Optically active bis-dioxane derivatives

Details Optically active bis-dioxane derivatives Optically active bis-dioxane derivatives

1996-12-02

2001-05-01

Stockton, Laura L. (Department: 1626)

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

C252S299610

Reexamination Certificate

active

06225479

ABSTRACT:

FIELD OF THE INVENTION
The invention relates to optically active bis-methyldioxanes, liquid crystalline mixtures which contain such compounds, the use of such compounds and mixtures for optical and electro-optical devices, and electro-optical devices containing one or more of such compounds.
BACKGROUND OF THE INVENTION
Liquid crystals are used primarily as dielectrics in display devices, since the optical properties of such substances can be influenced by an applied voltage. Electro-optical devices based on liquid crystals are known and are based on various effects. Such devices are, for example, cells having dynamic scattering, DAP cells (deformation of aligned phases), guest/host cells, TN cells having a “twisted nematic” structure, STN cells (“super twisted nematic”), SBE cells (“super birefringence effect”) and OMI cells (“optical mode interference”). Displays having a high content of information actively controlled cells, for example, TFT cells (“thin film transistor”), have in particular recently become important in addition to the passively controlled, multiplexed cells. In addition to the aforementioned cell types, which are based on the use of nematic or cholesteric liquid crystals, cell types which are based on the principle of chiral tilted smectic phases are known. Thereto there belong SSF cells (surface stabilized ferroelectric), SBF cells (short-pitch bistable ferroelectric) or DHF cells (deformed helix ferroelectric). For these cells types there are generally preferred as tilted smectic phases chiral smectic C (S
C
*) phases, which permit especially large response speeds.
Materials for display devices based on chiral tilted smectic phases can preferably consist of a material having a tilted smectic phase, usually a S
C
phase, and one or more optically active dopants. The use of such chiral dopants in ferroelectric liquid crystals primarily serves to produce or alter a twisting of the tilted smectic phase and to induce a spontaneous polarization. The chiral dopants should have an adequate thermal and photochemical stability, should have a good compatibility with the tilted smectic liquid crystals, should have a viscosity which is as low as possible and should not limit the mesophase range too severely. Further, a spontaneous polarization which is as high as possible and, depending on the cell type, a rather small twisting capacity (SSF cells) or a twisting capacity which is as high as possible (SBF, DHF cells) is desirable.
As chiral dopants there also come into consideration in principle compounds which themselves have no tilted phase or generally no mesophase. This is especially frequent in the case of dopants having a very high twisting capacity. However, such dopants usually have the disadvantage that they severely narrow the tilted phase range of post mixtures to which they are added. Accordingly, dopants have been sought which do not have this disadvantage or which have this disadvantage only to a small extent.
SUMMARY OF THE INVENTION
Compounds having the formula
wherein
R
1
and R
2
each independently are alkyl or alkenyl; alkyl or alkenyl in which one methylene group is replaced by —O—, —COO—, or —OOC—; alkyl or alkenyl in which two non-adjacent methylene groups are replaced by —O—, —COO—, or —OOC—; alkyl or alkenyl in which at least one hydrogen atom is replaced by fluorine, chlorine, or cyano; alkyl or alkenyl in which one methylene group is replaced by —O—, —COO—, or —OOC— and at least one hydrogen atom is replaced by fluorine, chlorine, or cyano; or alkyl or alkenyl in which two non-adjacent methylene groups are replaced by —O—, —COO—, or —OOC— and at least one hydrogen atom is replaced by fluorine, chlorine or cyano;
one of rings A, B and C is a 1,4-phenylene which is unsubstituted or substituted with 1 or 2 fluorine atoms, pyridine-2,5-diyl or pyrimidine-2,5-diyl and the other two rings each independently are 1,4-phenylene which is unsubstituted or substituted with 1 or 2 fluorine atoms or trans-1,4-cyclohexylene;
