Patent Publication Number: US-2019173014-A1

Title: Benzodiazaborole derivatives and organic light-emitting diodes using the same

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This Non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No(s). 106142208 filed in Taiwan, Republic of China on Dec. 1, 2017, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND 
     Technology Field 
     The present disclosure relates to electroluminescent materials and light-emitting elements by using the same and, in particular, to benzodiazaborole derivatives and organic light-emitting diodes by using the same. 
     Description of Related Art 
     With the advances in electronic technology, a light weight and high efficiency flat display device has been developed. An organic electroluminescent device possibly becomes the mainstream of the next generation flat panel display device due to its advantages of self-luminosity, no restriction on viewing angle, power conservation, simple manufacturing process, low cost, high response speed, full color and so on. 
     In general, the organic electroluminescent device includes an anode, an organic luminescent layer and a cathode. When applying a direct current to the organic electroluminescent device, electron holes and electrons are injected into the organic luminescent layer from the anode and the cathode, respectively. Charge carriers move and then recombine in the organic luminescent layer because of the potential difference caused by an applied electric field. The excitons generated by the recombination of the electrons and the electron holes may excite the luminescent molecules in the organic luminescent layer. The excited luminescent molecules then release the energy in the form of light. 
     Nowadays, the organic electroluminescent device usually adopts a host-guest emitter system. The organic luminescent layer disposed therein includes a host material and a guest material. The electron holes and the electrons are mainly transmitted to the host material to perform recombination and thereby generate energy, and then the energy is transferred to the guest material to generate light. The guest material can be categorized into fluorescent material and phosphorescent material. Theoretically, the internal quantum efficiency can approach 100% by using appropriate phosphorescent materials. Therefore, the phosphorescent materials recently have become one of the most important developments in the field of organic electroluminescent materials. 
     In the development of blue host materials, the triplet energy level of the host materials must be higher than or equal to that of the guest materials to avoid the energy lost caused by reverse energy transfer. The energy lost can result in low luminous efficiency (i.e., low current efficiency) and short lifespan, etc. Therefore, it is necessary for the host materials to have a greater triplet energy level. 
     Besides, the selection of organic electroluminescent material is not only based on the matching energy level but also the high temperature of decomposition. These properties can avoid pyrolysis and the decrease of stability. 
     Accordingly, the present disclosure provides benzodiazaborole derivatives and organic light-emitting diodes by using the same which have good optical efficiency and thermal stability. 
     SUMMARY 
     In view of the foregoing, an objective of the present disclosure is to provide benzodiazaborole derivatives and organic light-emitting diodes by using the same which have good optical efficiency and thermal stability. 
     To achieve the above objective, the present disclosure provides a benzodiazaborole derivative, comprising a structure of the following General Formula (1). 
     
       
         
         
             
             
         
       
     
     Wherein, R 1  is selected from the group consisting of hydrogen atom, General Formula (2), General Formula (3) and General Formula (4), R 2  is selected from the group consisting of hydrogen atom, General Formula (3) and General Formula (4), R 1  and R 2  are different and at least one of them is a hydrogen atom, R 3  is General Formula (4) when R 2  is General Formula (4), and R 3  is a hydrogen atom when R 2  is a hydrogen atom or General Formula (3). 
     
       
         
         
             
             
         
       
     
     Wherein, R 4  to R 19  are independently selected from the group consisting of hydrogen atom, fluorine atom, cyano group, alkyl group, cycloalkyl group, alkoxy group, haloalkyl group, thioalkyl group, silyl group and alkenyl group. 
     In one embodiment, the alkyl group is selected from the group consisting of a substituted or unsubstituted straight-chain C1˜C6 alkyl group, and a substituted or unsubstituted branched-chain C3˜C6 alkyl group, the cycloalkyl group is a substituted or unsubstituted C3˜C6 cycloalkyl group, the alkoxy group is selected from the group consisting of a substituted or unsubstituted straight-chain C1˜C6 alkoxy group, and a substituted or unsubstituted branched-chain C3˜C6 alkoxy group, the haloalkyl group is selected from the group consisting of a substituted or unsubstituted straight-chain C1˜C6 haloalkyl group, and a substituted or unsubstituted branched-chain C3˜C6 haloalkyl group, the thioalkyl group is selected from the group consisting of a substituted or unsubstituted straight-chain C1˜C6 thioalkyl group, and a substituted or unsubstituted branched-chain C3˜C6 thioalkyl group, the silyl group is selected from the group consisting of a substituted or unsubstituted straight-chain C1˜C6 silyl group, and a substituted or unsubstituted branched-chain C3˜C6 silyl group, the alkenyl group is selected from the group consisting of a substituted or unsubstituted straight-chain C2˜C6 alkenyl group, and a substituted or unsubstituted branched-chain C3˜C6 alkenyl group. 
     In one embodiment, the benzodiazaborole derivative comprises a structure of any of the following Chemical Formulas (1) to (5): 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     To achieve the above objective, the present disclosure also provides an organic light-emitting diode, which comprises a first electrode layer, a second electrode layer, and an organic luminescent unit disposed between the first electrode layer and the second electrode layer. The organic luminescent unit comprises at least a benzodiazaborole derivative, and the benzodiazaborole derivative comprises a structure of the following General Formula (1): 
     
       
         
         
             
             
         
       
     
     Wherein, R 1  is selected from the group consisting of hydrogen atom, General Formula (2), General Formula (3) and General Formula (4), R 2  is selected from the group consisting of hydrogen atom, General Formula (3) and General Formula (4), R 1  and R 2  are different and at least one of them is a hydrogen atom, R 3  is General Formula (4) when R 2  is General Formula (4), and R 3  is a hydrogen atom when R 2  is a hydrogen atom or General Formula (3). 
     
       
         
         
             
             
         
       
     
     Wherein, R 4  to R 19  are independently selected from the group consisting of hydrogen atom, fluorine atom, cyano group, alkyl group, cycloalkyl group, alkoxy group, haloalkyl group, thioalkyl group, silyl group and alkenyl group. 
     In one embodiment, the alkyl group is selected from the group consisting of a substituted or unsubstituted straight-chain C1˜C6 alkyl group, and a substituted or unsubstituted branched-chain C3˜C6 alkyl group, the cycloalkyl group is a substituted or unsubstituted C3˜C6 cycloalkyl group, the alkoxy group is selected from the group consisting of a substituted or unsubstituted straight-chain C1˜C6 alkoxy group, and a substituted or unsubstituted branched-chain C3˜C6 alkoxy group, the haloalkyl group is selected from the group consisting of a substituted or unsubstituted straight-chain C1˜C6 haloalkyl group, and a substituted or unsubstituted branched-chain C3˜C6 haloalkyl group, the thioalkyl group is selected from the group consisting of a substituted or unsubstituted straight-chain C1˜C6 thioalkyl group, and a substituted or unsubstituted branched-chain C3˜C6 thioalkyl group, the silyl group is selected from the group consisting of a substituted or unsubstituted straight-chain C1˜C6 silyl group, and a substituted or unsubstituted branched-chain C3˜C6 silyl group, the alkenyl group is selected from the group consisting of a substituted or unsubstituted straight-chain C2˜C6 alkenyl group, and a substituted or unsubstituted branched-chain C3˜C6 alkenyl group. 
     In one embodiment, the benzodiazaborole derivative comprises a structure of any of the following Chemical Formulas (1) to (5): 
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
     In one embodiment, the organic luminescent unit comprises an organic luminescent layer. 
     In one embodiment, the organic luminescent unit further comprises a hole transport layer and an electron transport layer, and the organic luminescent layer is disposed between the hole transport layer and the electron transport layer. 
     In one embodiment, the organic luminescent unit further comprises a hole transport layer, an electron blocking layer, an electron transport layer and an electron injection layer, and the electron blocking layer, the organic luminescent layer and the electron transport layer are sequentially disposed between the hole transport layer and the electron injection layer. 
     In one embodiment, the organic luminescent layer comprises the benzodiazaborole derivative. 
     In one embodiment, the organic luminescent unit further comprises an electron blocking layer, and the electron blocking layer comprises the benzodiazaborole derivative. 
     As mentioned above, in the benzodiazaborole derivatives and the organic light-emitting diodes by using the same according to the present disclosure, it utilizes 1,3,2-benzodiazaborole as a core structure. Because of the 10 π electrons of the 1,3,2-benzodiazaborole and an empty p z  orbital of the boron atom, it shows unique photoelectric properties and high triplet energy levels. Different substituents are introduced to the ortho and/or meta positions of the benzo group to improve its thermal stability and adjust its electrochemical properties. In addition, the 1,3,2-benzodiazaborole derivatives of the present disclosure can be used as the material of the electron blocking layer and the organic luminescent layer. Besides, as the 1,3,2-benzodiazaborole derivatives of the present disclosure have good optical efficiency and thermal stability, they are suitable for the blue phosphorescent organic light-emitting diodes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will become more fully understood from the detailed description and accompanying drawings, which are given for illustration only, and thus are not limitative of the present disclosure, and wherein: 
         FIG. 1  is a sectional view of an organic light-emitting diode according to a second embodiment of this disclosure; 
         FIG. 2  is a sectional view of an organic light-emitting diode according to a third embodiment of this disclosure; 
         FIG. 3  is a sectional view of an organic light-emitting diode according to a fourth embodiment of this disclosure; 
         FIG. 4  is a schematic graph showing the charge injection properties of the hole-only device (HOD) with the organic layer made of mCb or the benzodiazaborole derivative of Chemical Formula (5); and 
         FIG. 5  is a schematic graph showing the charge injection properties of the electron-only device (EOD) with the organic layer made of mCb or the benzodiazaborole derivative of Chemical Formula (5). 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     The present disclosure will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements. 
     Benzodiazaborole Derivatives 
     A first embodiment of the present disclosure provides a benzodiazaborole derivative, comprising a structure of the following General Formula (1), 
     
       
         
         
             
             
         
       
     
     Wherein, R 1  is selected from the group consisting of hydrogen atom, General Formula (2), General Formula (3) and General Formula (4), R 2  is selected from the group consisting of hydrogen atom, General Formula (3) and General Formula (4), R 1  and R 2  are different and at least one of them is a hydrogen atom, R 3  is General Formula (4) when R 2  is General Formula (4), and R 3  is a hydrogen atom when R 2  is a hydrogen atom or General Formula (3). 
     
