WO2014054912A1

WO2014054912A1 - Organic electroluminescent compounds and organic electroluminescent device comprising the same

Info

Publication number: WO2014054912A1
Application number: PCT/KR2013/008891
Authority: WO
Inventors: Chi-Sik Kim; Seon-Woo Lee; Su-Hyun Lee; Young-Kwang Kim; Kyung-Joo Lee; Hyo-Nim Shin; Se-Hwa PARK; Kyoung-Jin Park; Young-Jun Cho; Hyuck-Joo Kwon; Bong-Ok Kim
Original assignee: Rohm And Haas Electronic Materials Korea Ltd.
Priority date: 2012-10-04
Filing date: 2013-10-04
Publication date: 2014-04-10
Also published as: CN104812750A; TW201425527A

Abstract

The present invention relates to organic electroluminescent compounds and an organic electroluminescent device comprising the same. An organic electroluminescent device having low driving voltage, and excellent luminescent efficiency and power efficiency can be prepared by using the organic electroluminescent compounds according to the present invention.

Description

ORGANIC ELECTROLUMINESCENT COMPOUNDS AND ORGANIC ELECTROLUMINESCENT DEVICE COMPRISING THE SAME

The present invention relates to organic electroluminescent compounds and an organic electroluminescent device comprising the same.

An electroluminescent (EL) device is a self-light-emitting device with the advantage of providing a wider viewing angle, a greater contrast ratio, and a faster response time. An organic EL device was first developed by Eastman Kodak, by using small aromatic diamine molecules and aluminum complexes as material for forming a light-emitting layer [see Appl. Phys. Lett. 51, 913, 1987].

The organic EL device can be prepared by using the reduced cost and material costs, and has the advantage of providing a wider viewing angle, a greater light and shade ratio, and a faster response time, compared with a liquid crystalline display (LCD). The organic EL device has been rapidly developed in technology after its first development, which improves efficiency by eighty (80) times and lifespan by one-hundred (100) times or more.

Furthermore, the organic EL device is an advantage in enlargement of display, and thus forty (40) inches of organic EL device panels were announced and enlargement is rapidly conducted. However, for enlargement of the organic EL device, enhancement of lifespan and improvement of luminescent efficiency of the device should be accompanied.

In order to improve lifespan of the organic EL device, crystallization of material due to Joule heat, which is generated in driving the device, should be inhibited. Thus, it is necessary to develop an organic compound having a greater injection and mobility of an electron and electrochemical stability.

Meanwhile, the most important factor determining luminescent efficiency of an organic EL device is a light-emitting material. Until now, fluorescent materials have been widely used as a light-emitting material. However, in view of electroluminescent mechanisms, developing phosphorescent materials is one of the best methods to theoretically enhance luminescent efficiency by four (4) times compared to fluorescent materials.

A host/dopant system can be used as a light-emitting material. If only one material is used as a light-emitting material, some problems may occur, such as shift of maximum light-emitting wavelength to a long wavelength and deterioration of color purity due to intermolecular interaction, and reduction of efficiency of a device due to light-emitting decrease effect. A host/dopant system is an advantage in improving color purity and enhancing luminescent efficiency and stability through energy transfer.

Until now, Iridium(III) complexes have been widely known as phosphorescent materials, including bis(2-(2’-benzothienyl)-pyridinato-N,C3’)iridium(acetylacetonate) ((acac)Ir(btp)₂), tris(2-phenylpyridine)iridium (Ir(ppy)₃) and bis(4,6-difluorophenylpyridinato-N,C2)picolinate iridium (Firpic) as red, green and blue materials, respectively.

In conventional technique, 4,4’-N,N’-dicarbazol-biphenyl (CBP) is the most widely known phosphorescent host material. Pioneer (Japan) et al., currently developed a high performance organic EL device by employing bathocuproine (BCP) and aluminum(III)bis(2-methyl-8-quinolinate)(4-phenylphenolate) (BAlq), which were used in a hole blocking layer, as host materials.

Although these phosphorescent host materials provide good light-emitting characteristics, they have the following disadvantages: (1) Due to their low glass transition temperatures and poor thermal stability, their degradation may occur during a high-temperature deposition process in a vacuum. (2) The power efficiency of an organic EL device is given by [(π/voltage) × current efficiency], and the power efficiency is inversely proportional to voltage. An organic EL device comprising phosphorescent host materials provides higher current efficiency (cd/A) and has a higher driving voltage than one comprising fluorescent host materials. Thus, the EL device using conventional phosphorescent materials has no advantage in terms of power efficiency (lm/W). (3) Furthermore, the operating lifespan and luminous efficiency of the organic EL device are not satisfactory.

Korean Patent Nos. 10-0957288 and 10-0948700 disclose, as compounds for an organic EL device, organic compounds wherein the respective nitrogen position of two carbazole groups, which are substituted with phenyl groups on the 3- and 6-position of their carbon atoms, is linked via a nitrogen-containing heteroarylene group.

Furthermore, Korean Patent Application Laid-Open No. 10-2008-0080306 discloses, as compounds for an organic EL device, organic compounds wherein the respective carbon position of two dibenzothiophene or dibenzofuran is linked via a nitrogen-containing heteroarylene group.

However, the publications do not specifically disclose the organic electroluminescent compounds wherein the carbon position of heteroaryl groups such as dibenzothipehene, dibenzofuran or carbazole, or an aryl group such as fluorene, and the nitrogen position of a carbazole group are linked via a nitrogen-containing heteroarylene group.

The objective of the present invention is to provide an organic electroluminescent compound which can be used in preparing an organic electroluminescent device having low driving voltage, high luminescent efficiency and high power efficiency.

The present inventors found that the above objective can be achieved by a compound represented by the following formula 1:

wherein

L₁ and L₂each independently represent a single bond, a substituted or unsubstituted 3- to 30-membered heteroarylene group, or a substituted or unsubstituted (C6-C30)arylene group;

X₁ and X₂ each independently represent CH or N;

Y represents -O-, -S-, -CR₁₁R₁₂- or -NR₁₃-;

Ar₁ represents a substituted or unsubstituted (C6-C30)aryl group, or a substituted or unsubstituted 3- to 30-membered heteroaryl group;

Ar₂ represents hydrogen, deuterium, a halogen, a substituted or unsubstituted (C1-C30)alkyl group, a substituted or unsubstituted (C6-C30)aryl group, or a substituted or unsubstituted 3- to 30-membered heteroaryl group;

R₁ to R₃ each independently represent hydrogen, deuterium, a halogen, a substituted or unsubstituted (C1-C30)alkyl group, a substituted or unsubstituted (C6-C30)aryl group, a substituted or unsubstituted 3- to 30-membered heteroaryl group, a substituted or unsubstituted (C3-C30)cycloalkyl group, a substituted or unsubstituted 5- to 7-membered heterocycloalkyl group, a substituted or unsubstituted (C6-C30)aryl(C1-C30)alkyl group, -NR₁₄R₁₅, -SiR₁₆R₁₇R₁₈, -SR₁₉, -OR₂₀, a cyano group, a nitro group, or a hydroxyl group; or are linked to an adjacent substituent(s) to form a mono- or polycyclic, 5- to 30-membered alicyclic or aromatic ring whose carbon atom(s) may be replaced with at least one hetero atom selected from nitrogen, oxygen and sulfur;

R₁₁ to R₂₀ each independently represent hydrogen, deuterium, a halogen, a substituted or unsubstituted (C1-C30)alkyl group, a substituted or unsubstituted (C6-C30)aryl group, a substituted or unsubstituted 3- to 30-membered heteroaryl group, a substituted or unsubstituted 5- to 7-membered heterocycloalkyl group, or a substituted or unsubstituted (C3-C30)cycloalkyl group; or are linked to an adjacent substituent(s) to form a mono- or polycyclic, 5- to 30-membered alicyclic or aromatic ring whose carbon atom(s) may be replaced with at least one hetero atom selected from nitrogen, oxygen and sulfur;

a and c each independently represent an integer of 1 to 4; where a or c is an integer of 2 or more, each of R₁ or each of R₃ is the same or different;

b represents an integer of 1 to 3; where b is an integer of 2 or more, each of R₂ is the same or different; and

the heteroarylene group, heterocycloalkyl group and heteroaryl group contain at least one hetero atom selected from B, N, O, S, P(=O), Si and P.

An organic electroluminescent device having low driving voltage, high luminescent efficiency and high power efficiency can be prepared by using the organic electroluminescent compounds according to the present invention.

Hereinafter, the present invention will be described in detail. However, the following description is intended to explain the invention, and is not meant in any way to restrict the scope of the invention.

The present invention relates to an organic electroluminescent compound represented by formula 1 above, an organic electroluminescent material comprising the organic electroluminescent compound, and an organic electroluminescent device comprising the material.

The organic electroluminescent compound represented by formula 1 is described in detail below.

The compound of formula 1 is represented by the following formula 2, 3 or 4:

wherein

L₁, L₂, X₁, X₂, Y, Ar₁, Ar₂, R₁ to R₃, and a to c are as defined in formula 1.

