AROMATIC COMPOUNDS

Abstract

The present invention relates to aromatic compounds suitable for preparation of asymmetric polydentate ligands. The present invention further describes a process for preparing asymmetric polydentate ligands and metal complexes comprising these ligands which are suitable for use as emitters in organic electroluminescent devices.

Claims

1-14. (canceled)

15. A compound of formula (I): ##STR00388## wherein Z.sup.a, Z.sup.b, and Z.sup.c are the same or different and are Cl, Br, I, B(OR).sub.2, OH, OSO.sub.2R, Si(R).sub.3, or an alkoxy or thioalkoxy group having 1 to 20 carbon atoms; X is the same or different in each instance and is CR or N, or C if one R.sup.a, R.sup.b, or R.sup.c radical binds to X, with the proviso that not more than three X symbols per cycle are N; R, R.sup.a, R.sup.b, and R.sup.c are the same or different at each instance and are H, D, F, Cl, Br, I, N(R.sup.1).sub.2, CN, NO.sub.2, OH, COOH, C(O)N(R.sup.1).sub.2, Si(R.sup.1).sub.3, B(OR.sup.1).sub.2, C(O)R.sup.1, P(O)(R.sup.1).sub.2, S(O)R.sup.1, S(O).sub.2R.sup.1, OSO.sub.2R.sup.1, a straight-chain alkyl, alkoxy, or thioalkoxy group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl, alkoxy, or thioalkoxy group having 3 to 20 carbon atoms, where each alkyl, alkoxy, thioalkoxy, alkenyl or alkynyl group may be substituted by one or more R.sup.1 radicals, wherein one or more nonadjacent CH.sub.2 groups are optionally replaced by R.sup.1CCR.sup.1, CC, Si(R.sup.1).sub.2, CO, NR.sup.1, O, S, or CONR.sup.1, or an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and is optionally substituted in each case by one or more R.sup.1 radicals, or an aryloxy or heteroaryloxy group which has 5 to 40 aromatic ring atoms and is optionally substituted by one or more R.sup.1; and wherein two R radicals together or together with one of the R.sup.a, R.sup.b, or R.sup.c radicals optionally defines a ring system; R.sup.1 is the same or different in each instance and is H, D, F, Cl, Br, I, N(R.sup.2).sub.2, CN, NO.sub.2, Si(R.sup.2).sub.3, B(OR.sup.2).sub.2, C(O)R.sup.2, P(O)(R.sup.2).sub.2, S(O)R.sup.2, S(O).sub.2R.sup.2, OSO.sub.2R.sup.2, a straight-chain alkyl, alkoxy, or thioalkoxy group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl, alkoxy, or thioalkoxy group having 3 to 20 carbon atoms, where each alkyl, alkoxy, thioalkoxy, alkenyl, or alkynyl group is optionally substituted by one or more R.sup.2 radicals, wherein one or more nonadjacent CH.sub.2 groups are optionally replaced by R.sup.2CCR.sup.2, CC, Si(R.sup.2).sub.2, CO, NR.sup.2, O, S, or CONR.sup.2, or an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and is optionally substituted in each case by one or more R.sup.2 radicals, or an aryloxy or heteroaryloxy group which has 5 to 40 aromatic ring atoms and is optionally substituted by one or more R.sup.2 radicals, or an aralkyl or heteroaralkyl group which has 5 to 40 aromatic ring atoms and is optionally substituted by one or more R.sup.2 radicals, or a diarylamino group, diheteroarylamino group, or arylheteroarylamino group which has 10 to 40 aromatic ring atoms and is optionally substituted by one or more R.sup.2 radicals; and wherein two or more R.sup.1 radicals together optionally define a ring system; and R.sup.2 is the same or different in each instance and is H, D, F, or an aliphatic, aromatic, and/or heteroaromatic organic radical having 1 to 20 carbon atoms, wherein one or more hydrogen atoms is optionally replaced by F; and wherein two or more R.sup.2 radicals together optionally define a ring system; and wherein the compound of formula (I) does not have C.sub.3 symmetry.

16. The compound of claim 15, wherein the Z.sup.a group is not the same as the Z.sup.b or Z.sup.c group.

17. The compound of claim 15, wherein the R.sup.a group is not the same as the R.sup.b or R.sup.c group.

18. The compound of claim 15, wherein the compound is a compound of formula (II): ##STR00389## wherein n is 0, 1, 2 or 3.

