Organic electroluminescent materials and devices

Provided is a new composition of matter for phosphorescent emitters containing a chelating ligand including five or more fused carbocyclic or heterocyclic rings that form two bonds to a metal forming a 7-membered chelate. This fused ring structure provides added rigidity to the molecule for enhanced stability in an OLED device and improve photophysical properties.

FIELD

The present disclosure generally relates to organometallic compounds and formulations and their various uses including as emitters in devices such as organic light emitting diodes and related electronic devices.

BACKGROUND

Opto-electronic devices that make use of organic materials are becoming increasingly desirable for various reasons. Many of the materials used to make such devices are relatively inexpensive, so organic opto-electronic devices have the potential for cost advantages over inorganic devices. In addition, the inherent properties of organic materials, such as their flexibility, may make them well suited for particular applications such as fabrication on a flexible substrate. Examples of organic opto-electronic devices include organic light emitting diodes/devices (OLEDs), organic phototransistors, organic photovoltaic cells, and organic photodetectors. For OLEDs, the organic materials may have performance advantages over conventional materials.

OLEDs make use of thin organic films that emit light when voltage is applied across the device. OLEDs are becoming an increasingly interesting technology for use in applications such as flat panel displays, illumination, and backlighting.

SUMMARY

This disclosure provides a new composition of matter for phosphorescent emitters containing a chelating ligand comprised of five or more fused cathocyclic or heterocyclic rings. The five or more fused rings form two bonds to a metal forming a 7-membered chelate. This fused ring structure provides added rigidity to the molecule for enhanced stability in an OLED device and improved photophysical properties.

In one aspect, the present disclosure provides a compound having a fragment with at least five rings fused next to each other consecutively wherein the fragment has at least two atoms coordinated to a metal.

In another aspect, the present disclosure provides a compound comprising a ligand LAof Formula I

wherein: rings A, B, C, D, and E are each independently a 5-membered or 6-membered carbocyclic or heterocyclic ring; Z1-Z12are each independently C or N; RA, RB, RC, RD, and REeach independently represents zero, mono, or up to a maximum allowed substitutions to its associated ring; RA, RB, RC, RD, and REare each independently a hydrogen or a substituent selected from the group consisting of deuterium, halide, alkyl, cycloalkyl, fluorinated alkyl, heteroalkyl, alkylalkyl, alkoxy, aryloxy, amino, silyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof; and two substituents can be joined or fused together to form a ring, wherein the ligand LAis complexed to a metal M selected from the group consisting of Ir, Rh, Re, Ru, Os, Pt, Pd, Au, Ag, and Cu; wherein M can be coordinated to other ligands; and wherein the ligand LAcan be linked with other ligands to form a tridentate, tetradentate, pentadentate, or hexadentate ligand.

In another aspect, the present disclosure provides a formulation comprising a compound having a fragment with at least five rings fused next to each other consecutively wherein the fragment has at least two atoms coordinated to a metal.

In yet another aspect, the present disclosure provides a formulation comprising a compound of Formula I described herein.

In yet another aspect, the present disclosure provides an OLED having an organic layer comprising a compound having a fragment with at least five rings fused next to each other consecutively wherein the fragment has at least two atoms coordinated to a metal.

In yet another aspect, the present disclosure provides an OLED having an organic layer comprising the compound of Formula I described herein.

In yet another aspect, the present disclosure provides a consumer product comprising an OLED having an organic layer comprising a compound having a fragment with at least five rings fused next to each other consecutively wherein the fragment has at least two atoms coordinated to a metal.

In yet another aspect, the present disclosure provides a consumer product comprising an OLED with an organic layer comprising the compound of Formula I described herein.

In yet another aspect, the present disclosure provides an OLED device comprising an emitter wherein the device emits a luminescent radiation at room temperature when a voltage is applied across the device, wherein the luminescent radiation comprises a first radiation component emitted from the emitter, and wherein the first radiation component has a full width at half maximum equal or less than 15 nm.

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 Rscan be same or different.

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

The term “boryl” refers to a —B(Rs)2radical or its Lewis adduct —B(Rs)3radical, wherein 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 may be optionally substituted.

The term “alkynyl” refers to and includes both straight and branched chain alkyne radicals. Alkynyl groups are essentially alkyl groups that include at least one carbon-carbon triple bond in the alkyl chain. Preferred alkynyl groups are those containing two to fifteen carbon atoms. Additionally, the alkynyl group may be 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 may be 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 more preferred general substituents are selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, alkoxy, aryloxy, amino, silyl, boryl, aryl, heteroaryl, sulfanyl, and combinations thereof.

In yet other instances, the most 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 zero or 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.