Herein, “alkyl” includes methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, etc. “alkenyl” includes vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2- butenyl, 3- butenyl, 2-methylbut-2-enyl, etc. “alkynyl” includes ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2- butynyl, 3-butynyl, 1-methylpent-2-ynyl, etc. “cycloalkyl” cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc. “5- to 7-membered heterocycloalkyl” is a cycloalkyl having at least one heteroatom selected from the group consisting of B, N, O, S, P(=O), Si and P, preferably O, S and N, and 5 to 7 ring backbone atoms, and includes tetrahydrofurane, pyrrolidine, thiolan, tetrahydropyran, etc. “aryl(ene)” is a monocyclic or fused ring derived from an aromatic hydrocarbon and includes phenyl, biphenyl, terphenyl, naphthyl, binaphthyl, phenylnaphthyl, naphthylphenyl, fluorenyl, phenylfluorenyl, benzofluorenyl, dibenzofluorenyl, phenanthrenyl, phenylphenanthrenyl, anthracenyl, indenyl, triphenylenyl, pyrenyl, tetracenyl, perylenyl, chrysenyl, naphthacenyl, fluoranthenyl, etc. “3- to 30-membered heteroaryl(ene)” is an aryl group having at least one, preferably 1 to 4 heteroatom selected from the group consisting of B, N, O, S, P(=O), Si and P, and 3 to 30 ring backbone atoms; is a monocyclic ring, or a fused ring condensed with at least one benzene ring; may be partially saturated; may be one formed by linking at least one heteroaryl or aryl group to a heteroaryl group via a single bond(s); and includes a monocyclic ring-type heteroaryl including furyl, thiophenyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, thiadiazolyl, isothiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, triazinyl, tetrazinyl, triazolyl, tetrazolyl, furazanyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, etc., and a fused ring-type heteroaryl including benzofuranyl, benzothiophenyl, isobenzofuranyl, dibenzofuranyl, dibenzothiophenyl, benzonapthothiophenyl, benzoimidazolyl, benzothiazolyl, benzoisothiazolyl, benzoisoxazolyl, benzoxazolyl, isoindolyl, indolyl, indazolyl, benzothiadiazolyl, quinolyl, isoquinolyl, cinnolinyl, quinazolinyl, napthyridyl, quinoxalinyl, carbazolyl, phenoxazinyl, phenanthridinyl, benzodioxolyl, dihydroacridinyl, etc. “Halogen” includes F, Cl, Br and I.

Herein, “substituted” in the expression “substituted or unsubstituted” means that a hydrogen atom in a certain functional group is replaced with another atom or group, i.e., a substituent. Substituents of the substituted alkyl group, the substituted aryl(ene) group, the substituted heteroaryl(ene) group, the substituted cycloalkyl group, the substituted heterocycloalkyl group, and the substituted aralkyl group in L₁, L₂, Ar₁, Ar₂, R₁ to R₃, and R₁₁ and R₂₀ each independently are at least one selected from the group consisting of deuterium; a halogen; a (C1-C30)alkyl group which is unsubstituted or substituted with a halogen; a (C6-C30)aryl group; a 3- to 30-membered heteroaryl group which is unsubstituted or substituted with a (C6-C30)aryl group; a (C3-C30)cycloalkyl group; a 5- to 7-membered heterocycloalkyl group; a tri(C1-C30)alkylsilyl group; a tri(C6-C30)arylsilyl group; a di(C1-C30)alkyl(C6-C30)arylsilyl group; a (C1-C30)alkyldi(C6-C30)arylsilyl group; a (C2-C30)alkenyl group; a (C2-C30)alkynyl group; a cyano group; a carbazolyl group; a di(C1-C30)alkylamino group; a di(C6-C30)arylamino group; a (C1-C30)alkyl(C6-C30)arylamino group; a di(C6-C30)arylboronyl group; a di(C1-C30)alkylboronyl group; a (C1-C30)alkyl(C6-C30)arylboronyl group; a (C6-C30)aryl(C1-C30)alkyl group; and a (C1-C30)alkyl(C6-C30)aryl group; a carboxyl group; a nitro group; and a hydroxyl group; and preferably at least one selected from the group consisting of deuterium; a halogen; (C1-C6)alkyl group; a (C6-C12)aryl group; a 3- to 15-membered heteroaryl group which is unsubstituted or substituted with a (C6-C12)aryl group; a (C6-C12)cycloalkyl group; a tri(C6-C12)arylsilyl group; and a cyano group.

In formula 1 above, preferably, L₁ and L₂ each independently represent a single bond, a substituted or unsubstituted 3- to 15-membered heteroarylene group, or a substituted or unsubstituted (C6-C15)arylene group; and more preferably a single bond, or an unsubstituted (C6-C12)arylene group.

Ar₁ preferably represents a substituted or unsubstituted (C6-C20)aryl group, or a substituted or unsubstituted 3- to 15-membered heteroaryl group; and more preferably a (C6-C20)aryl group which is unsubstituted or substituted with deuterium, a halogen, a (C1-C6)alkyl group, a (C6-C12)aryl group, a 3- to 15-membered heteroaryl group unsubstitued or substitued with a (C6-C12)aryl group, or a (C6-C12)cycloalkyl group; or a 3- to 15-membered heteroaryl group which is unsubstituted or substituted with a (C6-C12)aryl group.

Ar₂ preferably represents hydrogen, a substituted or unsubstituted (C6-C15)aryl group, or a substituted or unsubstituted 3- to 15-membered heteroaryl group; and more preferably hydrogen; a (C6-C15)aryl group which is unsubstituted or substituted with deuterium, a (C1-C6)alkyl group, a (C6-C12)aryl group, a 3- to 15-membered heteroaryl group, a (C6-C12)cycloalkyl group, a tri(C6-C12)arylsilyl group or a cyano group; or a 3- to 15-membered heteroaryl group which is substituted with a (C6-C12)aryl group.

Preferably, R₁ to R₃ each independently represent hydrogen, a substituted or unsubstituted (C6-C15)aryl group, or a substituted or unsubstituted 3- to 30-membered heteroaryl group; or are linked to an adjacent substituent(s) to form a mono- or polycyclic, 5- to 30-membered alicyclic or aromatic ring whose carbon atom(s) may be replaced with at least one hetero atom selected from nitrogen, oxygen and sulfur. More preferably, R₁ to R₃ each independently represent hydrogen or an unsubstituted (C6-C12)aryl group; or are linked to an adjacent substituent(s) to form a mono- or polycyclic, 5- to 15-membered aromatic ring.

Preferably, R₁₁ to R₂₀ each independently represent a substituted or unsubstituted (C1-C30)alkyl group, or a substituted or unsubstituted (C6-C30)aryl group; and more preferably an unsubstituted (C1-C6)alkyl group, or an unsubstituted (C6-C12)aryl group.

According to one embodiment of the present invention, in formula 1, L₁ and L₂ each independently represent a single bond, a substituted or unsubstituted 3- to 15-membered heteroarylene group, or a substituted or unsubstituted (C6-C15)arylene group; X₁ and X₂ each independently represent CH or N; Y represents -O-, -S-, -CR₁₁R₁₂- or -NR₁₃-; Ar₁ represents a substituted or unsubstituted (C6-C20)aryl group, or a substituted or unsubstituted 3- to 15-membered heteroaryl group; Ar₂ represents hydrogen, a substituted or unsubstituted (C6-C15)aryl group, or a substituted or unsubstituted 3- to 15-membered heteroaryl group; R₁ to R₃ each independently represent hydrogen, a substituted or unsubstituted (C6-C15)aryl group, or a substituted or unsubstituted 3- to 30-membered heteroaryl group; or R₁ to R₃ are linked to an adjacent substituent(s) to form a mono- or polycyclic, 5- to 30-membered alicyclic or aromatic ring whose carbon atom(s) may be replaced with at least one hetero atom selected from nitrogen, oxygen and sulfur; and R₁₁ to R₂₀ each independently represent a substituted or unsubstituted (C1-C30)alkyl group, or a substituted or unsubstituted (C6-C30)aryl group.

According to another embodiment of the present invention, in formula 1, L₁ and L₂ each independently represent a single bond, or an unsubstituted (C6-C12)arylene group; X₁ and X₂ each independently represent CH or N; Y represents -O-, -S-, -CR₁₁R₁₂- or -NR₁₃-; Ar₁ represents a (C6-C20)aryl group which is unsubstituted or substituted with deuterium, a halogen, a (C1-C6)alkyl group, a (C6-C12)aryl group, a 3- to 15-membered heteroaryl group unsubstitued or substitued with a (C6-C12)aryl group, or a (C6-C12)cycloalkyl group; or Ar₁ represents a 3- to 15-membered heteroaryl group which is unsubstituted or substituted with a (C6-C12)aryl group; Ar₂ represents hydrogen; a (C6-C15)aryl group which is unsubstituted or substituted with deuterium, a (C1-C6)alkyl group, a (C6-C12)aryl group, a 3- to 15-membered heteroaryl group, a (C6-C12)cycloalkyl group, a tri(C6-C12)arylsilyl group or a cyano group; or Ar₂ represents a 3- to 15-membered heteroaryl group which is substituted with a (C6-C12)aryl group; R₁ to R₃ each independently represent hydrogen or an unsubstituted (C6-C12)aryl group; or R₁ to R₃ are linked to an adjacent substituent(s) to form a mono- or polycyclic, 5- to 15-membered aromatic ring; and R₁₁ to R₂₀ each independently represent an unsubstituted (C1-C6)alkyl group, or an unsubstituted (C6-C12)aryl group.

The organic electroluminescent compounds of formula 1 of the present invention include the following compounds, but are not limited thereto:

The organic electroluminescent compounds according to the present invention can be prepared by known methods to one skilled in the art, and can be prepared, for example, according to the following reaction scheme 1.

[Reaction Scheme 1]

wherein Ar₁, Ar₂, L₁, L₂, Y, X₁, X₂, R₁ to R₃, a, b and c are as defined in formula 1 above, and Hal represents a halogen.

The present invention further provides an organic electroluminescent material comprising the organic electroluminescent compound of formula 1 above, and an organic electroluminescent device comprising the material. The material can be comprised of the organic electroluminescent compound according to the present invention alone, or can further include conventional materials generally used in organic electroluminescent materials.

The organic electroluminescent device of the present invention may comprise a first electrode, a second electrode, and at least one organic layer between the first and second electrodes, wherein the organic layer comprises at least one organic electroluminescent compound of formula 1 above.

One of the first electrodes and the second electrodes can be an anode and the other can be a cathode. The organic layer may comprise a light-emitting layer, and may further comprise at least one layer selected from the group consisting of a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, an interlayer, and a hole blocking layer.

The light-emitting layers can include the organic electroluminescent compound of the present invention. When used in the light-emitting layer, the organic electroluminescent compounds of the present invention can be included as a host material. Preferably, the light-emitting layer may further comprise at least one dopant. If necessary, other compounds in addition to the organic electroluminescent compound of the present invention may be further included as a second host material.

