(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY(PCT)
`
`(19) World Intellectual Property Organization
`International Bureau
`
`(43) International Publication Date
`10 January 2002 (10.01.2002)
`
`
`
`PCT
`
`(10) International Publication Number
`WO 02/02714 A2
`
`(51) International Patent Classification’:
`
`CO9K 11/00
`
`(21) International Application Number:
`
`PCT/US01/20539
`
`(74) Agent: WANG, Chen; E. I. Du Pont De Nemours And
`Company, Legal Patent Records Center, 1007 Market
`Street, Wilmington, DE 19898 (US).
`
`(22) International Filing Date:
`
`27 June 2001 (27.06.2001)
`
`(25) Filing Language:
`
`(26) Publication Language:
`
`English
`
`English
`
`(30) Priority Data:
`60/215,362
`60/224,273
`
`30 June 2000 (30.06.2000)
`10 August 2000 (10.08.2000)
`
`US
`US
`
`(71) Applicant (for all designated States except US): E.1. DU
`PONT DE NEMOURS AND COMPANY[US/US]; 1007
`MarketStreet, Wilmington, DE 19898 (US).
`
`(72)
`(75)
`
`Inventors; and
`Inventors/Applicants (for US only): PETROV, Viach-
`eslav, A. [RU/US]; 2 Cappa Court, Hockessin, DE 19707
`(US). WANG, Ying [US/US]; 4010 Greenmount Road,
`Wilmington, DE 19810 (US). GRUSHIN, Vladimir
`[CA/US]; 533 Runnymeade Road, Hockessin, DE 19707
`(US).
`
`(81) Designated States (national): AE, AG, AL, AM, AT, AU,
`AZ, BA, BB, BG, BR, BY, BZ, CA, CH, CN, CO, CR, CU,
`CZ, DE, DK, DM, DZ, EE, ES, Fl, GB, GD, GH, GH, GM,
`HR, HU,ID,IL, IN,IS, JP, KE, KG, KP, KR, KZ, LC, LK,
`LR, LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX,
`MZ, NO, NZ, PL, P'T, RO, RU, SD, SE, SG, SI, SK, SL,
`TJ, TM, TR, TT, TZ, UA, UG, US, UZ, VN, YU, ZA, ZW.
`
`(84) Designated States (regional): ARIPO patent (GH, GM,
`KE, LS, MW, MZ, SD, SL, SZ, TZ, UG, ZW), Eurasian
`patent (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), European
`patent (AT, BE, CH, CY, DE, DK,ES, FI, FR, GB, GR,IE,
`IT, LU, MC, NL, PT, SE, TR), OAPI patent (BF, BJ, CF,
`CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG).
`
`Published:
`
`without international search report and to be republished
`upon receipt of that report
`
`For two-letter codes and other abbreviations, refer to the "Guid-
`ance Notes on Codes andAbbreviations"appearing al the begin-
`ning ofeach regular issue ofthe PCT Gazette.
`
`ELECTROLUMINESCENT IRIDIUM COMPOUNDS WITH FLUORINATED PHENYLPYRIDINES,
`(54) Title:
`PHENYLPYRIMIDINES, AND PHENYLQUINOLINES AND DEVICES MADE WITH SUCH COMPOUNDS
`
`(57) Abstract: The present invention is
`generally directed to electroluminescent
`
`TrdI) the©substitutedcompounds,
`
`2-phenylpyridines,
`phcenylpyrimidincs,
`and phenylquinolines that are used to
`make the IrdID compounds, and devices
`that are made with the Ir(1]) compounds.
`
`100
`
`WO02/02714A2
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`

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`
`TITLE
`
`ELECTROLUMINESCENT IRIDIUM COMPOUNDS WITH FLUORINATED
`
`PHENYLPYRIDINES, PHENYLPYRIMIDINES, AND PHENYLQUINOLINES
`AND DEVICES MADE WITH SUCH COMPOUNDS
`
`BACKGROUNDOF THE INVENTION
`
`Field of the Invention
`
`This invention relates to electroluminescent complexes of iridium(III) with
`fluorinated phenylpyridines, phenylpyrimidines, and phenylquinolines. It also
`relates to electronic devices in which the active layer includes an
`electroluminescent Ir(III) complex.
`Description of the Related Art
`Organic electronic devices that emit light, such as light-emitting diodes
`that make up displays, are present in many different kinds of electronic
`equipment. In all such devices, an organic active layer is sandwiched between
`two electrical contact layers. At least one ofthe electrical contact layersis light-
`transmitting so that light can pass throughthe electrical contact layer. The
`organic active layer emits light through the light-transmitting electrical contact
`layer upon application of electricity across the electrical contact layers.