In some instance, a pair of adjacent substituents can be optionally joined or fused into a ring. The preferred ring is a five, six, or seven-membered carbocyclic or heterocyclic ring, includes both instances where the portion of the ring formed by the pair of substituents is saturated and where the portion of the ring formed by the pair of substituents is unsaturated. As used herein, “adjacent” means that the two substituents involved can be on the same ring next to each other, or on two neighboring rings having the two closest available substitutable positions, such as 2, 2′ positions in a biphenyl, or 1, 8 position in a naphthalene, as long as they can form a stable fused ring system.

B. The Compounds of the Present Disclosure

In one aspect, the present disclosure provides a compound having a fragment with at least five rings fused next to each other consecutively wherein the fragment has at least two atoms coordinated to a metal.

In some embodiments, the compound can be a metal coordination compound comprising a ligand, wherein the ligand comprises a fragment having at least five rings fused next to each other consecutively in a row; and wherein the fragment has at least two atoms coordinated to a metal.

In some embodiments, the at least five rings can comprise two 5-membered rings and three 6-membered rings fused to each other consecutively.

In some embodiments, the at least five rings can comprise five aromatic rings fused next to each other consecutively.

In some embodiments, the fragment can comprise at least six rings fused next to each other consecutively.

In some embodiments, the fragment can comprise at least seven rings fused next to each other consecutively.

In another aspect, the present disclosure provides a ligand LAof Formula I

wherein: rings A, B, C, D, and E are each independently a 5-membered or 6-membered cathocyclic or heterocyclic ring; Z1-Z12are each independently C or N; RA, RB, RC, RD, and REeach independently represents zero, mono, or up to a maximum allowed substitution to its associated ring; RA, RB, RC, RD, and REare each independently a hydrogen or a substituent selected from the group consisting of the general substituents defined herein; two substituents can be joined or fused together to form a ring, wherein the ligand LAis complexed to a metal M selected from the group consisting of Ir, Rh, Re, Ru, Os, Pt, Pd, Au, Ag, and Cu; wherein M can be coordinated to other ligands; and wherein the ligand LAcan be linked with other ligands to form a tridentate, tetradentate, pentadentate, or hexadentate ligand.

In some embodiments, RA, RB, RC, RD, and REeach can be independently a hydrogen or a substituent selected from the group consisting of the preferred general substituents defined herein.

In some embodiments, M can be Ir, Pt or Pd.

In some embodiments, the ligand LAcan be bidentate.

In some embodiments, the ligand LAcan be linked with other ligands to form a tetradentate ligand.

In some embodiments, ring A, ring C, and ring E can be 6-membered rings, and ring B and ring D can be 5-membered rings.

In some embodiments, ring A, ring C, and ring E can be 5-membered rings, and ring B and ring D can be 6-membered rings.

In some embodiments, ring A and ring E can be 5-membered rings, and ring B, ring C, and ring D can be 6-membered rings.

In some embodiments, ring A and ring E can be 6-membered rings, and ring B, ring C, and ring D can be 5-membered rings.

In some embodiments, ring A, ring B, ring D, and ring E can be 5-membered rings, and ring C can be a 6-membered ring.

In some embodiments, Z1-Z12can be C.

In some embodiments, at least one of Z1-Z12can be N.

In some embodiments, one of Z1and Z6can be N and the other can be C.

In some embodiments of LAof Formula I, the ligand LAcan be selected from the group consisting of:

wherein each X1-X22is independently selected from the group consisting of C and N; wherein no more than two N atoms are bond to one another; wherein each Y1-Y5is selected from the group consisting of O, S, Se, NR, CRR′, SiRR′, GeRR′, and BR; and wherein R and R′ are each independently selected from the group consisting of hydrogen, deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, and combinations thereof.

In some embodiments of LAof Formula I, the ligand LAcan be selected from the group consisting of the structures shown in LIST 1 below:

wherein each X1-X6is independently selected from the group consisting of C and N; wherein no more than two N atoms are bond to one another; wherein each Y1-Y7is selected from the group consisting of O, S, Se, NR, CRR′, SiRR′, GeRR′, and BR; and wherein R and R′ are each independently selected from the group consisting of hydrogen, deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, boryl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, and combinations thereof.

In some embodiments, the ligand LAcan be selected from the group consisting of the structures shown in LIST 2 below. It should be noted that the variables Yi and Yj used in LIST 2 and the subscripted variables Y1-Y7used above are different set of variables.

