U.S. patent application number 09/919908 was filed with the patent office on 2002-01-31 for naphthyl organic compounds.
Invention is credited to Day, Sally Elizabeth, Goodby, John William, Gray, George William, Harrison, Kenneth John, Hird, Michael, McDonnel, Damien Gerad, Raynes, Edward Peter, Seed, Alexander, Toyne, Kenneth Johnson.
Application Number | 20020011588 09/919908 |
Document ID | / |
Family ID | 26298580 |
Filed Date | 2002-01-31 |
United States Patent
Application |
20020011588 |
Kind Code |
A1 |
Toyne, Kenneth Johnson ; et
al. |
January 31, 2002 |
Naphthyl organic compounds
Abstract
A liquid crystalline compounds:
R.sub.1--A--(X).sub.m--(B).sub.n--R.sub.2 are described where A is
naphthyl, fluorinated naphthyl or brorninated naphthyl; B is
phenyl, methylated phenyl, brominated phenyl, fluorinated phenyl or
pyrimidine; R.sub.1 and R.sub.2 are independently C.sub.1-15 alkyl,
alkoxy, alkynyl, thioalkyl, perfluoroalkyl, perfluoroalkoxy or Br,
CN, SCN, NCS and hydrogen; X is COO or C.dbd.C, m is 0 or 1, and n
is 1.
Inventors: |
Toyne, Kenneth Johnson;
(Humberside, GB) ; Goodby, John William;
(Humberside, GB) ; Seed, Alexander; (Humberside,
GB) ; Gray, George William; (Dorset, GB) ;
McDonnel, Damien Gerad; (Worcestershire, GB) ;
Raynes, Edward Peter; (Worcestershire, GB) ; Day,
Sally Elizabeth; (Worcestershire, GB) ; Harrison,
Kenneth John; (Worcestershire, GB) ; Hird,
Michael; (Humberside, GB) |
Correspondence
Address: |
NIXON & VANDERHYE P.C.
8th Floor
1100 North Glebe Road
Arlington
VA
22201-4714
US
|
Family ID: |
26298580 |
Appl. No.: |
09/919908 |
Filed: |
August 2, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09919908 |
Aug 2, 2001 |
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09150737 |
Sep 10, 1998 |
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6291034 |
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09150737 |
Sep 10, 1998 |
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08470153 |
Jun 6, 1995 |
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5820781 |
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08470153 |
Jun 6, 1995 |
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08243714 |
Jul 10, 1995 |
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08243714 |
Jul 10, 1995 |
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08002396 |
Jan 13, 1993 |
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08002396 |
Jan 13, 1993 |
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PCT/GB92/00411 |
Mar 9, 1992 |
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Current U.S.
Class: |
252/299.62 ;
252/299.61; 252/299.66 |
Current CPC
Class: |
C07D 333/24 20130101;
C07D 333/20 20130101; C09K 19/322 20130101; C07C 323/62 20130101;
C07C 331/28 20130101; C09K 2323/00 20200801; Y10T 428/10 20150115;
C09K 19/3461 20130101; C09K 19/3441 20130101; C07D 239/26 20130101;
C09K 19/3497 20130101; C09K 19/544 20130101; C07C 255/54 20130101;
C09K 19/3458 20130101; C07C 255/52 20130101 |
Class at
Publication: |
252/299.62 ;
252/299.61; 252/299.66 |
International
Class: |
C09K 019/32; C09K
019/34; C09K 019/12 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 13, 1991 |
GB |
9105359.5 |
Claims
1. A liquid crystalline compound characterised by formula I are
provided; R.sub.1--A--(X).sub.m--(B).sub.n--R.sub.2 Formula Iwhere
A is selected from nathyl, fluorinated naphthyl, brominated
naphthyl. B is selected from phenyl, methylated phenyl, brominated
phenyl, fluorinated phenyl, thiophene, pyrimidine and pyridine,
R.sub.1 and R.sub.2 are independently selected from alkyl, alkoxy,
alkynyl, thioalkyl, Br, CN, SCN, NCS, perfluoroalkyl,
perfluoroalkoxy and hydrogen, X is selected from C.ident.C, COO and
C.dbd.C, m is 0 or 1, n is 0 or 1 where m is 1 and n is 0 where m
is 0; provided that where A is naphthyl, n is 1 and m is 0 then B
is selected from methylated phenyl, brominated phenyl, thiophene,
pyrimidne and pyridine; and further provided that where A is
naphthyl, X is C.ident.C, m is 1 and n is 1, then B is selected
from thiophene, pyrimidine and pyridine.
2. A compound according to claim 1 where at least one of terminal
groups R.sub.1 and R.sub.2 is selected from alkyl, alkoxy, alkynyl
and thioalkyl.
3. A compound according to claim 2 where at least one of the
termianl groups is straight chain.
4. A compound according to claim 1 where B is thiophene and A is
naphthyl.
5. A compound according to claim 4 where m is 1 and X is
C.ident.C.
6. A compound according to claim 5 where at least one of the
terminal groups is alkynyl.
7. A compound according to claim 5 where at least one of the
terminal groups is NCS.
8. A compound according to claim 5 where at least one of the
terminal groups is thioalkyl.
9. A compound according to claim 5 where at least one of the
terminal groups is CN.
10. A compound according to claim 6 where one of the terminal
groups is NCS and the other is alkynyl.
11. A compound according to claim 4 where m is 0.
12. A compound according to claim 11 where at least one of the
terminal groups is alkynyl.