       
         
         
             
             
         
       
     
     Wherein, R 4  to R 19  are independently selected from the group consisting of hydrogen atom, fluorine atom, cyano group, alkyl group, cycloalkyl group, alkoxy group, haloalkyl group, thioalkyl group, silyl group and alkenyl group. 
     Herein, the alkyl group is selected from the group consisting of a substituted or unsubstituted straight-chain C1˜C6 alkyl group, and a substituted or unsubstituted branched-chain C3˜C6 alkyl group, the cycloalkyl group is a substituted or unsubstituted C3˜C6 cycloalkyl group, the alkoxy group is selected from the group consisting of a substituted or unsubstituted straight-chain C1˜C6 alkoxy group, and a substituted or unsubstituted branched-chain C3˜C6 alkoxy group, the haloalkyl group is selected from the group consisting of a substituted or unsubstituted straight-chain C1˜C6 haloalkyl group, and a substituted or unsubstituted branched-chain C3˜C6 haloalkyl group, the thioalkyl group is selected from the group consisting of a substituted or unsubstituted straight-chain C1˜C6 thioalkyl group, and a substituted or unsubstituted branched-chain C3˜C6 thioalkyl group, the silyl group is selected from the group consisting of a substituted or unsubstituted straight-chain C1˜C6 silyl group, and a substituted or unsubstituted branched-chain C3˜C6 silyl group, the alkenyl group is selected from the group consisting of a substituted or unsubstituted straight-chain C2˜C6 alkenyl group, and a substituted or unsubstituted branched-chain C3˜C6 alkenyl group. 
     The benzodiazaborole derivative of General Formula (1) according to the embodiment can be a host material of an organic luminescent layer in an organic electroluminescent device. A preferred example is the compound of Chemical Formula (1), mNp, where R 2  is the structure of the General Formula (3), and R 1  and R 3  to R 19  are independent hydrogen atoms. 
     
       
         
         
             
             
         
       
     
     Alternatively, another preferred example is the compound of Chemical Formula (2), oPh, where R 1  is the structure of the General Formula (2), and R 2  to R 19  are independent hydrogen atoms. 
     
       
         
         
             
             
         
       
     
     Alternatively, another preferred example is the compound of Chemical Formula (3), oNp, where R 1  is the structure of the General Formula (3), and R 2  to R 19  are independent hydrogen atoms. 
     
       
         
         
             
             
         
       
     
     Alternatively, another preferred example is the compound of Chemical Formula (4), oCb, where R 1  is the structure of the General Formula (4), and R 2  to R 19  are independent hydrogen atoms. 
     
       
         
         
             
             
         
       
     
     Alternatively, another preferred example is the compound of Chemical Formula (5), dCb, where R 2  and R 3  are the structure of the General Formula (4), and R 1  and R 4  to R 19  are independent hydrogen atoms. 
     
       
         
         
             
             
         
       
     
     In the Chemical Formulas (1) to (5), 1,3,2-benzodiazaborole is utilized as a core structure, and different substituents are introduced to the ortho and/or meta positions of the benzo group to improve its thermal stability and adjust its electrochemical properties, thereby providing a series of benzodiazaborole derivatives. 
     Accordingly, the benzodiazaborole derivatives have good electrochemical properties and thermal stability. Moreover, as the 1,3,2-benzodiazaborole has 10 π electrons and an empty p z  orbital of the boron atom, it has unique photoelectric properties and high triplet energy levels. Thus, they can be the host materials for the blue phosphorescent organic light-emitting diodes. 
     In this embodiment, the guest materials for use with the host materials may be any suitable materials applied to the organic luminescent layer of the organic electroluminescent device, for example but not limited to, the following Chemical Formula (6) (Ir(2-phq) 3 ), Chemical Formula (7) (Ir(ppy) 3 ), and Chemical Formula (8) (FIrpic). 
     
       
         
         
             
             
         
       
     
     To be noted, the structure of the General Formula (1) of this embodiment can not only be applied to the organic luminescent layer, but also be used in the electron blocking layer of the organic light-emitting unit. 
     Organic Light-Emitting Diodes 
     Please refer to  FIG. 1 , an organic light-emitting diode  100  according to the second embodiment of the disclosure includes a first electrode layer  120 , a second electrode layer  140  and an organic luminescent unit  160 . In the embodiment, the first electrode layer  120  can be a transparent electrode material, such as indium tin oxide (ITO), and the second electrode layer  140  can be a metal, transparent conductive substance or any other suitable conductive material. On the other hand, the first electrode layer  120  can also be a metal, transparent conductive substance or any other suitable conductive material, and the second electrode layer  140  can also be a transparent electrode material. Overall, at least one of the first electrode layer  120  and the second electrode layer  140  of the embodiment is a transparent electrode material, so that the light emitted from the organic luminescent unit  160  may pass through the transparent electrode, thereby enabling the organic light-emitting diode  100  to emit light. 
     In addition, please also refer to  FIG. 1 , the organic luminescent unit  160  can comprise a hole transport layer  162 , an electron blocking layer  164 , an organic luminescent layer  166 , an electron transport layer  168  and an electron injection layer  169 . The electron blocking layer  164 , the organic luminescent layer  166  and the electron transport layer  168  are sequentially disposed between the hole transport layer  162  and the electron injection layer  169 . 
     Herein, the materials of the hole transport layer  162  may be 1,1-Bis[4-[N,N′-di(p-tolyl)amino]phenyl]cyclohexane (TAPC), N,N-bis-(1-naphthyl)-N,N-diphenyl-1,1-biphenyl-4,4-diamine (NPB) or N-N′-diphenyl-N-Nbis(3-methylphenyl)-[1-1′-biphenyl]-4-4′-diamine (TPD) and so on. Moreover, the thickness of the hole transport layer  162  of the embodiment ranges, for example, from 0 nm to 100 nm. In the embodiment, the hole transport layer  162  can increase the injection rate of electron holes from the first electrode layer  120  to the organic luminescent layer  166  and can also reduce the driving voltage of the organic light-emitting diode  100 . 
     The materials of the electron blocking layer  164  may be N,N′-dicarbazolyl-3,5-benzene (mCP) or any other material with low electron affinity. In the embodiment, the thickness of the electron blocking layer  164  ranges, for example, from 0 nm to 30 nm. The electron blocking layer  164  may further increase the transport rate of the electron hole from the hole transport layer  162  to the organic luminescent layer  166 . 
     In addition, the thickness of the organic luminescent layer  166  of the embodiment is, for example, between 5 nm and 60 nm. For example, the thickness of the organic luminescent layer  166  of the embodiment is 30 nm. The organic luminescent layer  166  includes a host material and a guest material, and the host material can be the above-mentioned benzodiazaborole derivative which has a structure of the following General Formula (1). 
     
       
         
         
             
             
         
       
     
     Wherein, R 1  is selected from the group consisting of hydrogen atom, General Formula (2), General Formula (3) and General Formula (4), R 2  is selected from the group consisting of hydrogen atom, General Formula (3) and General Formula (4), R 1  and R 2  are different and at least one of them is a hydrogen atom, R 3  is General Formula (4) when R 2  is General Formula (4), and R 3  is a hydrogen atom when R 2  is a hydrogen atom or General Formula (3). 
     
       
         
         
             
             
         
       
     
     Wherein, R 4  to R 19  are independently selected from the group consisting of hydrogen atom, fluorine atom, cyano group, alkyl group, cycloalkyl group, alkoxy group, haloalkyl group, thioalkyl group, silyl group and alkenyl group. 
     Herein, the alkyl group is selected from the group consisting of a substituted or unsubstituted straight-chain C1˜C6 alkyl group, and a substituted or unsubstituted branched-chain C3˜C6 alkyl group, the cycloalkyl group is a substituted or unsubstituted C3˜C6 cycloalkyl group, the alkoxy group is selected from the group consisting of a substituted or unsubstituted straight-chain C1˜C6 alkoxy group, and a substituted or unsubstituted branched-chain C3˜C6 alkoxy group, the haloalkyl group is selected from the group consisting of a substituted or unsubstituted straight-chain C1˜C6 haloalkyl group, and a substituted or unsubstituted branched-chain C3˜C6 haloalkyl group, the thioalkyl group is selected from the group consisting of a substituted or unsubstituted straight-chain C1˜C6 thioalkyl group, and a substituted or unsubstituted branched-chain C3˜C6 thioalkyl group, the silyl group is selected from the group consisting of a substituted or unsubstituted straight-chain C1˜C6 silyl group, and a substituted or unsubstituted branched-chain C3˜C6 silyl group, the alkenyl group is selected from the group consisting of a substituted or unsubstituted straight-chain C2˜C6 alkenyl group, and a substituted or unsubstituted branched-chain C3˜C6 alkenyl group. 
     A preferred example is the compound of Chemical Formula (1), mNp, where R 2  is the structure of the General Formula (3), and R 1  and R 3  to R 19  are independent hydrogen atoms. 
     
       
         
         
             
             
         
       
     
     Alternatively, another preferred example is the compound of Chemical Formula (2), oPh, where R 1  is the structure of the General Formula (2), and R 2  to R 19  are independent hydrogen atoms. 
     
       
         
         
             
             
         
       
     
     Alternatively, another preferred example is the compound of Chemical Formula (3), oNp, where R 1  is the structure of the General Formula (3), and R 2  to R 19  are independent hydrogen atoms. 
     
       
         
         
             
             
         
       
     
     Alternatively, another preferred example is the compound of Chemical Formula (4), oCb, where R 1  is the structure of the General Formula (4), and R 2  to R 19  are independent hydrogen atoms. 
     
       
         
         
             
             
         
       
     
     Alternatively, another preferred example is the compound of Chemical Formula (5), dCb, where R 2  and R 3  are the structure of the General Formula (4), and R 1  and R 4  to R 19  are independent hydrogen atoms. 
     
       
         
         
             
             
         
       
     
     In addition, the guest materials may be any suitable materials applied to the organic luminescent layer of the organic electroluminescent device, for example but not limited to, the following Chemical Formula (6) (Ir(2-phq) 3 ), Chemical Formula (7) (Ir(ppy) 3 ), and Chemical Formula (8) (FIrpic). 
     
