U.S. patent application number 12/479999 was filed with the patent office on 2010-12-09 for liquid crystal compositions.
This patent application is currently assigned to E. I. DU PONT DE NEMOURS AND COMPANY. Invention is credited to MARC B. GOLDFINGER.
Application Number | 20100308268 12/479999 |
Document ID | / |
Family ID | 43300092 |
Filed Date | 2010-12-09 |
United States Patent
Application |
20100308268 |
Kind Code |
A1 |
GOLDFINGER; MARC B. |
December 9, 2010 |
LIQUID CRYSTAL COMPOSITIONS
Abstract
This invention relates to a liquid crystal composition and
articles comprising the composition. The composition comprises at
least one compound of each of the Formulas (I), (II) and (III),
##STR00001## as defined herein. A process for making the
composition is also provided.
Inventors: |
GOLDFINGER; MARC B.; (West
Chester, PA) |
Correspondence
Address: |
E I DU PONT DE NEMOURS AND COMPANY;LEGAL PATENT RECORDS CENTER
BARLEY MILL PLAZA 25/1122B, 4417 LANCASTER PIKE
WILMINGTON
DE
19805
US
|
Assignee: |
E. I. DU PONT DE NEMOURS AND
COMPANY
Wilmington
DE
|
Family ID: |
43300092 |
Appl. No.: |
12/479999 |
Filed: |
June 8, 2009 |
Current U.S.
Class: |
252/299.62 ;
252/299.66 |
Current CPC
Class: |
C09K 19/2007 20130101;
C09K 19/3068 20130101; C09K 19/322 20130101 |
Class at
Publication: |
252/299.62 ;
252/299.66 |
International
Class: |
C09K 19/32 20060101
C09K019/32; C09K 19/12 20060101 C09K019/12 |
Claims
1. A process for making a composition comprising: (a) providing one
or more organic polyol(s) comprising at least two hydroxyl groups
and at least two covalently bonded carbon atoms, each hydroxyl
group being bonded to a different carbon atom within an organic
polyol; (b) reacting the organic polyol(s), optionally in the
presence of a base, with (i) one or more functionalized alkyl
acid(s) or acid halide(s) represented by the structure of the
following Formula (X): Z-(CH.sub.2).sub.n--C(O)X (X) wherein X is
Cl, Br, I, or OH; Z is F, Cl, Br, I, --OTs, --OTf, --OMs, CN, or
NO.sub.2; and n is an integer equal to 3 to 20; and (ii) one or
more non-functionalized alkyl acid(s) or acid halide(s) represented
by the structure of the following Formula (XI):
Y--(CH.sub.2).sub.t--C(O)X (XI) wherein X is Cl, Br, I, or OH; Y is
H, F, Cl, Br, I, --OTs, --OTf, --OMs, CN, or NO.sub.2; and t is an
integer equal to 3 to 20; with the proviso that Z is not equal to
Y; in a reaction solvent and at a reaction temperature to provide a
mixture comprising a composition and a spent reaction mixture.
2. The process of claim 1 wherein the polyol comprises a diol
selected from the group of compounds represented by the structures
of the following Formulas (XIIIa-XIIIg): ##STR00050## ##STR00051##
wherein R.sup.3-R.sup.10 are selected from the group: H,
C.sub.1-C.sub.8 straight or branched chain alkyl, C.sub.1-C.sub.8
straight or branched chain alkyloxy, F, Cl, phenyl, --C(O)CH.sub.3,
CN and CF.sub.3; and R.sup.11 is H, --CH.sub.3 or --OCH.sub.3.
3. The process of claim 1 wherein the polyol comprises a diester
diol selected from the group of materials represented by the
structures of the following Formulas (XIVa-XIVf): ##STR00052##
wherein R.sup.3-R.sup.10 are selected from the group: H,
C.sub.1-C.sub.8 straight or branched chain alkyl, C.sub.1-C.sub.8
straight or branched chain alkyloxy, F, Cl, phenyl, --C(O)CH.sub.3,
CN and CF.sub.3; and R.sup.11 is H, --CH.sub.3 or --OCH.sub.3.
4. A composition as prepared according to the process of claim 1.
Description
TECHNICAL FIELD
[0001] This invention relates to liquid crystal compositions that
contain mixtures of functionalized and non-functionalized
compounds, to processes for preparing the liquid crystal
compositions. and to articles fabricated from the compositions,
BACKGROUND
[0002] Thermotropic liquid crystals are generally crystalline
compounds with significant anisotropy in shape. That is, at the
molecular level, they are characterized by a rod-like or disc like
structure. When heated they typically melt in a stepwise manner,
exhibiting one or more thermal transitions from a crystal to a
final isotropic phase. The intermediate phases, known as
mesophases, can include several types of smectic phases wherein the
molecules are generally confined to layers; and a nematic phase
wherein the molecules are aligned parallel to one another with no
long range positional order. The liquid crystal phase can be
achieved in a heating cycle, or can be arrived at in cooling from
an isotropic phase. The structure of liquid crystals in general,
and twisted nematic liquid crystals in particular, is further
discussed in "The Physics of Liquid Crystals", de Gennes and Prost,
Oxford University Press, 1995.
[0003] An important variant of the nematic phase is one wherein a
chiral moiety is present, referred to as a twisted nematic or
cholesteric phase. In this case, the molecules are parallel to each
other as in the nematic phase, but the director of molecules (the
average direction of the rodlike molecules) changes direction
through the thickness of a layer to provide a helical packing of
the nematic molecules. The pitch of the helix is perpendicular to
the long axes of the molecules. This helical packing of anisotropic
molecules leads to important and characteristic optical properties
of twisted nematic phases including circular dichroism, a high
degree of rotary power; and the selective reflection of light,
including ultraviolet, visible, and near-IR light. Reflection in
the visible region leads to brilliantly colored layers. The sense
of the helix can either be right-handed or left-handed, and the
rotational sense is an important characteristic of the material.
The chiral moiety either may be present in the liquid crystalline
molecule itself, for instance, as in a cholesteryl ester, or can be
added to the nematic phase as a dopant, with induction of the
cholesteric phase. This phenomenon is further discussed in sources
such as Bassler and Labes, J. Chem. Phys., 52, 631 (1970).
[0004] There has been interest in preparing stable polymer layers
exhibiting nematic and/or cholesteric optical properties. One
approach has been to synthesize monofunctional and/or
polyfunctional reactive monomers that exhibit a nematic or
cholesteric phase upon melting, formulate a low melting liquid
crystal composition, and polymerize the liquid crystal composition
in its nematic or cholesteric phase to provide a polymer network
exhibiting stable optical properties of the nematic or cholesteric
phase. Use of cholesteric monomers alone, as disclosed in U.S. Pat.
No. 4,637,896 for example, provides cholesteric layers with the
desired optical properties, but the polymer layers possess
relatively weak mechanical properties.
[0005] A need thus remains for liquid crystal compositions that
have broad thermal windows, low melting points and good phase
stability against crystallization, and that are easy to prepare and
can be tuned to give desired properties.