13. A compound according to claim 11 where at least one of the
terminal groups is NCS.
14. A compound according to claim 11 where at least one of the
terminal groups is CN.
15. A compound according to claim 11 where at least one of the
terminal groups is thioalkyl.
16. A compound according to claim 1 where B is pyrimidyl and A is
naphtlhyl.
17. A compound according to claim 16 where m is 1 and X is
C.ident.C.
18. A compound according to claim 17 where at least one of the
terminal groups is NCS.
19. A compound according to claim 16 where m is 0.
20. A compound according to claim 19 where at least on of the
terminal groups is alkynyl.
21. A compound according to claim 1 where A is naphthyl, B is
phenyl, m is 1, X is C.dbd.C and at least one of the terminal
groups is NCS.
22. A compound according to claim 21 where R.sub.2 is NCS and
R.sub.1 is alkoxy.
23. A liquid crystalline material, being a mixture of compounds,
and characterised in that it comprises at least one compound
according to claim 1.
24. A liquid crysatlline material, being a mixture of compounds,
and characterised in that it comprises at least on compound of
claims 1 to 22.
25. A material according to claim 23 and further characterised in
that it comprises at least on compound of formula III 23here
R.sub.1 is selected from a group comprising hydrogen, alkyl,
alkoxy, alkynyl, thioalkyl, CN, and Br; R.sub.2 is selected from a
group comprising hydrogen, NCS, SCN, CN, alkyl, alkoxy, alkynyl,
and thioalkyl; m and n are 1 or 0 such that m is 1 where n is 0 and
m is 0 where n is 1 or 0; p is independently 1 or 0; X is selected
from a group comprising of naphthyl, fluorinated naphthyl and
brominated naphthyl; and Y is selected from a group comprising of
phenyl, methylated phenyl, brominated phenyl, thiophene and
pyrimidine and pyridine.
26. A material according to claim 23 and further characterised in
that it comprises at least one compound of formula IV 24where
R.sub.A is selected from CN, alkyl and alkoxy.
27. A material according to claim 23 and further characterised in
that it comprisess at least one compound of formula V 25where
R.sub.1 is C.sub.1-10 n-alkyl or n-alkoxyl and the
fluorosubstituent(s) may be in any one or two of the available
substitution positions.
28. A liquid crystal device characterised in that it uses a
material according to claim 23.
29. A liquid crystal device characterised in that it comprises a
material according to claim 24.
30. A liquid crystal compound characterised in that it is suitable
for inclusion in devices utilising pretransitional characterisitcs
of liquid crystalline materials in the isotropic phase and is given
by formula II R.sub.3--J--(Y).sub.p--(Z).sub.q--R.sub.4 Formula
IIwhere J is selected from nathyl, fluorinated naphthyl, brominated
naphthyl, Z is selected from phenyl, methylated phenyl, brominated
phenyl, fluorinated phenyl, thiophene, pyrimidine and pyridine,
R.sub.1 and R.sub.2 are independently selected from alkyl, alkoxy,
alkynyl, thioalkyl, Br, CN, SCN, NCS, perfluoroalkyl,
perfluoroalkoxy and hydrogen, Y is selected from C.ident.C, COO and
C.dbd.C, p is 0 or 1, q is 0 or 1 where p is 1 and q is 0 where p
is 0;
31. A compound according to claim 30 where at least one of terminal
groups R.sub.3 and R.sub.4 is selected from alkyl, alkoxy, alkynyl
and thioalkyl.
32. A compound according to claim 31 where at least one of the
termianl groups is straight chain.
33. A compound according to claim 30 where Z is thiophene and J is
naphthyl.
34. A compound according to claim 33 where p is 1 and X is
C.ident.C.
35. A compound according to claim 34 where at least one of the
terminal groups is alkynyl.
36. A compound according to claim 34 where at least one of the
terminal groups is NCS.
37. A compound according to claim 34 where at least one of the
terminal groups is thioalkyl.
38. A compound according to claim 34 where at least one of the
terminal groups is CN.
39. A compound according to claim 35 where one of the terminal
groups is NCS and the other is alkynyl.
40. A compound according to claim 33 where p is 0.
41. A compound according to claim 40 where at least one of the
terminal groups is alkynyl.
42. A compound according to claim 40 where at least one of the
terminal groups is NCS.
43. A compound according to claim 40 where at least one of the
terminal groups is CN.
44. A compound according to claim 40 where at least one of the
terminal groups is thioalkyl.
45. A compound according to claim 30 where Y is pyrimidyl and A is
naphthyl.
46. A compound according to claim 45 where p is 1 and X is
C.ident.C.
47. A compound according to claim 46 where at least one of the
terminal groups is NCS.
48. A compound according to claim 45 where p is 0.
49. A compound according to claim 48 where at least on of the
terminal groups is alkynyl.
50. A compound according to claim 30 where J is naphthyl and Y is
phenyl.
51. A compound according to claim 50 where p is 1 and X is
C.dbd.C.
52. A compound according to claim 51 where one of the terminal
groups is NCS.
53. A compound according to claim 50 having a formula 26
54. A compound according to claim 52 having a formula 27
55. A compound according to claim 53 having a formula 28
56. A compound according to claim 54 having a formula 29
57. A compound according to claim 50 where at least one of the
terminal groups is CN.
58. A liquid crystalline material, being a mixture of compounds,
and characterised in that it comprises at least one compound
according to claim 29.