LIST 2Name of ligand LAStructurei, jLAI-[(i)(j)] having the structurewherein i and j are independently an integer from 1 to 30, andLAII-[(i)(j)(k)] having the structurewherein i, j, and k are independently an integer from 1 to 30, andLAIII-[(i)(j)] having the structureWherein i and j are independently an integer from 1 to 30, andLAIV[(i)] having the structurewherein i is an integer from 1 to 30, andLAV-[(i)(j)] having the structurewherein i and j are independently an integer from 1 to 30, andLAVI-[(i)(j)] having the structurewherein i and j are independently an integer from 1 to 30, andLAVII-[(i)] having the structurewherein i is an integer from 1 to 30, andLAVIII-[(i)(j)] having the structurewherein i and j are independently an integer from 1 to 30, andLAIX-[(i)(j)] having the structurewherein i and j are independently an integer from 1 to 30, andLAX-[(i)(j)] having the structurewherein i and j are independently an integer from 1 to 30, andLAXI-[(i)(j)] having the structurewherein i and j are independently an from 1 to 30, andLAXII-[(i)] having the structurewherein i is an integer from 1 to 30, andLAXIII-[(i)(j)] having the structurewherein i and j are independently an integer from 1 to 30, andLAXIV-[(i)(j)] having the structurewherein i, j, are independently an integer from 1 to 30, andLAXV-[(i)] having the structurewherein i is an integer from 1 to 30, andLAXVI-[(i)(j)] having the structurewherein i is an integer from 1 to 30, andLAXVII-[(i)(j)] having the structurewherein i and j are independently an integer from 1 to 30, andLAXVIII-[(i)(j)]having the structurewherein i and j are independently an integer from 1 to 30, and
wherein Y1 through Y30 have the structures defined below:

In some embodiments, the compound can have the formula Ir(LA)3, the formula Ir(LA)(LB)2, the formula Ir(LA)2(LB), or the formula Ir(LA)2(LC), wherein:LAis selected from the group consisting of the structures shown in LIST 2 above;LBis selected from the group consisting of LB1through LB468as shown in LIST 3 below:

andLCis selected from the group consisting of LC1through LC1260based on a structure of Formula X

wherein for each of the ligands LC1through LC1260, R1, R2, and R3are defined in LIST 4 below:

In some embodiments, the compound can have the formula Pt(LA) or the formula Pd(LA), wherein the ligand LAcan be selected from the group consisting of the structures defined in LIST 5 below:

wherein the structures of B1 to B50 are as shown below:

wherein in the structures of A1 to A200, and B1 to B50, * represents the point of attachment to LAand the dashed line represents the coordination bond to Pt or Pd.

In some embodiments, the compound can have the formula Au(LA), wherein the ligand LAcan be selected from the group consisting of the structures shown in LIST 6 below:

In some embodiments, the compound can have the formula Pt(LC)(LC′) or the formula Pt(LC)(LB), wherein LCand LC′are selected from the group consisting of the structures shown in LIST 7 below:

Name of ligands LCand LC′Structure of Ligand LCand LC′i, j, k, lLCI-[(i)(j)] having the structurewherein i and j are independently an integer from 1 to 30, andLCII-[(i)(j)(k)] having the structurewherein i, j and k are independently an integer from 1 to 30, andLCIII-[(i)(j)] having the structurewherein i and j are independently an integer from 1 to 30, andLCIV-[(i)(j)(k)] having the structurewherein i, j, and k are independently an integer from 1 to 30, andLCV-[(i)(j)(k)] having the structurewherein i, j, and k are independently an integer from 1 to 30, andLCVI-[(i)(j)(k)] having the structurewherein i, j, and k are independently an integer from 1 to 30, andLCVII-[(i)(j)(k)] having the structurewherein i, j, and k are independently an integer from 1 to 30, andLCVIII-[(i)(j)(k)] having the structurewherein i, j, and k are independently an integer from 1 to 30, andLCIX-[(i)(j)(k)] having the structurewherein i, j, and k are independently an integer from 1 to 30, andLCX-[(i)(j)(k)] having the structurewherein i, j, and k are independently an integer from 1 to 30, andLCXI-[(i)(j)(k)] having the structurewherein i, j, and k are independently an integer from 1 to 30, andLCXII-[(i)(j)(k)(l)] having the structurewherein i, j, k, and l are independently an integer from 1 to 30, andLCXIII-[(i)(j)(k)] having the structurewherein i, j, and k are independently an integer from 1 to 30, andLCXIV-[(i)(j)] having the structurewherein i and j are independently an integer from 1 to 30, andLCXV-[(i)(j)] having the structurewherein i and j are independently an integer from 1 to 30, andLCXVI-[(i)(j)(k)] having the structurewherein i, j, and k are independently an integer from 1 to 30, and
wherein Y1 to Y30 have the structures as defined herein; and wherein LByhave the structures defined in LIST 9 below:

and wherein R1 to R330 have the structures defined in LIST 10 below:

In some embodiments, the compound can comprise a ligand LAof Formula II

wherein rings H, I, F, and G are each independently a 5-membered or 6-membered cathocyclic or heterocyclic ring; Z13-Z20are each independently C or N; RH, RI, RF, and RGeach independently represents zero, mono, or up to a maximum allowed substitutions to its associated ring; RH, RI, RF, and RGare each independently selected from the group consisting of hydrogen or a substituent selected from a group consisting of the general substituents defined herein; M is Pt or Pd; and wherein rings A, B, C, D, and E are all defined the same as above for Formula I; Z1-Z12are all defined the same as above for Formula I; and RA, RB, RC, and REare all defined the same as above for Formula I.