`It is well known to use organic electroluminescent compounds as the
`active componentin light-emitting diodes. Simple organic molecules such as
`anthracene, thiadiazole derivatives, and coumarin derivatives are known to show
`electroluminescence. Semiconductive conjugated polymers have also been used
`as electroluminescent components, as has been disclosed in, for example, Friend
`et al., U.S. Patent 5,247,190, Heegeret al., U.S. Patent 5,408,109, and Nakano
`et al., Published European Patent Application 443 861. Complexes of
`8-hydroxyquinolate with trivalent metal ions, particularly aluminum, have been
`extensively used as electroluminescent components, as has been disclosed in, for
`example, Tang et al., U.S. Patent 5,552,678.
`Burrows and Thompson havereported that fac-tris(2-phenylpyridine)
`iridium can be used as the active componentin organic light-emitting devices.
`(Appl. Phys. Lett. 1999, 75, 4.) The performance is maximized when the iridium
`compound is present in a host conductive material. Thompson has further
`reported devices in which the active layer is poly(N-vinyl carbazole) doped with
`fac-tris[2-(4',5'-difluoropheny])pyridine-C'2,N]iridium(II}). (PolymerPreprints
`2000, 41(1), 770.)
`However,there is a continuing need for electroluminescent compounds
`having improved efficiency.
`
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`SUMMARY OF THE INVENTION
`
`The present invention is directed to an iridium compound(generally
`referred as “Ir(III) compounds”) having at least two 2-phenylpyridine ligands in
`whichthere is at least one fluorine or fluorinated group on the ligand. The iridium
`compound hasthe following First Formula:
`IrLaLbLe,LL",
`
`(First Formula)
`
`5
`
`where:
`
`10
`
`x=Oor 1, y=0, 1 or 2, and z=0or 1, with the proviso that:
`x=Oory+z=0and
`when y = 2 then z= 0;
`L'= a bidentate ligand or a monodentate ligand, and is nota
`phenylpyridine, phenylpyrimidine, or phenylquinoline; with the
`proviso that:
`when L' is a monodentate ligand, y+z = 2, and
`when L'is a bidentate ligand, z = 0;
`L" = a monodentate ligand, and is not a phenylpyridine, and
`phenylpyrimidine, or phenylquinoline; and
`La, Lb and L¢ are alike or different from each other and each of La, L>
`and L° hasstructure (1) below:
`
`15
`
`20
`
`Ro
`Ry
`Rs
`Re
`Ry @
`Rg
`Ney
`
`N
`
`A
`
`wherein:
`
`adjacent pairs of Ry-Ry and Rs5-Rg can be joined to formafive- or
`25
`six-memberedring,
`at least one of R,-Rg is selected from F, C)Fon+1, OCyFan+1, and
`OCF2X, where n= 1-6 and X = H,Cl, or Br, and
`A=CorN,provided that when A =N,there is no Rj.
`In another embodiment, the present invention is directed to substituted
`30=.2-phenylpyridine, phenylpyrimidine, and phenylquinoline precursor compounds
`from. which the above Ir(IIT) compounds are made. The precursor compounds
`have a Structure (IJ) or(IIT) below:
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`Re
`
`Rs
`
`Ry
`
`Rg
`
`Ro
`
`Ry
`A
`
`C)
`
`N
`
`Ro
`
`Ra
`
`R3
`
`qa)
`
`5
`
`10
`
`15.
`
`20
`
`25
`
`where A and Rj-Rg are as defined in structure (I) above,
`and Rg is H.
`
`
`
`dal)
`
`where:
`
`at least one of Rj 9-Ryg is selected from F, CyFon41,
`OC,Fon+1, and OCF2X, where n = 1-6 and X = H,Cl, or Br, and
`Roo is H.
`
`It is understoodthat there is free rotation about the phenyl-pyridine,
`phenyl-pyrimidine and the phenyl-quinoline bonds. However, for the discussion
`herein, the compoundswill be described in terms of one orientation.
`In another embodiment, the present invention is directed to an organic
`electronic device having at least one emitting layer comprising the aboveIr(ITT)
`compound, or combinations of the above Ir(III) compounds.
`As usedherein, the term “compound” is intended to mean an electrically
`uncharged substance made up of molecules that further consist of atoms, wherein
`the atoms cannot be separated by physical means. Theterm “ligand”is intended
`to mean a molecule, ion, or atom that is attached to the coordination sphere of a
`metallic ion. The term “complex”, when used as a noun,is intended to mean a
`compound havingat least one metallic ion and at least one ligand. The term
`“group”is intended to mean a part of a compound, such a substituent in an
`organic compoundor a ligand ina complex. The term “facial” is intended to
`mean one isomer of a complex, Ma3b3, having octahedral geometry, in which the
`
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`three “a’’ groupsare all adjacent, i.e. at the corners of one face of the octahedron.