59. A liquid crysatlline material, being a mixture of compounds,
and characterised in that it comprises at least on compound of
claims 29 to 57.
60. A material according to claim 58 and further characterised in
that it comprises at least on compound of formula III 30here
R.sub.1 is selected from a group comprising hydrogen, alkyl,
alkoxy, alkynyl, thioalkyl, CN, and Br; R.sub.2 is selected from a
group comprising hydrogen, NCS, SCN, CN, alkyl, alkoxy, alkynyl,
and thioalkyl; m and n are 1 or 0 such that m is 1 where n is 0 and
m is 0 where n is 1 or 0; p is independently 1 or 0; X is selected
from a group comprising of naphthyl, fluorinated naphthyl and
brominated naphthyl; and Y is selected from a group comprising of
phenyl, methylated phenyl, brominated phenyl, thiophene and
pyrimidine and pyridine.
59. A material according to claim 58 and further characterised in
that it comprises at least one compound of formula IV 31where
R.sub.A is selected from CN, alkyl and alkoxy.
60. A material according to claim 58 and further characterised in
that it comprisess at least one compound of formula V 32where
R.sub.1 is C.sub.1-10 n-alkyl or n-alxoxyl and the
fluorosubstituent(s) may be in any one or two of the available
substitution positions.
63. A liquid crystal device characterised in that it uses a
material according to claim 58.
Description
[0001] This invention relates to compounds containing a naphthyl
group and which have liquid crystalline properties and/or which are
suitable for use as constituents of liquid crystal materials. The
invention also relates to use of such compounds in liquid crystal
materials.
[0002] Liquid crystal materials and devices exploit the
electro-optical propertiesof nematic and cholesteric (N or N*), or
smectic (S) with particularly useful smectic phases being chiral
smectic C (S.sub.c*) or smectic A.
[0003] Liquid crystal materials which show ferroelectric S.sub.c*
phase are useful in fast switching displays such as television or
VDU screens as the S.sub.c* phase can be swithched in a few
milliseconds or even microseconds. The principle of S.sub.c*
switching is described inter alia by N A Clark and S T Lagerwall in
App Phys Lett 36 (1980) p899.
[0004] Materials which show an S.sub.A liquid crystal phase may be
used in display devices which exploit the electroclinic effect.
[0005] The use of liquid crystal materials to exhibit
electro-optical effects in displays and other optical devices such
as digital calculators. watches, meters and alphanumeric laptop
computers is now well known. However, known liquid crystal
materials are not ideal in all respects and a considerable amount
of work is currently being carried out in the art to improve their
properties.
[0006] Liquid crystal materials normally consist of specially
selected mixture compositions and improved materials are often
obtained by forming new mixtures having an improved combination of
properties.
[0007] The composition of a liquid crystal mixture is generally
selected so that the mixture shows desirable properties. In
particular such properties include:
[0008] (1) a liquid crystalline temperature range--including room
temperature (20.degree. C.)--which is as wide as possible;
[0009] (2) a melting point (solid-to-liquid crystal transition
temperature) which is as low as possible;
[0010] (3) a clearing point (liquid crystalline to isotropic liquid
transition temperature) which is as high as possible;
[0011] (4) a positive or negative (as appropriate) dielectric
anisotropy (permittivity measured parallel to the molecular axis
less that measured perpendicular to the molecular axis) which is as
great as possible in order to minimise the display voltage;
[0012] (5) a viscosity which is as low as possible in order to
minimise the display switching speeds;
[0013] (6) an electro-optical response which varies as little as
possible with temperatures;
[0014] (7) a good chemical and photochemical stability;
[0015] Examples of further particular properties useful in specific
applications include:
[0016] (8) a good multiplexability;
[0017] (9) an ability to switch dielectric anisotropy with
frequency;
[0018] (10) a birefringence of selected magnitude;
[0019] (11) specific elastic constants which can be tailored to
meet specific device requirements; and
[0020] (12) high electrical resistivity for certain
applications.
[0021] Liquid crystal materials and devices exploit the
electro-optical properties of nematic or cholesteric (N and N*
respectively), or smectic (S) in particular chiral smectic C
(S.sub.c*) or smectic A (S.sub.a) phase. The most common type of
liquid crystal materials in use are those which show a nematic
phase and these are extensively used in, for example, watches,
clocks, calculators, electronic displays etc.
[0022] For some applications of liquid crystal materials a high
birefringence is sought, eg in so called "electrically controlled
birefringence" (ECB) effect devices (see, for example, M F
Schieckel and K Fahrensohn Applied Physics Letters 19 p2912 1971),
in thin film transistors and supertwisted nematic devices. It is
rare for the requisite desirable properties to be found in a single
liquid crystalline compound and generally liquid crystalline
materials consist of mixtures of component compounds. Very many
liquid crystalline compounds suitable for such uses are known and
will be apparent to those in the art.
[0023] Some liquid crystalline compounds based on the
phenyl-naphthalene system are known eg 1
[0024] For example, Bull Soc Chim Fr 11-12(2) p2521-2426 (1975)
describes compounds where A is alkoxy and B is alkyl or alkoxy, and
Helv Chim Acta 68(5) p1406-1426 describes those in which a is alkyl
or alkoxy and B is cyano or trifluoromethyl.
[0025] It is the aim of this invention to provide novel compounds
which provide improved or alternative liquid crystalline and/or
monotropic characteristics.