In some of the above embodiments, the compound can be selected from the group consisting of:

In some embodiments, the compounds as described herein emit light upon photoexcitation at room temperature, wherein the light emitted has an emission spectrum characterized by a peak emission wavelength λmaxwhen measured at a concentration of 0.1 mM in a solution of 2-methyl tetrahydrofuran; and wherein the full width at half maximum of the emission at λmaxthat is equal to or less than 20 nm.

In some of the above embodiments, the full width at half maximum of the emission at λmaxis equal to or less than 15 nm.

In some of the above embodiments, the full width at half maximum of the emission at λmaxis equal to or less than 10 nm.

C. The OLEDs and the Devices of the Present Disclosure

In another aspect, the present disclosure also provides an OLED device comprising a first organic layer that contains a compound as disclosed in the above compounds section of the present disclosure.

In some embodiments, the OLED comprises an anode, a cathode, and a first organic layer disposed between the anode and the cathode. The first organic layer can comprise a compound having a fragment with at least five rings fused next to each other consecutively wherein the fragment has at least two atoms coordinated to a metal.

In some embodiments, the organic layer can comprise a metal coordination compound comprising a ligand, wherein the ligand comprises a fragment having at least five rings fused next to each other consecutively; and wherein the fragment has at least two atoms coordinated to a metal.

In some embodiments, the fragment is a ligand LAof Formula I

wherein rings A, B, C, D, and E are each independently a 5-membered or 6-membered carbocyclic or heterocyclic ring; Z1-Z12are each independently C or N; RA, RB, RC, RD, and REeach independently represents zero, mono, or up to a maximum allowed substitutions to its associated ring; RA, RB, RC, RD, and REare each independently a hydrogen or a substituent selected from the group consisting of the general substituents defined herein; and two substituents can be joined or fused together to form a ring, wherein the ligand LAis complexed to a metal M selected from the group consisting of Ir, Rh, Re, Ru, Os, Pt, Pd, Au, Ag, and Cu; wherein M can be coordinated to other ligands; wherein the ligand LAcan be linked with other ligands to form a tridentate, tetradentate, pentadentate, or hexadentate ligand.

Also provided is an OLED comprising: an anode; a cathode; and an organic layer disposed between the anode and the cathode; wherein: the organic layer comprises a first compound as an emitter; the first compound is selected from the group consisting of phosphorescent emitter and delayed fluorescent emitter; the device emits a luminescent radiation at room temperature when a voltage is applied across the device; the luminescent radiation comprises a first radiation component emitted from the first compound; and the first radiation component has a full width at half maximum equal to or less than 15 nm.

In some embodiments, the organic layer may be an emissive layer and the compound as described herein may be an emissive dopant or a non-emissive dopant.

In some embodiments, the organic layer may further comprise a host, wherein the host comprises a triphenylene containing benzo-fused thiophene or benzo-fused furan, wherein any substituent in the host is an unfused substituent independently selected from the group consisting of CnH2n+1, OCnH2n+1, OAr1, N(CnH2n+1)2, N(Ar1)(Ar2), CH═CH—CnH2n+1, C≡CCnH2n+1, Ar1, Ar1-Ar2, CnH2n—Ar1, or no substitution, wherein n is from 1 to 10; and wherein Ar1and Ar2are independently selected from the group consisting of benzene, biphenyl, naphthalene, triphenylene, carbazole, and heteroaromatic analogs thereof.

In some embodiments, the organic layer may further comprise a host, wherein host comprises at least one chemical group selected from the group consisting of triphenylene, carbazole, indolocarbazole, dibenzothiophene, dibenzofuran, dibenzoselenophene, 5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene, aza-triphenylene, aza-carbazole, aza-indolocarbazole, aza-dibenzothiophene, aza-dibenzofuran, aza-dibenzoselenophene, and aza-(5,9-dioxa-13b-bomnaphtho[3,2,1-de]anthracene).

In some embodiments, the host may be selected from the HOST Group consisting of:

and combinations thereof.

In some embodiments, the organic layer may further comprise a host, wherein the host comprises a metal complex.

In some embodiments, the compound as described herein may be a sensitizer; wherein the device may further comprise an acceptor; and wherein the acceptor may be selected from the group consisting of fluorescent emitter, delayed fluorescence emitter, and combination thereof.

In yet another aspect, the OLED of the present disclosure may also comprise an emissive region containing a compound as disclosed in the above compounds section of the present disclosure.