19. The compound of claim 15, wherein the compound is a compound of formula (III): ##STR00390## wherein n is the same or different in each instance and is 0, 1, 2. or 3.

20. The compound of claim 15, wherein the compound is a compound of formula (IV): ##STR00391## wherein n is the same or different in each instance and is 0, 1, 2, or 3.

21. The compound of claim 15, wherein the Z.sup.a is not the same as the Z.sup.b group and the Z.sup.b group is not the same as the Z.sup.c group.

22. The compound of claim 15, wherein the Z.sup.a group is the same as the Z.sup.b group and the Z.sup.b group is the same as the Z.sup.c group.

23. The compound of claim 22, wherein the R.sup.a group is not the same as the R.sup.b group and the R.sup.c group, and the R.sup.b group is not the same as the R.sup.c group.

24. The compound of claim 15, wherein at least one of the R.sup.a, R.sup.b, and R.sup.c groups is selected from a straight-chain alkyl, alkoxy, or thioalkoxy group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 20 carbon atoms, wherein each alkyl, alkoxy, thioalkoxy, alkenyl, or alkynyl group is optionally substituted by one or more R.sup.1 radicals, wherein one or more nonadjacent CH.sub.2 groups is optionally replaced by R.sup.1CCR.sup.1, CC, Si(R.sup.1).sub.2, CO, NR.sup.1, O, S, or CONR.sup.1, or an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and is optionally substituted in each case by one or more R.sup.1 radicals, or an aryloxy or heteroaryloxy group having 5 to 40 aromatic ring atoms.

25. A process for preparing a polypodal ligand, comprising reacting a compound of claim 15 in a first step with a first reactive ligand in a coupling reaction to form product, reacting the product in a second step with a second reactive ligand in a coupling reaction, wherein the first and second reactive ligands are different, such that a bridge corresponding to the compound of claim 15 without the Z.sup.a, Z.sup.b, and Z.sup.c groups is formed between a sub-ligand derived from the first reactive ligand and a sub-ligand derived from the second reactive ligand.

26. The process of claim 25, further comprising reacting the product obtained in the second step in a third step with a further reactive ligand in a coupling reaction, wherein the first, second and third reactive ligands are different.

27. The process of claim 25, wherein at least one of the reactive ligands is a bidentate ligand of formula (L-1), (L-2), or (L-3): ##STR00392## wherein CyC is the same or different in each instance and is an optionally substituted aryl or heteroaryl group which has 5 to 14 aromatic ring atoms and can coordinate in each case to a metal via a carbon atom and which is bonded in each case to CyD via a covalent bond; the optional substituents here are preferably selected from R; CyD is the same or different in each instance and is an optionally substituted heteroaryl group which has 5 to 14 aromatic ring atoms and can coordinate to a metal via a nitrogen atom or via a carbene carbon atom and which is bonded to CyC via a covalent bond; and Z.sup.d is a reactive group.

28. The compound of claim 15, wherein R.sup.2 is a hydrocarbyl radical.

29. The compound of claim 19, wherein n is 0 or 1.

30. The compound of claim 24, wherein at least one of the R.sup.a, R.sup.b, and R.sup.c groups is selected from a straight-chain alkyl, alkoxy, or thioalkoxy group having 1 to 10 carbon atoms or an alkenyl or alkynyl group having 2 to 10 carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 10 carbon atoms, wherein each alkyl, alkoxy, thioalkoxy, alkenyl, or alkynyl group is optionally substituted by one or more R.sup.1 radicals, wherein one or more nonadjacent CH.sub.2 groups is optionally replaced by R.sup.1CCR.sup.1, CC, Si(R.sup.1).sub.2, CO, NR.sup.1, O, S, or CONR.sup.1.

31. The process of claim 25, wherein CyC and CyD are optionally substituted with one or more radicals R.

32. The process of claim 25, wherein Z.sup.d is selected from the group consisting of Cl, Br, I, B(OR).sub.2, OH, OSO.sub.2R, or an alkoxy or thioalkoxy group having 1 to 20 carbon atoms.

Description

EXAMPLES

[0160] The syntheses which follow, unless stated otherwise, are conducted under a protective gas atmosphere in dried solvents. The solvents and reagents can be purchased, for example, from Sigma-ALDRICH or ABCR. The respective figures in square brackets or the numbers quoted for individual compounds relate to the CAS numbers of the compounds known from the literature.

