Stock material or miscellaneous articles – Composite – Of inorganic material
Reexamination Certificate
2001-08-24
2004-07-27
Kelly, Cynthia H. (Department: 1774)
Stock material or miscellaneous articles
Composite
Of inorganic material
C428S917000, C313S503000, C313S504000, C252S062200, C568S001000, C568S003000, C568S006000
Reexamination Certificate
active
06767654
ABSTRACT:
TECHNICAL FIELD
The present invention relates to novel borane derivatives, various materials and organic electroluminescent devices (hereinafter referred to as “organic EL device”) comprising the borane derivatives. Specifically, this invention relates to borane derivatives having novel structures, and various materials and organic EL devices comprising the borane derivatives having the structures, which are useful as electronic functional materials and optical functional materials.
BACKGROUND ART
Various institutions have tried to apply &pgr; electron type organic compounds to optical functional materials and electronic functional materials in various ways.
Among them, borane compounds which intramolecularly contain boron atoms have unique optic and electronic properties probably owing to the existence of the empty p orbital of the boron atom. However, the borane compounds have generally been unsuitable for the use as such materials, because of their instability to air and water.
With respect to such a problem, it has been reported that the borane compound can become stable to air and water when constituted so as to be bulky, namely, when introducing bulky substituents around a boron atom so as not to expose the boron atom outward. Thus it is highly likely that the borane compound having such a structure can apply for nonlinear optical materials and organic EL devices.
Examples of borane compounds stable in the air have been reported in J. Chem. Soc. Chem. Commun., 1998, 963 (hereinafter referred to as Document 1), J. Am. Chem. Soc., 120, 10776(1998) (hereinafter referred to as Document 2), and J. Am. Chem. Soc., 120, 5112 (1998) hereinafter referred to as Document 3). Further, applications of borane compounds to nonlinear optical materials have been reported in Appl. Organomet. Chem., 10, 305(1996) (hereinafter referred to as Document 4). In addition, an application of borane compounds to organic EL devices has been reported in J. Am. Chem. Soc., 120, 9714 (1998) (hereinafter referred to as Document 5).
Documents 2 and 3 describe the maximum fluorescent wavelength, but the descriptions are limited to the luminescence property in solution state. There is no description on the luminescence property in solid state which is actually used in such application. Further, the structures disclosed are limited to polymers, and there is no description on any low molecular weight compounds.
Document 4 also describes the fluorescent property in the solution state, but there is neither description about the luminescence in the solid state, nor description about applications for the luminescent materials.
Thus the studies have not been made sufficiently for using the “bulky” borane compound in any substantial applications at present. Particularly, there has been a demand to apply the borane material to the organic EL devices. Many studies have been made in order to find such a compound as the device, which has not led to any satisfactory result yet.
The organic EL device essentially comprises a structure wherein an organic compound as a charge transport material and/or a luminescent material is sandwiched in between two electrodes. The highly efficient organic EL device of a low power consumption is required, and thus it is necessary to select an organic compound of high luminous efficiency as the luminescent material.
Document 5 describes some borane compounds such as 5,5′-bis(dimesitylboryl)-2,2′-(bithiophene) and 5,5″-bis(dimesitylboryl)-2,2′:5′,2″-(terthiophene) used for electron transport materials (charge transport materials), but does not mention their luminescence property or suitability for luminescent materials. This literature merely mentions the device comprising the borane compound having a lower current density, i.e., a more improved luminous efficiency, than that of the device of the same luminance not comprising the borane compound.
JP-A 7-102251 also describes an example of the boron compound used for the organic EL device. However, this boron compound requires a high voltage for driving the device, and has a low luminance.
Since there are few literatures on the luminescence property of borane compounds, any highly efficient organic EL device of a low power consumption has not been prepared by using borane compounds known as a raw material for the organic EL device. Therefore, there has been a demand for a borane compound having a specific structure effective as a material for an organic EL device.
DISCLOSURE OF THE INVENTION
The present inventors have made intensive studies in order to provide a new borane derivative, and various materials and organic EL devices each comprising the borane derivative. As a result, the inventors have found that a borane derivative having a specific structure, and a material, particularly an organic EL device, comprising the borane derivative can solve the above-mentioned problems, whereby the present invention have been achieved.
The present invention is described below in detail.
The borane derivative of the present invention is a new compound represented by the following formula (1). The present borane derivative is expected to be used in a wide variety of applications such as electronic functional materials and optical function materials taking advantage of electronic properties originating from the borane atom, as well as for luminescent materials and charge transport materials.
wherein R
1
to R
8
and Z
2
are each independently a hydrogen atom, a saturated or unsaturated hydrocarbon group, an aromatic group, a heterocyclic group, a substituted amino group, a substituted boryl group, an alkoxy group or an aryloxy group; X, Y and Z
1
are each independently a saturated or unsaturated hydrocarbon group, an aromatic group, a heterocyclic group, a substituted amino group, an alkoxy group or an aryloxy group; substituents of Z
1
and Z
2
may be united to form a condensed ring; and n is an integer of 1-3;
with the provisos that when n is two or more, Z
1
s may be different from each other; and that cases where n is 1, X, Y and R
2
are each methyl, and R
8
is a hydrogen atom or substituted boryl and those where n is 3 and Z
1
is methyl are excluded.
Among the borane derivatives represented by the formula (1), preferable are those wherein at least one substituted or unsubstituted 9-anthryl group is bonded to the boron atom.
Concrete examples of the borane derivative according to this invention include the compounds represented by the following formulae (3) to (9).
The compound represented by the formula (3) is one of the borane derivatives of the above formula (1) wherein n is 3, R
4
to R
8
are each hydrogen atom, and Z
1
and Z
2
are benzo-condensed.
The compound represented by the formula (4) is one of the borane derivatives of the above formula (1) wherein n is 3, R
4
to R
7
are each hydrogen atom, one R
8
is a dianthrylboryl group and the other two R
8
s are each hydrogen atom, and Z
1
and Z
2
are benzo-condensed.
The compound represented by the formula (5) is one of the borane derivatives of the above formula (1) wherein R
4
to R
7
are each hydrogen atom, R
8
is phenyl, n is 3, and Z
1
and Z
2
are benzo-condensed.
The compound represented by the formula (6) is one of the borane derivatives of the above formula (1) wherein n is 2, R
1
and R
3
to R
8
are each hydrogen atom, R
2
, X and Y are each methyl group, and Z
1
and Z
2
are benzo-condensed.
The compound represented by the formula (7) is one of the borane derivatives of the above formula (1) wherein n is 2, R
1
and R
3
to R
7
are each hydrogen atom, R
2
, X and Y are each methyl group, one R
8
is anthrylmesitylboryl, the other R
8
is a hydrogen atom, and Z
1
and Z
2
are benzo-condensed.
The compound represented by the formula (8) is one of the borane derivatives of the above formula (1) wherein n is 3, R
4
to R
8
are each hydrogen atom, Z
1
and Z
2
are benzo-condensed at one position, the other two Z
1
s not condensed are a methyl group, and the other two Z
2
s not condensed are a hydrogen atom.
The compound
Furukawa Kenji
Izumizawa Takenori
Koike Toshihiro
Nakano Takaharu
Tamao Kouhei
Chisso Corporation
Kelly Cynthia H.
Thompson Camie S
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