ORGANIC ELECTROLUMINESCENT MATERIALS AND DEVICES

A new series of novel organometallic complexes having two or more heteroatoms on a 5-membered anionic aromatic ring is disclosed. The organometallic complexes have a calculated T1 triplet energy in the deep blue region.

FIELD

The present invention relates to compounds for use as emitters, and devices, such as organic light emitting diodes, including the same.

BACKGROUND

SUMMARY

A new series of novel organometallic complexes having two or more heteroatoms on a 5-membered anionic aromatic ring is disclosed. Because of the particular placement of the two or more heteroatoms (for example, nitrogen atoms), the complexes have a calculated T1 triplet energy in the deep blue region, whereas its single heteroatom counterpart only gives a calculated T1 triplet energy in the green region. More than 620,000 new complexes are encompassed in this disclosure.

A compound of Formula I

is disclosed. In Formula I, A is a 5-membered or 6-membered aromatic ring. B is a 5-membered aromatic ring. Z1is an anionic carbon. Z2, and X1through X11are each independently selected from the group consisting of C and N. At least two of X1, X2, X3, and X4are N. Y is selected from the group consisting of O, S, NR, CRR′, SiRR′, aryl, heteroaryl, alkyl, cycloalkyl, carbonyl, and combinations thereof. L is selected from the group consisting of a direct bond, O, S, NR, CRR′, SiRR′, aryl, heteroaryl, alkyl, cycloalkyl, carbonyl, and combinations thereof. Each R1, R2, R3, and R4independently represents mono to a maximum possible number of substitutions, or no substitution, where each R, R′, R1, R2, R3, and R4is independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof. Any two substituents may be joined or fused together to form a ring. M is Pd or Pt.

An OLED comprising the compound of the present disclosure in an organic layer therein is also disclosed.

A consumer product comprising the OLED is also disclosed.

DETAILED DESCRIPTION

The term “ester” refers to a substituted oxycarbonyl (—O—C(O)—Rsor —C(O)—O—Rs) radical.

The term “ether” refers to an —ORsradical.

The term “sulfinyl” refers to a —S(O)—Rsradical.

The term “sulfonyl” refers to a —SO2—Rsradical.

The term “phosphino” refers to a —P(Rs)3radical, wherein each R can be same or different.

The term “silyl” refers to a —Si(Rs)3radical, wherein each Rscan be same or different.

The term “alkenyl” refers to and includes both straight and branched chain alkene radicals. Alkenyl groups are essentially alkyl groups that include at least one carbon-carbon double bond in the alkyl chain. Cycloalkenyl groups are essentially cycloalkyl groups that include at least one carbon-carbon double bond in the cycloalkyl ring. The term “heteroalkenyl” as used herein refers to an alkenyl radical having at least one carbon atom replaced by a heteroatom. Optionally the at least one heteroatom is selected from O, S, N, P, B, Si, and Se, preferably, O, S, or N. Preferred alkenyl, cycloalkenyl, or heteroalkenyl groups are those containing two to fifteen carbon atoms. Additionally, the alkenyl, cycloalkenyl, or heteroalkenyl group is optionally substituted.

The term “alkynyl” refers to and includes both straight and branched chain alkyne radicals. Preferred alkynyl groups are those containing two to fifteen carbon atoms. Additionally, the alkynyl group is optionally substituted.

The terms “aralkyl” or “arylalkyl” are used interchangeably and refer to an alkyl group that is substituted with an aryl group. Additionally, the aralkyl group is optionally substituted.

The term “heterocyclic group” refers to and includes aromatic and non-aromatic cyclic radicals containing at least one heteroatom. Optionally the at least one heteroatom is selected from O, S, N, P, B, Si, and Se, preferably, O, S, or N. Hetero-aromatic cyclic radicals may be used interchangeably with heteroaryl. Preferred hetero-non-aromatic cyclic groups are those containing 3 to 7 ring atoms which includes at least one hetero atom, and includes cyclic amines such as morpholino, piperidino, pyrrolidino, and the like, and cyclic ethers/thio-ethers, such as tetrahydrofuran, tetrahydropyran, tetrahydrothiophene, and the like. Additionally, the heterocyclic group may be optionally substituted.