SUMMARY
[0006] One embodiment of the inventions hereof provides a
composition that contains at least one compound of the group of
compounds represented by the structures of each of the following
Formulas (I), (II) and (III),
##STR00002##
wherein
[0007] Z is F, Cl, Br, I, --OTs, --OTf, --OMs, CN, or NO.sub.2;
[0008] Y is H, F, Cl, Br, I, --OTs, --OTf, --OMs, CN, or
NO.sub.2;
[0009] with the proviso that Z is not equal to Y; [0010] n1, n2,
n3, n4, n5, and n6 are each independently integers 3 to 20; [0011]
m and p are each independently integers 0, 1, or 2; [0012] A is a
divalent radical selected from the group:
##STR00003##
[0012] wherein R.sup.3 through R.sup.10 are each independently
selected from the group: H, C.sub.1 to C.sub.8 straight or branched
chain alkyl, C.sub.1 to C.sub.8 straight or branched chain
alkyloxy, F, Cl, phenyl, --C(O)CH.sub.3, CN, and CF.sub.3; X.sup.2
is a divalent radical selected from the group: --O--,
--(CH.sub.3).sub.2C--, and --(CF.sub.3).sub.2C--; and each B.sup.1
and B.sup.2 is a divalent radical independently selected from the
group: R.sup.11-substituted-1,4-phenyl, wherein R.sup.11 is H,
--CH.sub.3 or --OCH.sub.3; 2,6-naphthyl; and 4,4'-biphenyl; with
the proviso that when m+p is equal to 3 or 4, at least two of
B.sup.1 and B.sup.2 are R.sup.11-substituted-1,4-phenyl.
[0013] Another embodiment of the invention is a liquid crystal
composition comprising at least one compound of each of the
Formulas (I), (II), and (III), and in a further embodiment the
liquid crystal composition comprises at least one chiral
compound.
[0014] Another embodiment of the invention is an article comprising
the liquid crystal composition, and in a further embodiment the
article is fabricated as an optical element.
[0015] Another embodiment of the inventions hereof is a process for
preparing a composition by
[0016] (a) providing one or more organic polyol(s) comprising at
least two hydroxyl groups and at least two covalently bonded carbon
atoms, each hydroxyl group being bonded to a different carbon atom
within an organic polyol;
[0017] (b) reacting the organic polyol(s), optionally in the
presence of a base, with (i) one or more functionalized alkyl
acid(s) or acid halide(s) represented by the structure of the
following Formula (X):
Z-(CH.sub.2).sub.n--C(O)X (X)
wherein X is Cl, Br, I, or OH; Z is F, Cl, Br, I, --OTs, --OTf,
--OMs, CN, or NO.sub.2; [0018] and n is an integer equal to 3 to
20; and [0019] (ii) one or more non-functionalized alkyl acid(s) or
acid halide(s) represented by the structure of the following
Formula (XI):
[0019] Y--(CH.sub.2).sub.t--C(O)X (XI)
wherein X is Cl, Br, I, or OH; Y is H, F, Cl, Br, I, --OTs, --OTf,
--OMs, CN, or NO.sub.2; and t is an integer equal to 3 to 20;
[0020] with the proviso that Z is not equal to Y; in a reaction
solvent and at a reaction temperature to provide a mixture
comprising the composition and a spent reaction mixture.
[0021] In another embodiment, the invention provides a composition
as prepared by the process disclosed above; and in another
embodiment, the composition prepared by the process disclosed above
comprises at least one compound of each of the Formulas (I), (II)
and (III).
[0022] The composition as described herein has a variety of uses in
liquid crystal compositions. Choices may be made from within and
among the prescribed ranges for the variable radicals and
substituents such that each compound of the composition is, for
example, either symmetric or asymmetric.
DETAILED DESCRIPTION
[0023] One embodiment of the inventions hereof provides a
composition comprising at least one compound of each of the
Formulas (I), (II) and (III),
##STR00004##
wherein
[0024] Z is F, Cl, Br, I, --OTs, --OTf, --OMs, CN, or NO.sub.2;
[0025] Y is H, F, Cl, Br, I, --OTs, --OTf, --OMs, CN, or
NO.sub.2;
[0026] with the proviso that Z is not equal to Y;
[0027] n1, n2, n3, n4, n5, and n6 are each independently integers 3
to 20;
[0028] m and p are each independently integers 0, 1, or 2; and
[0029] A is a divalent radical selected from the group:
##STR00005##
wherein R.sup.3 through R.sup.10 are each independently selected
from the group: H, C.sub.1 to C.sub.8 straight or branched chain
alkyl, C.sub.1 to C.sub.8 straight or branched chain alkyloxy, F,
Cl, phenyl, --C(O)CH.sub.3, CN, and CF.sub.3; X.sup.2 is a divalent
radical selected from the group: --O--, --(CH.sub.3).sub.2C--, and
--(CF.sub.3).sub.2C--; and each B.sup.1 and B.sup.2 is a divalent
radical independently selected from the group:
R.sup.11-substituted-1,4-phenyl, wherein R.sup.11 is H, --CH.sub.3
or --OCH.sub.3; 2,6-naphthyl; and 4,4'-biphenyl; with the proviso
that when m+p is equal to 3 or 4, at least two of B.sup.1 and
B.sup.2 are R.sup.11-substituted-1,4-phenyl.
[0030] The abbreviation "--OTf", as used herein, refers to a
functional group with the formula CF.sub.3SO.sub.3--, which is also
referred to as a triflate or trifluoromethanesulfonate group. The
abbreviation "--OTs", as used herein, refers to a functional group
with the formula CH.sub.3C.sub.6H.sub.4SO.sub.3--, which is also
referred to as a tosylate group. The abbreviation "--OMs", as used
herein, refers to a functional group with the formula
CH.sub.3SO.sub.3--, which is also referred to as a mesylate or
methanesulfonate group.
[0031] In the phrase "each B.sup.1 and B.sup.2 is a divalent
radical independently selected from the group . . . ", when m=2,
the two B.sup.1 units are each selected independently, that is they
may be the same or different; and when p=2, the two B.sup.2 units
are each selected independently, that is they may be the same or
different. In addition, a C.sub.1-C.sub.8 group may be any one or
more of C.sub.1, C.sub.2, C.sub.3, C.sub.4, C.sub.5, C.sub.6,
C.sub.7 or C.sub.8. Throughout the specification, in Formulas (I),
(II), (III), when -A- is a trans-cyclohexyl moiety and one or both
of m and p is an integer equal to 0, the term "aryl alkanoate
ester(s)" can refer to cyclohexyl alkanoate ester(s).
[0032] For each compound of the composition, n1, n2, n3, n4, n5,
and n6 may each be independently integers 3 to 10. For each
compound of the composition, when m and p=2, B.sup.1 and B.sup.2
may each be independently R.sup.11-substituted-1,4-phenyl.
[0033] In one embodiment, Z is Br, I, --OTs, --OTf, or --OMs, and Y
is H, Br, I, --OTs, --OTf, or --OMs. In another embodiment, Z is Br
and Y is H. In another embodiment, for at least one compound of
each of the Formulas (I), (II), (III) of the composition, m is 0
and p is 0. In another embodiment, for at least one compound of
each of the Formulas (I), (II), (III) of the composition, m is 1
and p is 0. In another embodiment, for at least one compound of
each of the Formulas (I), (II), (III) of the composition, m is 1
and p is 1. In another embodiment, for at least one compound of
each of the Formulas (I), (II), (III) of the composition, m is 1
and p is 0, and for at least one compound of each of the Formulas
(I), (II), (III) of the composition, m is 1 and p is 1. In another
embodiment, n1, n2, and n4 are the same. In another embodiment, the
composition comprises only one compound of Formula (I). In another
embodiment, the composition comprises only one compound of Formula
(I) and n1, n2, and n4 are the same.