       
         
         
             
             
         
       
     
     In addition, the material of the electron transport layer  168  may be, but not limited to, a metal complex, such as Tris-(8-hydroxy-quinoline)aluminum (Alq 3 ), bis(10-hydroxybenzo-[h]quinolinato)beryllium (BeBq 2 ) and so on, or a heterocyclic compound, such as 2-(4-Biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD), 3-(4-Biphenyly)-4-phenyl-5-tert-butylphenyl-1,2,4-triazol e (TAZ), 2,2′,2″-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazol e) (TPBI), diphenylbis(4-(pyridin-3-yl)phenyl)silane (DPPS), 3,3′-[5′-[3-(3-Pyridinyl)phenyl][1,1′:3′,1″-terphenyl]-3,3″-diyl]bispyridine (TmPyPB) and so on. In the embodiment, the thickness of the electron transport layer  168  may be, for example, less than 100 nm. The electron transport layer  168  can facilitate the transfer of electrons from the second electrode layer  140  to the organic luminescent layer  166  to increase the transport rate of the electron. Moreover, the material of the electron injection layer  169  may be, for example, LiF. The thickness of the electron injection layer  169  may be, for example, 0.7 nm. 
     In addition,  FIG. 2  is a sectional view of an organic light-emitting diode  200  according to the third embodiment of the disclosure. The configuration of the organic light-emitting diode  200  is substantially similar with that of the organic light-emitting diode  100 , and same elements have substantial the same characteristics and functions. Therefore, the similar references relate to the similar elements, and detailed explanation is omitted hereinafter. 
     Please refer to  FIG. 2 , in the embodiment, the organic luminescent unit  160  can comprise a hole transport layer  162 , an organic luminescent layer  166  and an electron transport layer  168 . The organic luminescent layer  166  is disposed between the hole transport layer  162  and the electron transport layer  168 . 
     In addition,  FIG. 3  is a sectional view of an organic light-emitting diode  300  according to the fourth embodiment of the disclosure. The configuration of the organic light-emitting diode  300  is substantially similar with that of the organic light-emitting diode  100 , and same elements have substantial the same characteristics and functions. Therefore, the similar references relate to the similar elements, and detailed explanation is omitted hereinafter. 
     Please refer to  FIG. 3 , in the embodiment, the organic luminescent unit  160  can comprise an organic luminescent layer  166 . 
     The configuration of the organic light-emitting diode according to the disclosure is not limited to what is disclosed in the second, third or fourth embodiment. The second, third and fourth embodiments are for illustrations only. 
     In the above-mentioned second, third and fourth embodiments, the materials having the structures of General Formula (1), in addition to being applied to the organic luminescent layer, can also be applied to the electron blocking layer of an organic electroluminescent unit. 
     To illustrate the synthesis of Chemical Formula (1) to Chemical Formula (5), there are several examples shown below. 
     EXAMPLE 1 
     Synthesis of Compound 1 
     1,2-dibromobenzene (1.50 g, 6.40 mmol), palladium acetate (Pd(OAc) 2 , 0.04 g, 0.178 mmol), tri-tert-butylphosphonium tetrafluoroborate (0.15 g, 0.52 mmol), and sodium tert-butoxide (NaO t Bu, 1.82 g, 18.95 mmol) were provided in a 50 ml two-neck bottle in an inert atmosphere. The dehydrated and deoxygenated toluene (20 ml) and aniline (1.70 ml, 18.65 mmol) were added into the bottle. The mixture was subjected to reaction in refluxing for 18 hours. After cooling to the room temperature, the solution was filtered by diatomaceous earth. The filtrate was collected and extracted with aqueous ammonium chloride solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was purified through by column chromatography with n-hexane/DCM=4/1 as eluent to obtain compound 1 (1.45 g, yield: 87%) as a white solid. The foregoing reaction is shown in the Reaction Formula (1). 
     Spectral data as follow:  1 H NMR (400 MHz, DMSO-d 6 ): δ 7.28-7.23(m, 4H), 7.17(t, J=8.4Hz, 4H), 6.96-6.89(m, 6H), 6.75(t, J=7.3 Hz, 2H);  13 C NMR (100 MHz, DMSO-d 6 ): δ 144.47, 134.51, 128.94, 121.96, 119.88, 118.98, 116.16. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 2 
     Synthesis of Compound 2 
     1-bromo-2,3-dichlorobenzene (1.00 g, 4.43 mmol), phenylboronic acid (0.56 g, 4.60 mmol), potassium carbonate (K 2 CO 3 , 1.38 g, 10.00 mmol), and palladium(II) chloride (PdCl 2 , 4.00 mg, 0.02 mmol) were provided in a 100 ml single-neck bottle. After adding with 5 ml ethanol and 15 ml deionized water, the solution was stirred for a half hour at room temperature. The solution was then extracted with DCM/potassium carbonate aqueous solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was purified through by column chromatography with n-hexane as eluent to obtain compound 2 (0.80 g, yield: 82%) as a transparent liquid. The foregoing reaction is shown in the Reaction Formula (2). 
     Spectral data as follow:  1 H NMR (400 MHz, CDCl 3 ): δ 7.50-7.39(m, 6H), 7.31-7.25(m, 2H);  13 C NMR (100 MHz, CDCl 3 ): δ 142.86, 138.29, 133.57, 131.14, 129.47, 129.41, 129.25, 128.12, 127.92, 127.11; HRMS(FAB) m/z calcd for C 12 H 8 Cl 2  (M + ) 222.0003, obsd. 222.0003. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 3 
     Synthesis of Compound 3 
     Compound 2 (0.75 g, 3.38 mmol), Bis(dibenzylideneacetone)palladium(0) (Pd(dba) 2 , 0.19 g, 0.33 mmol), tri-tert-butylphosphonium tetrafluoroborate (0.19 g, 0.66 mmol), and sodium tert-butoxide (NaO t Bu, 0.95 g, 0.99 mmol) were provided in a 25 ml two-neck bottle in an inert atmosphere. The dehydrated and deoxygenated toluene (16 ml) and aniline (0.90 ml, 9.87 mmol) were added into the bottle. The mixture was heated to 110° C. for 18 hours. After cooling to the room temperature, the solution was filtered by diatomaceous earth. The filtrate was collected and extracted with aqueous ammonium chloride solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was purified through by column chromatography with n-hexane/DCM=4/1 as eluent to obtain compound 3 (0.83 g, yield: 73%) as a white solid. The foregoing reaction is shown in the Reaction Formula (3). 
     Spectral data as follow:  1 H NMR (400 MHz, DMSO-d 6 ): δ 7.35-7.18(m, 9H), 7.09-7.07(m, 4H), 7.95(t, J=7.4 Hz, 2H), 6.88-6.83(m, 2H), 6.50(t, J=7.2 Hz, 1H),6.44(d, J=7.6 Hz, 2H);  13 C NMR (100 MHz, DMSO-d 6 ): δ 146.66, 143.03, 141.09, 140.93, 129.08, 128.58, 128.53, 127.86, 127.32, 126.76, 126.12, 122.15, 120.39, 118.05, 116.97, 115.22, 113.15; HRMS(FAB) m/z calcd for C 24 H 20 N 2  (M + ) 336.1626, obsd. 336.1623. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 4 
     Synthesis of Compound 4 
     1-bromo-3,4-dichlorobenzene (1.00 g, 4.43 mmol), phenylboronic acid (0.56 g, 4.60 mmol), potassium carbonate (K 2 CO 3 , 1.38 g, 10.00 mmol), and palladium(II) chloride (PdCl 2 , 4.02 mg, 0.02 mmol) were provided in a 100 ml single-neck bottle. After adding with 5 ml ethanol and 15 ml deionized water, the solution was stirred for a half hour at room temperature. The solution was then extracted with DCM/potassium carbonate aqueous solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was purified through by column chromatography with n-hexane as eluent to obtain compound 4 (0.82 g, yield: 84%) as a transparent liquid. The foregoing reaction is shown in the Reaction Formula (4). 
     Spectral data as follow:  1 H NMR (400 MHz, CDCl 3 ): δ 7.66(d, J=2.1 Hz, 1H), 7.53-7.34(m, 7H),  13 C NMR (100 MHz, CDCl 3 ): δ 141.23, 138.76, 132.81, 131.41, 130.66, 128.99, 128.96, 128.11, 126.94, 126.35; HRMS(FAB) m/z calcd for C 12 H 8 Cl 2  (M + ) 222.0003, obsd. 222.0004. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 5 
     Synthesis of Compound 5 
     Compound 4 (0.58 g, 1.53 mmol), Bis(dibenzylideneacetone)palladium(0) (Pd(dba) 2 , 0.15 g, 0.15 mmol), tri-tert-butylphosphonium tetrafluoroborate (0.15 g, 0.30 mmol), and sodium tert-butoxide (NaO t Bu, 0.60 g, 3.83 mmol) were provided in a 25 ml two-neck bottle in an inert atmosphere. The dehydrated and deoxygenated toluene (3.80 ml) and aniline (0.35 ml, 3.83 mmol) were added into the bottle. The mixture was heated to 110° C. for 18 hours. After cooling to the room temperature, the solution was filtered by diatomaceous earth. The filtrate was collected and extracted with aqueous ammonium chloride solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was purified through by column chromatography with n-hexane/DCM=3/1 as eluent to obtain compound 5 (0.43 g, yield: 84%) as a white solid. The foregoing reaction is shown in the Reaction Formula (5). 
     Spectral data as follow:  1 H NMR (400 MHz, DMSO-d 6 ): δ 7.55(d, J=7.4 Hz, 2H), 7.50(s, J=2.0 Hz, 1H), 7.43-7.39(m, 4H), 7.34-7.27(m, 2H), 7.23-7.18(m, 5H),6.44(d, J=7.6 Hz, 4H), 6.81-6.76(m, 2H);  13 C NMR (100 MHz, DMSO-d 6 ): δ 144.44, 144.09, 140.20, 134.50, 134.34, 133.52, 129.10, 129.05, 128.89, 126.72, 126.03, 120.40, 119.52, 119.36, 119.16, 117.96, 116.66, 116.33; HRMS(FAB) m/z calcd for C 24 H 20 N 2 (M + )336.1626, obsd. 336.1629. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 6 
     Synthesis of Compound 6 
     1-bromo-2,3-dichlorobenzene (1.00 g, 4.43 mmol), 2-Naphthaleneboronic acid (0.81 g, 4.71 mmol), potassium carbonate (K 2 CO 3 , 1.38 g, 10.00 mmol), and palladium(II) chloride (PdCl 2 , 4.05 mg, 0.02 mmol) were provided in a 100 ml single-neck bottle. After adding with 5 ml ethanol and 10 ml deionized water, the solution was stirred for a half hour at room temperature. The solution was then extracted with DCM/potassium carbonate aqueous solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was purified through by column chromatography with n-hexane as eluent to obtain compound 6 (0.80 g, yield: 66%) as a white solid. The foregoing reaction is shown in the Reaction Formula (6). 
     Spectral data as follow:  1 H NMR (400 MHz, CD 2 Cl 2 ): δ 7.90-7.87(m, 4H), 7.58-7.52(m, 4H), 7.38-7.32(m, 2H);  13 C NMR (100 MHz, CDCl 3 ): δ 142.81, 136.80, 133.62, 133.04, 132.73, 131.32, 129.71, 129.51, 128.26, 128.17, 127.72, 127.58, 127.26, 127.19, 126.44, 126.38; HRMS(FAB) m/z calcd for C 16 H 10 Cl 2  (M + ) 272.0160, obsd. 272.0159. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 7 
     Synthesis of Compound 7 
     Compound 6 (0.67 g, 2.46 mmol), Bis(dibenzylideneacetone)palladium(0) (Pd(dba) 2 , 0.14 g, 0.24 mmol), tri-tert-butylphosphonium tetrafluoroborate (0.14 g, 0.49 mmol), and sodium tert-butoxide (NaO t Bu, 0.59 g, 6.15 mmol) were provided in a 25 ml two-neck bottle in an inert atmosphere. The dehydrated and deoxygenated toluene (12 ml) and aniline (0.57 ml, 6.25 mmol) were added into the bottle. The mixture was heated to 110° C. for 18 hours. After cooling to the room temperature, the solution was filtered by diatomaceous earth. The filtrate was collected and extracted with aqueous ammonium chloride solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was purified through by column chromatography with n-hexane/DCM=4/1 as eluent to obtain compound 7 (0.80 g, yield: 84%) as a white solid. The foregoing reaction is shown in the Reaction Formula (7). 
     Spectral data as follow:  1 H NMR (400 MHz, CDCl 3 ): δ 7.82-7.68(m, 4H), 7.48-7.43(m, 2H), 7.41(dd, J 1 =8.2 Hz, J 2 =1.2 Hz, 1H), 7.33(dd, J 1 =8.4 Hz, J 2 =1.6 Hz, 1H), 7.27(t, J=7.9 Hz, 2H), 7.21-7.10(m, 5H), 6.99-6.94(m, 2H), 6.82(t, J=7.28 Hz, 1H), 6.62(d, J=8.0 Hz, 2H), 6.13(br, 1H), 5.14(br, 1H);  13 C NMR (100 MHz, CDCl 3 ): δ 145.98, 142.25, 140.87, 139.67, 136.82, 133.29, 132.52, 129.41, 129.26, 128.07, 127.83, 127.59, 127.27, 126.69, 126.19, 126.05, 121.81, 121.72, 119.77, 119.56, 114.68, 113.97; HRMS(FAB) m/z calcd for C 28 H 22 N 2  (M + ) 386.1783, obsd. 386.1781. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 8 
     Synthesis of Compound 8 
     1-bromo-3,4-dichlorobenzene (1.00 g, 4.43 mmol), 2-Naphthaleneboronic acid (0.81 g, 4.71 mmol), potassium carbonate (K 2 CO 3 , 1.38 g, 10.00 mmol), and palladium(II) chloride (PdCl 2 , 4.01 mg, 0.02 mmol) were provided in a 100 ml single-neck bottle. After adding with 5 ml ethanol and 15 ml deionized water, the solution was stirred for a half hour at room temperature. The solution was then extracted with DCM/potassium carbonate aqueous solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was purified through by column chromatography with n-hexane as eluent to obtain compound 8 (0.90 g, yield: 75%) as a white solid. The foregoing reaction is shown in the Reaction Formula (8). 
     Spectral data as follow:  1 H NMR (400 MHz, CDCl 3 ): δ 7.98(d, J=0.3 Hz, 1H), 7.92-7.84(m, 3H), 7.79(t, J=1.2 Hz, 3H), 7.65(dd, J 1 =8.5Hz, J 2 =1.8Hz, 1H), 7.53-7.49(m, 4H);  13 C NMR (100 MHz, CDCl 3 ): δ 141.16, 136.02,133.52, 132.93, 132.89, 131.75, 129.17, 128.79, 128.24, 127.68, 126.68, 126.62, 126.59, 125.95, 124.87; HRMS(FAB) m/z calcd for C 16 H 10 Cl 2  (M + ) 272.0161, obsd. 272.0160. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 9 
     Synthesis of Compound 9 
     Compound 8 (0.82 g, 3.00 mmol), Bis(dibenzylideneacetone)palladium(0) (Pd(dba) 2 , 0.17 g, 0.30 mmol), tri-tert-butylphosphonium tetrafluoroborate (0.17 g, 0.60 mmol) and sodium tert-butoxide (NaO t Bu, 0.72 g, 7.50 mmol) were provided in a 25 ml two-neck bottle in an inert atmosphere. The dehydrated and deoxygenated toluene (15 ml) and aniline (0.70 ml, 7.68 mmol) were added into the bottle. The mixture was heated to 110° C. for 18 hours. After cooling to the room temperature, the solution was filtered by diatomaceous earth. The filtrate was collected and extracted with aqueous ammonium chloride solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was purified through by column chromatography with n-hexane/DCM=4/1 as eluent to obtain compound 9 (0.83 g, yield: 72%) as a white solid. The foregoing reaction is shown in the Reaction Formula (9). 
     Spectral data as follow:  1 H NMR (400 MHz, DMSO-d 6 ): δ 8.09(s, 1H), 7.96(d, J=8.4 Hz, 2H), 7.91(d, J=7.6 Hz, 1H), 7.76(d, J=8.4 Hz, 1H), 7.66(s, 1H), 7.51-7.38(m, 6H), 7.24-7.19(m, 4H), 7.07-7.02(m, 4H), 6.83-6.76(m, 2H);  13 C NMR (100 MHz, DMSO-d 6 ): δ 144.60, 143.97, 137.53, 134.79, 134.32, 133.40, 133.15, 131.89, 129.10, 129.06, 128.37, 128.00, 127.43, 126.31, 125.72, 124.82, 124.09, 120.94, 119.48, 119.32, 119.04, 118.66, 116.82, 116.14; HRMS(FAB) m/z calcd for C 28 H 22 N 2  (M + ) 386.1783, obsd. 386.1782 
     
