Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2001-11-21
2003-11-18
McKane, Joseph K. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C430S059500
Reexamination Certificate
active
06649772
ABSTRACT:
BACKGROUND
Electroluminescent (EL) devices based on organic thin layers have recently attracted much attention because of their potential uses in large-area flat-panel displays and light-emitting diodes (LED). Organic LEDs have been made with both low molecular-weight organic materials and with polymers. The performance of these devices is significantly influenced by the charge balance between electrons and holes from opposite electrodes. The charge can be balanced by using a bilayer structure including a hole transporting layer and an electron transporting layer. One or both of these layers can be luminescent.
An important quality of organic EL materials is their durability, i.e., thermal and morphological stability. Thus, it is desirable that organic EL materials are not only light-emitting and hole-transporting, but also robust.
SUMMARY
This invention relates to substituted carbazole compounds, which are hole-transporting, light-emitting molecules with high glass transition temperatures. These compounds have a number of qualities that make them useful in electroluminescence devices.
In one aspect, the present invention features substituted carbazole compounds of formula (I):
Each of Z
1
and Z
2
, independently, is
[referred to hereinafter as N(R
2
R
3
), A
1
Y
1
, or A
2
Y
2
N(R
4
R
5
)]; each of A
1
and A
2
, independently, is S, O, NR, or CH═CH; each of Y
1
and Y
2
, independently, is aryl or heteroaryl; each of R
1
-R
5
, independently, is aryl or heteroaryl; and each of R
6
-R
11
, independently, is H, CN, alkyl, OR, NRR′, COR, or C(O)OR; in which each of R and R′, independently, is H or alkyl. Note that Z
1
and Z
2
can be two different N(R
2
R
3
), two different A
1
Y
1
, or two different A
2
Y
2
N(R
4
R
4
R
5
).
Referring to formula (I), a subset of the carbazole compounds of this invention is featured by that each of Z
1
and Z
2
, independently, is N(R
2
R
3
). In these compounds, each of R
6
-R
11
can be H; R
1
can be phenyl; each of R
2
and R
3
, independently, can be aryl. In some embodiments, one of R
2
and R
3
is pyrenyl and the other is phenyl. Exemplary compounds include 9-N,N′-triphenyl-N,N′-di-pyren-1-yl-9H-carbazole-3,6-diamine (Compound 1), 9-phenyl-N,N′-di-pyren-1-yl-N,N′-di-p-tolyl-9H-carbazole-3,6-diamine (Compound 2), and N,N′-bis-(4-methoxy-phenyl)-9-phenyl-N,N′-di-pyren-1-yl-9H-carbazole-3,6-diamine (Compound 3).
Another subset of the carbazole compounds of this invention is featured by that each of Z
1
and Z
2
, independently, is A
2
Y
2
N(R
4
R
5
). In these compounds, A
2
can be S; each of R
6
-R
11
can be H; R
1
can be phenyl; each of R
4
and R
5
, independently, can be phenyl. In some embodiments, Y
2
is phenyl, carbazolyl, or fluorenyl. Exemplary compounds include 9-phenyl-3,6-bis{5-[4-diphenylamino-phenyl]-thiophen-2-yl}-9H-carbazole (Compound 4), 9-phenyl-3,6-bis{5-[3,5-bis(diphenylamino)-phenyl]-thiophen-2-yl}-9H-carbazole (Compound 5), 9-phenyl-3,6-bis[5-(3-diphenylamino-9-ethyl-carbazol-6-yl)-thiophen-2-yl]-9H-carbazole (Compound 6), or 9-phenyl-3,6-bis[5-(2-di-phenylamino-9,9-diethyl-fluoren-7-yl)-thiophen-2-yl]-9H-carbazole (Compound 7).
Further, another subset of the carbazole compounds of this invention is featured by that each of Z
1
and Z
2
, independently, is A
1
Y
1
. In these compounds, A
1
can be S; and Y
1
can be heteroaryl. An exemplary compound is 9-phenyl-3,6-bis[5-(carbazol-3-yl)-thiophen-2-yl]-9H-carbazole (Compound 8).
Still further another subset of the carbazole compounds of this invention is featured by that one of Z
1
and Z
2
is N(R
2
R
3
) and the other is A
1
Y
1
.