`The term “meridional”is intended to mean one isomer of a complex, Ma3b3,
`having octahedral geometry, in which the three “a” groups occupy three positions
`such that two are trans to each other. The phrase “adjacent to,” when usedto refer
`to layers in a device, does not necessarily meanthat one layer is immediately next
`to another layer. On the other hand, the phrase “adjacent R groups,” is used to
`refer to R groupsthat are next to each other in a chemical formula (i.e., R groups
`that are on atoms joined by a bond). The term “photoactive” refers to any
`material that exhibits electroluminescence and/or photosensitivity.
`DESCRIPTION OF THE DRAWINGS
`
`Figure 1 is a schematic diagram of a light-emitting device (LED).
`Figure 2 is a schematic diagram of an LED testing apparatus.
`DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
`
`The IrdI1) compounds of the invention have the First Formula
`IrdINLaLeLe,Ly above.
`The above Ir(I1) compoundsare frequently referred to as cyclometalated
`complexes: Ir(IIJ) compounds having the following Second Formulais also
`frequently referred to as a bis-cyclometalated complex.:
`
`IrL@LbL' i",
`
`where:
`
`(Second Formula)
`
`y, Z, L@, LBL’, and L"are as defined in the First Formula above.
`
`10
`
`15
`
`20
`
`IrdIT) compounds having the following Third Formulais also frequently referred
`to as a tris-cyclometalated complex.:
`
`25
`
`TrLaLbie
`
`where:
`
`(Third Formula)
`
`La, Lb and L¢ are as defined in the First Formula described above.
`
`30
`
`35
`
`The preferred cyclometalated complexes are neutral and non-ionic, and
`can be sublimed intact. Thin films of these materials obtained via vacuum
`
`deposition exhibit good to excellent electroluminescent properties. Introduction
`of fluorine substituents into the ligands on the iridium atom increases both the
`stability and volatility of the complexes. As a result, vacuum deposition can be
`carried out at lower temperatures and decomposition of the complexes can be
`avoided. Introduction of fluorine substituents into the ligands can often reduce
`the non-radiative decay rate and the self-quenching phenomenoninthesolidstate.
`4
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`
`These reductions can lead to enhanced luminescence efficiency. Variation of
`substituents with electron-donating and electron-withdrawing properties allows
`for fine-tuning of electroluminescent properties of the compound and hence
`optimization of the brightness and efficiency in an electroluminescent device.
`While not wishing to be boundbytheory,it is believed that the emission
`from the iridium compoundsis ligand-based, resulting from metal-to-ligand
`charge transfer. Therefore, compoundsthat can exhibit electroluminescence
`include those of compounds of the Second Formula IrL@L>L' yL", above, and the
`Third Formula IrL@L>L¢ above, where all L4, L>, and L¢ in the Third Formula are
`phenylpyridines, phenylpyrimidines, or phenylquinolines.The R,-Rg groups of
`structures (1) and(II), and the Rj9-R19 groups ofstructure (III) above may be
`chosen from conventional substitutents for organic compounds, suchas alkyl,
`alkoxy, halogen, nitro, and cyano groups, as well as fluoro, fluorinated alkyl and
`fluorinated alkoxy groups. The groups can bepartially or fully fluorinated
`(perfluorinated). Preferred iridium compoundshaveall Rj-Rg and Rjg-Ry9
`substituents selected from fluoro, perfluorinated alkyl (C,F2y4;) and
`perfluorinated alkoxy groups (OC,F>,+1), where the perfluorinated alkyl and
`alkoxy groups have 1-6 carbon atoms,or a group of the formula OCF2X, where
`xX =H, Cl, or Br.
`It has been found that the electroluminescent properties of the
`cyclometalated iridium complexes are poorer when any one or more of the R1-Rg
`and R19-Rj9 groups is a nitro group. Therefore, it is preferred that none of the
`Ry-Rg and Rj9-Ryg9 groupsis a nitro group.
`The nitrogen-containing ring can be a pyridine ring, a pyrimidine or a
`quinoline. It is preferred that at least one fluorinated substituent is on the
`nitrogen-containing ring; most preferably CF3.
`Any conventional ligands known to transition metal coordination
`chemisiry is suitable as the L’ and L" ligands. Examples of bidentate ligands
`include compounds having two coordinating groups, such as ethylenediamine and
`acetylacetonate, which may be substituted. Examples of monodentate ligands
`include chloride and nitrate ions and mono-amines. It is preferred that the iridium
`complex be neutral and sublimable. Ifa single bidentate ligand is used, it should
`have a net charge of minus one (-1). If two monodentate ligands are used, they
`should have a combined net charge of minus one (-1). The bis-cyclometalated
`complexes can be useful in preparing tris-cyclometalated complexes where the
`ligands are notall the same.
`In a preferred embodiment, the iridium compound has the Third Formula
`IrL@L>L¢ as described above.
`
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`In amore preferred embodiment, L@= Lb=L°, These more preferred
`compounds frequently exhibit a facial geometry, as determined by single crystal
`X-ray diffraction, in which the nitrogen atoms coordinated to the iridium are trans
`with respect to carbon atoms coordinatedto the iridium. These morepreferred
`compounds have the following Fourth Formula:
`
`Jac-Ir(L*)3
`where L@ hasstructure (I) above.