The second host material can be any of the known phosphorescent hosts. The phosphorescent host selected from the following formulae 5 to 9 is preferable in view of luminescent efficiency:

wherein

Cz represents the following structure:

X represents -O- or -S-;

R₂₁ to R₂₄ each independently represent hydrogen, deuterium, a halogen, a substituted or unsubstituted (C1-C30)alkyl group, a substituted or unsubstituted (C6-C30)aryl group, a substituted or unsubstituted 5- or 30-membered heteroaryl group, or R₂₅R₂₆R₂₇Si-; or are linked to an adjacent substituent(s) to form a mono- or polycyclic, 5- to 30-membered alicyclic or aromatic ring whose carbon atom(s) may be replaced with at least one hetero atom selected from nitrogen, oxygen and sulfur;

R₂₅ to R₂₇ each independently represent a substituted or unsubstituted (C1-C30)alkyl group, or a substituted or unsubstituted (C6-C30)aryl group;

L₄ represents a single bond, a substituted or unsubstituted (C6-C30)arylene group, or a substituted or unsubstituted 5- or 30-membered heteroarylene group;

M represents a substituted or unsubstituted (C6-C30)aryl group, or a substituted or unsubstituted 5- or 30-membered heteroaryl group;

Y₁ and Y₂ each independently represent -O-, -S-, -N(R₃₁)- or -C(R₃₂)(R₃₃)-; and Y₁ and Y₂ are not simultaneously present;

R₃₁ to R₃₃ each independently represent a substituted or unsubstituted (C1-C30)alkyl group, a substituted or unsubstituted (C6-C30)aryl group, or a substituted or unsubstituted 5- or 30-membered heteroaryl group; are linked to an adjacent substituent(s) to form a mono- or polycyclic, 5- to 30-membered alicyclic or aromatic ring whose carbon atom(s) may be replaced with at least one hetero atom selected from nitrogen, oxygen and sulfur; and R₃₂ and R₃₃ may be the same or different;

h and i each independently represent an integer of 1 to 3;

j, k, l and m each independently represent an integer of 0 to 4;

where h, i, j, k, l or m is an integer of 2 or more, each of (Cz-L₄), each of (Cz), each of R₂₁, each of R₂₂, each of R₂₃ or each of R₂₄ is the same or different;

Specifically, the second host material includes the following:

wherein TPS represents triphenylsilyl.

The dopants applied to the organic electroluminescent device of the present invention are preferably one or more phosphorescent dopants. The phosphorescent dopant material applied to the organic electroluminescent device of the present invention is not specifically limited, but preferably may be selected from complex compounds of iridium (Ir), osmium (Os), copper (Cu), and platinum (Pt), more preferably ortho metallated complex compounds of iridium (Ir), osmium (Os), copper (Cu), and platinum (Pt), and even more preferably ortho metallated iridium complex compounds.

The phosphorescent dopant comprised in the organic electroluminescent device of the present invention may be selected from compound represented by the following formulae 10 to 12:

wherein

L is selected from the following structures:

;

R₁₀₀ represents hydrogen, a substituted or unsubstituted (C1-C30)alkyl group, or a substituted or unsubstituted (C3-C30)cycloalkyl group; R₁₀₁ to R₁₀₉ and R₁₁₁ to R₁₂₃ each independently represent hydrogen, deuterium, a halogen; a (C1-C30)alkyl group unsubstituted or substituted with halogen(s); a substituted or unsubstituted (C3-C30)cycloalkyl group, a cyano group, or a substituted or unsubstituted (C1-C30)alkoxy group; R₁₂₀ to R₁₂₃ are linked to an adjacent substituent(s) to form a fused ring, for example, a quinoline ring; R₁₂₄ to R₁₂₇ each independently represent hydrogen, deuterium, a halogen, a substituted or unsubstituted (C1-C30)alkyl group, or a substituted or unsubstituted (C6-C30)aryl group; when R₁₂₄ to R₁₂₇ are aryl groups, they are linked to an adjacent substituent(s) to form a fused ring, for example, a fluorene ring; R₂₀₁ to R₂₁₁ each independently represent hydrogen, deuterium, a halogen, a (C1-C30)alkyl group unsubstituted or substituted with halogen(s), a substituted or unsubstituted (C3-C30)cycloalkyl group, or a substituted or unsubstituted (C6-C30)aryl group; f and g each independently represent an integer of 1 to 3; where f or g is an integer of 2 or more, each of R₁₀₀ may be the same or different; and n represents an integer of 1 to 3.

The phosphorescent dopant material includes the following:

The present invention further provides the material for the organic electroluminescent device. The material comprises the compounds of the present invention as a host material. If the compounds of the present invention is included as a host material, the material may further comprise a second host material. The first host material and the second host material may be in the range of 1:99 to 99:1 in a weight ratio.

Furthermore, the organic electroluminescent device of the present invention comprises a first electrode, a second electrode, and at least one organic layer between said first and second electrodes, wherein the organic layer comprises the material for the organic electroluminescent device of the present invention.

The organic electroluminescent device of the present invention comprises the organic electroluminescent compounds of formula 1 in the organic layer and may further include at least one compound selected from the group consisting of arylamine-based compounds and styrylarylamine-based compounds.

In the organic electroluminescent device of the present invention, the organic layer may further comprise, in addition to the organic electroluminescent compounds of formula 1, at least one metal selected from the group consisting of metals of Group 1, metals of Group 2, transition metals of the 4^th period, transition metals of the 5^th period, lanthanides, and organic metals of d-transition elements of the Periodic Table, or at least one complex compound comprising the metal. Furthermore, the organic layer may further comprise at least one light-emitting layer or charge generating layer.

In addition, the organic electroluminescent device of the present invention may emit white light by further comprising at least one light-emitting layer which comprises a blue electroluminescent compound, a red electroluminescent compound, or a green electroluminescent compound, besides the compound of the present invention; and may further include a yellow or orange light-emitting layer, if necessary.

Preferably, in the organic electroluminescent device according to the present invention, at least one layer (hereinafter, "a surface layer”) selected from a chalcogenide layer, a metal halide layer and a metal oxide layer may be placed on an inner surface(s) of one or both electrode(s). Specifically, it is preferred that a chalcogenide (includes oxides) layer of silicon or aluminum is placed on an anode surface of an electroluminescent medium layer, and a metal halide layer or metal oxide layer is placed on a cathode surface of an electroluminescent medium layer. The surface layer provides operating stability for the organic electroluminescent device. Preferably, the chalcogenide includes SiO_X(1≤X≤2), AlO_X(1≤X≤1.5), SiON, SiAlON, etc.; the metal halide includes LiF, MgF₂, CaF₂, a rare earth metal fluoride, etc.; and the metal oxide includes Cs₂O, Li₂O, MgO, SrO, BaO, CaO, etc.

Preferably, in the organic electroluminescent device according to the present invention, a mixed region of an electron transport compound and an reductive dopant, or a mixed region of a hole transport compound and an oxidative dopant may be placed on at least one surface of a pair of electrodes. In this case, the electron transport compound is reduced to an anion, and thus it becomes easier to inject and transport electrons from the mixed region to an electroluminescent medium. Further, the hole transport compound is oxidized to a cation, and thus it becomes easier to inject and transport holes from the mixed region to the electroluminescent medium. Preferably, the oxidative dopant includes various Lewis acids and acceptor compounds; and the reductive dopant includes alkali metals, alkali metal compounds, alkaline earth metals, rare-earth metals, and mixtures thereof. A reductive dopant layer may be employed as a charge generating layer to prepare an electroluminescent device having two or more electroluminescent layers and emitting white light.

In order to form each layer constituting the organic electroluminescent device according to the present invention, dry film-forming methods, such as vacuum evaporation, sputtering, plasma, ion plating methods, etc., or wet film-forming methods, such as spin coating, dip coating, flow coating methods, etc., can be used.

When using a wet film-forming method, a thin film is formed by dissolving or dispersing the material constituting each layer in suitable solvents, such as ethanol, chloroform, tetrahydrofuran, dioxane, etc. The solvents are not specifically limited as long as the material constituting each layer is soluble or dispersible in the solvents, which do not cause any problems in forming a layer.

Hereinafter, the organic electroluminescent compound of the present invention, the preparation method of the compound, and the luminescent properties of the device comprising the compound will be explained in detail with reference to the following examples:

Example 1: Preparation of compound H-2

Preparation of compound 1-1

After adding 1-bromo-2-nitrobenzene (6.0 g, 29.5 mmol), [1,1’-biphenyl]-4-ylboronic acid (7.0 g, 35.4 mmol), tetrakis(triphenylphosphine)palladium(O) (Pd(PPh₃)₄) (1.1 g, 0.88 mmol) and K₂CO₃ (7.8 g, 73.7 mmol) to toluene (160.0 mL), ethanol (EtOH) (40.0 mL) and distilled water (40.0 mL), the mixture was stirred for 5 hours at 120°C. After stirring, distilled water was slowly added to the mixture to complete the reaction, the mixture was cooled to room temperature, and the organic layer was extracted with distilled water and methylene chloride (MC). The organic layer was concentrated and was separated through column chromatography [MC/hexane (Hex)] to obtain compound 1-1 (7.1 g, Yield: 87 %).

Preparation of compound 1-2

Compound 1-1 (7.1 g, 25.6 mmol) was dissolved in triethylphophite (P(OEt)₃) (65.0 mL) and the mixture was stirred for 12 hours at 140°C. After stirring, the solvent was extracted. The residue was solidified and was recrystallized with dichlorobenzene to obtain compound 1-2 (5.0 g, Yield: 80 %).