[0034] Another embodiment of the invention is a composition
comprising at least one compound of each of the Formulas (I), (II),
and (III), wherein for at least one compound of each of the
Formulas (I), (II) and (III), m is 0 and p is 0, and, Formula (I)
is selected from the group compounds represented by the structures
of the following Formulas (VIIa-VIIf):
##STR00006##
[0035] In this embodiment, Formula (II) is selected from the group
of compounds represented by the structures of the following
Formulas (XVIIa-XVIIf):
##STR00007##
and Formula (III) is selected from the group of compounds
represented by the structures of the following Formulas
(XVIIIa-XVIIIf):
##STR00008##
[0036] Compositions comprising at least one compound of each of the
Formulas (VIIa-VIIf), (XVIIa-XVIIf), and (XVIIIa-XVIIIf) are useful
as diluents and viscosity modifiers for liquid crystal
compositions. Methods for synthesizing these compositions are
described below. Preferred compositions comprise at least one
compound as described in Formulas (VIIa-VIId) wherein
R.sup.3-R.sup.8 are H; in Formula (VIIa) wherein R.sup.3-R.sup.5
are H and R.sup.6 is CH.sub.3; and in Formula (VIIe) wherein
X.sup.2 is --C(CH.sub.3).sub.2-- or --O--.
[0037] Another embodiment of the invention is a composition
comprising at least one compound of each of the Formulas (I), (II)
and (III), wherein for at least one compound of each of the
Formulas (I), (II) and (III), m is 1 and p is 0, and Formula (I) is
selected from the group of compounds represented by the structures
of the following Formulas (VIIIa-VIIIe):
##STR00009##
[0038] In this embodiment, Formula (II) is selected from the group
of compounds represented by the structures of the following
Formulas (XIXa-XIXe):
##STR00010##
and Formula (III) is selected from the group of compounds
represented by the structures of the following Formulas
(XXa-XXe):
##STR00011##
[0039] Compositions comprising at least one compound of each of the
Formulas (VIIIa-VIIIe), (XIXa-XIXe), and (XXa-XXe) are useful in
liquid crystal compositions. Such compositions, when comprising at
least one compound as described in Formula (VIIIa-VIIIe), exhibit
nematic phases at or near room temperature (RT, about 25.degree.
C.). Other liquid crystal monomers can be added to the composition
to provide nematic phases over broad temperature ranges. Other
compounds within this group may exhibit low melting points and can
be used as reactive diluents and viscosity modifiers in liquid
crystal mixtures. Preferred compositions comprise at least one
compound as described in Formula (VIIIa) wherein R.sup.3-R.sup.6 is
H. Methods for synthesizing these compositions are described
below.
[0040] Another embodiment of the invention is a composition
comprising at least one compound of each of the Formulas (I), (II),
and (III), wherein for at least one compound of each of the
Formulas (I), (II), and (III), m is 1 and p is 1, and Formula (I)
is selected from the group of compounds represented by the
structures of the following Formulas (IXa-IXe):
##STR00012##
[0041] In this embodiment, Formula (II) is selected from the group
of compounds represented by the structures of the following
Formulas (XXIa-XXIe):
##STR00013##
and Formula (III) is selected from the group of compounds
represented by the structures of the following Formulas
(XXIIa-XXIIe):
##STR00014##
[0042] Compositions comprising at least one compound of each of the
Formulas (IXa-IXe), (XXIa-XXIe), and (XXIIa-XXIIe) are useful in
liquid crystal compositions. Such compositions, when comprising at
least one compound as described in Formula (IXa-IXe), exhibit
nematic phases over broad temperature ranges. Other liquid crystal
monomers can be added to the composition to provide nematic phases
over broad temperature ranges. Preferred compositions comprise at
least one compound as described in Formula (IXa) wherein B.sup.1
and B.sup.2 are R.sup.11-substituted-1,4-phenyl. Within this group
of compositions, a more preferred composition further comprises at
least one compound wherein one of the group R.sup.3-R.sup.6 is Cl
or CH.sub.3; and three of the group R.sup.3-R.sup.6 are H--as
shown, for example, in the following Formula (XXIII):
##STR00015##
[0043] Within these preferred compositions, more preferred are
those comprising compounds wherein n1 and n2 are, independently,
integers 3 to 10. Methods for synthesizing these compositions are
described below.
[0044] Another embodiment of the invention is a composition
comprising at least one compound of each of the Formulas (I), (II)
and (III), wherein for at least one compound of each of the
Formulas (I), (II) and (III), m is 1 and p is 0; and wherein for at
least one compound of each of the Formulas (I), (II) and (III), m
is 1 and p is 1. Such compositions can be useful in liquid crystal
compositions and can exhibit nematic phases at or near room
temperature (RT). Other liquid crystal monomers can be added to the
composition to provide nematic phases over broad temperature
ranges. Preferred compositions comprise at least one compound as
described in Formula (VIIIa) and/or Formula (IXa) wherein
R.sup.3-R.sup.6 is H. Other preferred compositions comprise at
least one compound of Formula (XXIII). Other preferred compositions
comprise at least one compound as described in Formula (VIIIa)
and/or Formula (IXa) wherein one of the groups R.sup.3-R.sup.6 is
CH.sub.3; and three of the groups R.sup.3-R.sup.6 are H. Methods
for synthesizing these compositions are described below.
[0045] In another embodiment, the total amount of compounds of
Formula (I) are present in the range of about 0.1 mole percent to
about 95 mole percent based on the total content of the
composition. In another embodiment, the total amount of compounds
of Formula (I) are present in the range of about 5 mole percent to
about 95 mole percent based on the total content of the
composition. In another embodiment, the total amount of compounds
of each of Formula (I) are present in the range of about 20 mole
percent to about 80 mole percent based on the total content of the
composition.
[0046] In another embodiment, the total amount of compounds of
Formula (II) are present in the range of about 5 mole percent to
about 50 mole percent, based on the total content of the
composition. In another embodiment, the total amount of compounds
of Formula (II) are present in the range of about 10 mole percent
to about 50 mole percent based on the total content of the
composition.
[0047] In another embodiment, the total amount of compounds of
Formula (III) are present in the range of about 0.1 mole percent to
about 90 mole percent based on the total content of the
composition. In another embodiment, the total amount of compounds
of Formula (III) are present in the range of about 0.1 mole percent
to about 60 mole percent based on the total content of the
composition.
[0048] When the compositions of this invention are prepared by one
embodiment of a process hereof (such as is disclosed below), rather
than by synthesizing each compound individually and then combining
them to form the desired composition, one result of the use of that
embodiment of the process is that the relative amounts of the
compounds of each of the Formulas (I), (II) and (III) in the
composition will be determined by a fixed relationship that is
given effect by the process. When the composition is prepared by
that embodiment of a process hereof, a desired amount of the
compounds of one of Formulas (I), (II) or (III) is pre-selected,
and an appropriate ratio of the reactants is employed to produce
the desired amount of the compounds of that Formula. The ratio of
reactants selected to produce the desired amount of one of the
Formula (II), (II) or (III) compounds will, however, also produce
an amount of the other two compounds that adheres to the fixed
relationship. For example, in this embodiment of the process, the
amount of each of the Formula (I), (II) or (III) compounds that is
produced in relation to the amount of leaving groups used in the
reactants will adhere to a fixed relationship that may be
determined in advance.
