Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2002-01-24
2003-10-07
Richter, Johann (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S632000, C568S633000, C568S439000, C564S441000, C564S315000, C558S411000, C558S414000, C558S415000, C558S419000, C558S420000, C428S690000
Reexamination Certificate
active
06630607
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to novel aromatic methylidene compounds which are useful as a functional material in electrophotographic photosensitive bodies or as a functional material, such as a charge transport material or a light-emitting material, in organic electroluminescent devices or as a functional material used in other various types of organic semiconductor devices. The invention also relates to intermediate aromatic aldehyde compounds and methylstyryl compounds, both useful for preparing the methylidene compounds, and methods for preparing the intermediate compounds and the methylidene compounds.
2. Description of the Prior Art
Electroluminescent devices that make use of an electroluminescent phenomenon of a substance are self-luminescent in nature, and are thus higher in visuality than liquid crystal devices, ensuring a clear display. Because of the complete solid-state device, they have prominent features of good impact resistance and the like, and are expected as being widely used in the fields of thin displays, back light of liquid crystal displays, plane light sources and the like.
Existing electroluminescent devices are those of a dispersion type which make use of inorganic materials such as zinc sulfide. However, such dispersion-type electroluminescent devices are not in wide use because a relatively high AC voltage is necessary for their drive, with the attendant problem that a drive circuit becomes complicated along with low luminance.
On the other hand, an organic electroluminescent device using organic materials has been proposed by C. W. Tang, for example, in Japanese Laid-open Patent Application No. Hei 63-264692. The device includes a builtup structure of an electron transport organic fluorescent material layer and a hole-transport organic material layer wherein both electron and hole carriers are injected into the fluorescent material layer to permit light emission. It is stated in the application that this electroluminescent device has a much improved luminascent efficiency, and is capable of emission at 1000 cd/m
2
or more on application of a voltage of 10V or below. Since the beginning of the above proposal, extensive studies have been made on the related fields of the organic electroluminescent device. At present, various types of materials and device structures have been proposed with extensive studies and developments being directed to practical applications.
Organic electroluminescent devices using materials proposed up to now have, in fact, several problems to solve. Mention is made of some instances of the problems including the lowering of an emission luminance through degradation in function of a device which is only stored irrespective of whether the device is in a driven or non-driven condition, the occurrence of a degradation phenomenon wherein a non-emitting region called dark spot occurs and grows in the course of driving or non-driving, finally resulting in the breakage of the device via short-circuiting.
Such phenomena rely greatly on the fundamental problem of the materials used in the device, and the device may not be satisfactory with respect to the service life thereof. For the service of the device, limitation has to be placed on applications to devices of a type which are responsible only for a relatively short life.
Further, taking the color mode of the device into consideration, systems and light-emitting materials meeting this requirement are not provided satisfactorily at present. In order to solve the above problems and find use in wide fields of organic electroluminescent devices, there has been a strong demand of development of novel materials used in the device such as novel high-performance light-emitting materials, charge transport materials, and the like.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide novel aromatic methylidene compounds useful as a light-emitting material so as to realize an organic electroluminescent device that can be driven at low voltage, ensures light emission of high luminance and is excellent in durability.
It is another object of the invention to provide novel aromatic aldehyde compounds and methylstyryl compounds, both useful for preparing the above-mentioned novel aromatic methylidene compounds.
It is a further object of the invention to provide methods for preparing the aromatic methylidene compounds.
It is a still further object of the invention to provide methods for preparing the aromatic aldehyde compounds and methylstyryl compounds, respectively.
According to one embodiment of the invention, there is provided a novel aromatic methylidene compound selected from the group consisting of compounds of the following general formulas (1), (1a), (1b), (1c) and (1d):
wherein R
11
and R
21
independently in each occurrence represent an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxy group, a halogen, e.g. chlorine, bromine, iodine, fluorine, a cyano group or a nitro group, n
11
is an integer of 0, 1, 2, 3, 4, 5 or 6, and n
21
is an integer of 0, 1, 2, 3 or 4 provided that when n
11
and n
21
are, respectively, an integer of 2 or more, R
11
and R
21
may be, respectively, the same or different, and R
31
and R
41
independently represent hydrogen except the case where both R
31
and R
41
are hydrogen at the same time, an unsubstituted or substituted alkyl group except the case where both R
31
and R
41
are an alkyl group at the same time, an unsubstituted or substituted cycloalkyl group except the case where both R
31
and R
41
are the cycloalkyl group at the same time, an unsubstituted or substituted aromatic group, or an unsubstituted or substituted aromatic heterocyclic group, or may join to complete a condensed ring of unsubstituted or substituted aromatic rings or unsubstituted or substituted aromatic heterocyclic rings;
wherein R
11a
, R
21a
, n
11a
, n
21a
, R
31a
and R
41a
, respectively, have the same meanings as R
11
, R
21
, n
11
, n
21
, R
31
and R
41
defined with respect to the formula (1);
wherein R
11b
, R
21b
, n
11b
, n
21b
, R
31b
and R
41b
, respectively, have the same meanings as R
11
, R
21
, n
11
, n
21
, R
31
and R
41
defined with respect to the formula (1);
wherein R
11c
, R
21c
, n
11c
, n
21c
, R
31c
and R
41c
, respectively, have the same meanings as R
11
, R
21
, n
11
, n
21
, R
31
and R
41
defined with respect to the formula (1), like formulas (1a) and (1c); and
wherein R
11d
, R
21d
, n
11d
, n
21d
, R
31d
and R
41d
, respectively, have the same meanings as R
11
, R
21
, n
11
, n
21
, R
31
and R
41
defined with respect to the formula (1), like formulas (1a) and (1c).
According to another embodiment of the invention, there are also provided intermediate compounds useful for preparing the corresponding aromatic methylidene compounds of the above formulas (1), (1a), (1b), (1c) and (1c). The novel intermediate compounds corresponding to the aromatic methylidene compound (1) are indicated as having the following general formulas (2) and (3):
wherein R
12
and R
22
, respectively, correspond to R
11
and R
21
and independently in each occurrence represent an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxy group, a halogen, a cyano group or a nitro group, n
12
is an integer of 0, 1, 2, 3, 4, 5 or 6, and n
22
is an integer of 0, 1, 2, 3 or 4 provided that when n
12
and n
22
are, respectively, an integer of 2 or more, R
12
's and R
22
's may be, respectively, the same or different; and
wherein R
13
and R
23
, respectively, correspond to R
12
and R
22
and independently in each occurrence represent an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxy group, a halogen, a cyano group or a nitro group, n
13
is an integer of 0, 1, 2, 3, 4, 5 or 6, and n
23
is an integer of 0, 1, 2, 3 or 4 provided that when n
13
and n
23
are, respectively, an integer of 2 or more, R
13
's and R
23
's may be, respectively, the same or different.
Likewise, the inte
Richter Johann
Witherspoon Sikarl A.
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