In some embodiments, the emissive region can comprise a compound comprising a ligand LAof Formula I

wherein rings A, B, C, D, and E are each independently a 5-membered or 6-membered carbocyclic or heterocyclic ring; Z1-Z12are each independently C or N; RA, RB, RC, RD, and REeach independently represents zero, mono, or up to a maximum allowed substitutions to its associated ring; RA, RB, RC, RD, and REare each independently a hydrogen or a substituent selected from the group consisting of the general substituents defined herein; and two substituents can be joined or fused together to form a ring, wherein the ligand LAis complexed to a metal M selected from the group consisting of Ir, Rh, Re, Ru, Os, Pt, Pd, Au, Ag, and Cu; wherein M can be coordinated to other ligands; wherein the ligand LAcan be linked with other ligands to form a tridentate, tetradentate, pentadentate, or hexadentate ligand.

In some embodiments of the emissive region, the compound can be an emissive dopant or a non-emissive dopant. In some embodiments, the emissive region further comprises a host, wherein the host contains at least one group 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 Host Group defined above.

In yet another aspect, the present disclosure also provides a consumer product comprising an organic light-emitting device (OLED) having an anode; a cathode; and an organic layer disposed between the anode and the cathode, wherein the organic layer may comprise a compound as disclosed in the above compounds section of the present disclosure.

In some embodiments, the consumer product comprises an OLED having an anode; a cathode; and an organic layer disposed between the anode and the cathode, wherein the organic layer can comprise a compound having a fragment with at least five rings fused next to each other consecutively wherein the fragment has at least two atoms coordinated to a metal.

In some embodiments, the consumer product comprises an OLED having an anode; a cathode; and an organic layer disposed between the anode and the cathode, wherein the organic layer can comprise a compound comprising a ligand LA of Formula I as described herein.

In some embodiments, the consumer product can be one of a flat panel display, a computer monitor, a medical monitor, a television, a billboard, a light for interior or exterior illumination and/or signaling, a heads-up display, a fully or partially transparent display, a flexible display, a laser printer, a telephone, a cell phone, tablet, a phablet, a personal digital assistant (PDA), a wearable device, a laptop computer, a digital camera, a camcorder, a viewfinder, a micro-display that is less than 2 inches diagonal, a 3-D display, a virtual reality or augmented reality display, a vehicle, a video wall comprising multiple displays tiled together, a theater or stadium screen, a light therapy device, and a sign.

Several OLED materials and configurations are described in U.S. Pat. Nos. 5,844,363, 6,303,238, and 5,707,745, which are incorporated herein by reference in their entirety.

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. In some embodiments, the emissive dopant can be a racemic mixture, or can be enriched in one enantiomer. In some embodiments, the compound can be homoleptic (each ligand is the same). In some embodiments, the compound can be heteroleptic (at least one ligand is different from others). When there are more than one ligand coordinated to a metal, the ligands can all be the same in some embodiments. In some other embodiments, at least one ligand is different from the other ligands. In some embodiments, every ligand can be different from each other. This is also true in embodiments where a ligand being coordinated to a metal can be linked with other ligands being coordinated to that metal to form a tridentate, tetradentate, pentadentate, or hexadentate ligands Thus, where the coordinating ligands are being linked together, all of the ligands can be the same in some embodiments, and at least one of the ligands being linked can be different from the other ligand(s) in some other embodiments.

In some embodiments, the compound can be used as a phosphorescent sensitizer in an OLED where one or multiple layers in the OLED contains an acceptor in the form of one or more fluorescent and/or delayed fluorescence emitters. In some embodiments, the compound can be used as one component of an exciplex to be used as a sensitizer. As a phosphorescent sensitizer, the compound must be capable of energy transfer to the acceptor and the acceptor will emit the energy or further transfer energy to a final emitter. The acceptor concentrations can range from 0.001% to 100%. The acceptor could be in either the same layer as the phosphorescent sensitizer or in one or more different layers. In some embodiments, the acceptor is a TADF emitter. In some embodiments, the acceptor is a fluorescent emitter. In some embodiments, the emission can arise from any or all of the sensitizer, acceptor, and final emitter.

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

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.

The present disclosure encompasses any chemical structure comprising the novel compound of the present disclosure, or a monovalent or polyvalent variant thereof. In other words, the inventive compound, or a monovalent or polyvalent variant thereof, can be a part of a larger chemical structure. Such chemical structure can be selected from the group consisting of a monomer, a polymer, a macromolecule, and a supramolecule (also known as supermolecule). As used herein, a “monovalent variant of a compound” refers to a moiety that is identical to the compound except that one hydrogen has been removed and replaced with a bond to the rest of the chemical structure. As used herein, a “polyvalent variant of a compound” refers to a moiety that is identical to the compound except that more than one hydrogen has been removed and replaced with a bond or bonds to the rest of the chemical structure. In the instance of a supramolecule, the inventive compound can also be incorporated into the supramolecule complex without covalent bonds.

D. Combination of the Compounds of the Present Disclosure With Other Materials

In one aspect, (Y101-Y102) is a 2-phenylpyridine derivative. In another aspect, (Y101-Y102) is a cathene ligand. In another aspect, Met is selected from Ir, Pt, Os, and Zn. In a further aspect, the metal complex has a smallest oxidation potential in solution vs. Fc+/Fc couple less than about 0.6 V.