       
         
         
             
             
         
       
     
     EXAMPLE 10 
     Synthesis of Compound 10 
     1,2-Dibromo-4-fluorobenzene (6.82 g, 26.86 mmol), Carbazole (4.71 g, 28.20 mmol) and Cesium carbonate (Cs 2 CO 3 , 13.13 g, 40.29 mmol) were provided in a 250 ml single-neck bottle. The mixture was added with 34 ml dimethylformamide (dried by calcium hydride) and heated to 130° C. for 18 hours. After cooling to the room temperature, dimethylformamide was removed under vacuum. The residual was added with DCM and filtered. The filtrate was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was purified through by column chromatography with n-hexane/DCM=8/1 as eluent to obtain compound 10 (8.02 g, yield: 75%) as a white solid. The foregoing reaction is shown in the Reaction Formula (10). 
     Spectral data as follow:  1 H NMR (400 MHz, DMSO-d 6 ): δ 8.24(d, J=7.6 Hz, 2H), 8.05-8.02(m, 2H), 7.60(dd, J 1 =8.4 Hz, J 2 =2.4 Hz, 1H), 7.46-7.40(m, 4H), 7.33-7.29(m, 2H);  13 C NMR (100 MHz, DMSO-d 6 ): δ 139.77, 137.36, 135.08, 131.66, 127.72,126.43, 125.11, 122.93, 122.75, 120.55, 120.51; HRMS(FAB) m/z calcd for C 18 H 11 Br 2 N (M + )398.9258, obsd. 398.9259. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 11 
     Synthesis of Compound 11 
     Compound 10 (1.5 g, 3.77 mmol), Bis(dibenzylideneacetone)palladium(0) (Pd(dba) 2 , 0.22 g, 0.38 mmol), tri-tert-butylphosphonium tetrafluoroborate (0.22 g, 0.75 mmol) and sodium tert-butoxide (NaO t Bu, 1.08 g, 11.25 mmol) were provided in a 25 ml two-neck bottle in an inert atmosphere. The dehydrated and deoxygenated toluene (25 ml) and aniline (1.05 ml, 11.52 mmol) were added into the bottle. The mixture was heated to 110° C. for 18 hours. After cooling to the room temperature, the solution was filtered by diatomaceous earth. The filtrate was collected and extracted with aqueous ammonium chloride solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was purified through by column chromatography with n-hexane/DCM=3/1 as eluent to obtain compound 11 (1.12 g, yield: 69%) as a white solid. The foregoing reaction is shown in the Reaction Formula (11). 
     Spectral data as follow:  1 H NMR (400 MHz, DMSO-d 6 ): δ 8.21(d, J=7.7 Hz, 2H), 7.57(s, 1H), 7.53(s,1H), 7.48 (d, J=8.4 Hz, 1H), 7.44 (d, J=4.0 Hz, 4H), 7.31-7.23(m, 5H), 7.19(t, J=7.8 Hz, 2H), 7.12-7.06(m, 5H), 6.83(t, J=7.3 Hz, 1H), 6.78(t, J=7.3 Hz, 1H);  13 C NMR (100 MHz, DMSO-d 6 ): δ 144.09, 143.57, 140.32, 136.11, 133.53, 130.25, 129.08, 126.13, 122.45, 120.42, 120.20, 119.99, 119.72, 119.53, 119.44, 117.41, 116.79, 116.28, 109.65; HRMS(FAB) m/z calcd for C 30 H 23 N 3 (M + ) 425.1892, obsd. 425.1895. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 12 
     Synthesis of Compound 12 
     1,2-Dibromo-4,5-difluorobenzene (10.00 g, 36.78 mmol), Carbazole (13.50 g, 80.84 mmol) and Cesium carbonate (Cs 2 CO 3 , 30.00 g, 91.95 mmol)were provided in a 500 ml single-neck bottle. The mixture was added with 92 ml dimethylformamide (dried by calcium hydride) and heated to 130° C. for 18 hours. After cooling to the room temperature, dimethylformamide was removed under vacuum. The residual was added with DCM and filtered. The organic layer was concentrated under vacuum. The crude was hot washed by ethyl acetate and filtered to obtain compound 12 (16.62 g, yield: 80%) as a white solid. The foregoing reaction is shown in the Reaction Formula (12). 
     Spectral data as follow:  1 H NMR (400 MHz, CDCl 3 ): δ 8.07(s, 1H), 7.78-7.76(m, 4H), 7.13-7.11(m, 4H), 7.06-7.04(m, 8H;  13 C NMR (100 MHz, CDCl 3 ): δ 139.33, 134.82, 134.47, 125.68, 124.32, 123.65, 120.45, 120.04, 109.38; HRMS(FAB) m/z calcd for C 30 H 18 Br 2 N 2 (M + )563.9837, obsd. 563.9840. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 13 
     Synthesis of Compound 13 
     Compound 12 (1.75 g, 3.10 mmol), Bis(dibenzylideneacetone)palladium(0) (Pd(dba) 2 , 0.18 g, 0.31 mmol), tri-tert-butylphosphonium tetrafluoroborate (0.18 g, 0.62 mmol) and sodium tert-butoxide (NaO t Bu, 0.74 g, 7.71 mmol) were provided in a 25 ml two-neck bottle in an inert atmosphere. The dehydrated and deoxygenated toluene (25 ml) and aniline (1.05 ml, 11.52 mmol) were added into the bottle. The mixture was heated to 110° C. for 18 hours. After cooling to the room temperature, the solution was filtered by diatomaceous earth. The filtrate was collected and extracted with aqueous ammonium chloride solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was purified through by column chromatography with n-hexane/DCM=2/1 as eluent to obtain compound 13 (1.02 g, yield: 55%) as a white solid. The foregoing reaction is as shown in the Reaction Formula (13). 
     Spectral data as follow:  1 H NMR (400 MHz, DMSO-d 6 ): δ 7.89(d, J=7.6 Hz, 4H), 7.80(s, 2H), 7.39-7.36(m, 6H), 7.22(d, J=4.1 Hz, 8H), 7.12(t, J=7.2 Hz, 4H), 7.02(t, J=7.2 Hz, 4H), 6.83-6.79(m, 2H);  13 C NMR (100 MHz, DMSO-d 6 ): δ 143.17, 140.00, 135.51, 129.19, 126.24, 125.55, 122.47, 120.54, 120.03, 119.60, 118.05, 109.89; HRMS(FAB) m/z calcd for C 42 H 30 N 4 (M + )590.2470, obsd. 590.2463 
     