Preparation of compound 1-3

Dibenzo[b,d]thiophene-4-ylboronic acid (50.0 g, 219.0 mmol), 2,4-dichloropyrimidine (42.4 g, 284.7 mmol), ) Pd(PPh₃)₄ (7.6 g, 6.58 mmol), K₂CO₃ (75.67 g, 547.5 mmol), H₂O (220 mL), EtOH (180.0 mL) and toluene (440.0 mL) were reflux stirred for 2 hours. After completing the reaction, the mixture was cooled and was solidified by adding MeOH. The obtained solid was purified through column chromatography on silica gel to obtain compound 1-3 (35.0 g, Yield: 54 %).

Preparation of compound H-2

After adding compound 1-3 (5.9 g, 0.020 mol), compound 1-2 (7.0 g, 0.018 mol), NaH (1.1 g, 0.028 mol) and dimethylformamide (DMF) (350.0 mL) were stirred for 5 hours at room temperature. After completing the reaction, the mixture was washed with distilled water and obtained solid was purified through column chromatography to obtain compound H-2 (5.3 g, Yield: 59 %).

Example 2: Preparation of compound H-4

Preparation of compound 2-1

After adding ethylene glycol dimethyl ester (300.0 mL) to 2,4,6-trichloropyrimidine (36.0 g, 0.196 mol), phenyboronic acid (15.0 g, 0.123 mol), dichlorobis(triphenylphosphine)palladium(II) (PdCl₂(PPh₃)₂) (842.0 mg, 0.0012 mol), Na₂CO₃ (19.5 g, 0.184 mol) and H₂O (125.0 mL), the mixture was heated to 80℃ and was stirred for 12 hours. After completing the reaction, the mixture was washed with distilled water and the organic layer was extracted with ethyl acetate (EA). The organic layer was dried on MgSO₄ and the solvent was removed with a rotary evaporator. The obtained solid was purified through column chromatography to obtain compound 2-1 (20.0 g, Yield: 71 %).

Preparation of compound 2-2

After adding ethylene glycol dimethyl ester (170.0 mL) to compound 2-1 (10.0 g, 0.044 mol), 4-dibenzothiopheneboronic acid (11.6 g, 0.051 mol), Pd(PPh₃)₄ (1.5 g, 0.0013 mol), K₂CO₃ (2M, 44.0 mL) and EtOH (20.0 mL), the mixture was heated to 110℃ and was stirred for 3 hours. After completing the reaction, the mixture was washed with distilled water and the organic layer was extracted with EA. The organic layer was dried on MgSO₄ and the solvent was removed with a rotary evaporator. The obtained solid was purified through column chromatography to obtain compound 2-2 (14.0 g, Yield: 85 %).

Preparation of compound H-4

Compound 2-2 (5.0 g, 0.020 mol), compound 1-2 (7.0 g, 0.018 mol), NaH (1.1 g, 0.028 mol) and DMF (350.0 mL) were stirred for 5 hours at room temperature. After completing the reaction, the mixture was washed with distilled water and the obtained solid was purified through column chromatography to obtain compound H-4 (4.5 g, Yield: 41 %).

Example 3: Preparation of compound H-9

Preparation of compound 3-1

Biphenyl-3-ylboronic acid (20.0 g, 101.0 mmol), 1-bromo-4-iodobenzene (31.4 g, 111.0 mmol), Pd(PPh₃)₄ (3.5 g, 3.0 mmol), K₂CO₃ (28.0 g, 202.0 mmol), toluene (300.0 mL), EtOH (100.0 mL) and H₂O (100.0 mL) were reflux stirred. After 13 hours, the mixture was extracted with dichloromethane (DCM) and H₂O, and the DCM layer was dried on MgSO₄ and was filtered. The obtained solid was dissolved in CHCl₃, and was purified through column chromatography on silica gel to obtain compound 3-1 (26.37 g, Yield: 84 %).

Preparation of compound 3-2

Compound 3-1 (26.37 g, 96.2 mmol) and tetrahydrofuran (THF) (200.0 mL) were cooled to -78℃. 2.5M n-butyl lithium (46.0 mL, 115.0 mmol) was added to the mixture, and after 1 hour, isopropyl borate (33.3 mL, 114.0 mmol) was added to the mixture. After 17 hours, the mixture was extracted with EA and H₂O, and the EA layer was dried on MgSO₄. The EA layer was concentrated to obtain compound 3-2 (15.1 g, Yield: 59 %).

Preparation of compound 3-3

After adding compound 3-2 (15.0 g, 54.7 mmol), 2-bromonitrobenzene (10.03 g, 49.7 mmol), Pd(PPh₃)₄ (2.0 g, 1.63 mmol) and Na₂CO₃ (14.5 g, 136.7 mmol) to toluene (300.0 mL), EtOH (75.0 mL) and distilled water (75.0 mL), the mixture was stirred for 5 hours at 120°C. After stirring, distilled water was slowly added to the mixture to complete the reaction, the mixture was cooled to room temperature, and the organic layer was extracted with distilled water and MC. The organic layer was concentrated and was separated through column chromatography (MC/Hex) to obtain compound 3-3 (14.2 g, Yield: 81 %).

Preparation of compound 3-4

Compound 3-3 (15.67 g, 44.6 mmol), P(OEt)₃ (100.0 mL) and 1,2-dichlorobenzene (1,2-DCB) (50.0 mL) were reflux stirred. After 13 hours, the solvent was distilled, the obtained solid was dissolved in CHCl₃, and was purified through column chromatography on silica gel to obtain compound 3-4 (7.06 g, Yield: 50 %).

Preparation of compound H-9

Compound 3-4 (5.6 g, 17.6 mmol), compound 1-3 (5.9 g, 20.0 mmol), NaH (1.1 g, 28.0 mmol) and DMF (350.0 mL) were stirred for 5 hours at room temperature. After completing the reaction, the mixture was washed with distilled water, and the obtained solid was purified through column chromatography to obtain compound H-9 (3.4 g, Yield: 33 %).

Example 4: Preparation of compound H-22

Preparation of compound 4-1

2,5-Dibromonitrobenzene (30.0 g, 106.80 mmol), phenylboronic acid (15.0 g, 128.16 mmol), Pd(PPh₃)₄ (6.4 g, 5.33 mmol) and 2M Na₂CO₃ (200.0 mL) were dissovled in toluene (530.0 mL) and EtOH (200.0 mL), and the mixture was refluxed for 5 hours at 120°C. After completing the reaction, the organic layer was extracted with EA and was dried by removing the remaining moisture with MgSO₄. The organic layer was separated through column chromatography to obtain compound 4-1 (16.0 g, Yield: 55 %).

Preparation of compound 4-2

According to the same synthesis method as Preparation of compound 4-1 by using compound 4-1 (16.0 g, 57.53 mmol) and t-butyl phenyl boronic acid (12.8 g, 69.04 mmol), compound 4-2 (19.0 g, Yield: 96 %) was obtained.

Preparation of compound 4-3

Compound 4-2 (19.0 g, 57.33 mmol) was dissolved in triethyl phosphate (190.0 mL) and the mixture was stirred for 6 hours at 150°C. After completing the reaction, the mixture was distilled and was crushed with methanol (MeOH) to obtain compound 4-3 (11.5 g, Yield: 68 %).

Preparation of compound H-22

According to the same synthesis method as Preparation of compound H-2 by using compound 4-3 (3.9 g, 13.03 mmol) and compound 1-3 (4.3 g, 14.33 mmol), compound H-22 (1.0 g, Yield: 14 %) was obtained.

Example 5: Preparation of compound H-51

Preparation of compound 5-1

After dissolving 4-phenyldibenzo[b,d]thiophene (33.5 g, 128.0 mmol) in THF (650.0 mL), the mixture was cooled to -78℃, n-butyl lithium (2.5M, in hexane) (62.0 mL, 153.0 mmol) was slowly added thereto, and the mixture was stirred for 1 hour. At the same temperature, after adding boron triisopropoxide [B(OiPr)₃] (44.0 mL, 192.0 mmol) to the mixture, the mixture was stirred for one (1) day. After stirring, 1M HCl was added to the mixture thereby quenching the mixture, the organic layer was extracted with distilled water and EA, and the organic layer was concentrated. The organic layer was recrystallized with EA and Hex to obtain compound 5-1 (19.0 g, 64.0 mmol, Yield: 50 %).

Preparation of compound 5-2

Compound 2-1 (18.0 g, 35.54 mmol), compound 5-1 (12.9 g, 42.65 mmol), Pd(PPh₃)₄ (1.2 g, 1.06 mmol), 2M K₂CO₃ (35.0 mL), ethylene glycol dimethyl ester (150.0 mL) and EtOH (100.0 mL) were reflux stirred. After 3 hours, the mixture was cooled to room temperature, MeOH was added thereto, and the obtained solid was filtered under reduced pressure. The solid was separated through column chromatography to obtain compound 5-2 (9.0 g, Yield: 56.4 %).

Preparation of compound H-51

According to the same synthesis method as Preparation of compound H-2 by using compound 5-2 (9.0 g, 20.0 mmol) and compound 1-2 (7.0 g, 0.018 mol), compound H-51 (1.8 g, Yield: 27 %) was obtained.

Example 6: Preparation of compound H-55

Preparation of compound 6-1

After adding 1,4-dibromo-2-nitrobenzene (50.0 g, 278.0 mmol), [1,1’-biphenyl]-4-ylboronic acid (32.0 g, 252.0 mmol), Pd(PPh₃)₄ (5.5 g, 7.56 mmol), Na₂CO₃ (42.7 g, 403.0 mol), H₂O (400.0 mL), EtOH (400.0 mL) and toluene (800.0 mL) to 3L round bottom flask, the mixture was reflux stirred for 3 hours. After completing the reaction, the mixture was cooled, and the organic layer was extracted with EA and H₂O. The EA layer was dried on MgSO₄. The EA layer was concentrated under reduced pressure and was purified through column chromatography on silica gel. The obtained solution was concentrated under reduced pressure to obtain compound 6-1 (30.5 g, Yield: 34 %).