`
`(Fourth Formula)
`
`The compounds can also exhibit a meridional geometry in which two ofthe
`nitrogen atoms coordinated to the iridium are trans to each other. These
`compounds have the following Fifth Formula:
`
`mer- \r(L4)3
`where L? has structure (I) above.
`
`(Fifth Formula)
`
`Examples of compoundsof the Fourth Formula and Fifth Formula above
`are given in Table | below:
`
`
`
`TABLE1
`
`10
`
`15
`
`20
`
`
`
`H
`
`3
`
`t
`
`61c
`
`et|
`
`— 5 C C
`
`we(ot,|weoe|pete
`
`
`
`H {|H
`
`H lH|
`|-[cr|
`I-q
`H
`
`—
`
`i
`
`

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`
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`
`
`
`
`
`TABLE1
`
`
`
`Examples compounds ofthe Second Formula TrLaboLyi", above include
`compounds 1-n, J-o, I-p, 1-w and 1-x, respectively having structure (IV), (V),
`(VI), (EX) and (X) below:
`
`F3C COL.
`
`bo >—crFs
`
`O
`
`oO Ny
`
`TS 2
`
`F
`
`Cl
`
`a NN
`WN
`
`OH
`
`O
`
`re 2
`~
`O
`
`CF3
`
`(Iv)
`
`(V)
`
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`

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`
`
`
`(vl)
`
`F
`
`a ~N
`|
`
`ww
`
`CF;
`
`4
`
`F
`
`oO
`aN
`by
`
`Ir
`
`oa ~N Nov
`~ J
`
`CFs;
`
`CF3/2
`
`5
`
`(IX)
`
`F
`
`Br
`
`Ir.
`
`ai | Ny
`G
`SI
`CF 2
`Br
`
`10
`
`(X)
`
`The iridium complexes of the Third Formula IrL@L>L°¢ aboveare generally
`prepared from the appropriate substituted 2-phenylpyridine, phenylpyrimidine, or
`
`8
`
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`PCT/US01/20539
`
`phenylquinoline. The substituted 2-phenylpyridines, phenylpyrimidines, and
`phenylquinolines, as shown in Structure (II) above, are prepared, in good to
`excellent yield, using the Suzuki coupling of the substituted 2-chloropyridine,
`2-chloropyrimidine or 2-chloroquinoline with arylboronic acid as described in
`O. Lohse, P.Thevenin, E. Waldvogel Synlett, 1999, 45-48. This reaction is
`illustrated for the pyridine derivative, where X and Y represent substituents, in
`Equation (1) below:
`
`_ ome
`
`s
`
`Nz
`
`5
`
`10
`
`Examples of 2-phenylpyridine and 2-phenylpyrimidine compounds,
`having structure (II) above, are given in Table 2 below:
`
`
`TABLE 2
`
`[Compound|A f Ry
`
`oe
`
`eS
`
` Q
`
`\es) Qryuo
`
`eriPerelelel
`EEREEES CF,
`
`
`mi ERS1O
`2-a2-b
`or,
`
`
`
`Qfryud
`
`adto
`fi
`=io
`Q|=
`
`fe1
`
`x
`
`lo
`
`Qsy2
`
`Qrytad
`Q
`
`
`
`q
`
`

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`
`
`Ry
`Rg
`Rg
`
`
`
`ofH
`
`F
`
`
`
`H
`
`H
`
`ferjan[a|nF tw
`
` rrr
`etar
`
`CF3
`
`
`
`F
`
`H
`
`One example of a substituted 2-phenylquinoline compound, having
`structure (IIT) above, is compound 2-u, which has R17 = CF3 and R19-R16 and
`R1g-R20 = H.
`The 2-phenylpyridines, pyrimidines, and quinolines thus prepared are used
`for the synthesis of the cyclometalated iridium complexes. A convenient one-step
`method has been developed employing commercially available iridium trichloride
`hydrate and silver trifluoroacetate. The reactions are generally carried out with an
`excess of 2-phenylpyridine, pyrimidine, or quinoline, without a solvent, in the
`presence of 3 equivalents of AZOCOCF3. This reactionis illustrated for a
`2-phenylpyridine in Equation (2) below:
`
`5
`
`10
`
`Y
`
`Y
`
`IrCh, ASOCOCF;aad
`190-195°C
`Ir
`(2)
`
`A
`
`Xx
`
`|
`
`SS
`
`x
`
`~~
`SS
`
`~N
`|
`
`15=The tris-cyclometalated iridium complexes wereisolated, purified, and fully
`characterized by elemental analysis, 1H and 19F NMR spectral data, and, for
`compounds I-b, 1-c, and l-e, single crystal X-ray diffraction. In some cases,
`mixtures of isomers are obtained. Often the mixture can be used withoutisolating
`the individual isomers.