       
         
         
             
             
         
       
     
     EXAMPLE 14 
     Synthesis of Compound 14 
     2-chloro,6-fluorobromobenzene (1.00 g, 4.78 mmol), Carbazole (0.83 g, 4.97 mmol) and sodium tert-butoxide (NaO t Bu, 0.67 g, 6.98 mmol) were provided in a 50 ml two-neck bottle. The mixture was added with 12 ml dimethylformamide (dried by calcium hydride) and heated to 130° C. for 18 hours. After cooling to the room temperature, dimethylformamide was removed under vacuum. The residual was added with DCM and filtered. The filtrate was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was purified through by column chromatography with n-hexane/DCM=8/1 as eluent to obtain compound 14 (1.30 g, yield: 76%) as a white solid. The foregoing reaction is shown in the Reaction Formula (14). 
     Spectral data as follow:  1 H NMR (400 MHz, CDCl 3 ): δ 8.14(d, J=8.0 Hz, 2H), 7.66(dd, J 1 =8.0 Hz, J 2 =1.6 Hz, 1H), 7.46(t, J=8.0 Hz, 1H), 7.41-7.38(m, 3H), 7.30(t, J=8.0 Hz, 2H), 7.04(d, J=8.0 Hz, 2H);  13 C NMR (100 MHz, CDCl 3 ): δ 140.57, 138.81, 136.87, 130.62, 129.28, 128.92, 126.05, 124.99, 123.31, 120.40, 120.21, 109.93; HRMS(FAB) m/z calcd for C 18 H 11 BrClN(M + ) 311.9763, obsd. 354.9765. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 15 
     Synthesis of Compound 15 
     Compound 12 (0.4 g, 1.13 mmol), 1,1′-Bis(diphenylphosphino)ferrocene (0.06 g, 0.11 mmol), palladium acetate (0.13 g, 0.11 mmol) and sodium tert-butoxide (NaO t Bu, 0.12 g, 0.13 mmol) were provided in a 25 ml two-neck bottle in an inert atmosphere. The dehydrated and deoxygenated toluene (3 ml) and aniline (0.11 ml, 1.24 mmol) were added into the bottle. The mixture was heated to 110° C. for 18 hours. After cooling to the room temperature, the solution was filtered by diatomaceous earth. The filtrate was collected and extracted with aqueous ammonium chloride solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was purified through by column chromatography with n-hexane/DCM=6/1 as eluent to obtain compound 15 (0.22 g, yield: 48%) as a white solid. The foregoing reaction is shown in the Reaction Formula (15). 
     Spectral data as follow:  1 H NMR (400 MHz, CDCl 3 ): δ 8.10(d, J=8.0 Hz, 1H), 7.66 (dd, J 1 =8.0 Hz, J 2 =1.6 Hz, 1H), 7.47-7.39(m, 3H), 7.39-7.22 (m, 5H), 6.71(t, J=8.0 Hz, 2H), 6.59(t, J=8.0 Hz, 2H), 6.39(d, J=8.0 Hz, 2H), 5.81(s, 1H);  13 C NMR (100 MHz, CDCl 3 ): δ 141.15, 139.74, 137.43, 129.78, 129.75, 128.77, 128.05, 127.62, 125.62, 123.28, 122.70, 121.55, 119.99, 119.81, 118.37, 109.99; HRMS(ESI) m/z calcd for C 24 H 17 BrN 2 (MH + ) 369.1159, obsd.369.1168. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 16 
     Synthesis of Compound 16 
     Compound 15 (0.50 g, 1.36 mmol), Bis(dibenzylideneacetone)palladium(0) (Pd(dba) 2 , 0.078 g, 0.14 mmol), tri-tert-butylphosphonium tetrafluoroborate (0.079 g, 0.27 mmol) and sodium tert-butoxide (NaO t Bu, 0.20 g, 2.04 mmol) were provided in a 25 ml two-neck bottle in an inert atmosphere. The dehydrated and deoxygenated toluene (3.50 ml) and aniline (0.19 ml, 2.08 mmol) were added into the bottle. The mixture was heated to 110° C. for 18 hours. After cooling to the room temperature, the solution was filtered by diatomaceous earth. The filtrate was collected and extracted with aqueous ammonium chloride solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was purified through by column chromatography with n-hexane/DCM=2/1 as eluent to obtain compound 16 (0.35 g, yield: 61%) as a white solid. The foregoing reaction is shown in the Reaction Formula (16). 
     Spectral data as follow:  1 H NMR (400 MHz, DMSO-d 6 ): δ 8.03(d, J=7.6 Hz, 2H), 7.47(dd, J 1 =8.0 Hz, J 2 =0.4 Hz, 1H), 7.40 (s, 1H), 7.31(t, J=7.6 Hz, 2H), 7.28-7.22(m, 5H), 7.17-7.12(m, 4H), 7.08(s, 1H), 6.98(dd, J 1 =8.0 Hz, J 2 =0.4 Hz, 1H), 6.87(t, J=7.6 Hz, 1H), 6.56(t, J=8.0 Hz, 1H), 6.27-6.23(m, 3H);  13 C NMR (100 MHz, DMSO-d 6 ): δ 144.20, 143.12, 140.90, 139.79, 133.26, 129.15, 128.46, 127.55, 125.28, 122.68, 120.47, 120.36, 119.97, 119.30, 117.75, 117.58, 116.46, 113.99, 110.31; HRMS(FAB) m/z calcd for C 30 H 23 N 3 (M + )425.1892, obsd. 425.1894. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 17 
     Synthesis of Compound 17 (NS) 
     Calcium hydride (1.30 g, 30.95 mmol) was provided in a 50 ml tri-neck bottle and two sets of dropping funnels were set in an inert atmosphere. The deoxygenated and dehydrated DCM (30 ml) was added into the reaction bottle. N 1 ,N 2 -diphenylbenzene-1,2-diamine (compound 1, 1.60 g, 6.15 mmol) was added in one dropping funnel. The dichlorophenylborane (0.90 ml, 7.20 mmol) was added into the other dropping funnel. Each of the dropping funnels was added with 18 ml DCM and slowly dropped into the bottle under ice bath. One hour later, the mixture was warmed to room temperature and stirred for 5 hours. The mixture was filtered and the filtrate was extracted with aqueous potassium carbonate solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was washed by ether to obtain compound 17 (NS, 1.75 g, yield: 82%) as a white solid. The foregoing reaction is shown in the Reaction Formula (17). 
     Spectral data as follow: m.p.=184° C.;  1 H NMR (400 MHz, CDCl 3 ): δ 7.44-7.40(m, 4H), 7.34-7.31(m, 6H), 7.23-7.18(tt, J 1 =7.1 Hz, J 2 =1.7 Hz, 1H), 7.14-7.07(m, 6H), 7.05-7.01(m, 2H);  13 C NMR (100 MHz, CDCl 3 ): δ 140.36, 137.79, 134.68, 129.24, 128.56, 127.78, 127.30, 126.29, 119.97, 110.10; HRMS(FAB) m/z calcd for C 24 H 19 BN 2 (M + ) 346.1641, obsd. 346.1642 
     
       
         
         
             
             
         
       
     