[0049] The choice of what amount to pre-select for which of the
compounds of the Formulas (I), (II) or (III) depends on the desired
end use of the composition, for example the degree of flexibility
or brittleness desired. The preparation by a process hereof of the
compositions hereof, which comprise at least one compound of each
of the Formulas (I), (II) and (III), can thus provide advantages
over compositions comprising a single compound, compositions
comprising compounds of less than all of the Formulas (I), (II) and
(III), or compositions prepared by blending separately made
compounds because the physical properties of the compositions
hereof may thus be tuned by adjusting the relative percentage
content of each of the Formula (I), (II) and (III) compounds. For
example, the rate of crystallization, the thermal characteristics,
or the degree of crosslinking (and thus the flexibility or
brittleness) of a composition hereof may be adjusted in such
manner.
[0050] Another embodiment of the invention hereof provides a
process for preparing a composition which comprises at least one
compound of each of the Formulas (I), (II) and (III). In one
embodiment, the process comprises
[0051] (a) providing one or more organic polyol(s) comprising at
least two hydroxyl groups and at least two covalently bonded carbon
atoms, each hydroxyl group being bonded to a different carbon atom
within an organic polyol; and
[0052] (b) reacting the organic polyol(s), optionally in the
presence of a base, with (i) one or more functionalized alkyl
acid(s) or alkyl acid halide(s) as represented by the structure of
the following Formula (X):
Z-(CH.sub.2).sub.n--C(O)X (X)
wherein X is Cl, Br, I, or OH; Z is F, Cl, Br, I, --OTs, --OTf,
--OMs, CN, or NO.sub.2; [0053] and n is an integer equal to 3 to
20; and [0054] (ii) one or more non-functionalized alkyl acid(s) or
acid halide(s) as represented by the structure of the following
Formula (XI):
[0054] Y--(CH.sub.2).sub.t--C(O)X (XI)
wherein X is Cl, Br, I, or OH; Y is H, F, Cl, Br, I, --OTs, --OTf,
--OMs, CN, or NO.sub.2; and t is an integer equal to 3 to 20; with
the proviso that Z is not equal to Y; in a reaction solvent and at
a reaction temperature to provide a mixture comprising at least one
compound of each of the Formulas (I), (II), and (III), as described
above, and a spent reaction mixture. Preferably, when X is OH, the
process further comprises the use of a carbodiimide dehydrating
agent.
[0055] In various embodiments of the processes of the invention,
the polyol(s) may be selected from the group of compounds
represented by the structures of the following Formulas
(XIIa-XIIf):
##STR00016##
wherein R.sup.3-R.sup.10 and X.sup.2 are as described above. These
embodiments of the process can be used to provide compositions
comprising compounds of Formula (VIIa-VIIf) as described above.
Specific diols of Formula (XIIa-XIIf) useful and preferred in the
process include: hydroquinone, methylhydroquinone,
chlorohydroquinone, 4,4'-dihydroxybiphenyl,
2,6-dihydroxynapthalene, 1,5-dihydroxynapthalene, Bisphenol A,
6F-Bisphenol A, 4,4'-oxydiphenol, and
trans-1,4-cyclohexanediol.
[0056] In other embodiments of the processes hereof, the polyol(s)
may include one or more ester diols selected from the group of
compounds represented by the structures of the following Formulas
(XIIIa-XIIIg):
##STR00017## ##STR00018##
wherein R.sup.3-R.sup.11 are as described above. These embodiments
of the process can be used to provide compositions comprising
compounds of Formulas (VIIIa-VIIIe) as described above. Specific
ester diols of Formulas (XIIIa-XIIIg) useful and preferred in the
process include: 4-hydroxyphenyl 4-hydroxybenzoate,
2-methyl-4-hydroxyphenyl 4-hydroxybenzoate,
3-methyl-4-hydroxyphenyl 4-hydroxybenzoate,
2-chloro-4-hydroxyphenyl 4-hydroxybenzoate,
3-chloro-4-hydroxyphenyl 4-hydroxybenzoate,
2-fluoro-4-hydroxyphenyl 4-hydroxybenzoate,
3-fluoro-4-hydroxyphenyl 4-hydroxybenzoate,
2-phenyl-4-hydroxyphenyl 4-hydroxybenzoate,
3-phenyl-4-hydroxyphenyl 4-hydroxybenzoate, 6-hydroxynaphthyl
4-hydroxybenzoate, 5-hydroxynaphtyl 4-hydroxybenzoate,
4-(4'-hydroxybiphenyl) 4-hydroxybenzoate, trans-4-hydroxycyclohexyl
4-hydroxybenzoate, trans-4-hydroxycyclohexyl
4-hydroxy-3-methoxybenzoate, 4-hydroxyphenyl
4-hydroxy-3-methoxybenzoate, 2-methyl-4-hydroxyphenyl
4-hydroxy-3-methoxybenzoate, 3-methyl-4-hydroxyphenyl
4-hydroxy-3-methoxybenzoate, 2-chloro-4-hydroxyphenyl
4-hydroxy-3-methoxybenzoate, 3-chloro-4-hydroxyphenyl
4-hydroxy-3-methoxybenzoate, 4-hydroxyphenyl
4-hydroxy-3-methylbenzoate, 2-methyl-4-hydroxyphenyl
4-hydroxy-3-methylbenzoate, and 3-methyl-4-hydroxyphenyl
4-hydroxy-3-methylbenzoate.
[0057] Other ester diols useful and preferred in the processes that
provide compositions comprising specific compounds as described by
Formula (XIIIe) derived from 6-hydroxy-2-napthalene carboxylic acid
are: 6-hydroxynapthalene-2-carboxylic acid 4-hydroxyphenyl ester
(CAS No. [17295-17-9]), 6-hydroxynapthalene-2-carboxylic acid
2-methyl-4-hydroxyphenyl ester, 6-hydroxynapthalene-2-carboxylic
acid 3-methyl-4-hydroxyphenyl ester,
6-hydroxynapthalene-2-carboxylic acid 2-chloro-4-hydroxyphenyl
ester, and 6-hydroxynapthalene-2-carboxylic acid
3-chloro-4-hydroxyphenyl ester.
[0058] Other ester diols useful and preferred in the processes that
provide compositions comprising specific compounds as described in
Formula (XIIIg) derived from 4'-hydroxy-4-biphenyl carboxylic acid
include: 4'-hydroxybiphenyl-4-carboxylic acid 4-hydroxyphenyl
ester, 4'-hydroxybiphenyl-4-carboxylic acid
2-methyl-4-hydroxyphenyl ester, 4'-hydroxybiphenyl-4-carboxylic
acid 3-methyl-4-hydroxyphenyl ester,
4'-hydroxybiphenyl-4-carboxylic acid 2-chloro-4-hydroxyphenyl
ester, and 4'-hydroxybiphenyl-4-carboxylic acid
3-chloro-4-hydroxyphenyl ester.
[0059] In other embodiments of the processes hereof, the polyol(s)
may include one or more diester diol(s) selected from the group of
compounds represented by the structures of the following Formulas
(XIVa-XIVf):
##STR00019##
wherein R.sup.3-R.sup.11 are as described above. These embodiments
of the process can be used to provide compositions comprising
compounds as described in Formula (IXa-IXe) described above.
Specific diester diols of Formula (XIVa-XIVf) useful and preferred
in the process include the compounds listed in Table 1 that are
specific examples of compounds of Formula (XIVa-XIVf).