In some instances, the preferred general substituents are selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, alkoxy, aryloxy, amino, silyl, aryl, heteroaryl, sulfanyl, and combinations thereof.

In yet other instances, the more preferred general substituents are selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, aryl, heteroaryl, and combinations thereof.

The terms “substituted” and “substitution” refer to a substituent other than H that is bonded to the relevant position, e.g., a carbon or nitrogen. For example, when R1represents mono-substitution, then one R1must be other than H (i.e., a substitution) Similarly, when R1represents di-substitution, then two of R1must be other than H. Similarly, when R1represents no substitution, R1, for example, can be a hydrogen for available valencies of ring atoms, as in carbon atoms for benzene and the nitrogen atom in pyrrole, or simply represents nothing for ring atoms with fully filled valencies, e.g., the nitrogen atom in pyridine. The maximum number of substitutions possible in a ring structure will depend on the total number of available valencies in the ring atoms.

A compound of Formula I

is disclosed. In Formula I, A is a 5-membered or 6-membered aromatic ring. B is a 5-membered aromatic ring. Z1is an anionic carbon. Z2, and X1through X11are each independently selected from the group consisting of C and N. At least two of X1, X2, X3, and X4are N. Y is selected from the group consisting of O, S, NR, CRR′, SiRR′, aryl, heteroaryl, alkyl, cycloalkyl, carbonyl, and combinations thereof. L is selected from the group consisting of a direct bond, O, S, NR, CRR′, SiRR′, aryl, heteroaryl, alkyl, cycloalkyl, carbonyl, and combinations thereof. Each R1, R2, R3, and R4independently represents mono to a maximum possible number of substitutions, or no substitution, where each R, R′, R1, R2, R3, and R4is independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof. Any two substituents may be joined or fused together to form a ring. M is Pd or Pt.

In some embodimenta, M is Pt.

In some embodiments, at least one of the pairs consisting of R1and R2, and R3and R4, are joined together to form a ring.

In some embodiments, Y is selected from the group consisting of O and CRR′. In some embodiments, Z2is C.

In some embodiments, A represents an imidazole ring. In some embodiments, A represents a benzene ring.

In some embodiments, the compound is the compound x having the formula Pt(LAj-Yi-LBk); where Yiis a linking group linking LAjto LBk; where LAj-Yi-LBkis a tetradentate ligand; where x=224(i−1)+j+2240(k−1), i is an integer from 1 to 10, j is an integer from 1 to 224, and k is an integer from 1 to 280; where Yiis selected from the group consisting of:

wherein * attaches to LA; ** attaches to LBwhere LAjis selected from the group consisting of LA1to LA224that are defined as follows:LA1to LA7having the structure

wherein in LA218, R═H, in LA219, R═CH3, in LA220, R═CD3, in LA221, R=iPr, in LA222, R=Ph, in LA223, R=2,6-dimethylphenyl, in LA224, R=2,6-diisopropylphenyl,wherein LBkis selected from the group consisting of LB1to LB280that are defined as follows:LB1to LB7having the structure

The present disclosure encompases more than 620,000 new neutral tetradentate platinum complexes based on at least one anionic five-membered heterocyclic ring. With the right ligand composition, the complex can show blue emission and strong bond dissociation energies (BDEs) by calculation. For example, Compound 238443 has a calculated T1 triplet energy of 431 nm but the BDE of its Pt—N bond is only 7.08 kcal/mol, whereas Compound 595946 has a calculated T1 triplet energy of 453 nm with a much stronger Pt—N bond which reform after breaking.

An organic light emitting device is disclosed which comprises an anode, a cathode, and an organic layer that is disposed between the anode and the cathode. The organic layer comprises a compound of Formula I

where the variables in Formula I are as defined above.

A consumer product comprising an organic light-emitting device (“OLED”) is disclosed where the OLED comprises an anode, a cathode, and an organic layer that is disposed between the anode and the cathode. The organic layer comprises a compound of Formula I

where the variables in Formula I are as defined above.