     EXAMPLE 18 
     Synthesis of Compound 18 (mPh) 
     Calcium hydride (0.50 g, 11.90 mmol) was provided in a 50 ml tri-neck bottle and two sets of dropping funnels were set in an inert atmosphere. The deoxygenated and dehydrated DCM (15 ml) was added into the reaction bottle. The N 3 ,N 4 -diphenyl-[1,1′-biphenyl]-3,4-diamine (compound 5, 0.70 g, 2.08 mmol) was added in one dropping funnel. The dichlorophenylborane (0.35 ml, 2.70 mmol) was added into the other dropping funnel. Each of the dropping funnels was added with 7.50 ml DCM and slowly dropped into the bottle under ice bath. One hour later, the mixture was warmed to room temperature and stirred for 5 hours. The mixture was filtered and the filtrate was extracted with aqueous potassium carbonate solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was washed by ether to obtain compound 18 (mPh, 0.71 g, yield: 81%) as a white solid. The foregoing reaction is shown in the Reaction Formula (18). 
     Spectral data as follow: m.p.=210° C.;  1 H NMR (400 MHz, CD 2 Cl 2 ): δ 7.57-7.55(m, 2H), 7.49-7.45(m, 4H), 7.41-7.35(m, 8H), 7.30-7.19(m, 6H), 7.14-7.11(m, 3H);  13 C NMR (100 MHz, CD 2 Cl 2 ): δ 142.54, 140.96, 140.87, 139.07, 138.12, 135.16, 134.20, 129.92, 129.88, 129.23, 129.17, 128.44, 128.30, 127.88, 127.57, 127.06, 127.01, 119.76, 110.72, 109.30; HRMS(FAB) m/z calcd for C 30 H 23 BN 2 (M + ) 422.1954, obsd. 422.1956; Anal. Calcd for C 30 H 23 BN 2 : C, 85.32; H, 5.49; B, 2.56; N, 6.63. Found: C, 85.10; H, 5.64; N, 6.56. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 19 
     Synthesis of Chemical Formula (1)-Compound 19 (mNp) 
     Calcium hydride (0.35 g, 8.33 mmol) was provided in a 50 ml tri-neck bottle and two sets of dropping funnels were set in an inert atmosphere. The deoxygenated and dehydrated DCM (11 ml) was added into the reaction bottle. 4-(naphthalen-2-yl)-N 1 ,N 2 -diphenylbenzene-1,2-diamine (compound 9, 0.65 g, 1.67 mmol) was added in one dropping funnel. The dichlorophenylborane (0.27 ml, 2.08 mmol) was added into the other dropping funnel. Each of the dropping funnels was added with 5.5 ml DCM and slowly dropped into the bottle under ice bath. One hour later, the mixture was warmed to room temperature and stirred for 5 hours. The mixture was filtered and the filtrate was extracted with aqueous potassium carbonate solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was washed by ether to obtain compound 19 (mNp, Chemical Formula (1), 0.61 g, yield: 77%) as a white solid. The foregoing reaction is shown in the Reaction Formula (19). 
     Spectral data as follow: m.p.=224° C.;  1 H NMR (400 MHz, CDCl 3 ): δ 7.94(s, 1H), 7.85-7.80(m, 3H), 7.69(dd, J 1 =8.5Hz, J 2 =1.8Hz, 1H), 7.45-7.71(m, 6H), 7.39-7.33(m, 8H), 7.20-7.18(m, 1H), 7.16(d, J=8.28Hz, 1H), 7.13-7.07(m, 4H);  13 C NMR (100 MHz, CDCl 3 ): δ 140.32, 140.24, 139.45, 138.42, 137.69, 133.72, 129.41, 129.34, 128.68, 128.15, 127.99, 127.86, 127.75, 127.57, 127.35, 126.47, 126.43, 126.12, 126.05, 125.48, 125.32, 119.65, 110.35, 109.16; HRMS(FAB) m/z calcd for C 34 H 25 BN 2  (M | ) 472.2111, obsd. 472.2117; Anal. Calcd for C 34 H 25 BN 2 : C, 86.45; H, 5.33; B, 2.29; N, 5.93. Found: C, 86.54; H, 5.33; N, 5.91. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 20 
     Synthesis of Chemical Formula (2)-Compound 20 (oPh) 
     Calcium hydride (0.21 g, 5 mmol) was provided in a 25 ml tri-neck bottle and two sets of dropping funnels were set in an inert atmosphere. The deoxygenated and dehydrated DCM (6 ml) was added into the reaction bottle. The N 2 ,N 3 -diphenyl-[1,1′-biphenyl]-2,3-diamine (compound 3, 0.34 g, 1.01 mmol) was added in one dropping funnel. The dichlorophenylborane (0.15 ml, 1.20 mmol) was added into the other dropping funnel. Each of the dropping funnels was added with 3 ml DCM and slowly dropped into the bottle under ice bath. One hour later, the mixture was warmed to room temperature and stirred for 5 hours. The mixture was filtered and the filtrate was extracted with aqueous potassium carbonate solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was washed by ether to obtain compound 20 (oPh, Chemical Formula (2), 0.34 g, yield: 80%) as a white solid. The foregoing reaction is shown in the Reaction Formula (20). 
     Spectral data as follow: m.p.=161° C.;  1 H NMR (400 MHz, CD 2 Cl 2 ): δ 7.46-7.43(m, 2H), 7.37-7.33(m, 3H), 7.19-7.15(m, 1H), 7.09-7.03(m, 6H), 6.99-6.91(m, 6H), 6.89-6.81(m, 5H);  13 C NMR (100 MHz, CD 2 Cl 2 ): δ 149.37, 141.04, 139.97, 139.65, 135.05, 134.05, 129.84, 129.80, 128.81, 128.66, 128.59, 128.27, 127.87, 127.62, 127.55, 126.99, 126.21, 125.79, 124.26, 120.08, 109.79; HRMS(FAB) m/z calcd for C 30 H 23 BN 2  (M + ) 422.1954, obsd. 422.1958; Anal. Calcd for C 30 H 23 BN 2 : C, 85.32; H, 5.49; B, 2.56; N, 6.63. Found: C, 85.23; H, 5.53; N, 6.60. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 21 
     Synthesis of Chemical Formula (3)-Compound 21 (oNp) 
     Calcium hydride (0.33 g, 7.85 mmol) was provided in a 50 ml tri-neck bottle and two sets of dropping funnels were set in an inert atmosphere. The deoxygenated and dehydrated DCM (12 ml) was added into the reaction bottle. The 3-(naphthalen-2-yl)-N 1 ,N 2 -diphenylbenzene-1,2-diamine (compound 7, 0.60 g, 1.55 mmol) was added in one dropping funnel. The dichlorophenylborane (0.30 ml, 1.87 mmol) was added into the other dropping funnel. Each of the dropping funnels was added with 5.70 ml DCM and slowly dropped into the bottle under ice bath. One hour later, the mixture was warmed to room temperature and stirred for 5 hours. The mixture was filtered and the filtrate was extracted with aqueous potassium carbonate solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was washed by ether to obtain compound 21 (oNp, Chemical Formula (3), 0.64 g, yield: 87%) as a white solid. The foregoing reaction is shown in the Reaction Formula (21). 
     Spectral data as follow: m.p.=190° C.;  1 H NMR (400 MHz, CDCl 3 ): δ 7.67-7.65(m, 1H), 7.57-7.54(m, 1H), 7.45-7.40(m, 3H), 7.37-7.31(m, 6H), 7.13-7.07(m, 4H), 7.04-6.97(m, 5H), 6.79(d, J=8.2 Hz, 2H), 6.59-6.50(m, 3H);  13 C NMR (100 MHz, CDCl 3 ): δ 140.61, 140.40, 138.99, 136.92, 134.62, 133.79, 132.48, 131.57, 129.26, 128.29, 128.06, 127.76, 127.53, 127.29, 127.08, 126.40, 126.25, 125.42, 125.30, 125.09, 123.85, 119.55, 109.49; HRMS(FAB) m/z calcd for C 34 H 25 BN 2  (M + ) 472.2111, obsd. 472.2114; Anal. Calcd for C 34 H 25 BN 2 : C, 86.45; H, 5.33; B, 2.29; N, 5.93. Found: C, 86.42; H, 5.32; N, 5.87. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 22 
     Synthesis of Compound 22 (mCb) 
     Calcium hydride (0.39 g, 9.40 mmol) was provided in a 50 ml tri-neck bottle and two sets of dropping funnels were set in an inert atmosphere. The deoxygenated and dehydrated DCM (14 ml) was added into the reaction bottle. The 4-(9H-carbazol-9-yl)-N 1 ,N 2 -diphenylbenzene-1,2-diamine (compound 11, 0.80 g, 1.88 mmol) was added in one dropping funnel. The dichlorophenylborane (0.29 ml, 2.26 mmol) was added into the other dropping funnel. Each of the dropping funnels was added with 7 ml DCM and slowly dropped into the bottle under ice bath. One hour later, the mixture was returned to room temperature and stirred for 10 hours. The mixture was filtered and the filtrate was extracted with aqueous potassium carbonate solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was washed by ether to obtain compound 22 (mCb, 0.70 g, yield: 73%) as a white solid. The foregoing reaction is shown in the Reaction Formula (22). 
     Spectral data as follow: m.p.=291° C.;  1 H NMR (400 MHz, CD 2 Cl 2 ): δ 8.12(dd, J 1 =7.7 Hz, J 2 =0.8 Hz, 2H), 7.51-7.48(m, 2H), 7.43-7.31(m, 11H), 7.29-7.20(m, 7H), 7.17-7.11(m, 4H);  13 C NMR (100 MHz, CD 2 Cl 2 ): δ 142.26, 140.73, 140.50, 139.47, 138.04, 130.56, 130.00, 129.97, 128.33, 128.14, 127.94, 127.25, 127.19, 126.35, 123.41, 120.62, 119.98, 119.91, 111.1, 110.31, 109.95; HRMS(FAB) m/z calcd for C 36 H 26 BN 3 (M + )511.2220, obsd.511.2219. Anal. Calcd for C 36 H 26 BN 3 : C, 84.55; H, 5.12; B, 2.11; N, 8.22. Found: C, 84.15; H, 5.11; N, 8.12. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 23 
     Synthesis of Chemical Formula (4)-Compound 23 (oCb) 
     Calcium hydride (0.17 g, 4.0 mmol) was provided in a 50 ml tri-neck bottle and two sets of dropping funnels were set in an inert atmosphere. The deoxygenated and dehydrated DCM (5 ml) was added into the reaction bottle. The 3-(9H-carbazol-9-yl)-N 1 ,N 2 -diphenylbenzene-1,2-diamine (compound 16, 0.34 g, 0.79 mmol) was added in one dropping funnel. The dichlorophenylborane (0.16 ml, 1.20 mmol) was added into the other dropping funnel. Each of the dropping funnels was added with 2.5 ml DCM and slowly dropped into the bottle under ice bath. One hour later, the mixture was warmed to room temperature and stirred for 10 hours. The mixture was filtered and the filtrate was extracted with aqueous potassium carbonate solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was washed by ether to obtain compound 23 (oCb, Chemical Formula (4), 0.30 g, yield: 73%) as a white solid. The foregoing reaction is as shown in the Reaction Formula (23). 
     Spectral data as follow: m.p.=224° C.;  1 H NMR (400 MHz, CD 2 Cl 2 ): δ 7.82(d, J=7.8 Hz, 2H), 7.50-7.46(m, 2H), 7.41-7.38(m, 3H), 7.31(t, J=7.6 Hz, 2H), 7.24-7.04(m, 8H), 6.98-6.97(m, 4H), 6.50-6.43(m, 3H), 6.19(t, J=7.6 Hz, 2H);  13 C NMR (100 MHz, CD 2 Cl 2 ): δ 142.33, 141.00, 140.83, 138.75, 134.98, 134.55, 129.94, 129.06, 128.47, 127.63, 127.22, 127.09, 126.73, 125.91, 125.81, 123.37, 122.69, 121.52, 120.94, 120.11, 119.56, 111.17, 110.67; HRMS(FAB) m/z calcd for C 36 H 26 BN 3 (M + )511.2220, obsd. 511.2221. Anal. Calcd for C 36 H 26 BN 3 : C, 84.55; H, 5.12; B, 2.11; N, 8.22. Found: C, 84.43; H, 5.17; N, 8.30. 
     