Preparation of compound 6-2

After adding compound 6-1 (30.0 g, 84.7 mmol), phenylboronic acid (13.42 g, 110.1 mmol), Pd(PPh₃)₄ (2.89 g, 2.5 mmol), K₂CO₃ (29.3 g, 211.8 mol), H₂O (100.0 mL), EtOH (100.0 mL) and toluene (300.0 mL) to 2L round bottom flask, the mixture was reflux stirred for 4 hours. After completing the reaction, the mixture was cooled, MeOH was added thereto and the obtained solid was filtered. The solid was purified through column chromatography on silica gel. The obtained solution was concentrated under reduced pressure to obtain compound 6-2 (26.5 g, Yield: 90 %).

Preparation of compound 6-3

According to the same synthesis method as Preparation of compound 1-2 by using compound 6-2 (26.5 g, 75.4 mmol), compound 6-3 (13.0 g, Yield: 60 %) was obtained.

Preparation of compound H-55

According to the same synthesis method as Preparation of compound H-2 by using compound 6-3 (4.5 g, 15.7 mmol) and compound 2-2 (6.5 g, 17.4 mmol), compound H-55 (6.0 g, Yield: 58 %) was obtained.

Example 7: Preparation of compound H-67

According to the same synthesis method as Preparation of compound H-2 by using compound 3-4 (5.6 g, 17.6 mmol) and compound 2-2 (7.5 g, 20.0 mmol), compound H-67 (2.7 g, Yield: 24 %) was obtained.

Example 8: Preparation of compound H-68

Preparation of compound 8-1

After adding dibenzothiophene-4-ylboronic acid (30.0 g, 131.0 mmol), 1-bromo-3-iodobenzene (44.65 g, 158.0 mmol), Pd(PPh₃)₄ (4.5 g, 4.0 mmol), K₂CO₃ (36.0 g, 263.0 mmol), toluene (300.0 mL), EtOH (75.0 mL) and H₂O (75.0 mL) to 1L round bottom flask, the mixture was reflux stirred. After 4 hours, the organic layer was extracted with DCM and H₂O, and the DCM layer was dried on MgSO₄ and was filtered. The obtained solid was dissolved in CHCl₃ and was purified through column chromatography on silica gel to obtain compound 8-1 (31.38 g, Yield: 69 %).

Preparation of compound 8-2

After adding compound 8-1 (31.0 g, 91.0 mmol) and THF (300.0 mL) to 500 mL round bottom flask, the mixture was cooled to -78℃. 2.5 M n-butyl lithium (44.0 mL, 110.0 mmol) was added thereto, and after 1 hour, isopropyl borate (31.6 mL, 137.0 mmol) was added thereto. After 17 hours, the organic layer was extracted with EA and H₂O, and the EA layer was dried on MgSO₄. The EA layer was concentrated to obtain compound 8-2 (22.0 g, Yield: 79 %).

Preparation of compound 8-3

After adding compound 8-2 (22.0 g, 72.0 mmol), 1,3-dichloropyrimidine (13.0 g, 87.0 mmol), Pd(PPh₃)₄ (2.5 g, 2.0 mmol), K₂CO₃ (20.0 g, 144.0 mol), toluene (280.0 mL), EtOH (70.0 mL) and H₂O (70.0 mL) to 1L round bottom flask, the mixture was reflux stirred. After 13 hours, the organic layer was extracted with DCM and H₂O, and the DCM layer was dried on MgSO₄ and was filtered. The obtained solid was dissolved in CHCl₃ and was purified through column chromatography on silica gel to obtain compound 8-3 (17.5 g, Yield: 65 %).

Preparation of compound H-68

According to the same synthesis method as Preparation of compound H-2 by using compound 3-4 (4.2 g, 13.2 mmol) and compound 8-3 (3.5 g, 11.0 mmol), compound H-68 (1.1 g, Yield: 18 %) was obtained.

Example 9: Preparation of compound H-69

According to the same synthesis method as Preparation of compound H-4 by using compound 6-3 (5.0 g, 15.6 mmol) and compound 8-3 (7.0 g, 18.8 mmol), compound H-69 (4.5 g, Yield: 43 %) was obtained.

Example 10: Preparation of compound H-70

Preparation of compound 10-1

After adding compound 5-1 (9.4 g, 30.9 mmol), 2,4-dichloropyrimidine (5.5 g, 37.1 mmol), Pd(PPh₃)₄ (1.1 g, 0.88 mmol) and Na₂CO₃ (8.2 g, 77.2 mmol) to toluene (160.0 mL), EtOH (40.0 mL) and distilled water (40.0 mL), the mixture was stirred for 5 hours at 120°C. After stirring, distilled water was slowly added to the mixture to complete the reaction, the mixture was cooled to room temperature, and the organic layer was extracted with distilled water and MC. The organic layer was concentrated, and was separated through column chromatography (MC/Hex) to obtain compound 10-1 (8.9 g, Yield: 78 %).

Preparation of compound H-70

According to the same synthesis method as Preparation of compound H-2 by using compound 1-2 (4.1 g, 17.0 mmol) and compound 10-1 (5.3 g, 14.2 mmol), compound H-70 (4.5 g, Yield: 55 %) was obtained.

Example 11: Preparation of compound H-71

Preparation of compound 11-1

After dissolving 2,4-dibromonitrobenzene (18.7 g, 66.57 mmol), biphenyl-4-boronic acid (14.5 g, 73.23 mmol), Pd(PPh₃)₄ (4.0 g, 3.33 mmol) and 2M Na₂CO₃ (130.0 mL) in toluene (330.0 mL) and EtOH (130.0 mL) in a flask, the mixture was refluxed for 5 hours at 120℃. After completing the reaction, the organic layer was extracted with EA, the EA layer was dried on MgSO₄ to remove the remaining moisture, and was separated through column chromatography to obtain compound 11-1 (12.0 g, Yield: 52 %).

Preparation of compound 11-2

According to the same synthesis method as Preparation of compound 4-1 by using compound 11-1 (12.0 g, 33.87 mmol) and phenylboronic acid (4.5 g, 37.26 mmol), compound 11-2 (11.0 g, Yield: 98 %) was obtained.

Preparation of compound 11-3

After dissolving compound 11-2 (11.0 g, 31.30 mmol) in triethyl phosphate (120.0 mL), the mixture was refluxed for 6 hours at 150℃. After completing the reaction, the mixture was distilled and was crushed with MeOH to obtain compound 11-3 (6.5 g, Yield: 60 %).

Preparation of compound H-71

According to the same synthesis method as Preparation of compound H-2 by using compound 11-3 (3.5 g, 10.95 mmol) and compound 1-3 (3.4 g, 13.14 mmol), compound H-71 (1.0 g, Yield: 16 %) was obtained.

Example 12: Preparation of compound H-72

According to the same synthesis method as Preparation of compound H-2 by using compound 6-3 (5.0 g, 15.7 mmol) and compound 1-3 (5.1 g, 17.3 mmol), compound H-72 (4.5 g, Yield: 49 %) was obtained.

Example 13: Preparation of compound H-73

According to the same synthesis method as Preparation of compound H-2 by using compound 1-2 (7.3 g, 30.0 mmol) and compound 8-3 (13.5 g, 36.0 mmol), compound H-73 (4.5 g, Yield: 25 %) was obtained.

Example 14: Preparation of compound H-147

Preparation of compound 14-1

After adding 2-bromo-9H-carbazole (37.0 g, 133.0 mmol), 4-biphenylboronic acid (31.0 g, 159.6 mmol), Pd(PPh₃)₄ (3.0 g, 2.66 mmol), K₂CO₃ (37.0 g, 266.0 mmol), EtOH (60.0 mL), purified water (60.0 mL) and toluene (250.0 mL) to 500 mL round bottom flask, the mixture was reflux stirred for 3 hours. After completing the reaction, the mixture was cooled to room temperature and was worked up through column chromatography to obtain compound 14-1 (33.0 g, Yield: 78 %).

Preparation of compound H-147

According to the same synthesis method as Preparation of compound H-2 by using compound 14-1 (5.0 g, 15.7 mmol) and compound 8-3 (6.4 g, 17.3 mmol), compound H-147 (1.1 g, Yield: 11 %) was obtained.

Example 15: Preparation of compound H-163

Preparation of compound 15-1

2-Bromothioanisole (25.0 g, 123.1 mmol) was dissolved in acetic acid (600.0 mL), H₂O₂ was slowly added thereto at 0℃, and the mixture was stirred for 12 hours. Then, acetic acid was removed by distillation under reduced pressure and the mixture was neutralized by using NaHCO₃. The obtained product was extracted with distilled water and MC. The obtained organic layer was distilled under reduced pressure and was purified through column chromatography (EA/Hex) to obtain compound 15-1 (26.0 g, 118.7 mmol).

Preparation of compound 15-2

After adding (4-bromophenyl) boronic acid (15.0 g, 74.0 mmol), compound 15-1 (17 g, 77.6 mmol), Pd(PPh₃)₄ (2.6 g, 2.22 mmol) and Na₂CO₃ (16.0 g, 148.0 mmol) to a solvent mixture of toluene (300.0 mL) and purified water (75.0 mL), the mixture was reflux stirred for 6 hours. After completing the reaction, the mixture was cooled to room temperature and was extracted with distilled water and EA. The obtained organic layer was distilled under reduced pressure and was purified through column chromatography (EA/Hex) to obtain compound 15-2 (42.0 g, Yield: 92 %).

Preparation of compound 15-3

After adding trifluoromethan sulfonic acid (CF3SO3H) (450.0 mL) to a mixture of compound 15-2 (9.5 g, 32.18 mmol) and P₂O₅ (19.0 g), the mixture was stirred for three (3) days at room temperature. After slowly adding the obtained mixture to ice water, the mixture was neutralized with NaOH and was extracted with MC. After adding pyridine to the obtained organic layer, the mixture was reflux stirred for 30 minutes and was extracted with distilled water and MC. The obtained organic layer was distilled under reduced pressure and was purified through column chromatography to obtain compound 15-3 (4.8 g, Yield: 57 %).