TABLE-US-00001 TABLE 1 Examples of Diester Diols of Formula
(XIVa-f) ##STR00020## ##STR00021## ##STR00022## ##STR00023##
##STR00024## ##STR00025## ##STR00026## ##STR00027## ##STR00028##
##STR00029## ##STR00030## ##STR00031## ##STR00032## ##STR00033##
##STR00034## ##STR00035## ##STR00036## ##STR00037## ##STR00038##
##STR00039## ##STR00040## ##STR00041## ##STR00042##
[0060] Using a mixture of two or more polyols is one means to
increase the complexity of the product distribution of the
resulting composition. This can be a way to tune the properties of
the composition or the properties of its end use. The polyols can
be selected to provide a composition having two or more mesogens,
for example a composition wherein for at least one compound of each
of the Formulas (I), (II) and (III) m is 1 and p is 0, and wherein
for at least one compound of each of the same Formulas m is 1 and p
is 1. Other combinations of polyols can also be used.
[0061] Preferred functionalized alkyl acid halide(s) as described
in Formula (X) are acid chlorides (X.dbd.Cl). In one embodiment, in
Formula (X) Z is Br, I, --OTs, --OTf, or --OMs. Preferred
non-functionalized alkyl acid halide(s) as described in Formula
(XI) are acid chlorides (X.dbd.Cl). In one embodiment, in Formula
(XI) Y is H, Br, I, --OTs, --OTf, or --OMs. In one embodiment, in
Formula (X) Z is Br and in Formula (XI) Y is H.
[0062] When the organic polyol is a diol, the total amount of the
functionalized alkyl acid halide(s) and the non-functionalized
alkyl acid halide(s) is preferably about 1.8 to about 2.5
equivalents, and more preferably about 2.0 equivalents, based on
the amount of the diol. The relative amounts of the functionalized
and non-functionalized alkyl acid halides used determine the
relative amounts of the compounds of Formulas (I), (II) and (III)
obtained in the composition. For example, a 1:1 mixture (on a mole
basis) of a functionalized and a non-functionalized alkyl acid
halide provides a composition wherein the relative molar amounts of
the compounds of Formulas (I), (II) and (III) are 1:2:1,
respectively. Alternatively, a 4:1 mixture (on a mole basis) of a
functionalized and a non-functionalized alkyl acid halide (for
example, 1.6 equivalents of a functionalized and 0.4 equivalents of
a non-functionalized alkyl acid halide, relative to the diol)
results in a composition having 64 mol % compounds of Formula (I),
32 mol % compounds of Formula (II), and 4 mol % compounds of
Formula (III). For a particular ratio of functionalized to
non-functionalized alkyl acid halide(s), the distribution of
products is a statistical mixture of all the possibilities.
Increasing the total number of functionalized and/or
non-functionalized alkyl acid halides is one means to increase the
complexity of the product distribution, i.e. the number of
compounds of each of Formulas (I), (II) and (III), of the resulting
composition.
[0063] In another embodiment, the relative amounts of the
functionalized and non-functionalized alkyl acid halides are
selected to provide a composition comprising at least one compound
of each of the Formulas (I), (II) and (III), wherein the total
amount of compounds of Formula (I) are present in the range of
about 0.1 mole percent to about 95 mole percent based on the total
content of the composition. In another embodiment, the relative
amounts of the functionalized and non-functionalized alkyl acid
halides are selected to provide a composition wherein the total
amount of compounds of Formula (I) are present in the range of
about 5 mole percent to about 95 mole percent based on the total
content of the composition. In another embodiment, the relative
amounts of the functionalized and non-functionalized alkyl acid
halides are selected to provide a composition wherein the total
amount of compounds of Formula (I) are present in the range of
about 20 to about 80 mole percent based on the total content of the
composition.
[0064] In another embodiment, the relative amounts of the
functionalized and non-functionalized alkyl acid halides are
selected to provide a composition comprising at least one compound
of each of the Formulas (I), (II) and (III), wherein the total
amount of compounds of Formula (II) are present in the range of
about 5 mole percent to about 50 mole percent based on the total
content of the composition. In another embodiment, the relative
amounts of the functionalized and non-functionalized alkyl acid
halides are selected to provide a composition wherein the total
amount of compounds of Formula (II) are present in the range of
about 10 to about 50 mole percent based on the total content of the
composition.
[0065] In another embodiment, the relative amounts of the
functionalized and non-functionalized alkyl acid halides are
selected to provide a composition comprising at least one compound
of each of the Formulas (I), (II) and (III), wherein the total
amount of compounds of Formula (III) are present in the range of
about 0.1 mole percent to about 90 mole percent based on the total
content of the composition. In another embodiment, the relative
amounts of the functionalized and non-functionalized alkyl acid
halides are selected to provide a composition wherein the total
amount of compounds of Formula (III) are present in the range of
about 0.1 mole percent to about 60 mole percent based on the total
content of the composition.
[0066] This process, or derivations thereof using several
functionalized alkyl acid halides in conjunction with several
non-functionalized alkyl acid halides, is a convenient and
preferred process to provide complex mixtures of the
composition.
[0067] The reaction solvent can be any solvent known in the art to
be useful in performing acid halide condensations with alcohols,
including alkyl ethers such as tetrahydrofuran (THF), dioxane or
dimethoxyethane; alkyl esters such as ethyl acetate or butyl
acetate; hydrocarbons such as xylenes or toluene; halogenated
hydrocarbons such as 1,2-dichloroethane or dichloromethane; and
amides such as dimethylformamide or dimethylacetamide (DMAc). A
preferred reaction solvent is THF.
[0068] The reaction temperature is a temperature that gives a
reasonable rate of reaction with a minimum of by-products. The
reaction temperature generally is between -30.degree. C. and about
50.degree. C., and preferably about 0.degree. C. to about room
temperature (RT, e.g. 25.degree. C.).
[0069] A base, when optionally used in step (b), can include an
inorganic base, for instance an alkali metal or alkali earth metal
hydroxide, carbonate or bicarbonate; or an organic base such as an
amine base that has at least two aliphatic groups, or in which the
N atom is in a cycloaliphatic or aromatic ring, substituted in a
manner that induces steric crowding around the N atom. Typically
the amine base will be of low water solubility and have a pK.sub.a
of the conjugate acid of about 10. Thus, it may be a heteroaromatic
base such as pyridine or a substituted pyridine, for example
2,6-dimethylpyridine; or it may be a secondary amine providing it
is sufficiently sterically hindered. An example of a suitable
secondary amine is 2,2,6,6-tetramethyl-piperidine. Preferably,
however, it is a tertiary amine of formula
R.sup.12R.sup.13R.sup.14N wherein R.sup.12, R.sup.13 and R.sup.14
are each independently C.sub.1-C.sub.10 alkyl groups or
C.sub.3-C.sub.6 cycloalkyl groups. The alkyl groups may be straight
or branched chain. Examples of suitable alkyl groups include
methyl, ethyl, isopropyl, n-propyl, n-butyl, sec-butyl and
tert-butyl. Suitable tertiary amines of formula
R.sup.12R.sup.13R.sup.14N are, for example,
N,N-diisopropylethylamine, N,N-dimethylaniline, triethylamine,
t-butyldimethylamine, N,N-diisopropylmethylamine,
N,N-diisopropylisobutylamine, N,N-diisopropyl-2-ethylbutylamine,
tri-n-butylamine. Preferred are amine bases selected from the
group: triethylamine, diisopropylethylamine, tributyl amine,
pyridine, and 2,6-dimethylpyridine. The base is preferably present
in an amount of about 0.8 to about 5 equivalents per equivalent of
the total alkyl acid halide(s) used, that is the sum of the
functionalized and the non-functionalized alkyl acid halides.