In one aspect, the metal complexes are:

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

E. Experimental Data

Synthesis of Compound 1

Synthesis of 4-(2,6-diisopropylphenyl)-1-(1-ethoxyethyl)-1H-pyrazole

A 1000 mL round-bottom-flask was charged with potassium carbonate (15.58 g, 113 mmol) and water (120 ml) and sparged with argon for 5 minutes. Dioxane (240 ml), 1-(1-ethoxyethyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (10.00 g, 37.6 mmol), and 2-bromo-1,3-diisopropylbenzene (9.97 g, 41.3 mmol) were added to the solution and was degassed for 15 minutes, then a pre-mixed and degassed solution (15 min) of palladium(II) acetate (0.211 g, 0.939 mmol) and di((3S,5S,7S)-adamantan-1-yl)(butyl) phosphane (0.808 g, 2.254 mmol) in Dioxane (20 ml) was added. The reaction mixture was heated to 110° C. overnight, under argon. After cooling to room temperature, the layers were separated, the aqueous layer was extracted with EtOAc (2×200 mL). The organic layers were combined, dried over Na2SO4, and concentrated under reduced pressure. The crude product was purified on a 330 g ISCO gold silica gel column, with 0-30% EtOAc/Hexane to obtain an amber semi-solid 4-(2,6-diisopropylphenyl)-1-(1-ethoxyethyl)-1H-pyrazole (65% Yield).

Synthesis of 4-(2,6-diisopropylphenyl)-1H-pyrazole

A 500 mL round-bottom-flask was charged with 4-(2,6-diisopropylphenyl)-1-(1-ethoxyethyl)-1H-pyrazole (18.3 g, 60.9 mmol) and dissolved in THF (162 ml) then hydrochloric acid (aq) (187 ml, 187 mmol) was added, the reaction mixture was stirred at 50° C. for 22 hours. The reaction was monitored by liquid chromatography (LC), and upon complete consumption of starting material the reaction mixture was allowed to cool to room temperature and neutralized with solid Na2CO3. The layers were separated, and the aqueous layer was extracted with EtOAc (2*200 mL). The organic layers were combined, washed with brine (200 mL), dried over Na2SO4, and concentrated under reduced pressure. The crude product was chromatographed on a 220 g Gold silica gel column, with 0-40% EtOAc/hexane to obtain a very light yellow solid, 4-(2,6-diisopropylphenyl)-1H-pyrazole (90% Yield).

Synthesis of 1-(3-bromo-4-fluorophenyl)-4-(2,6-diisopropylphenyl)-1H-pyrazole

A 250 mL round-bottom-flask was charged with 4-(2,6-diisopropylphenyl)-1H-pyrazole (6.91 g, 30.3 mmol) 2-bromo-1-fluoro-4-iodobenzene (10.02 g, 33.3 mmol) in 2-Propanol (80 ml) with copper(I) iodide (3.17 g, 16.64 mmol) Cs2CO3(32.5 g, 100 mmol). The reaction mixture was sparged with argon for 10 minutes, then heated to 100° C. for overnight. The reaction was monitored by LC, upon complete consumption of starting material the reaction mixture was quenched with water, the layers were separated and solids were filtered through a fritted funnel to access the crude product 1-(3-bromo-4-fluorophenyl)-4-(2,6-diisopropylphenyl)-1H-pyrazole with 86% yield.

A stirred solution of 1-(3-bromo-4-fluorophenyl)-4-(2,6-diisopropylphenyl)-1H-pyrazole (4.00 g, 9.97 mmol) in dry Et2O (49.8 ml) under argon atmosphere was cooled to −78° C. n-Butyllithium (4.98 ml, 11.96 mmol, 2.4 M) was added dropwise over 5 minutes and allowed to stir for 60 minutes at the same temperature. 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2.040 g, 10.96 mmol) was added in one portion and the reaction was stirred at −78° C. for 20 minutes then allowed to warm to room temperature and continued stirring for 30 minutes. The reaction was monitored by LC, upon complete consumption of starting material the reaction mixture was quenched with saturated ammonium chloride solution and extracted with ethyl acetate (2×200 mL). The combined organic layers were dried over Na2SO4followed by concentration under reduced pressure, the crude reaction mixture was subjected to trituration with hexane at −20° C. to obtain solid as product, 4-(2,6-diisopropylphenyl)-1-(4-fluoro-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) phenyl)-1H-pyrazole with 70% yield.