An emissive region in an organic light emitting device is disclosed, where the emissive region comprising a compound of Formula I

In Formula I, A is a 5-membered or 6-membered aromatic ring. B is a 5-membered aromatic ring. Z1is an anionic carbon. Z2, and X1through X11are each independently selected from the group consisting of C and N. At least two of X1, X2, X3, and X4are N. Y is selected from the group consisting of O, S, NR, CRR′, SiRR′, aryl, heteroaryl, alkyl, cycloalkyl, carbonyl, and combinations thereof. L is selected from the group consisting of a direct bond, O, S, NR, CRR′, SiRR′, aryl, heteroaryl, alkyl, cycloalkyl, carbonyl, and combinations thereof. Each R1, R2, R3, and R4independently represents mono to a maximum possible number of substitutions, or no substitution, where each R, R′, R1, R2, R3, and R4is independently a hydrogen or a substituent selected from the group consisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, heterocycloalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof. Any two substituents may be joined or fused together to form a ring. M is Pd or Pt.

In some embodiments of the emissive region, the compound is an emissive dopant or a non-emissive dopant.

In some embodiments of the emissive region, the emissive region further comprises a host, wherein the host comprises at least one selected from the group consisting of metal complex, triphenylene, carbazole, dibenzothiophene, dibenzofuran, dibenzoselenophene, aza-triphenylene, aza-carbazole, aza-dibenzothiophene, aza-dibenzofuran, and aza-dibenzoselenophene.

In some embodiments of the emissive region, the emissive region further comprises a host, wherein the host is selected from the group consisting of:

and combinations thereof.

In some embodiments, the compound can be an emissive dopant. In some embodiments, the compound can produce emissions via phosphorescence, fluorescence, thermally activated delayed fluorescence, i.e., TADF (also referred to as E-type delayed fluorescence; see, e.g., U.S. application Ser. No. 15/700,352, which is hereby incorporated by reference in its entirety), triplet-triplet annihilation, or combinations of these processes.

According to another aspect, a formulation comprising the compound described herein is also disclosed.

The organic layer can also include a host. In some embodiments, two or more hosts are preferred. In some embodiments, the hosts used maybe a) bipolar, b) electron transporting, c) hole transporting or d) wide band gap materials that play little role in charge transport. In some embodiments, the host can include a metal complex. The host can be a triphenylene containing benzo-fused thiophene or benzo-fused furan. Any substituent in the host can be an unfused substituent independently selected from the group consisting of CnH2+1, OCnH2n+1, OAr1, N(CnH2n+1)2, N(Ar1)(Ar2), CH═CH—CnH2n+1, C≡C—CnH2n+1, Ar1, Ar1-Ar2, and CnH2n-Ar1, or the host has no substitutions. In the preceding substituents n can range from 1 to 10; and Ar1and Ar2can be independently selected from the group consisting of benzene, biphenyl, naphthalene, triphenylene, carbazole, and heteroaromatic analogs thereof. The host can be an inorganic compound. For example a Zn containing inorganic material e.g. ZnS.

The host can be a compound comprising at least one chemical group selected from the group consisting of triphenylene, carbazole, dibenzothiophene, dibenzofuran, dibenzoselenophene, azatriphenylene, azacarbazole, aza-dibenzothiophene, aza-dibenzofuran, and aza-dibenzoselenophene. The host can include a metal complex. The host can be, but is not limited to, a specific compound selected from the group consisting of:

and combinations thereof.Additional information on possible hosts is provided below.

In yet another aspect of the present disclosure, a formulation that comprises the novel compound disclosed herein is described. The formulation can include one or more components selected from the group consisting of a solvent, a host, a hole injection material, hole transport material, electron blocking material, hole blocking material, and an electron transport material, disclosed herein.

Combination with Other Materials

In one aspect, the metal complexes are:

wherein k is an integer from 1 to 20; L101is an another ligand, k′ is an integer from 1 to 3.