[0070] When the base optionally used in step (b) is an amine base,
a by-product of the reaction is an amine salt such as an amine
hydrochloride. In one embodiment the amine salt is removed from the
spent reaction mixture by, for instance, filtering the reaction
mixture. In another embodiment, the mixture comprising at least one
compound of each of the Formulas (I), (II) and (III) provided by
step (b) can be separated from the spent reaction mixture by a
variety of methods known in the art. Preferred methods include any
one or more of the steps: filtering the amine salt by-product;
precipitating the reaction mixture into water and filtering;
partitioning the reaction mixture with water and/or organic
solvents; washing with reaction mixture with water; drying the
reaction mixture with a drying agent; removal of solvent by
evaporation; and washing the crude product with one or more
solvents which selectively remove byproducts without dissolving the
mixture of compounds of Formulas (I), (II) and (III).
[0071] When used in step (b), a suitable carbodiimide dehydrating
agent may be any diimide commonly used in coupling acids with
alcohols and phenols. A preferred carbodiimide for step (b) is
dicyclohexylcarbodiimide.
[0072] Another embodiment of this invention is a composition made
by a process of the invention, which may for example be a
composition of the invention. A composition comprising at least one
compound of each of the Formulas (I), (II) and (III) may be
obtained by
[0073] (a) providing one or more organic polyol(s) comprising at
least two hydroxyl groups and at least two covalently bonded carbon
atoms, each hydroxyl group being bonded to a different carbon atom
within an organic polyol; and
[0074] (b) reacting the organic polyol(s), optionally in the
presence of a base, with (i) one or more functionalized alkyl
acid(s) or acid halide(s) as represented by the structure of the
following Formula (X):
Z-(CH.sub.2).sub.n--C(O)X (X)
wherein X is Cl, Br, I, or OH; Z is Br, I, --OTs, --OTf, or --OMs;
and n is an integer equal to 3 to 20; and [0075] (ii) one or more
non-functionalized alkyl acid(s) or acid halide(s) represented by
the structure of the following Formula (XI):
[0075] Y--(CH.sub.2).sub.t--C(O)X (XI)
wherein X is Cl, Br, I, or OH; Y is H; and t is an integer equal to
3 to 20; with the proviso that Z is not equal to Y; in a reaction
solvent and at a reaction temperature to provide a mixture
comprising the composition and a spent reaction mixture.
[0076] The compositions of the invention, such as those comprising
at least one compound of Formulas (VIIIa-VIIIe) and (IXa-IXe), are
useful in liquid crystal compositions, which are another embodiment
of the invention. Many of these compositions exhibit nematic phases
upon melting. Compositions of various embodiments of the invention
are given below in the examples with their corresponding thermal
transitions that define their respective nematic phases.
[0077] In further embodiments of the invention, the liquid crystal
compositions may include at least one chiral compound, including
polymerizable and/or non-polymerizable chiral monomers. A preferred
liquid crystal composition comprises at least one compound of
Formulas (VIIIa-VIIIe) and (IXa-IXe).
[0078] Chiral compounds, including cholesteryl esters or
carbonates, such as benzoate esters, alkyl esters and alkyl
carbonates of cholesterol, are known to exhibit cholesteric phases
and are known to be useful in inducing chirality in a nematic phase
to produce a twisted nematic phase. The terms "twisted nematic
phase", "cholesteric phase" and "chiral nematic" as used herein are
synonymous. Cholesteryl esters useful for incorporation into liquid
crystal compositions of this invention include cholesteryl
benzoate, cholesteryl 4-alkylbenzoates and cholesteryl
4-alkoxybenzoates wherein the alkyl and alkoxy groups are C.sub.1
to C.sub.8 straight or branched chain alkyl groups, cholesteryl
propionate, cholesteryl butanoate, cholesteryl hexanoate,
cholesteryl octanoate, cholesteryl decanoate, cholesteryl
undecantoate, cholesteryl dodecanoate, cholesteryl hexadecanoate,
and cholesteryl octadecanoate. Cholesteryl carbonates useful for
this purpose include phenyl cholesteryl carbonate, 4-alkylphenyl
cholesteryl carbonates, 4-alkoxyphenyl cholesteryl carbonates, and
alkyl cholesteryl carbonates wherein the alkyl or alkoxy groups are
C.sub.1 to C.sub.8 straight or branched chain alkyl groups.
[0079] In one embodiment of a composition of this invention, the
incorporated chiral compounds are polymerizable chiral monomers and
include polymerizable cholesterol derivatives as described in U.S.
Pat. No. 4,637,896; polymerizable terpenoid derivatives as
described in U.S. Pat. No. 6,010,643; polymerizable derivatives
wherein the chiral center is an asymmetric carbon atom of a
branched alkyl chain as described in U.S. Pat. No. 5,560,864;
polymerizable derivatives of vicinal diols or substituted vicinal
diols as described in U.S. Pat. No. 6,120,859 and U.S. Pat. No.
6,607,677; and polymerizable chiral compounds as described in U.S.
Pat. No. 6,723,395, U.S. Pat. No. 6,217,792, U.S. Pat. No.
5,942,030, U.S. Pat. No. 5,885,242, and U.S. Pat. No. 5,780,629.
Additional examples of suitable chiral compounds are described in
copending and commonly owned published US-A-2007/0267599, WO
2009/023759, and WO 2009/023762. The references listed above in
this paragraph are by this reference each incorporated in its
entirety as a part hereof for all purposes.
[0080] A preferred group of polymerizable chiral monomers for use
in the compositions of this invention are those represented by the
structure of the following Formula (XV):
##STR00043##
wherein R.sup.1 and R.sup.2 are each independently selected from
the group: H, F, Cl and CH.sub.3; n1 and n2 are each independently
integers 3 to 20; q and r are each independently integers 0, 1 or 2
with the proviso that q+r is .gtoreq.1; D is a divalent chiral
radical selected from the group:
##STR00044##
and B.sup.3 and B.sup.4 are each divalent radicals independently
selected from the group: R.sup.11-substituted-1,4-phenyl, wherein
R.sup.11 is H, --CH.sub.3 or --OCH.sub.3; 2,6-naphthyl; and
4,4'-biphenyl; provided that when q+r 3, at least one of B.sup.3
and B.sup.4 is R.sup.4-substituted-1,4-phenyl; and when q+r 4, at
least two of B.sup.3 and B.sup.4 are
R.sup.4-substituted-1,4-phenyl. Preferably R.sup.1 and R.sup.2 are
independently H, or CH.sub.3; and n1 and n2 are independently an
integer 3 to 10.
[0081] Choices may be made from within and among the prescribed
ranges for the variable radicals and substituents such that the
compound of Formula (XV) is, for example, either symmetric or
asymmetric.
[0082] Another preferred group of polymerizable chiral monomers for
practicing this invention are those represented by the structure of
the following Formula (XVI):
##STR00045##
wherein R.sup.1 is selected from the group: H, F, Cl and CH.sub.3;
E is selected from the group: --(CH.sub.2).sub.n7--,
--(CH.sub.2).sub.n8O--, and --(CH.sub.2CH.sub.2O).sub.n9--; n7 and
n8 are each integers 3 to 20; n9 is an integer 1 to 4; and y is an
integer 0 or 1.