Synthesis of the Synthons S and of the Inventive Compounds P

Step 1

Example S1

[0161] ##STR00048##

[0162] To a well-stirred solution, cooled to 15 C., of 5.0 g (125 mmol) of NaOH in a mixture of 50 ml of water and 30 ml of ethanol are added 19.8 g (100 mmol) of 2-bromoacetophenone [2142-69-0] and then 18.5 g (100 mmol) of 2-bromobenzaldehyde [6030-33-7]. The reaction mixture is allowed to warm up to room temperature and stirred for a further 24 h. The reaction mixture is then cooled down to about 10 C. in an ice/salt bath, and a viscous yellow oil separates out. The supernatant solvent is decanted off, the oil is taken up in 300 ml of dichloromethane (DCM), and the organic phase is washed three times with 100 ml each time of water and once with 100 ml of saturated sodium chloride solution and then dried over magnesium sulfate. After the solvent has been removed under reduced pressure, a viscous oil is obtained, which crystallizes when left to stand. Yield: 34.8 g (95 mmol), 95%; purity: about 97% by .sup.1H NMR.

[0163] In an analogous manner, it is possible to prepare the following compounds:

TABLE-US-00001 Product Ex. Reactants Solvent added to the reaction Yield S2 [00049] [00050] 95% S3 [00051] [00052] 95% S4 [00053] [00054] 90% S5 [00055] [00056] 96% S6 [00057] [00058] 95% S7 [00059] [00060] 93% S8 [00061] [00062] 83% S9 [00063] [00064] 94% S10 [00065] [00066] 92% S11 [00067] [00068] 95% S12 [00069] [00070] 97% S13 [00071] [00072] 95% S14 [00073] [00074] 78% S15 [00075] [00076] 93% S16 [00077] [00078] 90% S17 [00079] [00080] 89% S18 [00081] [00082] 94% S19 [00083] [00084] 81% S20 [00085] [00086] 98% S21 [00087] [00088] 96% S22 [00089] [00090] 93% S23 [00091] [00092] 86% S24 [00093] [00094] 95% S25 [00095] [00096] 95% S26 [00097] [00098] 90% S27 [00099] [00100] 92% S28 [00101] [00102] 88% S29 [00103] [00104] 98% S30 [00105] [00106] 96% S31 [00107] [00108] 94% S32 [00109] [00110] 90% S33 [00111] [00112] 95% S34 [00113] [00114] 76% S35 [00115] [00116] 91% S36 [00117] [00118] 88% S37 [00119] [00120] 67%

Step 2

Example S100

[0164] ##STR00121##

[0165] To a solution of 36.6 g (100 mmol) of S1 in 100 ml of acetone are added 5.7 g (105 mmol) of sodium methoxide, and the mixture is stirred at 50 C. for 2 h. After the acetone has been removed under reduced pressure, the residue is taken up in 300 ml of ethyl acetate, washed twice with 100 ml each time of water and once with 100 ml of saturated sodium chloride solution, and dried over magnesium sulfate. After the solvent has been removed under reduced pressure, a viscous oil is obtained. Yield: 39.4 g (97 mmol), 97%; purity: about 97% by .sup.1H NMR.

[0166] In an analogous manner, it is possible to prepare the following compounds:

TABLE-US-00002 Ex. Reactants Products Yield S101 S2 [00122] 95% S102 S3 [00123] 96% S103 S4 [00124] 90% S104 S5 [00125] 94% S105 S6 [00126] 95% S106 S7 [00127] 95% S107 S8 [00128] 92% S108 S9 [00129] 97% S109 S10 [00130] 94% S110 S11 [00131] 95% S111 S12 [00132] 95% S112 S13 [00133] 96% S113 S14 [00134] 89% S114 S15 [00135] 92% S115 S16 [00136] 95% S116 S17 [00137] 93% S117 S18 [00138] 94% S118 S19 [00139] 96% S119 S20 [00140] 95% S120 S21 [00141] 95% S121 S22 [00142] 94% S122 S23 [00143] 95% S123 S24 [00144] 96% S124 S25 [00145] 93% S125 S26 [00146] 96% S126 S27 [00147] 89% S127 S28 [00148] 84% S128 S29 [00149] 90% S129 S30 [00150] 95% S130 S31 [00151] 97% S131 S32 [00152] 95% S132 S33 [00153] 93% S133 S34 [00154] 89% S134 S35 [00155] 77% S135 S36 [00156] 73% S136 S37 [00157] 67% S137 [00158] [00159] 73% S138 [00160] [00161] 84% S139 [00162] [00163] 57%