Synthesis of 1,1′-(6,6″-difluoro-3′,6′-dimethoxy-[1,1′,2′,1″-terphenyl]-3,3″-diyl)bis(4-(2,6-diisopropylphenyl)-1H-pyrazole)

A Solution of 2,3-dibromo-1,4-dimethoxybenzene (2.50 g, 8.45 mmol), and 4-(2,6-diisopropylphenyl)-1-(4-fluoro-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-1H-pyrazole (7.95 g, 17.74 mmol), potassium phosphate monohydrate (5.84 g, 25.3 mmol), in DME (77 mL) and water (7.6 mL) under argon atmosphere was equipped with a reflux condenser. The reaction mixture was argon bubbled for 10 minutes, then SPhos-3 (0.659 g, 0.845 mmol) was added and argon bubbling continued for 5 more minutes. The reaction mixture was heated to reflux 100° C. for 12 hours. The reaction was monitored by LC, upon complete consumption of starting material the reaction mixture was cooled to room temperature and water (50 mL) was added and extracted with ethyl acetate several times. combined organics were dried over MgSO4and concentrated under vacuum to yield gummy solid. The crude mixture was treated with hexane and vigorously stirred for 4 hours to access five flowing solid. The solid product was then filtered using funnel and dried in vacuo to afford pure off-white solid 1,1′-(6,6″-difluoro-3′,6′-dimethoxy-[1,1′:2′,1″-terphenyl]-3,3″-diyl)bis(4-(2,6-diisopropylphenyl)-1H-pyrazole) (5.21 g, 6.69 mmol, 79% yield).

Synthesis of 5,5″-bis(4-(2,6-diisopropylphenyl)-1H-pyrazol-1-yl)-2,2″-difluoro-[1,1′:2′,1″-terphenyl]-3′,6′-diol

A 250 mL RBF was charged with 1,1′-(6,6″-difluoro-3′,6′-dimethoxy[1,1′:2′,1″-terphenyl]-3,3″-diyl)bis(4-(2,6-diisopropylphenyl)-1H-pyrazole) (5.1 g, 6.55 mmol) and dissolved in dichloromethane (35 mL) under argon atmosphere then cooled to 0° C. Then Boron tribromide (1.547 ml, 16.37 mmol) was added at 0° C. and the resulting mixture was stirred at room temperature for about 2-4 hours until complete consumption of the starting material by LC. The reaction mixture was slowly cooled to 0° C., and quenched with methanol (5 ml) and concentrated in vacuo. The gummy residue was slowly quenched with water (100 mL) and the crude gummy mixture was stirred vigorously to precipitate solids, the solids were filtered and the slurry was washed with water (2×50 mL) to afford pure product 5,5″-bis(4-(2,6-diisopropylphenyl)-1H-pyrazol-1-yl)-2,2″-difluoro-[1,1″:2′,1″-terphenyl]-3′,6′-diol (4.1 g, 5.46 mmol, 83% yield).

Synthesis of Ligand 1

A 250 mL round-bottom-flask was charged with 5,5″-bis(4-(2,6-diisopropylphenyl)-1H-pyrazol-1-yl)-2,2″-difluoro-[1,1:2′,1″-terphenyl]-3′,6′-diol (5.60 g, 7.46 mmol) was dissolved in NMP (75 mL), under argon atmosphere. Then cesium carbonate (7.29 g, 22.37 mmol) was added, and the resulting mixture was stirred at 160° C. for about 2-4 hours until the complete consumption of the starting material was monitored by LC. Then reaction mixture was cooled to room temperature and quenched with water (50 mL) to precipitate out solids and the slurry was stirred for 1 hour, the solids were filtered and washed with water (2×100 mL) to afford the crude Ligand 1, which was purified by column chromatography (3.2 g, 5.6 mmol, 54% yield).

Synthesis of Compound 1

A mixture of Ligand 1 (50.8 mg, 0.071 mmol) and Pt(COD)Cl2(26.7 mg, 0.071 mmol) in a Schlenk tube was vacuumed and back-filled with nitrogen. 1,2-dichlorobenzene (2 ml) was added and refluxed for 2 weeks. The crude reaction mixture was coated on Celite and chromatographed on silica (DCM/Hep=1/1) yielding the product Compound 1 (15 mg, 23% yield).

Synthesis of Compound 2

Synthesis of (2-fluoro-5-(pyridin-2-yl) phenyl) Boronic Acid

To a stirred solution of 2-(4-fluorophenyl)pyridine (5.000 g, 28.9 mmol) in dry THF (144 mL) under argon atmosphere was added potassium 2-methylpropan-2-olate (3.56 g, 31.8 mmol) and the reaction mixture was cooled to −78° C. n-Butyllithium (13.23 ml, 31.8 mmol, 2.4 M) was added dropwise over 5 minutes and allowed to stir for 60 minutes at the same temperature. 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (8.06 g, 43.3 mmol) was added in one portion and the reaction was stirred at −78° C. for 20 minutes. The reaction was monitored by LCMS, after complete consumption of the starting material the reaction was quenched with saturated ammonium chloride solution and extracted with ethyl acetate (2×200 mL). The organic layers were combined and dried over Na2SO4followed by concentration under reduced pressure to afford crude product (2-fluoro-5-(pyridin-2-yl) phenyl) boronic acid with 72% yield.