[0083] Forming a liquid crystal layer from a composition of this
invention that optionally comprises a chiral monomer can be
accomplished by any method that gives a uniform layer, or if
desired, a patterned or non-uniform layer. Coating, including
rod-coating, extrusion coating, gravure coating and spin-coating,
spraying, printing, blading, knifing, or a combination of methods,
can be used. Coating and knifing are preferred methods. Many
commercial coating machines, devices such as a coating rod and
knife blade, and printing machines can be used to apply the liquid
crystal mixture as a liquid crystal or isotropic phase.
[0084] The ability of a twisted nematic phase to reflect light is
dependent upon the alignment or texture of the twisted nematic
phase. For many applications wherein a high degree of transparency
is required outside the reflection band, or in applications that
require very well defined reflection bands, a high degree of
uniformity in a planar or homogeneous alignment is required.
Discontinuities and domain boundaries in a planar alignment can
cause a high degree of haze and degradation of the reflection band.
A high degree of uniformity in planar alignment can be accomplished
with a combination of alignment layers and/or mechanical shearing
of the twisted nematic phase during and/or after application to the
substrate(s). Alignment layers typically are polymers that are
applied to substrates and mechanically buffed with a rubbing cloth
or optically aligned with polarized light. The buffing or optical
alignment allows the liquid crystal molecules applied to the
interface to align in one direction. Useful polyimide alignment
layers, for example, are described in U.S. Pat. No. 6,887,455.
Alignment of twisted nematic phases by coating of dilute liquid
crystal mixtures is described in U.S. Pat. No. 6,410,130.
[0085] Treating the liquid crystal layer to provide a desired
liquid crystal phase can include steps such as cooling or heating
the liquid crystal layer, for instance to achieve a desired phase
or optical property; application of a mechanical shear to the
liquid crystal layer, for instance by application of a knife blade
to the liquid crystal layer or shearing two or more substrates
wherein the liquid crystal layer is interposed; or vibration,
sonication or other form of agitation to the substrate(s).
[0086] Liquid crystal compositions as provided by this invention
may further comprise small amounts of a polymerizable diluent that
may include, for example, 2-ethoxyethyl acrylate, diethylene glycol
diacrylate, ethylene glycol dimethacrylate, diethylene glycol
dimethacrylate, triethylene glycol dimethacrylate, diethylene
glycol monomethyl ether acrylate, phenoxyethyl acrylate,
tetraethylene glycol dimethacrylate, pentaerythritol tetraacrylate
and ethoxylated pentaerythritol tetraacrylate.
[0087] Liquid crystal compositions as provided by this invention
may further comprise small amounts of typical additives such as one
or more of surfactants, leveling agents, viscosity modifiers,
wetting agents, defoamers and UV stabilizers. Selection will often
be based upon observed coating and alignment quality and the
desired adhesion of the liquid crystal coating to the substrate and
other layers. Typical surfactants comprise siloxy-, fluoryl-,
alkyl-and alkynyl-substituted surfactants. These include the
Byk.RTM. (Byk Chemie), Zonyl.RTM. (DuPont), Triton.RTM. (Dow),
Surfynol.RTM. (Air Products) and Dynol.RTM. (Air Products)
surfactants.
[0088] The ability of twisted nematic phases to selectively reflect
light in the infrared, visible or ultraviolet region is useful in
many applications. When the propagation direction of plane
polarized or unpolarized light is along the helical axis of the
twisted nematic layer, the wavelength of maximum reflection,
.lamda..sub.0, is governed by the equation .lamda..sub.0=n.sub.a p,
wherein n.sub.a is the average of n.sub.o and n.sub.e, and n.sub.o
and n.sub.e are defined as the ordinary and extraordinary
refractive indices respectively, of the twisted nematic phase
measured in the propagation direction and p is the pitch of the
helix (the distance the helix takes to repeat itself). Light
outside the vicinity of .lamda..sub.0 is essentially unaffected in
transmission. For light with a wavelength in the vicinity of
wavelength .lamda..sub.0, the twisted nematic phase exhibits
selective reflection of the light such that approximately 50% of
the light is reflected and approximately 50% of the light is
transmitted, with both the reflected and transmitted beams being
substantially circularly polarized. A right handed helix reflects
right handed circularly polarized light and transmits left handed
circularly polarized light. The bandwidth .DELTA..lamda. of this
reflected wavelength band centered about .lamda..sub.0 can be
determined by the formula
.DELTA..lamda.=.lamda..sub.0.DELTA.n/n.sub.a, where
.DELTA.n=n.sub.e-n.sub.o, reflecting the birefringence present in
liquid crystal materials. The pitch p can be tuned effectively by
manipulating the amount of chiral dopant, the twisting power of the
dopant and selection of the nematic materials. The pitch is
sensitive to temperature, unwinding or tightening with a change in
temperature; and to electric fields, dopants, and other
environmental considerations. Thus, in the twisted nematic phase,
manipulation of the pitch, and thus the wavelength of maximum
reflection, can be accomplished with a wide variety of tools.
Furthermore, the bandwidth .DELTA..lamda. of the reflected
wavelength band also can be manipulated in the manner described in
U.S. Pat. No. 5,506,704 and U.S. Pat. No. 5,793,456.
[0089] Articles derived from a composition of the invention are
useful as optical elements or components of an optical element. An
optical element is any film, coating or shaped object that is used
to modify the characteristics of light. The modifications produced
by optical elements include changes in the intensity of light
through changes in transmission or reflectivity, changes in
wavelength or wavelength distribution, changes in the state of
polarization, changes in the direction of propagation of part or
all of the light, or changes in the spatial distribution of
intensity by, for example, focusing, collimating, or diffusing the
light. Examples of optical elements include linear polarizers,
circular polarizers, lenses, mirrors, collimators, diffusers,
reflectors and the like. Examples of the usefulness of articles,
including optical elements, comprising liquid crystal compositions
are provided, for example, in a general review by P. Palffy-Muhoray
in "The Diverse World of Liquid Crystals", Physics Today (2007),
60(9), pp. 54-60.
EXAMPLES
[0090] The advantageous attributes and effects of this invention
may be more fully appreciated from a series of examples (Examples
1.about.3), as described below. The embodiments on which the
examples are based are representative only, however, and the
selection of those embodiments to illustrate the invention does not
indicate that materials, conditions, specifications, components,
regimes, reactants, steps, ingredients, or techniques not described
in these examples are not suitable for practicing this invention,
or that subject matter not described in these examples is excluded
from the scope of the appended claims and equivalents thereof.
[0091] In the following examples, thermal transitions are given in
degrees Centigrade. The following notations are used to describe
the observed phases: K=crystal, N=nematic, S=smectic, TN*=twisted
nematic, X=unidentified phase, I=isotropic, P=polymerized. The
thermal transitions and phase assignments were made with
differential scanning calorimetry and hotstage optical microscopy.
Unless noted otherwise, the phase behavior refers to the first
heating cycle.
[0092] Compound 1 was obtained as described in US-A-2007/0228326.
All other materials used in the examples were obtained from
commercial sources.