       
         
         
             
             
         
       
     
     EXAMPLE 24 
     Synthesis of Chemical Formula (5)-Compound 24 (dCb) 
     Calcium hydride (0.30 g, 7.14 mmol) was provided in a 50 ml tri-neck bottle and two sets of dropping funnels were set in an inert atmosphere. The deoxygenated and dehydrated DCM (10 ml) was added into the reaction bottle. The 4,5-di(9H-carbazol-9-yl)-N 1 ,N 2 -diphenylbenzene-1,2-diamine (compound 13, 0.80 g, 1.36 mmol) was added in one dropping funnel. The dichlorophenylborane (0.25 ml, 1.94 mmol) was added into the other dropping funnel. Each of the dropping funnels was added with 5 ml DCM and slowly dropped into the bottle under ice bath. One hour later, the mixture was warmed to room temperature and stirred for 10 hours. The mixture was filtered and the filtrate was extracted with aqueous potassium carbonate solution. The organic layer was dried with anhydrous MgSO 4  and concentrated under vacuum. The crude was washed by ether to obtain compound 24 (dCb, Chemical Formula (5), 0.65 g, yield: 71%) as a white solid. The foregoing reaction is as shown in the Reaction Formula (24). 
     Spectral data as follow:  1 H NMR (400 MHz, DMSO-d 6 ): δ 7.89(d, J=7.6 Hz, 4H), 7.50-7.48(m, 4H), 7.44(t, J=7.5 Hz, 4H), 7.33-7.25(m, 9H), 7.21-7.17(m, 4H), 7.10(t, J=7.4 Hz, 4H), 7.02(t, J=7.4 Hz, 4H);  13 C NMR (100 MHz, CD 2 Cl 2 ): δ 141.43, 140.24, 139.17, 135.20, 130.16, 129.67, 128.13, 128.05, 127.52, 125.78, 123.43, 120.24, 119.92, 111.88, 110.62; HRMS(FAB) m/z calcd for C 48 H 33 BN 4 (M + )676.2798, obsd. 676.2800. Anal. Calcd for C 48 H 33 BN 4 : C, 85.21; H, 4.92; B, 1.60; N, 8.28. Found: C, 84.28; H, 4.96; N, 8.34. 
     
       
         
         
             
             
         
       
     
     Evaluation methods for using benzodiazaborole derivative as the material of an organic light-emitting diode 
     The material of an organic light-emitting diode includes the compound which is mentioned above from Example 17 to Example 24 (compounds 17 to 24, i.e., Chemical Formulas (1) to (5), NS, mPh and mCb). The evaluation method for the material of an organic light-emitting diode is to discuss its thermal, photophysical and electrochemical properties, such as glass transition temperature (T g ), thermal decomposition temperature (T d ), melting point (T m ), absorption wavelength start value (λ onset   abs ), maximum absorption wavelength (λ max   abs ), maximum emission peak wavelength (λ max   FL ) of normal temperature fluorescence, maximum emission peak wavelength of low temperature fluorescence (λ max   LTFL ) initial value of low temperature phosphorescence emission peak (λ onset   LTPh ), quantum yield (Q.Y.), oxidation potential (E DPV   ox ), reduction potential (E DPV   re ), triplet energy level (E T ), highest occupied molecular orbital energy level (HOMO), lowest unoccupied molecular orbital energy level (LUMO), and energy gap (E g ). 
     The onset wavelength of absorbance (λ onset   abs ), the wavelength of maximum absorbance (λ max   abs ), and the wavelength of maximum normal temperature fluorescence emission (λ max   FL ) are measured by using tetrahydrofuran as the solvent. The wavelength of maximum low-temperature fluorescence emission (λ max   LTFL ) and the onset wavelength of low temperature phosphorescence emission (λ onset   LTPh ) are measured by using 2-methyltetrahydrofuran as the solvent. The quantum yield (Q.Y.) is measured by using toluene as the solvent and is calculated according to the following formula: Q.Y.=Q R ×(I/I R )×(OD R /OD)×(n/n R ) 2 , where QR is the reference quantum yield (the quantum yield of the reference phenanthrene in ethanol is 0.125), I and I R  are the integrated peak areas of the fluorescence emission of the sample and the reference at the same excitation wavelength, respectively. The OD and OD R  are respectively the absorbance of the sample and the reference at the same wavelength, and n and n R  are the refractive indices of the solvent of the sample and the reference, respectively (see Dawson, W R; Windsor, M W, Fluorescence yields of aromatic compounds.  The Journal of Physical Chemistry.  1968, 72 (9), 3251-3260.) 
     The melting point and the glass transition temperature are measured by differential scanning calorimeter (DSC), and the thermal decomposition temperature is measured by thermogravimetric analyzer (TGA), which is considered to be the basis of the stability for the fabrication and performance of unit. 
     The electrochemical properties (E DPV   ox , E DPV   re ) of the compound are dissolved in dichloromethane and dimethylformamide, and measured by differential pulse voltammetry (DPV), respectively. The potential value is calibrated by the Ferrocene/Ferrocenium (Fc/Fc + ) potential measured in the same condition. The highest occupied molecular orbital energy level (HOMO) is obtained by measuring the film state of the compound by atmospheric photoelectron spectroscopy. The energy gap (E g ) is derived from the onset wavelength of absorbance at room temperature. The lowest unoccupied molecular orbital energy level (LUMO) is the sum of HOMO and E g . Understanding HOMO and LUMO of a compound can help to find a matched charge injection or transporting material, thereby improving the efficiency. In addition, the triplet energy level (E T ) of the compound, which is an important basis for whether it can be used as a host material, is calculated by the λ onset   LTPh  measured at 0 K. The common guest emitter of the blue organic light-emitting diode is FIrpic (E T =2.65 eV). Therefore, the E T  of host emitter used with FIrpic should be higher than 2.65 eV to avoid low luminous efficiency caused by reverse energy transfer. 
     The thermal properties of compounds 17 to 24 (Chemical Formula (1) to Chemical Formula (5), NS, mPh and mCb) are listed in the following Table 1. 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Compound 
                 M.W. 
                 T g  (° C.) 
                 T m  (° C.) 
                 T d  (° C.) a   
               
               
                   
               
             
            
               
                 NS 
                 346.16 
                 —* 
                 184 
                 229 
               
               
                 mPh 
                 422.20 
                 65 
                 210 
                 248 
               
               
                 Chemical Formula (1) 
                 472.21 
                 80 
                 224 
                 287 
               
               
                 Chemical Formula (2) 
                 422.20 
                 56 
                 161 
                 210 
               
               
                 Chemical Formula (3) 
                 472.21 
                 72 
                 196 
                 282 
               
               
                 mCb 
                 511.22 
                 104  
                 291 
                 307 
               
               
                 Chemical Formula (4) 
                 511.22 
                 84 
                 224 
                 275 
               
               
                 Chemical Formula (5) 
                 676.28 
                 —* 
                     358 b   
                 374 
               
               
                   
               
               
                   a indicates that the thermal decomposition temperature is accompanied by a weight loss of 5%. 
               
               
                   b indicates that the data are measured at National Taiwan University Valuable Instrument Center. 
               
               
                 *indicates that it cannot be measured. 
               
            
           
         
       
     
     The optical properties of compounds 17 to 24 (Chemical Formula (1) to Chemical Formula (5), NS, mPh and mCb) are listed in the following Table 2. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                   
                 λ onset   abs   
                 λ max   abs   
                 λ max FL 
                 λ max   LTFL   
                 λ onset   LTPh   
                   
               
               
                 Compound 
                 (nm) 
                 (nm) 
                 (nm) 
                 (nm) 
                 (nm) 
                 Q.Y. 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 NS 
                 315 
                 295 
                 366 
                 342 
                 367 
                 0.62 
               
               
                 mPh 
                 334 
                 308 
                 356 
                 350 
                 424 
                 0.99 
               
               
                 Chemical 
                 350 
                 316 
                 381 
                 371 
                 479 
                 0.99 
               
               
                 Formula (1) 
               
               
                 Chemical 
                 322 
                 300 
                 370 
                 340 
                 403 
                 0.85 
               
               
                 Formula (2) 
               
               
                 Chemical 
                 329 
                 299 
                 382 
                 350 
                 466 
                 0.98 
               
               
                 Formula (3) 
               
               
                 mCb 
                 351 
                 293 
                 364 
                 354 
                 399 
                 0.71 
               
               
                 Chemical 
                 347 
                 294 
                 345 
                 346 
                 399 
                 0.88 
               
               
                 Formula (4) 
               
               
                 Chemical 
                 349 
                 293 
                 349 
                 345 
                 401 
                 0.64 
               
               
                 Formula (5) 
               
               
                   
               
            
           
         
       
     
     The electrochemical properties of compounds 17 to 24 (Chemical Formula (1) to Chemical Formula (5), NS, mPh and mCb) are listed in the following Table 3. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                   
                   
                   
                 HOMO 
                 E g   
                 LUMO 
                 E T   
               
               
                 Compound 
                 E DPV   ox   a   
                 E DPV   re   b   
                 (eV) 
                 (eV) c   
                 (eV) d   
                 (eV) e   
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 NS 
                 0.678 
                 −3.089 
                 −6.03 
                 3.88 
                 −2.15 
                 3.38 
               
               
                 mPh 
                 0.574 
                 −2.918 
                 −5.84 
                 3.67 
                 −2.17 
                 2.93 
               
               
                 Chemical Formula 
                 0.492 
                 −2.744 
                 −5.71 
                 3.55 
                 −2.16 
                 2.59 
               
               
                 (1) 
               
               
                 Chemical Formula 
                 0.607 
                 −3.039 
                 −5.88 
                 3.81 
                 −2.07 
                 3.08 
               
               
                 (2) 
               
               
                 Chemical Formula 
                 0.602 
                 −2.796 
                 −5.90 
                 3.76 
                 −2.14 
                 2.66 
               
               
                 (3) 
               
               
                 mCb 
                 0.467 
                 −2.999 
                 −5.65 
                 3.50 
                 −2.15 
                 3.11 
               
               
                 Chemical Formula 
                 0.612 
                 −3.134 
                 −5.92 
                 3.56 
                 −2.36 
                 3.11 
               
               
                 (4) 
               
               
                 Chemical Formula 
                 0.508 
                 −3.035 
                 −5.74 
                 3.56 
                 −2.18 
                 3.09 
               
               
                 (5) 
               
               
                   
               
               
                   a indicates that the compound is dissolved in DCM. 
               