`
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`
`The iridium complexes having the Second Formula IrL@L°L' yh", above,
`may, in some cases, be isolated from the reaction mixture using the same
`synthetic procedures as preparing those having Third Formula IrL@LL¢ above.
`The complexes can also be prepared by first preparing an intermediate iridium
`dimer having structure VII below:
`
`b
`
`B
`LAaNyL
`Ld No” ‘1
`
`c
`
`(vi)
`
`|B
`
`wherein:
`
`B =H, CHs3, or CoH, and
`La, L>,L¢, and L4 can be the sameor different from each
`other and each of L@, L®,L°, and L¢ hasstructure (I) above.
`The iridium dimers can generally be prepared by first reacting iridium trichloride
`hydrate with the 2-phenylpyridine, phenylpyrimidine or phenylquinoline, and
`adding NaOB.
`Oneparticularly useful iridium dimer is the hydroxo iridium dimer,
`having structure VIII below:
`
`F
`
`§
`We NN
`ZN NU
`°
`~
`2
`H
`
`CF3
`
`CFs
`
`>N
`7
`
`2
`
`F
`
`(VIII)
`
`This intermediate can be used to prepare compound1-p by the addition of
`ethyl acetoacetate.
`Electronic Device
`
`The present invention also relates to an electronic device comprising at
`least one photoactive layer positioned between twoelectrical contact layers,
`wherein the at least one layer of the device includes the iridium complex of the
`invention. Devicesfrequently have additional hole transport and electron transport
`layers. A typical structure is shown in Figure 1. The device 100 has an anode
`layer 110 and a cathode layer 150. Adjacentto the anodeis a layer 120
`
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`comprising hole transport material. Adjacent to the cathode is a layer 140
`comprising an electron transport material. Between the hole transport layer and
`the electron transport layer is the photoactive layer 130.
`Depending upon the application of the device 100, the photoactive layer
`130 can be a light-emitting layer that is activated by an applied voltage (such as in
`a light-emitting diode or light-emitting electrochemicalcell), a layer of material
`that respondsto radiant energy and generates a signal with or without an applied
`bias voltage (such as in a photodetector). Examples of photodetectors include
`photoconductive cells, photoresistors, photoswitches, phototransistors, and
`phototubes, and photovoltaic cells, as these terms are describe in Markus, John,
`Electronics and Nucleonics Dictionary, 470 and 476 (McGraw-Hill, Inc. 1966).
`The iridium compoundsofthe invention are particularly useful as the
`photoactive material in layer 130, or as electron transport material in layer 140.
`Preferably the iridium complexes ofthe invention are used as the light-emitting
`material in diodes. It has been foundthat in these applications, the fluorinated
`compounds of the invention do not need to be in a solid matrix diluent in order to
`be effective. A layer that is greater than 20% by weight iridium compound, based
`on the total weight of the layer, up to 100% iridium compound, can be used as the
`emitting layer. This is in contrast to the non-fluorinated iridium compound,
`tris(2-phenylpyridine) iridium (J), which was found to achieve maximum
`efficiency when present in an amountof only 6-8% by weight in the emitting
`layer. This was necessary to reduce the self-quenching effect. Additional
`materials can be present in the emitting layer with the iridium compound. For
`example, a fluorescent dye may be presentto alter the color of emission. A
`diluent may also be added. The diluent can be a polymeric material, such as
`poly(N-vinyl carbazole) and polysilane. It can also be a small molecule, such as
`4,4'-N,N'-dicarbazole biphenyl or tertiary aromatic amines. When a diluentis
`used, the iridium compoundis generally present in a small amount, usually less
`than 20% by weight, preferably less than 10% by weight, based on the total
`weight of the layer.
`In somecases the iridium complexes may be present in more than one
`isomeric form, or mixtures of different complexes may be present. It will be
`understood that in the above discussion of OLEDs,the term “the iridium
`compound”is intended to encompass mixtures of compounds and/or isomers.
`To achieve a highefficiency LED, the HOMO(highest occupied
`molecular orbital) of the hole transport material should align with the work
`function of the anode, the LUMO (lowest un-occupied molecular orbital) of the
`electron transport material should align with the work function of the cathode.
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`Chemical compatibility and sublimation temp of the materials are also important
`considerations in selecting the electron and hole transport materials.
`The other layers in the OLED can be made of any materials which are
`known to be useful in such layers. The anode 110, is an electrode thatis
`particularly efficient for injecting positive charge carriers. It can be madeof, for
`example materials containing a metal, mixed metal, alloy, metal oxide or mixed-
`metal oxide, or it can be a conducting polymer. Suitable metals include the
`Group 11 metals, the metals in Groups 4, 5, and 6, and the Group 8-10 transition
`metals. If the anodeisto be light-transmitting, mixed-metal oxides of Groups 12,
`13 and 14 metals, such as indium-tin-oxide, are generally used. The IUPAC
`numbering system is used throughout, where the groups from the Periodic Table
`are numbered from left to right as 1-18 (CRC Handbook of Chemistry and
`Physics, 815t Edition, 2000). The anode 110 may alsc comprise an organic
`material such as polyaniline as described in “Flexible light-emitting diodes made
`from soluble conducting polymer,” Nature vol. 357, pp 477-479 (11 June 1992),
`At least one of the anode and cathode should beat least partially transparent to
`allow the generated light to be observed.