Preparation of compound 15-4

After adding 1,4-dioxane (88.0 mL) to a mixture of compound 15-3 (4.6 g, 17.5 mmol), PdCl₂(PPh₃)₂ (0.6 g, 0.87 mmol), bis(pinacolato)diborone (5.33 g, 21.0 mmol) and potassium acetate (KOAc) (3.4 g, 35.0 mmol), the mixture was reflux stirred for one (1) day. After completing the reaction, the mixture was cooled to room temperature and was extracted with distilled water and MC. The obtained organic layer was distilled under reduced pressure and was purified through column chromatography (EA/Hex) to obtain compound 15-4 (4.6 g, Yield: 85 %).

Preparation of compound 15-5

After adding a mixed solvent of toluene (580.0 mL), EtOH (150.0 mL) and purified water (190.0 mL) to a mixture of bromonitrobenzene (30.0 g, 149.0 mmol), 4-biphenylboronic acid (32.3 g, 163.0 mmol), K₂CO₃ (51.3 g, 371.0 mmol) and Pd(PPh₃)₄ (8.6 g, 7.43 mmol), the mixture was reflux stirred for one (1) day. After completing the reaction, the mixture was cooled to room temperature and was extracted with distilled water and EA. The obtained organic layer was distilled under reduced pressure and was purified through column chromatography (MC/Hex) to obtain compound 15-5 (32.0 g, Yield: 78 %).

Preparation of compound 15-6

After adding P(OEt)₃ (290.0 mL) to compound 15-5 (32.0 g, 116.0 mmol), the mixture was reflux stirred for one (1) day at 150℃. After completing the reaction, the mixture was concentrated under reduced pressure and was extracted with MC. The obtained organic layer was concentrated and was purified through column chromatography (MC/Hex) to obtain compound 15-6 (20.0 g, Yield: 71 %).

Preparation of compound 15-7

After adding a mixture of 2,4,6-trifluoropyridine (48.0 g, 262.0 mmol), phenylboronic acid (20.0 g, 164.0 mmol), Na₂CO₃ (26.0 g, 246.0 mmol) and PdCl₂(PPh₃)₂ (1.2 g, 1.64 mmol) to a mixed solvent of toluene (1.5 L) and purified water (200.0 mL), the mixture was stirred for 3 hours at 90℃. After completing the reaction, the mixture was cooled to room temperature and was extracted with distilled water and EA. The obtained organic layer was distilled under reduced pressure and was purified through column chromatography (MC/Hex) to obtain compound 15-7 (13.3 g, Yield: 36 %).

Preparation of compound 15-8

A mixture of compound 15-6 (8.0 g, 33.0 mmol) and compound 15-7 (11.1 g, 49.3 mmol) was dissolved in dimethylformamide (DMF) (350.0 mL) and NaH (2.1 g, 52.6 mmol, 60% in mineral oil) was slowly added to the mixture. The obtained mixture was stirred for 12 hours at room temperature and distilled water was added thereto. The obtained solid was filtered under reduced pressure. The obtained solid was dissolved in CHCl₃ and was purified through column chromatography to obtain compound 15-8 (7.9 g, Yield: 56 %).

Preparation of compound H-163

After adding a mixed solvent of toluene (72.0 mL), EtOH (10.0 mL) and purified water (18.0 mL) to a mixture of compound 15-8 (6.1 g, 14.1 mmol), compound 15-4 (4.4 g, 14.1 mmol), Pd(PPh₃)₄ (0.82 g, 0.71 mmol) and K₂CO₃ (4.9 g, 35.3 mmol), the mixture was reflux stirred for 6 hours. After completing the reaction, the mixture was cooled to room temperature and was extracted with distilled water and MC. The obtained organic layer was distilled under reduced pressure and was purified through column chromatography (MC/Hex) to obtain compound H-163 (4.0 g, Yield: 49 %).

Example 16: Preparation of compound H-167

Preparation of compound 16-2

After adding P(OEt)₃ (350.0 mL) to compound 16-1 (35.0 g, 101.0 mmol), the mixture was reflux stirred for one (1) day at 150℃. After completing the reaction, the mixture was concentrated under reduced pressure and was extracted with MC. The obtained organic layer was concentrated and was purified through column chromatography (MC/Hex) to obtain compound 16-2 (16.0 g, Yield: 50 %).

Preparation of compound 16-3

After adding a mixed solvent of dimethylether (DME) (60.0 mL) and purified water (20.0 mL) to a mixture of compound 15-7 (3.9 g, 17.4 mmol), compound 15-4 (4.9 g, 15.8 mmol), Pd(PPh₃)₄ (0.57 g, 0.49 mmol) and Na₂CO₃ (4.36 g, 41.1 mmol), the mixture was reflux stirred for 6 hours. After completing the reaction, the mixture was cooled to room temperature and was extracted with distilled water and MC. The obtained organic layer was distilled under reduced pressure and was purified through column chromatography (MC/Hex) to obtain compound 16-3 (3.1 g, Yield: 53 %).

Preparation of compound H-167

After adding DMF (80.0 mL) to a mixture of compound 16-3 (3.1 g, 8.31 mmol), compound 16-2 (2.53 g, 7.92 mmol) and K₂CO₃ (2.74 g, 19.8 mmol), the mixture was reflux stirred for six (6) hours. After completing the reaction, the mixture was cooled to room temperature and was extracted with distilled water and MC. The obtained organic layer was distilled under reduced pressure and was purified through column chromatography (MC/Hex) to obtain compound H-167 (2.0 g, Yield: 38 %).

Example 17: Preparation of compound H-212

Preparation of compound 17-1

After adding dibenzothiophene (40.0 g, 217.0 mmol) and CHCl₃ (1 L) to 2L round bottom flask, the mixture was stirred. Bromine (11.2 mL, 2.1 mol) was added to the mixture. After 48 hours, the obtained mixture was extracted with an aqueous solution of DCM and Na2S2O3, and the DCM layer was dried on MgSO₄ and was filtered. The DCM layer was concentrated to obtain compound 17-1 (26. g, Yield: 45 %).

Preparation of compound 17-2

After adding compound 17-1 (29.0 g, 110.0 mmol), PdCl₂(PPh₃)₂ (3.85 g, 5.5 mmol), bis(pinacolato)diborane (27.9 g, 110.0 mmol), KOAc (18.0 g, 220.0 mmol) and 1,4-dioxane (550.0 mL) to 1L round bottom flask, the mixture was reflux stirred. After 5 hours, the organic layer was extracted with DCM and H₂O, and the DCM layer was dried on MgSO₄ and was filtered. The obtained solid was dissolved in CHCl₃ and was purified through column chromatography on silica gel to obtain compound 17-2 (23.0 g, Yield: 67 %).

Preparation of compound 17-3

After adding compound 15-7 (16.0 g, 71.0 mmol), compound 17-2 (18.6 g, 81.7 mmol), Pd(PPh₃)₄ (2.46 g, 2.14 mmol), K₂CO₃ (19.6 g, 142.0 mmol), DME (220.0 mL), EtOH (70.0 mL) and H₂O (70.0 mL) to 1L round bottom flask, the mixture was reflux stirred. After 30 minutes, the obtained mixture was extracted with DCM and H₂O, and the DCM layer was dried on MgSO₄ and was filtered. The obtained solid was dissolved in CHCl₃ and was purified through column chromatography on silica gel to obtain compound 17-3 (16.0 g, Yield: 60 %).

Preparation of compound H-212

After adding compound 15-6 (8.7 g, 35.7 mmol), compound 17-3 (16.0 g, 42.9 mmol), 4-dimethylaminopyridine (DMAP) (440 mg, 3.5 mmol), K₂CO₃ (9.9 g, 71.5 mmol) and DMF (400.0 mL) to 1L round bottom flask, the mixture was reflux stirred. After 1 hour, MeOH was added to obtained solid and the obtained solid was filtered. The obtained solid was dissolved in CHCl₃ and was purified through column chromatography on silica gel to obtain compound H-212 (1.1 g, Yield: 5 %).

The physical properties of the compounds, which were prepared in Examples 1 to 14 and further prepared according to the same method as the Examples, are provided in the Table 1 below:

Table 1

Measurement of thermal stability at high temperature

The organic electroluminescent compound according to the present invention was thermally exposed for a long time at vapor deposition temperature (Ts) for the production of a light-emitting device and higher temperature than the Ts, and then purity analysis of the compound was effected by using HPLC.

For the measurement of purity, the analysis equipment (1290 Infinity Binary Pump VL, 1290 Infinity Autosampler, 1290 Infinity Thermostatted Column Compartment, 1290 Infinity Diode Array Detector) was used, and the column ZORBAX eclipse plus C18 4.6 × 150 mm 3.5 MICRON was used.

2 mg of respective sample was dissolved in THF (10.0 mL) and the obtained solution (5 mL) was injected. A mixed solution of THF and distilled water (THF : distilled water = 55:45) was used as a mobile phase. The measurement was effected at a flow rate of 1 mL/min.

As a result, it was found that the compounds of the present invention retain the initial purity at high temperature without purity change.

