US-96155997-A",
  "family_id": "7809758",
  "citations": [
    "US5653911A",
    "US5702642A",
    "US5709911A"
  ]
}