`Examplesof hole transport materials for layer 120 have been summarized
`for example, in Kirk-Othmer Encyclopedia of Chemical Technology, Fourth
`Edition, Vol. 18, p. 837-860, 1996, by Y. Wang. Bothhole transporting
`molecules and polymers can be used. Commonly used hole transporting
`molecules are: N,N'-diphenyl-N,N'-bis(3-methylpheny])-[1,1'-biphenyl]-4,4'-
`diamine (TPD), 1,1-bis[(di-4-tolylamino) phenyl]cyclohexane (TAPC),
`N,N'-bis(4-methylphenyl)-N,N'-bis(4-ethylphenyl)-[1, 1'-(G,3'-dimethyl)bipheny]]-
`4,4'-diamine (ETPD), tetrakis-(3-methylphenyl)-N,N,N',N'-2,5-phenylenediamine
`(PDA), a-phenyl-4-N,N-diphenylaminostyrene (TPS), p-(diethylamino)-
`benzaldehyde diphenylhydrazone (DEH), triphenylamine (TPA), bis[4-(N,N-
`diethylamino)-2-methylphenyl](4-methylphenyl)methane (MPMP), 1-phenyl-3-
`[p-(diethylamino)styryl]-5-[p-(diethylamino)phenyl] pyrazoline (PPR or DEASP),
`1,2-trans-bis(9H-carbazol-9-yl)cyclobutane (DCZB), N,N,N',N'-tetrakis(4-methyl-
`pheny!)-(1,1'-bipheny])-4,4'-diamine (TTB), and porphyrinic compounds, such as
`copper phthalocyanine. Commonly used hole transporting polymers are
`polyvinylcarbazole, (phenylmethyl)polysilane, and polyaniline. It is also possible
`to obtain hole transporting polymers by doping hole transporting molecules such
`as those mentioned above into polymers such as polystyrene and polycarbonate.
`Examples of electron transport materials for layer 140 include metal
`chelated oxinoid compounds,such astris(8-hydroxyquinolato)aluminum (Alq3);
`phenanthroline-based compounds, such as 2,9-dimethyl-4,7-diphenyl-1,10-
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`phenanthroline (DDPA)or 4,7-diphenyl-1,10-phenanthroline (DPA), and azole
`compoundssuch as 2-(4-biphenylyl)-5-(4-t-butylpheny])-1,3,4-oxadiazole (PBD)
`and 3-(4-biphenylyl)-4-phenyl-5-(4-t-butylphenyl)-1,2,4-triazole (TAZ). Layer
`140 can function both to facilitate electron transport, and also serve as a buffer
`layer or confinementlayer to prevent quenching of the exciton at layer interfaces.
`Preferably, this layer promotes electron mobility and reduces exciton quenching.
`The cathode 150, is an electrode that is particularly efficient for injecting
`electrons or negative charge carriers. The cathode can be any metal or nonmetal
`having a lower work function than the anode. Materials for the cathode can be
`selected from alkali metals of Group 1 (e.g., Li, Cs), the Group 2 (alkaline earth)
`metals, the Group 12 metals, including the rare earth elements and lanthanides,
`and the actinides. Materials such as aluminum, indium, calcium, barium,
`samarium and magnesium, as well as combinations, can be used. Li-containing
`organometallic compoundscan also be deposited betweenthe organic layer and
`the cathode layer to lower the operating voltage.
`It is known to have other layers in organic electronic devices. For
`example, there can be a layer (not shown) between the conductive polymer layer
`120 and the active layer 130 to facilitate positive charge transport and/or band-gap
`matching of the layers, or to function as a protective layer. Similarly, there can be
`additional layers (not shown) betweenthe active layer 130 and the cathode layer
`150 to facilitate negative charge transport and/or band-gap matching between the
`layers, or to function as a protective layer. Layers that are known in the art can be
`used. In addition, any of the above-described layers can be made of two or more
`layers. Alternatively, someorall of inorganic anode layer 110, the conductive
`polymer layer 120, the active layer 130, and cathode layer 150, may be surface
`treated to increase charge carrier transport efficiency. The choice of materials for
`each of the componentlayers is preferably determined by balancing the goals of
`providing a device with high device efficiency.
`It is understood that each functional layer may be made up of more than
`one layer.