[0026] According to this invention, liquid crystal naphthyl
compounds of formula I are provided;
R.sub.1--A--(X).sub.m--(B).sub.nR.sub.2 Formula I
[0027] where A is selected from nathyl, fluorinated naphthyl,
brominated naphthyl, B is selected from phenyl, methylated phenyl,
brominated phenyl, fluorinated phenyl, thiophene, pyrimidine and
pyridine, R.sub.1 and R.sub.2 are independently selected from
alkyl, alkoxy, alkynyl, thioalkyl, Br, CN, SCN, NCS,
perfluoroalkyl, perfluoroalkoxy and hydrogen, X is selected from
C.ident.C, COO and C.dbd.C, m is 0 or 1, n is 0 or 1 where m is 1
and n is 0 where m is 0;
[0028] provided that
[0029] where A is naphthyl, n is 1and m is 0 then B is selected
from methylated phenyl, brominated phenyl, thiophene, pyrimidne and
pyridine;
[0030] and further provided that
[0031] where A is naphthyl, X is C.ident.C, m is 1 and n is 1, then
B is selected from thiophene, pyrimidine and pyridine.
[0032] The preferred embodiments of the invention discussed below
are inter alia chosen with respect to their liquid crystalline
properties. particularly with respect to suitability for use in
high birefringence nematic or ferro-electric Sc* liquid crystal
materials. Preferably for use in nematic materials alkyl, alkoxyl,
thioalkyl and alkynyl substituents R.sub.1 and R.sub.2 contain 1-15
carbon atoms, and more preferably contain 1-5 carbon atoms for use
as nematic materials and 3-9 carbon atoms for use as smectic
materials. Preferably for smectic C materials R.sub.1 and R.sub.2
are selected from n-alkyl or n-alkoxy.
[0033] According to a further aspect of this invention compounds
suitable for inclusion in devices utilising pretransitional
characterisitcs of liquid crystalline materials in the isotropic
phase are provided, of general Formula II
R.sub.3--J--(Y).sub.p--(Z).sub.q--R.sub.4 Formula II
[0034] where J is selected from nathyl, fluorinated naphthyl,
brominated naphthyl, Z is selected from phenyl. methylated phenyl,
brominated phenyl, fluorinated phenyl, thiophene, pyrimidine and
pyridine, R.sub.1 and R.sub.2 are independently selected from
alkyl, alkoxy, alkynyl. thioalkyl, Br, CN, SCN, NCS,
perfluoroalkyl, perfluoroalkoxy and hydrogen, Y is selected from
C.dbd.C, COO and C.ident.C, p is 0 or 1, q is 0 or 1 where p is 1
and q is 0 where p is 0;
[0035] Typically such compounds can be utilised in devices such as
Optical Kerr Effect devices. Such devices are often used as optical
shutters or optical modulators, and rely on the the fact that
birefringence (.DELTA.n) of a medium being proportional to the
square of an applied electric field. Such an effect is often termed
the quadratic electro-optic effect and can be investigated using
degenerate four wave mixing (P Madden et al IEEE J of Quantum
Electronics QE22 No 8 August 1986 p1287).
[0036] Preferably where R.sub.3 and R.sub.4 are selected from
C.sub.1-15 alkyl, alkoxy, thioalkyl and alkynyl; more preferably
C.sub.1-9 and even more preferably C.sub.3-9.
[0037] Preferred overall structures of formula I and formula II are
now listed: 2
[0038] Naphthyl materials of formula I and formula II may be
generally prepared by various routes which will be apparent to
those in the art. Typical routes which can be used include reaction
of an appropriate phenyl (or equivalent eg thiophene, pyrimidine
etc) boronic acid with an appropriate naphthol triflate.
Alternatively, an appropriate boronic acid can be reacted with such
appropriate compounds as bromonitro-eg acid can be reacted with
such appropriate compounds as bromonitro-eg appropriate benzene,
thiophene residues etc, for CN and NCS terminal groups. Terminal
groups of alkyls, alkoxys, alkynyls and thioalkyls can be achieved
by well known alkylation, 0-alkylation, alkynylation (via
appropriate triflate) and thioalkylation routes respectively.
Naphthyl materials of where m and n are 0 can be prepared from
bromonaphthol by using eg alkylation, thioalkylation etc, and also
be followed by eg cyanation (by use of eg CuCN) etc.
[0039] The invention also provides a liquid crystal material being
a mixture of at least two compounds. at least one of which is a
naphthyl compound of formula I. This material may show a nematic or
smectic (e.g. S.sub.a, S.sub.c* or S.sub.c) charateristics and also
sometimes isotropic properties.
[0040] In particular many naphthyl compounds of formula I have a
high anisotropy in polarisability (.DELTA.a), making them suitable
for applications in which this characteristic is required, as
discussed above. Naphthyl compounds of formula I may be used as
components of nematic liquid crystal materials together with other
liquid crystalline compounds. for example compounds of general
formula III: 3
[0041] where R.sub.1 is selected from a group comprising hydrogen,
alkyl, alkoxy, alkynyl, thioalkyl, CN, and Br; R.sub.2 is selected
from a group comprising hydrogen, NCS, SCN, CN, alkyl, alkoxy,
alkynyl, and thioalkyl; m and n are 1 or 0 such that m is 1 where n
is 0 and m is 0 where n is 1 or 0; p is independently 1 or 0; X is
selected from a group comprising of naphthyl, fluorinated naphthyl
and brominated naphthyl; and Y is selected from a group comprising
of phenyl, methylated phenyl, brominated phenyl, thiophene and
pyrimidine and pyridine.