Step 3

Example S200

[0167] ##STR00164##

[0168] 19.2 g (100 mmol) of 1-bromo-2-chlorobenzene and 2.4 g (100 mmol) of magnesium turnings, with activation of the magnesium turnings with a small grain of iodine, are used to prepare a 1 molar ethereal 2-chlorophenylmagnesium bromide solution. After the Grignard solution has been cooled to 5 C., a solution of 50 mmol of S100 in 150 ml of toluene is added dropwise thereto. The mixture is stirred for a further 3 h and then the reaction mixture is poured onto 500 g of ice. The organic phase is removed, and the aqueous phase is acidified with conc. HCl and extracted once with 100 ml of toluene. The combined organic phases are dried over magnesium sulfate, then the solvent is removed under reduced pressure and the oily residue is digested with n-heptane. The precipitated solids are filtered off with suction, washed with 30 ml of cold n-heptane and dried under reduced pressure. Yield: 14.0 g (27 mmol), 54%; purity: about 90-95% by .sup.1H NMR.

[0169] In an analogous manner, it is possible to prepare the following compounds:

TABLE-US-00003 Ex. Reactants Products Yield S201 S101 [00165] 48% S202 S102 [00166] 63% S203 S103 [00167] 67% S204 S104 [00168] 56% S205 S105 [00169] 58% S206 S106 [00170] 55% S207 S107 [00171] 57% S208 S108 [00172] 60% S209 S109 [00173] 63% S210 S110 [00174] 60% S211 S111 [00175] 64% S212 S112 [00176] 62% S213 S113 [00177] 59% S214 S114 [00178] 60% S215 S115 [00179] 58% S216 S116 [00180] 55% S217 S117 [00181] 57% S218 S118 [00182] 62% S219 S119 [00183] 60% S220 S120 [00184] 53% S221 S121 [00185] 48% S222 S122 [00186] 52% S223 S123 [00187] 55% S224 S124 [00188] 57% S225 S125 [00189] 56% S226 S126 [00190] 60% S227 S127 [00191] 60% S228 S128 [00192] 39% S229 S129 [00193] 56% S230 S130 [00194] 58% S231 S131 [00195] 60% S232 S132 [00196] 63% S233 S133 [00197] 47% S234 S134 [00198] 43% S235 S135 [00199] 49% S236 S136 [00200] 50% S237 S137 [00201] 33% S238 S138 [00202] 28% S239 S139 [00203] 19% S240 [00204] [00205] 63% S241 [00206] [00207] 60% S242 [00208] [00209] 59% S243 [00210] [00211] 54%

Step 4

Example P1

[0170] ##STR00212##

[0171] A solution of 10.4 g (20 mmol) of S200 and 500 mg of p-toluenesulfonic acid in 200 ml of chlorobenzene is heated on a water separator for 2 h, removing the water formed. The reaction mixture is cooled down to room temperature, 8.7 g (100 mmol) of manganese(IV) oxide and 100 g of glass beads (diameter 3 mm) are added, and the mixture is heated again on a water separator with good stirring for 4 h. After being cooled down to about 60 C., the reaction mixture is filtered through Celite, the Celite is washed through with 100 ml of chlorobenzene, and the filtrate is concentrated to dryness under reduced pressure. The residue is chromatographed on silica gel (n-heptane:EA, 9:1 vv) and finally recrystallized from methanol. Yield: 7.0 g (14 mmol), 70%; purity: 99% by .sup.1H NMR.

[0172] Rather than manganese(IV) oxide, it is also possible to use 25 mmol of DDQ (variant B).