Device Example 1: Production of an OLED device by using

the organic electroluminescent compound according to the present invention

An OLED device was produced using the organic electroluminescent compound according to the present invention. A transparent electrode indium tin oxide (ITO) thin film (15 Ω/sq) on a glass substrate for an organic light-emitting diode (OLED) device (Samsung Corning, Republic of Korea) was subjected to an ultrasonic washing with trichloroethylene, acetone, ethanol, and distilled water, sequentially, and then was stored in isopropanol. Then, the ITO substrate was mounted on a substrate holder of a vacuum vapor depositing apparatus. N¹,N^1’-([1,1’-biphenyl]-4,4’-diyl)bis(N¹-(naphthalene-1-yl)-N⁴,N⁴-diphenylbenzene-1,4-diamine was introduced into a cell of the vacuum vapor depositing apparatus, and then the pressure in the chamber of the apparatus was controlled to 10^-6 torr. Thereafter, an electric current was applied to the cell to evaporate the introduced material, thereby forming a hole injection layer having a thickness of 60 nm on the ITO substrate. Then, N,N’-di(4-biphenyl)-N,N’-di(4-biphenyl)-4,4’-diaminobiphenyl was introduced into another cell of the vacuum vapor depositing apparatus, and was evaporated by applying electric current to the cell, thereby forming a hole transport layer having a thickness of 20 nm on the hole injection layer. Thereafter, compound H-2 as a host was introduced into one cell of the vacuum vapor depositing apparatus, and compound D-1 as a dopant was introduced into another cell. The two materials were evaporated at different rates and the dopant was deposited in a doping amount of 15 wt%, based on the total weight of the host and dopant, to form a light-emitting layer having a thickness of 30 nm on the hole transport layer. Then, 2-(4-(9,10-di(naphthalene-2-yl)anthracene-2-yl)phenyl)-1-phenyl-1H-benzo[d]imidazole was introduced into one cell, and lithium quinolate was introduced into another cell. The two materials were evaporated at the same rates and were respectively deposited in a doping amount of 50 wt% to form an electron transport layer having a thickness of 30 nm on the light-emitting layer. Then, after depositing lithium quinolate as an electron injection layer having a thickness of 2 nm on the electron transport layer, an Al cathode having a thickness of 150 nm was deposited by another vacuum vapor deposition apparatus on the electron injection layer. Thus, an OLED device was produced. All the materials used for producing the OLED device were purified by vacuum sublimation at 10^-6 torr prior to use.

The produced OLED device showed green emission having a luminance of 1020 cd/m² and a current density of 2.10 mA/cm² at a driving voltage of 2.8 V. Furthermore, the time taken to be reduced to 80 % of the luminance at a luminance of 15,000nit was at least 190 hours.

Device Example 2: Production of an OLED device by using

the organic electroluminescent compound according to the present invention

An OLED device was produced in the same manner as in Device Example 1, except for using compound H-72 as a host and compound D-1 as a dopant in a light-emitting material.

The produced OLED device showed green emission having a luminance of 3200 cd/m² and a current density of 7.83 mA/cm² at a driving voltage of 3.1 V. Furthermore, the time taken to be reduced to 80 % of the luminance at a luminance of 15,000nit was at least 170 hours.

Device Example 3: Production of an OLED device by using

the organic electroluminescent compound according to the present invention

An OLED device was produced in the same manner as in Device Example 1, except for using compound H-5 as a host and compound D-1 as a dopant in a light-emitting material.

The produced OLED device showed green emission having a luminance of 2350 cd/m² and a current density of 5.93 mA/cm² at a driving voltage of 3.1 V. Furthermore, the time taken to be reduced to 80 % of the luminance at a luminance of 15,000nit was at least 120 hours.

Device Example 4: Production of an OLED device by using

the organic electroluminescent compound according to the present invention

An OLED device was produced in the same manner as in Device Example 1, except for using compound H-71 as a host and compound D-1 as a dopant in a light-emitting material.

The produced OLED device showed green emission having a luminance of 1500 cd/m² and a current density of 2.94 mA/cm² at a driving voltage of 2.9 V. Furthermore, the time taken to be reduced to 80 % of the luminance at a luminance of 15,000nit was at least 160 hours.

Device Example 5: Production of an OLED device by using

the organic electroluminescent compound according to the present invention

An OLED device was produced in the same manner as in Device Example 1, except for using compound H-4 as a host and compound D-1 as a dopant in a light-emitting material.

The produced OLED device showed green emission having a luminance of 1340 cd/m² and a current density of 2.84 mA/cm² at a driving voltage of 2.6 V. Furthermore, the time taken to be reduced to 80 % of the luminance at a luminance of 15,000nit was at least 230 hours.

Device Example 6: Production of an OLED device by using the organic electroluminescent compound according to the present invention

An OLED device was produced in the same manner as in Device Example 1, except for using compound H-9 as a host and compound D-1 as a dopant in a light-emitting material.

The produced OLED device showed green emission having a luminance of 2130 cd/m² and a current density of 4.73 mA/cm² at a driving voltage of 3.0 V. Furthermore, the time taken to be reduced to 80 % of the luminance at a luminance of 15,000nit was at least 180 hours.

Device Example 7: Production of an OLED device by using

the organic electroluminescent compound according to the present invention

An OLED device was produced in the same manner as in Device Example 1, except for using compound H-68 as a host and compound D-1 as a dopant in a light-emitting material.

The produced OLED device showed green emission having a luminance of 2610 cd/m² and a current density of 6.13 mA/cm² at a driving voltage of 3.2 V. Furthermore, the time taken to be reduced to 80 % of the luminance at a luminance of 15,000nit was at least 185 hours.

Device Example 8: Production of an OLED device by using

the organic electroluminescent compound according to the present invention

An OLED device was produced in the same manner as in Device Example 1, except for using compound H-26 as a host and compound D-1 as a dopant in a light-emitting material.

The produced OLED device showed green emission having a luminance of 3320 cd/m² and a current density of 8.09 mA/cm² at a driving voltage of 2.9 V. Furthermore, the time taken to be reduced to 80 % of the luminance at a luminance of 15,000nit was at least 230 hours.

Device Example 9: Production of an OLED device by using

the organic electroluminescent compound according to the present invention

An OLED device was produced in the same manner as in Device Example 1, except for using compound H-67 as a host and compound D-1 as a dopant in a light-emitting material.

The produced OLED device showed green emission having a luminance of 2040 cd/m² and a current density of 5.27 mA/cm² at a driving voltage of 2.7 V. Furthermore, the time taken to be reduced to 80 % of the luminance at a luminance of 15,000nit was at least 250 hours.

Device Example 10: Production of an OLED device by using

the organic electroluminescent compound according to the present invention

An OLED device was produced in the same manner as in Device Example 1, except for using compound H-55 as a host and compound D-1 as a dopant in a light-emitting material.

The produced OLED device showed green emission having a luminance of 1820 cd/m² and a current density of 4.57 mA/cm² at a driving voltage of 2.9 V. Furthermore, the time taken to be reduced to 80 % of the luminance at a luminance of 15,000nit was at least 250 hours.

Device Example 11: Production of an OLED device by using

the organic electroluminescent compound according to the present invention

An OLED device was produced in the same manner as in Device Example 1, except for using compound H-51 as a host and compound D-1 as a dopant in a light-emitting material.

The produced OLED device showed green emission having a luminance of 1640 cd/m² and a current density of 3.51 mA/cm² at a driving voltage of 2.8 V. Furthermore, the time taken to be reduced to 80 % of the luminance at a luminance of 15,000nit was at least 200 hours.

Device Example 12: Production of an OLED device by using

the organic electroluminescent compound according to the present invention

An OLED device was produced using the organic electroluminescent compound according to the present invention. A transparent electrode indium tin oxide (ITO) thin film (15 Ω/sq) on a glass substrate for an organic light-emitting diode (OLED) device (Samsung Corning, Republic of Korea) was subjected to an ultrasonic washing with trichloroethylene, acetone, ethanol, and distilled water, sequentially, and then was stored in isopropanol. Then, the ITO substrate was mounted on a substrate holder of a vacuum vapor depositing apparatus. N¹,N^1’-([1,1’-biphenyl]-4,4’-diyl)bis(N¹-(naphthalene-1-yl)-N⁴,N⁴-diphenylbenzene-1,4-diamine was introduced into a cell of the vacuum vapor depositing apparatus, and then the pressure in the chamber of the apparatus was controlled to 10^-6 torr. Thereafter, an electric current was applied to the cell to evaporate the introduced material, thereby forming a hole injection layer having a thickness of 60 nm on the ITO substrate. Then, N,N’-di(4-biphenyl)-N,N’-di(4-biphenyl)-4,4’-diaminobiphenyl was introduced into another cell of the vacuum vapor depositing apparatus, and was evaporated by applying electric current to the cell, thereby forming a hole transport layer having a thickness of 20 nm on the hole injection layer. Thereafter, compound H-163 as a host was introduced into one cell of the vacuum vapor depositing apparatus, and compound D-1 as a dopant was introduced into another cell. The two materials were evaporated at different rates and the dopant was deposited in a doping amount of 15 wt%, based on the total weight of the host and dopant, to form a light-emitting layer having a thickness of 30 nm on the hole transport layer. Then, 2-(4-(9,10-di(naphthalene-2-yl)anthracene-2-yl)phenyl)-1-phenyl-1H-benzo[d]imidazole was introduced into one cell, and lithium quinolate was introduced into another cell. The two materials were evaporated at the same rates and were respectively deposited in a doping amount of 50 wt% to form an electron transport layer having a thickness of 30 nm on the light-emitting layer. Then, after depositing lithium quinolate as an electron injection layer having a thickness of 2 nm on the electron transport layer, an Al cathode having a thickness of 150 nm was deposited by another vacuum vapor deposition apparatus on the electron injection layer. Thus, an OLED device was produced. All the materials used for producing the OLED device were purified by vacuum sublimation at 10^-6 torr prior to use.

The produced OLED device showed green emission having a luminance of 2610 cd/m² and a current density of 4.60 mA/cm² at a driving voltage of 2.7 V.

Device Example 13: Production of an OLED device by using

the organic electroluminescent compound according to the present invention

An OLED device was produced in the same manner as in Device Example 12, except for using compound H-212 as a host and compound D-1 as a dopant in a light-emitting material.

The produced OLED device showed green emission having a luminance of 1640 cd/m² and a current density of 3.44 mA/cm² at a driving voltage of 2.74 V.

Comparative Example 1: Production of an OLED device by using conventional light - emitting materials

An OLED device was produced in the same manner as in Device Example 1, except for using compound C-1 (instead of the compound of the present invention) as a host was introduced into one cell of the vacuum vapor depositing apparatus, and iridium tris(2-phenylpyridine) [Ir(ppy)₃] as a dopant was introduced into another cell.