In addition, salts of the carbazole compounds described above are within the scope of the invention. For example, a salt can be formed between a positively charged amino substituent and a negatively charged counterion.
Alkyl, aryl, heteroaryl, phenyl, pyrenyl, carbazolyl, and fluorenyl mentioned above include both substituted and unsubstituted moieties. The term “substituted” refers to one or more substituents (which may be the same or different), each replacing a hydrogen atom. Examples of substituents include, but are not limited to, halogen, amino, alkylamino, arylamino, dialkylamino, diarylamino, hydroxyl, mercapto, cyano, nitro, C
1
~C
6
alkyl, C
1
~C
6
alkenyl, C
1
~C
6
alkoxy, aryl, heteroaryl, or heterocyclyl, wherein alkyl, alkenyl, alkoxy, aryl, heteroaryl, and heterocyclyl are optionally substituted with C
1
~C
6
alkyl, halogen, amino, alkylamino, arylamino, dialkylamino, diarylamino, hydroxyl, mercapto, cyano, or nitro. The term “aryl” refers to a hydrocarbon ring system having at least one aromatic ring. Examples of aryl moieties include, but are not limited to, phenyl, naphthyl, and pyrenyl. The term “heteroaryl” refers to a hydrocarbon ring system having at least one aromatic ring which contains at least one heteroatom such as O, N, or S. Examples of heteroaryl moieties include, but are not limited to, pyridinyl, carbazolyl, and indolyl.
In another aspect, this invention features an electroluminescence device made with one or more of the carbazole compounds described above. The device includes a hole transporting layer, an emitting layer, and an electron transporting layer. The hole transporting layer, the emitting layer and the electron transporting layer are disposed in the above order, and at least one of the hole transporting layer and the emitting layer includes the carbazole compounds of this invention. In some embodiments, both the hole transporting layer and the emitting layer include the carbazole compounds.
The details of one or more embodiments of the invention are set forth in the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.
DETAILED DESCRIPTION
The invention features carbazole compounds, and EL devices made using these compounds. In particular, the carbazole compounds are substituted at the 3-, 6-, and 9-positions. The substituted carbazoles improve the thermal stability and/or glassy state durability of organic compounds when incorporated into the cores of these compounds and are thus useful for making organic LEDs.
A method for synthesizing certain substituted carbazoles follows: A 9-substituted carbazole is prepared by coupling a carbazole with a halide in the presence of a catalyst. Examples of suitable halides include aryl halides and heteroaryl halides, in which the aryl groups may be substituted. Other examples of suitable halides include alkyl halides and vinyl halides. The result of the coupling reaction is a 9-substituted carbazole.
The 1, 2, 4, 5, 7, and 8-positions of the starting carbazole may be H, or they may be CN, allyl, OR, NRR′, COR, or C(O)OR; wherein each of R and R′, independently, is H or alkyl. Thus, other positions of the carbazole may be substituted; however, the product of the coupling reaction will be referred to simply as a “9-substituted carbazole” for brevity.
The 9-substituted carbazole is converted to a 9-substituted, 3,6-dihalocarbazole by treating the 9-substituted carbazole with a halogenating agent. The 9-substituted, 3,6-dihalocarbazole is converted to a 9-substituted, 3,6-diaminocarbazole by coupling the dihalo compound with an amine, or a mixture of amines in presence of a catalyst, such as a catalyst developed by Koie (Nishiyama et al. (1998)
Tetrahedron Lett.
39: 617), or Hartwig (Hartwig et al. (1999)
J. Org. Chem.
64: 5575). The catalyst shown in Scheme 1, Pd(dba)
2
(dba=dibenzylideneacetone)/P(t-Bu)
3
, in the presence of NaO-t-Bu, can efficiently catalyze C—N bond formation between an aryl halide and an aryl amine
Secondary amines are preferred in the just-described reaction; the amines can be symmetrical or asymmetric. The amines can have saturated or unsaturated aliphatic substituents, or aromatic substituents, with aromatic substituents, especially fused aromatic substituents, being preferred. Th
Ko Chung-Wen
Lin Jiann T'Suen
Tao Yu-Tai
Thomas K. R. Justin
Academia Sinica
McKane Joseph K.
Saeed Kamal
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