Charge Generation Layer (CGL)

Experimental

Synthesis of Compound 238443:

4-(2,6-dimethylphenyl)-1H-benzo[d]imidazole 4-methylbenzenesulfonate: dimethylphenyl)-1-(tetrahydro-2H-pyran-2-yl)-1H-benzo[d]imidazole (2.33 g, 7.60 mmol) was dissolvede in MeOH (75 ml) and water (15 ml) and 4-methylbenzenesulfonic acid hydrate (4.34 g, 22.81 mmol) was added. The reaction mixture was heated at reflux for 18 hrs. MeOH was removed from the reaction mixture and extracted with ethyl acetate, then chromatographed on silica (EA/Hep=3/2) (87% yield).

2,2-bis(6-chloro-4-methylpyridin-2-yl)acetonitrile: 2,6-dichloro-4-methylpyridine (25 g, 154 mmol) and sodium hydride (12.34 g, 309 mmol) were suspended in THF (500 ml). Acetonitrile (16.12 ml, 309 mmol) was added and the mixture was refluxed for 16 hrs. The reaction was cooled to R.T. and partitioned between ether and brine. The aqueous was extracted 4 times more with ether and the combined organics washed with brine. The mixture was chromatographed on silica (DCM) (63% yield).

bis(6-chloro-4-methylpyridin-2-yl)methane: 2,2-bis(6-chloro-4-methylpyridin-2-yl)acetonitrile (8.6 g, 29.4 mmol) was dissolved in EtOH (150 ml) and HCl (123 ml, 1472 mmol) was added. The mixtrue was heated to reflux for 18 hrs, then cooled to 0° C. and basified with solid NaOH. The mixture was extracted 3 times with EtOAc and washed, then combined the organics 2 times with water and 1 time with brine. The mixture was chromatographed on silica (DCM/EtOAc=95/5) (97% yield).

6,6′-(propane-2,2-diyl)bis(2-chloro-4-methylpyridine): bis(6-chloro-4-methylpyridin-2-yl)methane (4.4 g, 16.47 mmol) was dissolved in THF (150 ml) and cooled to −78° C. Butyllithium (6.92 ml, 17.29 mmol) was added dropwise to the mixture causing the pale yellow solution to turn orange. The mixture was stirred for 3 hrs at −78° C. and then iodomethane (1.081 ml, 17.29 mmol) was added. The mixture was warmed to R.T. and stirred for 10 min, then cooled to −78° C. Butyllithium (7.25 ml, 18.12 mmol) was added to the mixture to give a deep red solution. The mixture was stirred for 1 hr, and then iodomethane (1.236 ml, 19.76 mmol) was added and the reaction was allowed to slowly warm to R.T. while being stirred for 18 hrs. The reaction was quenched with NH4Cl (aq.) and extracted with ether. The mixture was chromoatographed on (DCM/heptane=4/1) (97% yield).

1,1′-(propane-2,2-diylbis(4-methylpyridine-6,2-diyl))bis(4-(2,6-dimethylphenyl)-1H-benzo[d]imidazole): A mixture of (allyl)PdCl-dimer (14.87 mg, 0.041 mmol) and cBRIDP (57.3 mg, 0.163 mmol) was vacuumed and back-filled with nitrogen several times. Toluene (4 ml) was added to the reaction mixture and refluxed for 5 min. The reaction mixture was transferred to a mixture of 6,6′-(propane-2,2-diyl)bis(2-chloro-4-methylpyridine) (400 mg, 1.355 mmol), 4-(2,6-dimethylphenyl)-1H-benzo[d]imidazole 4-methylbenzenesulfonate (1123 mg, 2.85 mmol), and sodium 2-methylpropan-2-olate (521 mg, 5.42 mmol) in toluene (4.00 ml) via a syringe and the reaction mixture was refluxed for 18 hrs. The mixture was cooled down and coated on celite and chromatographed on silica (DCM/EA=20/1 to 10/1) (51% yield).

Compound 238443: A mixture of 1,1′-(propane-2,2-diylbis(4-methylpyridine-6,2-diyl))bis(4-(2,6-dimethylphenyl)-1H-benzo[d]imidazole) (20 mg, 0.030 mmol) and Pt(COD)Me2(10.00 mg, 0.030 mmol) in a Schlenk tube was vacuumed and back-filled with nitrogen several times. 1,2-dichlorobenzene (2 ml) was added to the reaction mixture and refluxed for a week. The product was detected by LCMS.