[0042] The mixture may also contain such materials as phenyl
thiazolenes of typical structure such as that seen in Formula IV
4
[0043] where typically R.sub.3 is CN, alkyl, alkoxy etc.
[0044] Other suitable mixture materials include for example those
of materials described in application Ser. No. 892828.6, where
their use as polymer network materials suitable for eg dispersion
within a matrix of transparent polymer is described.
[0045] The mixture may also contain one or more fluorinated
cyanobiphenyls or terphenyls of formula V: 5
[0046] where R.sub.1 is C.sub.1-10 n-alkyl or n-alkoxyl and the
fluorosubstituent(s) may be in any one or two of the available
substitution positions. Compounds of the formula V are known
(PCT/GB 89/00647) and with their inclusion in mixture, it is
possible to further increase birefringence.
[0047] A nematic liquid crystal of this invention may also contain
one or more optically active compounds to induce a cholestric phase
and one or more pleochroic dyes.
[0048] The materials of this aspect of the invention may be used in
any of the known forms of liquid crystal display devices, for
example a twisted nematic device, Freedricks effect device,
cholesteric memory mode device, cholesteric to nematic phase change
effect device, dynamic scattering effect device, two frequency
switching effect device, a supertwist effect device, or a
thermometer using a thermochromic material. The method of
construction and operation of such devices, and characteristics of
a liquid crystal material suitable for use therein, are well known
in the field. Typically an electro-optical display device will
consist of 2 substrates between which a layer of the liquid crystal
material may be sandwiched. At least one of the substrates is
optically transparent and both have addressable electrodes which
are preferably made of a transparent material on their opposing
faces. By applying an electric field across the layer of liquid
crystal material via the electrodes an electro-optical effect is
achieved which may be viewed directly or preferably through one or
more polarising filters.
[0049] Another aspect of the invention is a material, being a
mixture of compounds, characterised in that the mixture is suitable
for inclusion in devices utilising pretransitional characterisitcs
of liquid crystalline mixtures in the isotropic phase and that the
mixture includes at least one compound of formula II. Such
materials also contain compound(s) of formula III and/or
compound(s) of formula IV and/or compound(s) of formula V.
[0050] Compounds of formula II and also materials including
compound(s) of formula II may be used in devices that utilise the
optical Kerr Effect. Typically optical Kerr effect devices comprise
a glass cell containing two electrodes, where the glass cell is
filled with a polar liquid. The device is frequently termed a Kerr
cell. The Kerr cell can be positioned between two crossed
polarisers having transmisssion axes at .+-.45.degree. to an
electric field applied across the Kerr cell. With zero voltage
applied across the Kerr cell no light will be transmitted and the
cell operates as a closed shutter. Application of a modulating
voltage generates a field causing the Kerr cell to function as a
variable wave plate and thus operating the Kerr cell as a shutter
capable of opening proportionately to the applied field.
[0051] Nematic materials of this invention may be particularly
suitable for use in ECB effect devices, due to the high
birefringence of the materials. They may also be particularly
suitable for use in polymer dispersed liquid crystal (PDLC)
materials in which small droplets of a liquid crystal material are
dispersed within a matrix of a transparent polymer.
[0052] Non-limiting examples illustrating this invention will now
be described with reference to the accompanying figures, of which
FIGS. 1 to 5 schematically show synthetic routes for exemplified
compounds 1 to 5, and FIGS. 6 and 7 are schematic representations
of a liquid crystal device of the invention and a Kerr cell of the
invention.
EXAMPLE 1
Preparation of
[0053] 6
[0054] With reference to FIG. 1 it can be seen that
[0055] Step 1.1 5-Bromo-hydroxpyrimidine
[0056] Bromine (67.00 g, 0.419 mol) is added slowly dropwise to a
stirred solution of 2-hydroxypyrimidine hydrochloride (50.00 g,
0.377 mol) in water (200 ml) at room temperature (exothermic
reaction but no cooling used). The solution is stirred for 1 hour
(until cool) and then water and excess bromine is removed in vacuo
to give a pale yellow solid which is dried in vacuo (0.1 mmHg)
giving 5-Bromo-2-hydroxypyrimidine as a solid which is still
"wet"as a yield of 100 g.
[0057] Step 1.2 5-Bromo-2-chloropyrimidine
[0058] A solution of compound 1.1 (assume 100% yield from previous
preparation; 65.98 g, 0.377 mol) in phosphorous oxychloride (500
ml) and N,N-dimethylaniline (20 ml ) is heated under reflux for 4
hours. the cooled mixture is carefully poured onto ice and
extracted into ether (.times.2). The combined ethereal extracts are
washed with aqueous sodium hydrogen carbonate and dried
(MgSO.sub.4). The solvent is removed in vacuo to yield an off-white
solid. Yield (based on 2-hydroxypyrimidine hydrochloride) is 23.55
g, 32%.
[0059] Step 1.3 2-Chloro-5-pent-1-ynylpyrimidine
[0060] Quantities: pent-1-yne (3.00 g, 0.044 mol), n-butyllithium
(4.40 ml, 10.0M in hexane, 0.044 mol), zinc chloride (6.00 g, 0.044
mol), compound 1.2 (8.00 g, 0.041 mol), tetrakis
(triphenylphosphine)palladium(- O) (1.5 g, 1.30 mol).