               
                   b indicates that the compound is dissolved dimethylformamide. 
               
               
                   c indicates the result is calculated by the formula E g  (eV) = 1240.8/λ (film)onset   abs . 
               
               
                   d indicates the result is calculated by the formula LUMO = HOMO + E g . 
               
               
                   e indicates the result is calculated by the formula E T  (eV) = 1240.8/λ onset   LTPh . 
               
            
           
         
       
     
     As shown in Tables 1 to 3, the Chemical Formulas (1) to (5) all have a high thermal decomposition temperature, and the thermal decomposition temperature of the Chemical Formula (5) is even higher than 300° C. The Chemical Formulas (1) to (5) have quite good thermal stability, especially the Chemical Formula (5). Presumably it is because the Chemical Formula (5) contains a rigid polyphenyl ring structure and shows a better thermal stability. Based on the above measurement results, the Chemical Formulas (1) to (5) have good thermal stability, high triplet energy level and have the potential to be the host material of the organic light-emitting diode. 
     The efficiency of Chemical Formula (5) which was used as the host material in the organic light-emitting diode. 
     The unit structure is ITO/TAPC(50 nm)/mCP(10 nm)/host:emitter(30 nm)/DPPS(40 or 45 nm)/LiF(0.7 nm)/Al(120 nm). The host material of the organic luminescent layer is based on the compound 17 and Chemical Formula (5). The host materials are mixed with the guest material at various ratio of emitter (FIrpic). Herein, compound 17 is used as the reference group, and the material of the first electrode layer of the organic light-emitting diode is ITO. The material of the second electrode layer is aluminum with the thickness of 120 nm. The material of the hole transport layer is TAPC with the thickness of 50 nm. The thickness of the organic luminescent layer is 30 nm. The material of the electron blocking layer is mCP (1,3-Bis(N-carbazolyl)benzene) with the thickness of 10 nm. The material of the electron transport layer is DPPS with the thickness of 40 or 45 nm. The material of electron injecting layer is LiF with the thickness of 0.7 nm. The above-mentioned layers are made by vapor deposition to form the organic light-emitting diodes of the embodiment, and the driving voltage (V), the turn-on voltage, the maximum luminance (L max , cd/m 2 ), the maximum current efficiency (CE max , cd/A), the maximum power efficiency (PE max , 1 m/W) and the maximum external quantum efficiency (EQE max , %) of the organic light-emitting diode are measured. The results are shown in Table 4. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 4 
               
               
                   
               
               
                   
                 Driving 
                 Turn-on 
                   
                   
                   
                   
               
               
                   
                 voltage 
                 voltage 
                 L max   
                 CE max   
                 PE max   
                 EQE max   
               
               
                 Unit 
                 (V) 
                 (V) 
                 (cd/m 2 ) 
                 (cd/A) 
                 (lm/W) 
                 (%) 
               
               
                   
               
             
            
               
                 Compound 
                 8.19 
                 7.22 
                 3910 
                 12.54 
                 9.59 
                 — 
               
               
                 17-15% a   
                   
                   
                 @12 V 
                 @4.5 V 
                 @4 V 
               
               
                 Chemical 
                 6.69 
                 5.50 
                 11680 
                 18.07 
                 13.23 
                 8.26 
               
               
                 Formula 
                   
                   
                 @10.5 V 
                 @5 V 
                 @3.5 V 
               
               
                 (5)-18% a   
               
               
                   
               
               
                   a indicates the doping concentration of FIrpic 
               
            
           
         
       
     
     The character of the organic light-emitting diodes, which utilize Chemical Formula (5) as the host material, shown in Table 4 not only have low driving voltages but also have the fine maximum current efficiency, maximum power efficiency and maximum external quantum efficiency. Accordingly, the host materials of the present disclosure have high transmission rate of electrons and electron holes, and are not necessarily to be operated under high driving voltage. As shown in the above Table 3, the host materials of the present disclosure have higher triplet energy level which is beneficial to reduce reverse energy transfer and to improve the luminous efficiency of the organic light-emitting diodes. 
     Comparison of the efficiency of Chemical Formula (5) and mCP which is used as electron blocking layer in organic light-emitting diodes. 
     The unit structure is ITO/TAPC(50 nm)/EBL(10 nm)/host: emitter(30 nm:6% Firpic)/DPPS(45 nm)/LiF(0.7 nm)/Al(120 nm). The host materials is the 9,9′-(2-(1-phenyl-1H-benzo[d]imidazol-2-yl)-1,3-phenylene)bis(9H-carbazole) and mixed with the guest material (FIrpic) at various ratio. Herein, the material of the first electrode layer of the organic light-emitting diode is ITO. The material of the second electrode layer is aluminum with the thickness of 120 nm. The material of the hole transport layer is TAPC with the thickness of 50 nm. The material of the electron blocking layer is Chemical Formula (5) or mCP with the thickness of 10 nm. The thickness of the organic luminescent layer is 30 nm. The material of the electron transport layer is DPPS with the thickness of 45 nm. The material of electron injecting layer is LiF with the thickness of 0.7 nm. The above-mentioned layers are made by vapor deposition to form the organic light-emitting diodes of the embodiment, and the efficiency items of the units are evaluated. The results are shown in Table 5. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 5 
               
               
                   
               
               
                   
                 Driving 
                   
                   
                   
                   
               
               
                   
                 voltage 
                 L max   
                 CE max   
                 PE max   
                 EQE max   
               
               
                 Unit 
                 (V) 
                 (cd/m 2 ) 
                 (cd/A) 
                 (lm/W) 
                 (%) 
               
               
                   
               
             
            
               
                 mCP 
                 7.96 
                   15920@10 V 
                 56.91@4.0 V 
                 50.38@3.5 V 
                 26.99 
               
               
                 Chemical Formula 
                 7.86 
                 20890@11.5 V 
                 51.66@5.0 V 
                 39.10@4.0 V 
                 25.35 
               
               
                 (5) 
               
               
                   
               
            
           
         
       
     
     According to the results shown in Table 5, it is obviously known that the electron blocking layer made of Chemical Formula (5) has a lower driving voltage and a larger maximum luminance, which means that the compound of Chemical Formula (5) can be utilized as the electron blocking layer. 
     Comparison of the efficiency of Chemical Formula (5) and mCb which are used as hole-only devices (HOD) and hole transport layers in organic light-emitting diodes. 
     The theory of a hole transporting element (or electron transporting element) is that the designed element only allows holes (or electrons) to be injected while blocking the relative electrons (or holes) from the organic layer. Therefore, the recombination of charges does not occur in the organic layer and does not emit light. The mobility of holes or electrons is determined by the driving voltage and the current density of the unit. Theoretically, if the driving voltage is lower, the larger current density can obtain the larger mobility of holes or electrons. 
     The structure of the hole transporting element is Al(50 nm)/MoO 3 (10 nm)/mCP(10 nm)/Chemical Formula (5) or mCb (100 nm)/mCP(10 nm)/MoO 3 (10 nm)/Al(100 nm). The material of the organic layer is based on Chemical Formula (5), and mCb is used as the reference material. The material of the first electrode layer of the hole transporting element is aluminum with the thickness of 50 nm, and the material of the second electrode layer is aluminum with the thickness of 100 nm. The material of the hole injecting layer is MoO 3  with the thickness of 10 nm. The material of the hole transport layer is mCP with the thickness of 10 nm. The organic layer is Chemical Formula (5) or mCb with the thickness of 100 nm. The above-mentioned layers are made by vapor deposition to form the hole transporting elements of the embodiment, and the current characteristics and charge injection benefits are evaluated. The results are shown in  FIG. 4 . 
     The structure of the electron transporting element is Al(50 nm)/LiF(1.5 nm)/DPPS(10 nm)/Chemical Formula (5) or mCb (100 nm)/DPPS(10 nm)/LiF(1.5 nm)/Al(100 nm). The material of the organic layer is based on Chemical Formula (5), and mCb is used as the reference material. The material of the first electrode layer of the electron transporting element is aluminum with the thickness of 50 nm, and the material of the second electrode layer is aluminum with the thickness of 100 nm. The material of the electron injecting layer is LiF with the thickness of 1.5 nm. The material of the electron transport layer is DPPS with the thickness of 10 nm. The organic layer is Chemical Formula (5) or mCb with the thickness of 100 nm. The above-mentioned layers are made by vapor deposition to form the electron transporting elements of the embodiment, and the current characteristics and charge injection benefits are evaluated. The results are shown in  FIG. 5 . 
     Please refer to  FIGS. 4 and 5 .  FIG. 4  is a schematic graph showing the charge injection properties of the hole transporting element with the organic layer made of mCb or Chemical Formula (5), and  FIG. 5  is a schematic graph showing the charge injection properties of the electron transporting element with the organic layer made of mCb or Chemical Formula (5). As shown in  FIG. 4 , the organic layer made of Chemical Formula (5) has a better current density than the organic layer made of mCb, which means the organic layer made of Chemical Formula (5) has better hole transporting ability. As shown in  FIG. 5 , the changes cannot be injected into the organic layer made of Chemical Formula (5) under the high voltage circumstance, and the charges in the organic layer made of Chemical Formula (5) is saturated. This property allows the organic layer made of Chemical Formula (5) to have the function of electronic blocking layer. 
     As mentioned above, in the benzodiazaborole derivatives and the organic light-emitting diodes by using the same according to the present disclosure, it utilizes 1,3,2-benzodiazaborole as a core structure, and different substituents are introduced to the ortho and/or meta positions of the benzo group. Thus, the benzodiazaborole derivatives of this disclosure can be used as the host material of the blue phosphorescent organic light-emitting diodes with high efficiency and good thermal stability. In addition, the benzodiazaborole derivatives of this disclosure can also be used as the electron blocking layer. 
     Although the disclosure has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the disclosure.