Example 1
[0093] This example illustrates the formation of Mixture 1, a
liquid crystal mixture of one embodiment of the invention. Mixture
1 corresponds to a composition comprising one compound of Formula
(I), two compounds of Formula (II), and one compound of Formula
(III).
##STR00046##
[0094] 10 g of Compound 1 was dissolved in 40 mL THF and 9.5 mL
triethylamine and cooled to 0.degree. C. A mixture of 8.96 g
6-bromohexanoyl chloride and 1.68 g valeroyl chloride in 60 mL THF
was added dropwise over 20 minutes. Stirring was continued for
another 30 minutes at 0.degree. C. The cooling bath was removed and
the reaction allowed to stir for an additional 90 minutes. The
reaction was filtered to remove salts and the salts were washed
with THF. Approximately 75% of the solvent was removed under
reduced pressure and the crude oil was added to an excess of water,
forming a colorless precipitate. The solids were filtered, washed
with water, methanol, and dried to provide 17.74 g of Mixture 1.
1.sup.st heating: K 81-85 N 177-179 I
Example 2
[0095] This example illustrates the formation of Mixture 2, a
liquid crystal mixture of one embodiment of the invention. Mixture
2 corresponds to a composition comprising one compound of Formula
(I), four compounds of Formula (II), and four compounds of Formula
(III).
##STR00047## ##STR00048##
[0096] 10 g of Compound 1 was dissolved in 40 mL THF and 9.5 mL
triethylamine and the solution was cooled to 0.degree. C. A mixture
of 9.56 g 6-bromohexanoyl chloride, 0.75 g hexanoyl chloride, and
0.91 g octanoyl chloride in 30 mL THF was added dropwise over 20
minutes. The reaction mixture was stirred for another 30 minutes at
0.degree. C., the cooling bath was removed and the reaction was
allowed to stir for an additional 90 minutes. The reaction mixture
was filtered to remove salts, the salts were rinsed with THF and
the organics were diluted with diethyl ether and washed with water.
The organics were dried over MgSO.sub.4, filtered, and concentrated
to provide 18.58 g of Mixture 2 as an off-white solid. 1.sup.st
heating: K 85-91 N 166-171 I
Example 3
[0097] This example illustrates the formation of Mixture 3, a
liquid crystal mixture of one embodiment of the invention. Mixture
3 corresponds to a composition comprising four compounds of Formula
(I), eight compounds of Formula (II), and four compounds of Formula
(III).
##STR00049##
TABLE-US-00002 TABLE 2 Statistical Mixture of Compounds with
Average Molecular Weight of 678.4535 g/mol in Mixture 3 Isomer Mole
% a Z b Y 1 30.25 5 Br 5 Br 2 13.75 5 Br 3 Br 3 5.50 5 Br 5 H 4
5.50 5 Br 7 H 5 13.75 3 Br 5 Br 6 6.25 3 Br 3 Br 7 2.50 3 Br 5 H 8
2.50 3 Br 7 H 9 5.50 5 H 5 Br 10 2.50 5 H 3 Br 11 1.00 5 H 5 H 12
1.00 5 H 7 H 13 5.50 7 H 5 Br 14 2.50 7 H 3 Br 15 1.00 7 H 5 H 16
1.00 7 H 7 H
[0098] Each of the formulae shown herein describes each and all of
the separate, individual compounds that can be formed in that
formula by (i) selection from within the prescribed range for one
of the variable, substituents or numerical coefficients while all
of the other variable radicals, substituents or numerical
coefficients are held constant, and (ii) performing in turn the
same selection from within the prescribed range for each of the
other variable radicals, substituents or numerical coefficients
with the others being held constant. In addition to a selection
made within the prescribed range for any of the variable radicals,
substituents or numerical coefficients of only one of the members
of the group described by the range, a plurality of compounds may
be described by selecting more than one but less than all of the
members of the group of radicals, substituents or numerical
coefficients. When the selection made within the prescribed range
for any of the variable radicals, substituents or numerical
coefficients is a subgroup containing (a) only one of the members
of the group described by the range, or (b) more than one but less
than all of the members of the group, the selected member(s) are
selected by omitting those member(s) of the whole group that are
not selected to form the subgroup. The compound, or plurality of
compounds, may in such event be described as containing one or more
variable radicals, substituents or numerical coefficients each of
which variable radicals, substituents or numerical coefficients is
defined by the members of the whole group, described by the range
for that variable radical, substituent or numerical coefficient in
the absence of the member(s) omitted to form the subgroup.
[0099] Certain features of this invention are described herein in
the context of an embodiment that combines various such features
together, whether as described in the disclosure or in one of the
drawings. The scope of the invention is not, however, limited by
the description of only certain features within any particular
embodiment, and the invention also includes (1) a subcombination of
fewer than all of the features of any described embodiment, which
subcombination is characterized by the absence of the features
omitted to form the subcombination; (2) each of the features,
individually, included within the combination of the described
embodiment; and (3) other combinations of features formed from one
or more or all of the features of the described embodiment together
with other features as disclosed elsewhere herein.
[0100] Where a range of numerical values is recited herein, the
range includes the endpoints thereof and all the individual
integers and fractions within the range, and also includes each of
the narrower ranges therein formed by all the various possible
combinations of those endpoints and internal integers and fractions
to form subgroups of the larger group of values to the same extent
as if each of those narrower ranges was explicitly recited. Where a
range of numerical values is stated herein as being greater than a
stated value, the range is nevertheless finite and is bounded on
its upper end by a value that is operable within the context of the
invention as described herein. Where a range of numerical values is
stated herein as being less than a stated value, the range is
nevertheless bounded on its lower end by a non-zero value.
[0101] In this specification, unless explicitly stated otherwise or
indicated to the contrary by the context of usage, where an
embodiment of this invention is stated or described as comprising,
including, containing, having, being composed of or being
constituted by or of certain features or elements, one or more
features or elements in addition to those explicitly stated or
described may be present in the embodiment. An alternative
embodiment of this invention, however, may be stated or described
as consisting essentially of certain features or elements, in which
embodiment features or elements that would materially alter the
principle of operation or the distinguishing characteristics of the
embodiment are not present therein. A further alternative
embodiment of this invention may be stated or described as
consisting of certain features or elements, in which embodiment, or
in insubstantial variations thereof, only the features or elements
specifically stated or described are present.
[0102] In this specification, unless explicitly stated otherwise or
indicated to the contrary by the context of usage,
[0103] (a) amounts, sizes, formulations, parameters, and other
quantities and characteristics recited herein, particularly when
modified by the term "about", may but need not be exact, and may be
approximate and/or larger or smaller than stated (as desired),
reflecting tolerances, conversion factors, rounding off,
measurement error and the like, as well as the inclusion within a
stated value of those values outside it that have, within the
context of this invention, functional and/or operable equivalence
to the stated value;
[0104] (b) all numerical quantities of parts, percentage or ratio
are given as parts, percentage or ratio by weight;
[0105] (c) use of the indefinite article "a" or "an" with respect
to a statement or description of the presence of an element or
feature of this invention, does not limit the presence of the
element or feature to one in number;
[0106] (d) the words "include", "includes" and "including" are to
be read and interpreted as if they were followed by the phrase
"without limitation" if in fact that is not the case; and
[0107] (e) the word "or", as used herein, is inclusive; more
specifically, the phrase "A or B" means "A, B, or both A and B";
and use of "or" in an exclusive sense is designated, for example,
by terms such as "either A or B" and "one of A or B".
* * * * *