[0061] This experimental procedure is a zinc coupling reaction. The
n-butyllithium solution is added dropwise to a stirred, cooled
(-5.degree. C. to 0.degree. C.) solution of the pent-1-yne in dry
THF under dry nitrogen. This mixture is stirred fro 10 minutes and
then a solution of the zinc chloride (dry) in dry THF is added
dropwise at about -5.degree. C. to 0.degree. C. The mixture is
stirred at room temperature for 15 minutes and a solution of
compound 1.2 in dry THF is added dropwise at -5.degree. C. to
0.degree. C. followed by addition of the tetrakis
(triphenylphosphine)palladium(O). the mixture is heated under
reflux for 22 hours (glc analysis revealing a complete reaction).
The crude product is purified by column chromatography [silica
gel/petroleum fraction (bp40-60.degree. C.)- dichloromethane, 1:20]
to give a colourless solid which is crystalised from hexane to
yield colourless crystals.Yield is 6.27 g (85%).
[0062] Step 1.4
2-butoxy-6-(5-pent-1-ynylpyrimidine-2-yl)naphthalene
[0063] Quantities: compound 1.3 (1.60 g, 8.86 mol),
6-butoxynaphth-2-ylboronic acid (2.60 g, 0.011 mol),
tetrakis(triphenylphosphine)palladium(O) (0.35 g, 0.30 mol).
[0064] This experimental procedure is a boronic acid coupling
reaction. A solution of the boronic acid in dimethoxyethane is
added to a stirred mixture of compound 1.3 and
tetrakis(triphenylphosphine)palladium(O) in dimethoxymethane and 2M
sodium carbonate at room temperature under dry nitrogen. The
mixture is heated under reflux for 18 hours (glc analysis revealing
a complete reaction). The crude product is purified by column
chromatography [silica gel/petroleum fraction (bp40-60.degree.
C.)-dichloromethane, 1:2] to give a colourless solid which is
recrystallised from ethyl acetate-ethanol (1:1) to yield colourless
crystals. Yield is 2.25 g (74%).
Example 2
Preparation of
[0065] 7
[0066] With reference to FIG. 2 it can be seen that
[0067] Step 2.1 2-pent-1-ynylthiophene
[0068] Quantities: pent-1-yne (6.80 g, 0.10 mol), n-butyllithium
(10.0 ml, 10.0M in hexane, 0.044 mol), zinc chloride (13.60 g, 0.10
mol), 2-bromothiophene (16.00 g, 0.098 mol), tetrakis
(triphenylphosphine)palla- dium(O) (3.40 g 2.94 mol).
[0069] The experimental procedure is as described for step 1.3. The
crude product is distilled to yield a colourless liquid. Yield is
12.96 g (88%).
[0070] Step 2.2 5-pent-1-ynylthiophen-2ylboronic acid
[0071] Quantities: compound 2.1 (10.0 g, 0.067 mol), n-butyllithium
(6.80 g. 10.0M in hexane, 0.068 mol), trimethyl borate (14.20 g,
0.137 mol).
[0072] This experimental procedure is a standard boronic acid
preparation and yields a brown solid. The yield is 12.00 g
(93%).
[0073] Step 2.3 2-(6-Cyanonaphth-2-yl)-5-pent-1-ylthiophene
[0074] Quantities: 6-cyanonaphth-2-yl triflate (2.00 g, 6.64 mol),
5-pent-1-ynylthiophen-2-ylboronic acid (1.55 g, 7.99 mmol),
tetrakis (triphenyl phosphine)palladium(O) (3.40 g 2.94 mol),
lithium chloride (0.85 g, 0.020 mol).
[0075] This experimental procedure is as for the boronic acid
coupling reaction described in step 1.4, except for the addition of
lithium chloride as a catalyst. The crude product is purified by
column chromotography [silica gel/petroleum fraction
(bp40-60.degree. C.)-dichloromethane, 1:1] to give a yellow solid,
which is recrystallised from ethanol to yield pale yellow crystals.
Yield is 1.55 g (78%).
Example 3
Preparation of:
[0076] 8
[0077] With reference to FIG. 3 it can be seen that
[0078] Step 3.1 2-Bromo-6-ethoxynaphthalene
[0079] This experimental procedure is an O-alkylation. A solution
of bromomethane (48.90 g, 0.45 mol) is added dropwise to a stirred
refluxing mixture of 6-Bromo-2-naphthol (40.00 g, 0.18 mol) and
potassium carbonate (63.00 g, 0.46 mol) in acetone. The stirred
mixture is heated under reflux for 24 hours (ie until glc analysis
reveals a complete reaction). The potassium carbonate is filtered
off, water is added to filtrate and the product is recrystallised
from ethanol to give a yield of 43.92 g (97%).
[0080] Step 3.2 2-Ethoxy-6-cyanonaphthalene
[0081] This experimental procedure is a cyanation where compound
3.1 (3.00 g, 0.012 mol) is reacted with Copper (I) cyanide (1.30 g.
0.015 mol), with the crude product purified by column
chromatography [silica gel/petroleum fraction (bp40-60.degree.
C.)-dichloromethane, 1:2) to give a colourless solid which is
distilled [Kugeklrohr, 170.degree. C. (maximum) at 0.1 mmHg] to
yield 1.75 g (74%) of colourless solid.