The produced OLED device showed green emission having a luminance of 2420 cd/m² and a current density of 14.97 mA/cm² at a driving voltage of 4.3 V. Furthermore, the time taken to be reduced to 80 % of the luminance at a luminance of 15,000nit was at least 23 hours.

Comparative Example 2: Production of an OLED device by using conventional light - emitting materials

An OLED device was produced in the same manner as in Device Example 1, except for using compound C-2 (instead of the compound of the present invention) as a host was introduced into one cell of the vacuum vapor depositing apparatus, and Ir(ppy)₃ as a dopant was introduced into another cell.

The produced OLED device showed green emission having a luminance of 1820 cd/m² and a current density of 4.85 mA/cm² at a driving voltage of 4.2 V. Furthermore, the time taken to be reduced to 80 % of the luminance at a luminance of 15,000nit was at least 54 hours.

Comparative Example 3: Production of an OLED device by using conventional light - emitting materials

An OLED device was produced in the same manner as in Device Example 1, except for using compound C-3 (instead of the compound of the present invention) as a host was introduced into one cell of the vacuum vapor depositing apparatus, and Ir(ppy)₃ as a dopant was introduced into another cell.

The produced OLED device showed green emission having a luminance of 2810 cd/m² and a current density of 8.15 mA/cm² at a driving voltage of 4.8 V. Furthermore, the time taken to be reduced to 80 % of the luminance at a luminance of 15,000nit was at least 35 hours.

Comparative Example 4: Production of an OLED device by using conventional light - emitting materials

An OLED device was produced in the same manner as in Device Example 1, except for using compound C-4 (instead of the compound of the present invention) as a host was introduced into one cell of the vacuum vapor depositing apparatus, and Ir(ppy)₃ as a dopant was introduced into another cell.

The time taken to be reduced to 80 % of the luminance at a luminance of 15,000nit was at least 75 hours in the produced OLED device.

Comparative Example 5: Production of an OLED device by using conventional light - emitting materials

An OLED device was produced in the same manner as in Device Example 12, except for using 4,4’-N,N’-dicarbazole-biphenyl as a host and Ir(ppy)₃ as a dopant in the light-emitting material to form a light-emitting layer having a thickness of 30 nm on the hole transport layer, and using aluminum(III) bis(2-methyl-8-quinolinato)-4-phenyl phenolate to form a hole blocking layer having a thickness of 10 nm.

The produced OLED device showed green emission having a luminance of 3000 cd/m² and a current density of 8.56 mA/cm² at a driving voltage of 5.8 V.

The organic electroluminescent device by using the organic electroluminescent compounds of the present invention as a host material has low driving voltage, high luminescent efficiency, and high power efficiency.

Claims

An organic electroluminescent compound represented by the following formula 1:

wherein

L₁ and L₂ each independently represent a single bond, a substituted or unsubstituted 3- to 30-membered heteroarylene group, or a substituted or unsubstituted (C6-C30)arylene group;

X₁ and X₂ each independently represent CH or N;

Y represents -O-, -S-, -CR₁₁R₁₂- or -NR₁₃-;

Ar₁ represents a substituted or unsubstituted (C6-C30)aryl group, or a substituted or unsubstituted 3- to 30-membered heteroaryl group;

Ar₂ represents hydrogen, deuterium, a halogen, a substituted or unsubstituted (C1-C30)alkyl group, a substituted or unsubstituted (C6-C30)aryl group, or a substituted or unsubstituted 3- to 30-membered heteroaryl group;

R₁ to R₃ each independently represent hydrogen, deuterium, a halogen, a substituted or unsubstituted (C1-C30)alkyl group, a substituted or unsubstituted (C6-C30)aryl group, a substituted or unsubstituted 3- to 30-membered heteroaryl group, a substituted or unsubstituted (C3-C30)cycloalkyl group, a substituted or unsubstituted 5- to 7-membered heterocycloalkyl group, a substituted or unsubstituted (C6-C30)aryl(C1-C30)alkyl group, -NR₁₄R₁₅, -SiR₁₆R₁₇R₁₈, -SR₁₉, -OR₂₀, a cyano group, a nitro group, or a hydroxyl group; or are linked to an adjacent substituent(s) to form a mono- or polycyclic, 5- to 30-membered alicyclic or aromatic ring whose carbon atom(s) may be replaced with at least one hetero atom selected from nitrogen, oxygen and sulfur;

R₁₁ to R₂₀ each independently represent hydrogen, deuterium, a halogen, a substituted or unsubstituted (C1-C30)alkyl group, a substituted or unsubstituted (C6-C30)aryl group, a substituted or unsubstituted 3- to 30-membered heteroaryl group, a substituted or unsubstituted 5- to 7-membered heterocycloalkyl group, or a substituted or unsubstituted (C3-C30)cycloalkyl group; or are linked to an adjacent substituent(s) to form a mono- or polycyclic, 5- to 30-membered alicyclic or aromatic ring whose carbon atom(s) may be replaced with at least one hetero atom selected from nitrogen, oxygen and sulfur;

a and c each independently represent an integer of 1 to 4; where a or c is an integer of 2 or more, each of R₁ or each of R₃ is the same or different;

b represents an integer of 1 to 3; where b is an integer of 2 or more, each of R₂ is the same or different; and

the heteroarylene group, heterocycloalkyl group and heteroaryl group contain at least one hetero atom selected from B, N, O, S, P(=O), Si and P.
The organic electroluminescent compound according to claim 1, wherein the compound of formula 1 is represented by the following formula 2, 3 or 4:

wherein

L₁, L₂, X₁, X₂, Y, Ar₁, Ar₂, R₁ to R₃, and a to c are as defined in claim 1.
The organic electroluminescent compound according to claim 1, wherein the substituents of the substituted alkyl group, the substituted aryl(ene) group, the substituted heteroaryl(ene) group, the substituted cycloalkyl group, the substituted heterocycloalkyl group, and the substituted aralkyl group in L₁, L₂, Ar₁, Ar₂, R₁ to R₃, and R₁₁ to R₂₀ each independently are at least one selected from the group consisting of deuterium; a halogen; a (C1-C30)alkyl group which is unsubstituted or substituted with a halogen; a (C6-C30)aryl group; a 3- to 30-membered heteroaryl group which is unsubstituted or substituted with a (C6-C30)aryl group; a (C3-C30)cycloalkyl group; a 5- to 7-membered heterocycloalkyl group; a tri(C1-C30)alkylsilyl group; a tri(C6-C30)arylsilyl group; a di(C1-C30)alkyl(C6-C30)arylsilyl group; a (C1-C30)alkyldi(C6-C30)arylsilyl group; a (C2-C30)alkenyl group; a (C2-C30)alkynyl group; a cyano group; a carbazolyl group; di(C1-C30)alkylamino group; di(C6-C30)arylamino group; a (C1-C30)alkyl(C6-C30)arylamino group; a di(C6-C30)arylboronyl group; a di(C1-C30)alkylboronyl group; a (C1-C30)alkyl(C6-C30)arylboronyl group; a (C6-C30)aryl(C1-C30)alkyl group; a (C1-C30)alkyl(C6-C30)aryl group; a carboxyl group; a nitro group; and a hydroxyl group.
The organic electroluminescent compound according to claim 1, wherein L₁ and L₂ each independently represent a single bond, a substituted or unsubstituted 3- to 15-membered heteroarylene group, or a substituted or unsubstituted (C6-C15)arylene group;

X₁ and X₂ each independently represent CH or N;

Y represents -O-, -S-, -CR₁₁R₁₂- or -NR₁₃-;

Ar₁ represents a substituted or unsubstituted (C6-C20)aryl group, or a substituted or unsubstituted 3- to 15-membered heteroaryl group;

Ar₂ represents hydrogen, a substituted or unsubstituted (C6-C15)aryl group, or a substituted or unsubstituted 3- to 15-membered heteroaryl group;

R₁ to R₃ each independently represent hydrogen, a substituted or unsubstituted (C6-C15)aryl group, or a substituted or unsubstituted 3- to 30-membered heteroaryl group; or are linked to an adjacent substituent(s) to form a mono- or polycyclic, 5- to 30-membered alicyclic or aromatic ring whose carbon atom(s) may be replaced with at least one hetero atom selected from nitrogen, oxygen and sulfur; and

R₁₁ to R₂₀ each independently represent a substituted or unsubstituted (C1-C30)alkyl group, or a substituted or unsubstituted (C6-C30)aryl group.
The organic electroluminescent compound according to claim 1, wherein L₁ and L₂ each independently represent a single bond, or an unsubstituted (C6-C12)arylene group;

X₁ and X₂ each independently represent CH or N;

Y represents -O-, -S-, -CR₁₁R₁₂- or -NR₁₃-;

Ar₁ represents a (C6-C20)aryl group which is unsubstituted or substituted with deuterium, a halogen, a (C1-C6)alkyl group, a (C6-C12)aryl group, a 3- to 15-membered heteroaryl group unsubstitued or substitued with a (C6-C12)aryl group, or a (C6-C12)cycloalkyl group; or a 3- to 15-membered heteroaryl group which is unsubstituted or substituted with a (C6-C12)aryl group;

Ar₂ represents hydrogen; a (C6-C15)aryl group which is unsubstituted or substituted with deuterium, a (C1-C6)alkyl group, a (C6-C12)aryl group, a 3- to 15-membered heteroaryl group, a (C6-C12)cycloalkyl group, a tri(C6-C12)arylsilyl group or a cyano group; or a 3- to 15-membered heteroaryl group which is substituted with a (C6-C12)aryl group;

R₁ to R₃ each independently represent hydrogen or an unsubstituted (C6-C12)aryl group; or are linked to an adjacent substituent(s) to form a mono- or polycyclic, 5- to 15-membered aromatic ring; and

R₁₁ to R₂₀ each independently represent an unsubstituted (C1-C6)alkyl group, or an unsubstituted (C6-C12)aryl group.
The organic electroluminescent compound according to claim 1, wherein the compound represented by formula 1 is selected from the group consisting of the following compounds:
An organic electroluminescent device comprising the organic electroluminescent compound according to claim 1.