Z
1
and Z
4
each independently are a single bond, —CH
2
CH
2
—, —CH
2
O—, —OCH
2
—, —C≡C—, —(CH
2
)
4
—, —(CH
2
)
3
O—, —O(CH
2
)
3
—, —CH═CH—CH
2
O—, —OCH
2
—CH═CH—, —CH═CH—(CH
2
)
2
— or —(CH
2
)
2
CH═CH—, with the proviso that the oxygen atom is not linked directly with the chiral dioxane ring;
Z
2
and Z
3
each independently are a single bond, —CH
2
—CH
2
—, —O—CH
2
—, —CH
2
—O—, —COO—, —OOC—, —C≡C—, —(CH
2
)
4
—, —O(CH
2
)
3
—, —(CH
2
)
3
O—, —CH═CH—CH
2
O—, —OCH
2
—CH═CH—, —(CH
2
)
2
—CH═CH— or —CH═CH—(CH
2
)
2
—; and
R* and S* signify that the denoted carbon have the (R) configuration or its optical antipode or the (S) configuration or its optical antipode.
The compounds of formula I, which have a high twisting capacity and a comparatively high spontaneous polarization, also have mostly smectic mesophases, partially even S
C
* phases at comparatively high temperatures. In mixtures with S
C
basic mixtures they give rise to no lowering or only to a relatively small lowering of the S
C
* phase. In spite of their basic structure comprising five rings they have a surprisingly good solubility in S
C
basic mixtures. Having regard to these properties, they are suitable as dopants for use in ferroelectric cells, especially in DHF cells. Moreover, they can also be used for cholesteric mixtures, especially in applications as cholesteric filters or as polarizers.
DETAILED DESCRIPTION OF THE INVENTION
R
1
and R
2
embrace straight-chain and branched (optionally chiral) groups such as alkyl, 2-alkenyl, 3-alkenyl, 4-alkenyl, alkenyl having a terminal double bond, alkoxyalkyl, alkenyloxyalkyl, alkylcarbonyloxyalkyl, alkoxycarbonylalkyl, fluoroalkyl, difluoroalkyl, trifluoroalkyl, chloroalkyl, cyanoalkyl, 1-methylalkyl, 2-methylalkyl and the like, in each case with a maximum of 16 carbon atoms, preferably a maximum of 12 carbon atoms. Examples of preferred groups are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, 1-methylpropyl, 1-methylheptyl, 2Z-pentenyl, 2Z-hexenyl, 2Z-heptenyl, 2Z-octenyl 3E-pentenyl, 3E-hexenyl, 3E-heptenyl, 3E-octenyl, 5E-octenyl, 3-butenyl, 4-pentenyl, 5-hexenyl, 6-heptenyl, 7-octenyl, methoxyethyl, methoxypropyl, methoxybutyl, ethoxyethyl, propyloxyethyl, 2-fluoropropyl, 2-fluoropentyl, 2-fluorooctyl, 2-chlorohexyl, 2-chlorooctyl and the like.
The term “1,4-phenylene which is unsubstituted or substituted with 1 or 2 fluorine atoms” signifies 1,4-phenylene, 2- or 3-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,6- or 3,5-difluoro-1,4-phenylene. Preferred fluorine-substituted rings are 2- or 3-fluoro-1,4-phenylene or 2,3-difluoro-1,4-phenylene.
Preferred compounds of formula I are those in which Z
1
and Z
4
signify a single bond, —CH
2
CH
2
—, —CH
2
O— or —OCH
2
—; and Z
2
and Z
3
signify a single bond, —CH
2
CH
2
—, —CH
2
O—, —OCH
2
—, —COO— or —OOC—, with the oxygen atom present in groups Z
1
to Z
4
preferably being linked with an aromatic ring. In especially preferred compounds, no more than two of the groups Z
1
, Z
2
, Z
3
and Z
4
are other than a single bond.
Also, preferred compounds of formula I are those in which rings A, B and C each independently signify 1,4-phenylene, 2- or 3-fluoro-1,4-phenylene or 2,3-difluoro-1,4-phenylene; or one of rings A, B and C signifies 1,4-phenylene, 2- or 3-fluoro-1,4-phenylene or 2,3-difluoro-1,4-phenylene and the other two rings each independently signify 1,4-trans-cyclohexylene, 1,4-phenylene, 2- or 3-fluoro-1,4-phenylene or 2,3-difluoro-1,4-phenylene.
Quite especially preferred compounds are those of the formulas
wherein
R
11
and R
21
each independently are C
1
-C
12
alkyl or C
2
-C
12
alkenyl; or C
1
-C
12
alkyl or C
2
-C
12
alkenyl in which one methylene group is replaced by —O—, —COO— or —OOC—;
Z
11
, Z
33
and Z
41
each independently are a single bond or —CH
2
CH
2
—;
Z
21
and Z
31
each independently are a single bond, —COO— or —OOC—;
Z
22
and Z
32
each independently are a single bond, —CH
2
CH
2
— or —OCH
2
—;
Z
23
is a single bond, —CH
2
CH
2
—

Affiliated with

Also associated with

Rating

Optically active bis-dioxane derivatives does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Optically active bis-dioxane derivatives, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optically active bis-dioxane derivatives will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2442789