[0082] Step 3.3 1-Bromo-6-cyano-2-ethoxynaphthalene
[0083] A solution of bromine (1.72 g, 0.011 mol) in glacial acetic
acid (4 ml) is added dropwise to stirred solution of compound 3.2
(1.93 g, 9.80 mol) in glacial acetic acid (35 ml) at 80.degree. C..
The solution is stirred for an additional 10 minutes (glc revealing
a complete reaction and only one product peak). The solution is
added to water and the product is extracted from ether (.times.2)
and the combined ethereal extracts are washed with water and sodium
metabisulphite and dried. The solvent is removed in vacuo and the
residue purified by column chromotography [silica gel/petroleum
fraction (bp40-60.degree. C.)-dichloromethane, 1:1] to give a
colourless solid (1.72 g) which is recrystallised from
hexanedimethoxymethane (1:1) to yield 1.55 g (57%) colourless
crystals.
Example 4
Preparation of
[0084] 9
[0085] With reference to FIG. 4 it can be seen that
[0086] Step 4.1 2-Bromo-6-thiobutylnaphthalene
[0087] Trifluoromethanesulphonic acid (14.85 g, 0.099 mol) is added
dropwise to a stirred mixture of 6-bromo-2-naphthol (20.00 g, 0.090
mol) and butanethiol (8.07 g, 0.090 mol) in dry benzene (180 ml)
under dry nitrogen. The resulting solution is stirred at 50.degree.
C. for 4 hours (glc analysis revealing a complete reaction), cooled
and poured into ice-cold water. The product is extracted into ether
(.times.2), the combined organic phases washed with 5%sodium
hydroxide and water and dried (MgSO.sub.4). The solvent can then be
removed in vacuo and the residue distilled to give a colourless
solid. Yield is 13.80 g (52%).
[0088] Step 4.2 6-Thiobutylnaphth-2-ylboronic acid
[0089] Quantities: compound 4.1 (6.80 g, 0.023 mol), n-butyllithium
(2.30 ml. 10.0M in hexane, 0.023 mol), trimethylborate (4.80 g,
0.046 mol).
[0090] This experimental procedure is a preparation of the
appropriate boronic acid by standard procedures, giving a yield of
3.49 g (58%) after the product of the reaction is extracted into
10% potassium hydroxide, the basic extract washed with ether and
acidified, extracted into ether and dried (MgSO.sub.4), and removal
of solvent in vacuo to give a colourless liquid.
[0091] Step 4.3 2-(4-Cyanophenyl)-6-thiobutylnaphthalene
[0092] Quantities: compound 4.2 (1.81 g, 6.96
mol),4-bromobenzonitrile (1.15 g,6.32 mol),
tetrakis(triphenylphosphine)palladium(O) (0.235 g, 0.22 mol).
[0093] This experimental procedure is a boronic acid coupling
reaction as previously described in step 1.4, followed by
purification of the crude product by column chromatography [silica
gel/petroleum fraction (bp40-60.degree. C.)-dichloromethane, 1:1]
to give a colourless solid which is then recrystallised from
ethanol-ethyl acetate (4:1) to yield 1.63 g (81%) of colourless
crystals.
Example 5
Preparation of
[0094] 10
[0095] With reference to FIG. 5 it can be seen that
[0096] Step 5.1 2-Bromothiophene
[0097] A solution of thiophene (31.88 g, 0.380 mol) and
N-bromosuccinimide (64.00 g, 0.360 mol) in a mixture of chloroform
(80 ml) and glacial acetic acid (80 ml) was heated under reflux
(with stirring) for 0.5 hours (constant glc analysis revealed a
complete reaction with minimal formation of 2.5-dibromothiophene).
The reaction mixture was diluted with water and washed with
dichloromethane (2.times.100 ml); the combined organic extracts
were washed successively with water (300 ml) and aqueous potassium
hydroxide (5%, 300 ml) before being dried (MgSO.sub.4). The solvent
was removed in vacuo and the residue was distilled to give a
colourless liquid.
[0098] Yield 24.34 g (42%).
[0099] Step 5.2 2-Bromo-5-nitrothiophene
[0100] Nitric acid (24.00 g, 1.42 sp gr, 0.381 mol) in acetic
anhydride (50 ml) at 0.degree. C. was added dropwise to a cooled
(0.degree. C.) rapidly stirred solution of the compound of step 5.1
(24.77 g, 0.152 mol) in acetic anhydride (50ml). At the end of the
addition the stirring was continued for 0.5 hr and the mixture was
refrigerated overnight. The mixture was poured into ice water (400
ml) and the precipitate was filtered off, dissolved in ether
(2.times.200 ml), and washed with water until free of acid. The
solvent was removed in vacuo and the residue was purified by column
chromatography [silica gel/petroleum fraction (bp 40-60.degree.
C.), dichloromethane, 5:1] and was recrystallised from
ethanol/dimethoxyethane, 100:1 to give a pale yellow solid which
was dried in vacuo (P.sub.2O.sub.5) to give 66% yield of 20.89
g.
[0101] Step 5.3 2-(6-Thiobutyl-2-naphthyl)-5-nitrothiophene
[0102] Quantities: Compound of step 4.2 (4.00 g, 0.015 mol),
compound of step 5.2 (3.31 g, 0.016 mol),
tetrakis(triphenylphosphine)palladium(O) (0.910 g, 0.001 mol),
sodium carbonate (15.8 ml, 2.0M, 0.03 mol).