[0173] In an analogous manner, it is possible to prepare the following compounds:

TABLE-US-00004 Ex. Reactants Products Yield P2 S201 [00213] 66% P3 S202 [00214] 73% P4 S203 [00215] 65% P5 S204 Variant B [00216] 70% P6 S205 Variant B [00217] 72% P7 S206 Variant B [00218] 68% P8 S207 Variant B [00219] 70% P9 S208 [00220] 69% P10 S209 [00221] 73% P11 S210 [00222] 72% P12 S211 [00223] 67% P13 S212 [00224] 69% P14 S213 [00225] 58% P15 S214 [00226] 71% P16 S215 [00227] 66% P17 S216 [00228] 68% P18 S217 [00229] 63% P19 S218 Variant B [00230] 65% P20 S219 [00231] 74% P21 S220 [00232] 75% P22 S221 [00233] 72% P23 S222 [00234] 70% P24 S223 Variant B [00235] 68% P25 S224 [00236] 63% P26 S225 [00237] 58% P27 S226 [00238] 65% P28 S227 [00239] 67% P29 S228 [00240] 54% P30 S229 Variant B [00241] 70% P31 S230 Variant B [00242] 66% P32 S231 Variant B [00243] 63% P33 S232 Variant B [00244] 69% P34 S233 Variant B [00245] 65% P35 S234 [00246] 64% P36 S235 [00247] 65% P37 S236 Variant B [00248] 63% P38 S237 Variant B [00249] 68% P39 S238 Variant B [00250] 69% P40 S239 Variant B [00251] 67% P41 S240 Variant B [00252] 65% P42 S241 Variant B [00253] 69% P43 S242 Variant B [00254] 65% P44 S243 Variant B [00255] 68%

Synthesis of the Ligands

Example Ligand L1

[0174] ##STR00256##

Step 1, L1 Intermediate

[0175] ##STR00257##

[0176] A mixture of 5.0 g (10 mmol) of P1, 5.9 g (21 mmol) of 2-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]pyridine [908350-80-1], 6.4 g (60 mmol) of sodium carbonate, 347 mg (0.3 mmol) of tetrakis(triphenylphosphino)palladium(0), 60 ml of toluene, 15 ml of ethanol and 30 ml of water is heated under reflux with good stirring for 18 h. After cooling, the organic phase is extended with 100 ml of ethyl acetate, removed, washed three times with 50 ml each time of water and once with 100 ml of saturated sodium chloride solution, and dried over magnesium sulfate. The mixture is filtered through a silica gel bed in the form of an ethyl acetate slurry, which is washed through with a little ethyl acetate, the solvent is removed under reduced pressure and the oily residue is recrystallized twice from about 30 ml of acetonitrile with addition of a little ethyl acetate. Yield: 5.2 g (8 mmol), 80%. Purity: about 98% by .sup.1H NMR.

Step 2, Ligand L1

[0177] A mixture of 5.2 g (8 mmol) of L1 intermediate, 2.5 g (9 mmol) of [4-(4-phenyl-2-pyridinyl)phenyl]boronic acid [1714084-80-6], 4.3 g (20 mmol) of tripotassium phosphate, 82 mg (0.2 mmol) of SPhos [657408-07-6], 34 mg (0.15 mmol) of palladium(II) acetate, 50 ml of toluene, 10 ml of dioxane and 40 ml of water is heated under reflux with good stirring for 18 h. After cooling, the organic phase is extended with 100 ml of ethyl acetate, removed, washed three times with 50 ml each time of water and once with 100 ml of saturated sodium chloride solution, and dried over magnesium sulfate. The mixture is filtered through a silica gel bed in the form of an ethyl acetate slurry, which is washed through with a little ethyl acetate, the solvent is removed under reduced pressure and the oily residue is recrystallized twice from about 30 ml of acetonitrile with addition of a little ethyl acetate. Yield: 5.1 g (6 mmol), 75%. Purity: about 98% by .sup.1H NMR.

[0178] In an analogous manner, the unit shown can be used to prepare the ligands which follow in comparable yields. The intermediates and end products can also be purified by chromatographypreferably using an automatic column system, for example from A. Semrauor by fractional sublimation:

TABLE-US-00005 Triaryl- Boronic ben- acid/ester 1 Boronic Ex. zene Step 1 acid/ester 2 Step 2 Product L2 P1 [00258] [00259] [00260] L3 P8 [00261] [00262] [00263] L4 P15 [00264] [00265] [00266] L5 P35 [00267] [00268] [00269] L6 P1 [00270] [00271] [00272] L7 P1 [00273] [00274] [00275] L8 P1 [00276] [00277] [00278] L9 P1 [00279] [00280] [00281] L10 P1 [00282] [00283] [00284] L11 P1 [00285] [00286] [00287]