A Solution of 2,3-dibromo-1,4-dimethoxybenzene (5.000 g, 16.89 mmol), and (2-fluoro-5-(pyridin-2-yl)phenyl)boronic acid (8.43 g, 38.9 mmol), potassium carbonate (8.17 g, 59.1 mmol), in DME (77 mL) and water (7.6 mL) under argon atmosphere with a reflux condenser. The reaction mixture was argon bubbled for 10 minutes, then SPhos-4 (1.341 g, 1.689 mmol) was added and continued bubbling argon for 5 more minutes. The reaction mixture was heated to reflux 100° C. for 12 hours. The reaction was monitored by LCMS and after complete consumption of starting material, the reaction mixture was cooled to room temperature and water (50 mL) was added and extracted with ethyl acetate several times. The combined organics were dried over MgSO4and concentrated in vacuo to yield a gummy solid. The crude product was treated with hexane and vigorously stirred for 4 hours to access free flow solid. The solid product was then filtered using funnel and dried under vacuum to afford pure off-white solid 2,2′-(6,6″-difluoro-3′,6′-dimethoxy-[1,1′:2′,1″-terphenyl]-3,3″-diyl)dipyridine. (12.2 g, 40.7 mmol, 65% yield).

Synthesis of 2,2″-difluoro-5,5″-di(pyridin-2-yl)-[1,1′:2′,1″-terphenyl]-3′,6′-diol

A 500 mL round-bottom-flask was charged with 2,2′-(6,6″-difluoro-3′,6′-dimethoxy-[1,1′:2′,1″-terphenyl]-3,3″-diyl)dipyridine (6.500 g, 13.53 mmol) and dissolved in dichloromethane (68 mL) under argon atmosphere then cooled to 0° C. Then Boron tribromide (3.20 ml, 33.8 mmol) was added at 0° C. and the resulting mixture was stirred at room temperature for about 2-4 hours until the starting material was completely consumed as monitored by LC. The reaction mixture was slowly cooled to 0° C. and quenched with methanol (5 ml) then concentrated in vacuo. The gummy residue was slowly quenched with water (100 mL) and the crude gummy mixture was stirred vigorously to precipitate solids, filter the solids and slurry wash with water (2*50 mL) to afford pure product 2,2″-difluoro-5,5″-di(pyridin-2-yl)-[1,1′:2′,1″-terphenyl]-3′,6′-diol (7.00 g, 15.47 mmol, 80% yield).

A 250 mL RBF was charged with 2,2″-difluoro-5,5″-di(pyridin-2-yl)-[1,1′:2′,1″-terphenyl]-3′,6′-diol (7.00 g, 15.47 mmol) dissolved in NMP (77 ml), under argon atmosphere. Then cesium carbonate (15.12 g, 46.4 mmol) was added, and the resulting mixture was stirred at 160° C. for about 2-4 h until the complete consumption of the starting material by LC. Then reaction mixture was cooled to room temperature and quenched with water (50 mL) to precipitate grey colored solids, which were filtered and washed with water (2×100 mL) to afford the crude product. The wet solid was dried under vacuum for 1 hour, then performed slurry wash with methanol (2×50 mL), trituration with diethyl ether, trituration DMF, trituration with hot diethyl ether, and charcoal treatment in DCM to access the product Benzo[1,2-b:4,3-b′]bisbenzofuran-2,11-2-pyridine (Ligand 2) (2.86 g, 6.96 mmol, 45% yield).

Synthesis of Compound 2

A mixture of Ligand 2 (100 mg, 0.242 mmol) and Pt(COD)Cl2(91 mg, 0.242 mmol) in a Schlenk tube was vacuumed and back-filled with nitrogen. 1,2-dichlorobenzene (2 ml) was added and refluxed for 2 weeks. The reaction mixture was cooled down, coated on celite, and chromatographed on silica (DCM/Hep=2/1) to obtain the product Compound 2 (7 mg, 4.8% yield).

The emission spectra of Compounds 1 and 2 in a solution of 2-methyl tetrahydrofuran were collected on a Horiba Fluorolog-3 spectrophotometer at both room temperature (RT) and in frozen glass at 77K. The peak wavelengths (λmax) and the full width at half maximum (FWHM) of each of the compounds are given in Table 1. In general, the FWHM for a phosphorescent emitter complex is greater than 60 nm. It has been a long-sought goal to achieve the narrow FWHM. The narrower FWHM, the better color purity for the display application. As a background information, the ideal line shape is a single wavelength (single line). As can be seen here, the current inventive compounds can reach a single digit of FWHM, this is remarkably unexpected and is a breakthrough in OLED industry. Compound 2 has much larger FWHM at room temperature. Without being bound by any theory, this is probably due the higher metal to ligand charge transfer in the room temperature.