`The device can be prepared by sequentially vapor depositing the individual
`layers on a suitable substrate. Substrates such as glass and polymeric films can be
`used. Conventional vapor deposition techniques can be used, such as thermal
`evaporation, chemical vapor deposition, and the like. Alternatively, the organic
`layers can be coated from solutions or dispersions in suitable solvents, using any
`conventional coating technique. In general, the different layers will have the
`following range of thicknesses: anode 110, 500-5000A, preferably 1000-2000A;
`hole transport layer 120, 50-1000A, preferably 200-800A;light-emitting layer
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`130, 10-1000 A, preferably 100-800A;electron transport layer 140, 50-1000A,
`preferably 200-800A; cathode 150, 200-10000A,preferably 300-5000A. The
`location of the electron-hole recombination zone in the device, and thus the
`emission spectrum of the device, can be affected by the relative thickness of each
`layer. Thus the thickness of the electron-transport layer should be chosen so that
`the electron-hole recombination zoneis in the light-emitting layer. The desired
`ratio of layer thicknesses will depend on the exact nature of the materials used.
`Tt is understood thatthe efficiency of devices made with the iridium
`compoundsof the invention, can be further improved by optimizing the other
`layers in the device. For example, more efficient cathodes such as Ca, Ba or LiF
`can be used. Shaped substrates and novel hole transport materials that result in a
`reduction in operating voltage or increase quantum efficiency are also applicable.
`Additional layers can also be addedto tailor the energy levels of the various layers
`and facilitate electroluminescence.
`
`The iridium complexesof the invention often are phosphorescent and
`photoluminescent and may be useful in applications other than OLEDs. For
`example, organometallic complexesof iridium have been used as oxygen
`sensitive indicators, as phosphorescent indicators in bioassays, and as catalysts.
`The bis cyclometalated complexes can be used to sythesize tris cyclometalated
`complexes where the third ligand is the same or different.
`EXAMPLES
`
`The following examplesillustrate certain features and advantages of the
`present invention. They are intendedto beillustrative of the invention, but not
`limiting. All percentages are by weight, unless otherwise indicated.
`EXAMPLE1
`
`This example illustrates the preparation of the 2-phenylpyridines and
`2-phenylpyrimidines whichare used to form the iridium compounds.
`The general procedure used was described in O. Lohse, P. Thevenin,
`E. Waldvogel Synlett, 1999, 45-48. In a typical experiment, a mixture of 200 ml
`of degassed water, 20 g of potassium carbonate, 150 ml of 1,2-dimethoxyethane,
`0.5 g of Pd(PPh3)4, 0.05 mol of a substituted 2-chloropyridine (quinoline or
`pyrimidine) and 0.05 molof a substituted phenylboronic acid was refluxed
`(80-90°C) for 16-30 h. The resulting reaction mixture was diluted with 300 ml of
`water and extracted with CH2Cl5 (2 x 100 ml). The combinedorganic layers
`were dried over MgSOu, and the solvent removed by vacuum. Theliquid
`products were purified by fractional vacuum distillation. The solid materials were
`recrystallized from hexane. The typical purity of isolated materials was >98%.
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`The starting materials, yields, melting and boiling points of the new materials are
`given in Table 3. NMRdata and analytical data are given in Table 4.
`
`TABLE 3
`
`Preparation of 2-Phenyl Pyridines, Phenylpyrimidines and Phenylquinolines
` B.p./ mm Hg (m.p.) in °C
`Compound
`Yield in %
`2-8
`70
`2-a
`72
`2-b
`48
`2-u
`75
`2-C
`41
`2-d
`38
`2-e
`55
`2-g
`86
`2-t
`65
`2-k
`50
`2-m
`80
`2-f£
`22
`2-v
`63
`2-w
`72
`2-X
`35
`2-y
`62
`2-Z
`42
`2-aa
`60
`
`(76-78)
`(95-96)
`(39-40)
`74,5/0.1
`71-73/0.07
`71-78/0.046
`(38-40)
`72-73/0.01
`52-33/0.12
`95-96/13
`
`61-62/0.095
`(68-70)
`66-67/0.06 (58-60)
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`TABLE4
`
`Properties of 2-Phenyl Pyridines, Phenylpyrimidines and Phenylquinolines
`Analysis %, found (calc.)
