Organic compounds -- part of the class 532-570 series – Organic compounds – Four or more ring nitrogens in the bicyclo ring system
Reexamination Certificate
2000-01-21
2001-05-08
Raymond, Richard L. (Department: 1624)
Organic compounds -- part of the class 532-570 series
Organic compounds
Four or more ring nitrogens in the bicyclo ring system
C544S216000
Reexamination Certificate
active
06229012
ABSTRACT:
COPENDING APPLICATIONS
Illustrated in copending applications U.S. Ser. No. 09/489,144, and U.S. Ser. No. 09/489,754, disclosures of which are totally incorporated herein by reference, are triazines and electroluminescent devices containing triazines. The appropriate components and processes of the above copending applications may be selected for the present invention in embodiments thereof.
BACKGROUND OF THE INVENTION
The present invention is directed to organic electronic materials, and more specifically, to organic electron transport materials or luminescent materials comprised of novel triazine compounds, and which compounds can be selected for organic electroluminescent (EL) devices, and other optoelectronic devices including photoconductive devices and the like.
PRIOR ART
Organic electron transport materials or n-type organic semiconductors are useful for a number of device applications. For example, they can be selected for electron transport materials or luminescent materials in organic EL devices. An organic EL device with a multilayer structure can be formed as a dual layer structure comprising one organic layer adjacent to the anode supporting hole transport, and another organic layer adjacent to the cathode supporting electron transport and acting as the organic luminescent zone of the device. Another alternate device configuration for an EL device is comprised of three separate layers, a hole transport layer, a luminescent layer, and an electron transport layer, which layers are laminated in sequence and are sandwiched between an anode and a cathode. Optionally, a fluorescent dopant material can be added to the emission zone or layer whereby the recombination of charges results in the excitation of the fluorescent.
Typically, organic EL devices with multi-layered configurations comprise an anode, a hole transport layer, and an electron transport layer in contact with a cathode. This electron transport layer is intended to assist injection of electrons from the cathode. A known class of electron transport materials, which may also function as an luminescent layer, are the metal complexes of 8-hydroxyquinoline, as disclosed in U.S. Pat. Nos. 4,539,507, 4,720,432, and 5,151,629. A another known class of electron transport materials for EL devices are 1,3,5-oxidiazole compounds, such as those disclosed in
Japanese Journal of Applied Physics
, Part 2, vol. 34, L824 (1995), and 1,3,5-triazine a hole blocking layer in organic EL devices, reference Fink et al. in
Macromolecular Symposia
, vol. 125, 151 (1997).
While recent progress in organic EL research has elevated the potential of organic EL devices for widespread applications, the performance levels of current available devices may still be below certain expectations. Further, for visual display applications, organic luminescent materials should provide a satisfactory color in the visible spectrum, normally an emission maxima at about 460, 550 and 630 nanometers for blue, green and red. The metal complexes of 8-hydroxyquinoline, such as tris(8-hydroxyquinolinate) aluminum, generally fluoresce in green or a longer wavelength region, and which materials are suitable for use in EL devices with light emission in green or longer wavelength region. Although, a number of known electron transport materials may fluoresce in blue region, the performance characteristics of the EL devices may possess many disadvantages such as poor operation stability. Thus, there continues to be a need for electron transport materials for organic EL devices, which are suitable for the design of EL devices with satisfactory emission in the visible spectrum of, for example, from about 400 nanometers to about 700 nanometers. There is also a need for electron transport materials, which can enhance the EL charge transporting characteristics, thus desirably lowering device driving voltages; electron transport materials for EL devices comprised of a cathode comprised of a less active metal such as aluminum and which device can maintain desirable performance characteristics such as low driving voltage, and acceptable operation stability. Further, there is a need for electron transport materials, which are vacuum evaporable and can form thin films with excellent thermal stability. These and other needs and advantages can be achievable with the present invention in embodiments thereof.
SUMMARY OF THE INVENTION
It is an feature of the present invention to provide a class of triazine compounds, which can be selected for organic EL devices.
It is another feature of the present invention to provide a class of triazine compounds useful an optoelectronic materials that is for example, organic electron transport materials or fluorescent materials.
In an another feature of the present invention there is provided a class of triazine compounds with many advantageous properties, such as physical stability, for example a glass transition temperature exceeding about 100° C., photochemical stability, for example no detectable degradation under exposure to UV light, and electrochemical stability, for example reversible behavior in cyclic voltametry.
Further in another feature of the present invention there is provided triazine compounds with intense blue luminescence, including photoluminescence and electroluminescence.
Yet in another feature of the present invention there is provided triazine compounds comprised of two s-triazine rings covalently linked with a biphenyl unit.
Aspects of the present invention relate to triazine compounds illustrated by, or encompassed by the formula
wherein Ar
1
, A
2
, Ar
3
, and Ar
4
are each an aryl group, an aliphatic group, or a heteroaromatic group, wherein the aryl group contains for example, from about 6 to about 60 carbon atoms and preferably from about 6 to about 30 carbon atoms, which aryl group is more specifically independently selected for example, from the group consisting of a phenyl, a stilbenyl, a biphenylyl, a naphthyl, and the like; and wherein aliphatic refers primarily to alkyl; and heteroaromatic refers for example, to groups that may contain from about 2 to about 30 carbon atoms, and more specifically wherein the heteroaromatic is selected from the group consisting of a pyridyl, a quinolyl, a thienyl, a 1,3,5-oxadiazolyl and the like; and wherein the aryl group, aliphatic group or the heteroaromatic group may contain a suitable substituent selected for example, from the group consisting of hydrogen, an alkyl group with, for example, from 1 to about 6 carbon atoms, an aryl group with from 6 to about 30 carbon atoms, an alkoxy group with for example, from 1 to about 6 carbon atoms, a dialkylamino group with from about 1 to about 3 carbon atoms, a halogen, a cyano group and the like; R
1
and R
2
are each independently a substituent selected from the group consisting of hydrogen, an alkyl group with, for example, from 1 to about 6 carbon atoms, an alkoxy group with, for example, from 1 to about 6 carbon atoms, a halogen, a cyano group and the like; L which is optional, can be Ln wherein n is a number such as zero (no covalent bond) or 1, and which L when present is a suitable group, and preferably is a divalent group selected from the group consisting of an alkylene such as methylene or ethylene, a vinylene, an oxygen atom, a sulfur atom, —Si(R′R″)—, wherein R′ and R″ are selected from the group consisting of hydrogen, alkyl, alkoxy, and aryl and the like; and preferably L is —C(R′R″)—, wherein R′ and R″ is a hydrogen atom, an alkyl group containing from 1 to about 10 carbon atoms, or an alkoxyl group containing from 1 to about 10 carbon atoms, and the like.
Aspects of the present invention relate to; triazine compounds as represented by formula:
wherein the aryl groups of Ar
1
, Ar
2
, Ar
3
, and Ar
4
; and the substituents of R
1
and R
2
are as indicated herein; or by the formula
wherein the substituents such as L, aryl groups of Ar
1
, Ar
2
, Ar
3
, and Ar
4
; and the substituents of R
1
and R
2
are as indicated herein.
The triazine compounds possess a num
Aziz Hany
Hu Nan-Xing
Ong Beng S.
Popovic Zoran D.
Balasubramanian Venkataraman
Palazzo E. O.
Raymond Richard L.
Xerox Corporation
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