[0103] The compound of step 5.2 was added all at once to a rapidly
stirred mixture of the palladium catalyst, the compound of step
4.2, and aqueous sodium carbonate solution in dimethoxymethane
under dry nitrogen. The reaction mixture was refluxed overnight
(tlc and glc revealed a complete reaction) and the product was
extracted into ether; the combined ethereal solutions were washed
with saturated sodium chloride solution and dried (MgSO.sub.4). The
solvent was removed in vacuo and the product was purified by column
chromatography [silica gel/petroleum fraction (bp40-60),
dichloromethane, 5:1] to give an orange solid with a 71% yield
(3.41 g).
[0104] Step 5,4 2-(6-thiobutyl-2-naphtyl)-5-aminothiophene
[0105] A stirred solution of compound of step 5.3 (2.62 g, 0.008
mol) and palladium on carbon (10%, 2.22 g) in ethanol and
tetrahydrofuran was stirred under hydrogen overnight. The catalyst
was removed by filtration through "Hyflo supercel" and the solvent
was removed in vacuo to afford a black solid which was used in the
next step without purification after yielding 2.39 g (100%), purity
(glc) 50%.
[0106] Step 5.5
2-(6-thioputyl-2-naphthyl)-5-isothionatothiophene
[0107] A solution of compound of step 5.4 (2.30 g, 0.007 mol), in
chloroform was added to a stirred, cooled (0-5.degree. C.) solution
of calcium carbonate (1.17 g, 0.012 mol) and thiophosgene (0.97 g,
0.008 mol) in water and chloroform at 0-5.degree. C.. The mixture
was heated at 35.degree. C. for 1 h (glc and tlc analysis confirmed
a complete reaction) and poured into water. The organic layer was
washed with hydrochloric acid (1%, 100 ml) and dried (MgSO.sub.4).
The compound was purified by column chromatography [silica
gel/petroleum (bp40-60.degree. C.), dichloromethane, 5:1] and was
recrystallised to give 0.57 g (22% yield) of a pale green solid
which was dried in vacuo (CaCO.sub.3). having an indicated (hplc)
purity of >99%.
[0108] Liquid crystal transition temperatures between crystalline
(K), nematic (N), smectic B (S.sub.B) and isotropic (I) are given
in Table 1 below for compounds of Formula I and Formula II. The
table also contains a comparison of anisotropy in polarisability
.DELTA.a with that of 4-cyano-(4'pentyl)-1-phenylcyclohexane (5PCH)
and the birefringence (.DELTA.n) of the compounds. [ ] denotes a
virtual phase transition.
1TABLE 1 PHASE TRANSITION TEMPS COMPOUND. (.degree. C.) .DELTA.a
.DELTA.n 11 D 146 [N 136.5] I 12 K 84 [79.5] I 4.88 13 K 163.5 [N
79.5] I 1.41 14 K 92 [N 107] I 4.11 15 0.405 16 K 100.5 S.sub.B
104.5 [N 47] I 0.345 17 K 108.2 N 118.7 I 18 4.88 19 6.21 20 2.37
21 4.11
[0109] The n measurements are normalized for 25.degree. C. and were
carried out using an Abbe refractometer and using 3 wt % of the
compound to be measured in a non-polar eutectic nematic host,
typically such as 22
[0110] where R and R' are alkyl.
[0111] FIG. 6 a liquid crystal cell comprises a layer 1 of liquid
crystal material, where the material is a mixture incorporating
compounds of formula I, sandwiched between a glass slide 2 having a
conducting layer 3 on its surface, eg of indium tin oxide, and a
glass slide 4 having a transparent conducting layer 5 on its
surface. The slides 2,4 bearing the layers 3,5 are respectively
coated with films 6,7 of a polyimide layer. Prior to construction
of the cell the films 6 and 7 are rubbed with a soft tissue in a
given direction, the rubbing directions being arranged parallel to
the construction of the cell. A spacer 8 eg of
polymethylmethacrylate, separates the slides 2,4 to the required
distance eg 5 microns. The liquid crystal material 1 is introduced
between the slides 2,4 by filling the space between the slides 2,4
and spacer 8 and sealing the spacer 8 in a vacuum in a known
way.
[0112] A polarizer 9 is arranged with its polarization axis
parallel to the rubbing direction on the films 6,7 and an analyzer
(crossed polariser) 10 is arranged with its polarization axis
perpendicular to that rubbing direction. When a voltage is applied
across the cell by making contact with the layers 3 and 5 the cell
is switched.
[0113] In an alternative device (not shown) based on a cell
construction as shown in FIG. 6 the layers 3 and 5 may be
selectively etched in a known way, eg by photoetching or deposition
through a mask, eg to provide one or more display symbols, eg
letters, numerals, words or graphics and the like as conventionally
seen on displays. The electrode portions thereby may be addressed
in a variety of ways which include multiplexed operation.
[0114] FIG. 7 shows a Kerr cell 20. It comprises a glass cell 21
having two electrodes 22 and 23, which can be filled with a polar
isotropic medium such as compounds of formula II or materials
comprising mixtures including at least one compound of formula II.
The cell 20 can be positioned between crossed linear polarisers 24
and 25, whose transmission axes are arranged to be at
.+-.45.degree. to an applied electric field. Where there is zero
voltage across the electrodes 22 and 23, and the cell 20 acts as a
closed shutter. The application of a modulating electric field from
voltage source 26 generates an electric field causing the cell 20
to act as a variable wave plate and thus operating as a variable
aperture shutter where opening is proportional to the electric
field.
* * * * *