`or MS (M*)
`19F NMR
`C,64.50
`-62.68
`(64.57)
`1,3.49
`(3.59)
`N,6.07
`(6.28)
`C,59.56
`(59.75)
`13.19
`(2.90)
`N, 5.52
`(5.81)
`C, 53.68
`(53.60)
`H,2.61
`
`Compound
`2-s
`
`2-b
`
`2-d
`
`tH NMR
`7.48(3E),
`7.70(1H),
`7.83(1H),
`7.90(2H),
`8.75(1H)
`
`7.19(1H),
`7.30(1H),
`7.43(11),
`7.98(2H),
`8.07 (1H)
`9.00(1 H)
`7.58(1E),
`7.66(1E),
`7.88(1H),
`8.03(1H),
`8.23(1H),
`8.35 (1H)
`8.99(1H)
`7.55(1H),
`7.63(1),
`7.75(2H),
`7.89(2H),
`8.28(2H),
`8.38(1H),
`8.50 (1H)
`7.53(1H),
`7.64(1H),
`7.90(1H),
`8.18(1H),
`8.30(1H),
`8.53(1H),
`9.43(1H)
`7.06(1E),
`7.48(1H),
`7.81(3H),
`8.0101),
`8.95(1H),
`
`-60.82 (3F,s),
`-116.96 (1F, m)
`
`-62.75 (3F,8),
`-63.10 (3F, s)
`
`-62.89 (s)
`
`~62.14 (Ss)
`
`-62.78 (3F, s),
`-112.61
`
`(1F,m)
`
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`
`C, 53.83 (53.73)
`H, 2.89
`(2.61)
`N,9.99
`(10.44)
`
`C, 59.73
`(59.75)
`12.86
`(2.90)
`N, 5.70
`(5.81)
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`TABLE 4
`
`(continued)
`
`Analysis %, found (calc.)
`
`Compound
`‘HNMR
`19F NMR
`or MS (M*)
`2-e
`3.80(3H)
`-62.63
`C, 61.66
`6.93(2H),
`(s)
`(61.90)
`7.68),
`H, 3.95
`7.85(1H),
`(4.04)
`7.96(2H),
`N, 5.53
`8.82(1H),
`(5.38)
`
`2-g
`
`2-t
`
`2-k
`
`2-m
`
`2-f£
`
`2-V
`
`2.70(3H)
`7.10(3H),
`7.48(1H),
`7.60(1H),
`8.05(2H),
`
`7.1022),
`7.35(2H),
`7.96(1H),
`8.78(1H),
`
`7.08(2H),
`7.62(1H),
`7.90(3H),
`8.80(1H),
`
`7.1022E),
`7.80(2H),
`8.00(1H),
`8.75(1H),
`
`7.55(3H),
`7.77(2H),
`8.06(1H),
`8.87(1H)
`
`3.8(3H),
`6.95(1H),
`7.30(1H),
`7.50(0H),
`7.58(1H),
`7.75(1H),
`7.90(1H),
`8.87(1H)
`
`-114.03
`(m)
`
`-62.73
`(3F,s)
`-113.67
`(1F, m)
`
`-62.75
`(3F,s)
`-111.49
`(m)
`
`-62.63
`(3F,s)
`-111.24
`(m)
`
`-62.57(s)
`
`C, 76.56
`(77.00)
`H,5.12
`(5.30)
`N, 5.43
`(7.50)
`
`C, 50.51
`(52.17)
`H,1.97
`(2.17)
`N, 5.09
`(5.07)
`C, 60.39
`(59.75), H,3.38
`(2.90),
`N, 5.53
`(5.51)
`
`C, 52.13
`(52.17)
`H,2.16
`(2.17)
`N, 4.85
`(5.07)
`257(M*,
`C19H7F3CIN*),
`222(M-Cl)
`
`-62.70 ppm
`
`C, 61.66 (61.37),
`H, 3.98 (3.67),
`N,5.53 (5.48)
`
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`Analysis %, found (calc.)
`or MS (M*)
`
`TABLE 4
`
`(continued)
`
`19F NMR
`-63.08 (3F, s)
`
`-109.70 (1F, m),
`—_-113.35(1F, m).
`
`-62.72 (3F, s),
`-109.11 (2F, m)
`
`-62.80 (3F, s),
`-107.65 (1F, m),
`-112.45(1F, m).
`
`Compound
`2-w
`
`2-x
`
`2-y
`
`2-7
`
`2-aa
`
`4!HNMR
`8.54 (1H,d),
`8.21 (2H,d),
`7.70 (2H,d),
`7.24 (1H, 8),
`6.82 (1H, dd),
`3.91 (3H,s)
`6.9 (2H, m),
`7.18(2H,m),
`7.68 (2H, m),
`7.95(1H, m),
`8.65(1H, m);
`—«6.94(1ED),
`7.62(2H),
`7.82(1H),
`8.03(1H),
`8.96(1H);
`~—«6.85(1H),
`6.93(1H),
`7.80, 7.90,
`8.05(3H),
`8.89(1H);
`
`7.70(3H,m),
`7.85(3H, m),
`7.80, 7.90,
`8.85(1H,m).
`
`EXAMPLE2
`
`5
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`This example illustrates the preparation of iridium compoundsof the
`Fourth Formulafac-Ir(L4)3 above.
`In a typical experiment, a mixture of IrCl3-nH2O (53-55% Ir), AgOCOCF3
`(3.1 equivalents per Ir), 2-arylpyridine (excess), and (optionally) a small amount
`of water was vigorously stirred under N> at 180-195°C (oil bath) for 2-8 hours.
`The resulting mixture was thoroughly extracted with CHCl, until the extracts
`were colorless