Example Ligand L100

[0179] ##STR00288##

Step 1, L100 Intermediate 1

[0180] ##STR00289##

[0181] A mixture of 5.5 g (10 mmol) of P2, 3.1 g (10 mmol) of 2-[4-(4,4,5,5-tetramethyl-1,3.2-dioxaborolan-2-yl)phenyl]pyridine [908350-80-1], 3.2 g (10 mmol) of tetra-n-butylammonium bromide, 2.8 g (20 mmol) of potassium carbonate, 231 mg (0.2 mmol) of tetrakis(triphenylphosphino)palladium(0), 30 ml of toluene and 30 ml of water is heated under reflux with good stirring for 18 h. After cooling, the organic phase is extended with 100 ml of ethyl acetate, removed, washed three times with 50 ml each time of water and once with 100 ml of saturated sodium chloride solution, and dried over magnesium sulfate. The mixture is filtered through a silica gel bed in the form of an ethyl acetate slurry, which is washed through with a little ethyl acetate, the solvent is removed under reduced pressure and the oily residue is recrystallized twice from about 30 ml of acetonitrile with addition of a little ethyl acetate. Yield: 5.2 g (8 mmol), 80%. Purity: about 98% by .sup.1H NMR.

Step 2, L100 Intermediate 2

[0182] ##STR00290##

[0183] A mixture of 5.2 g (8 mmol) of L100 intermediate 1, 2.7 g (8 mmol) of 4-tert-butyl-2-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]pyridine [1989596-74-8], 3.2 g (30 mmol) of sodium carbonate, 173 mg (0.15 mmol) of tetrakis(triphenylphosphino)palladium(0), 60 ml of toluene, 15 ml of ethanol and 30 ml of water is heated under reflux with good stirring for 18 h. After cooling, the organic phase is extended with 100 ml of ethyl acetate, removed, washed three times with 50 ml each time of water and once with 100 ml of saturated sodium chloride solution, and dried over magnesium sulfate. The mixture is filtered through a silica gel bed in the form of an ethyl acetate slurry, which is washed through with a little ethyl acetate, the solvent is removed under reduced pressure and the oily residue is recrystallized twice from about 20 ml of acetonitrile with addition of a little ethyl acetate. Yield: 4.2 g (6 mmol), 75%. Purity: about 98% by .sup.1H NMR.

Step 3, Ligand L100

[0184] A mixture of 4.2 g (6 mmol) of L100 intermediate 2, 2.0 g (7 mmol) of [4-(4-phenyl-2-pyridinyl)phenyl]boronic acid [1714084-80-6], 3.2 g (15 mmol) of tripotassium phosphate, 82 mg (0.2 mmol) of SPhos [657408-07-6], 34 mg (0.15 mmol) of palladium(II) acetate, 50 ml of toluene, 10 ml of dioxane and 40 ml of water is heated under reflux with good stirring for 18 h. After cooling, the organic phase is extended with 100 ml of ethyl acetate, removed, washed three times with 50 ml each time of water and once with 100 ml of saturated sodium chloride solution, and dried over magnesium sulfate. The mixture is filtered through a silica gel bed in the form of an ethyl acetate slurry, which is washed through with a little ethyl acetate, the solvent is removed under reduced pressure and the oily residue is recrystallized twice from about 25 ml of acetonitrile with addition of a little ethyl acetate. Yield: 4.5 g (5 mmol), 85%. Purity: about 98% by .sup.1H NMR.

[0185] In an analogous manner, P2 and the units shown can be used to prepare the ligands which follow in comparable yields. The intermediates and end products can also be purified by chromatographypreferably using an automatic column system, for example from A. Semrauor by fractional sublimation:

TABLE-US-00006 Boronic Boronic Boronic acid/ester 1 acid/ester 2 acid/ester 3 Ex. Step 1 Step 2 Step 3 Product L101 [00291] [00292] [00293] [00294] L102 [00295] [00296] [00297] [00298] L103 [00299] [00300] [00301] [00302] L104 [00303] [00304] [00305] [00306] L105 [00307] [00308] [00309] [00310] L106 [00311] [00312] [00313] [00314] L107 [00315] [00316] [00317] [00318] L108 [00319] [00320] [00321] [00322] L109 [00323] [00324] [00325] [00326] L110 [00327] [00328] [00329] [00330] L111 [00331] [00332] [00333] [00334]

Synthesis of the Metal Complexes

[0186] The complexes which follow can be prepared with the ligands obtained in accordance with the invention by the processes described in WO 2016/124304. The yields after purification by repeated hot extraction and fractional sublimation are in the range of 30-70%, with a purity by HPLC of 99.8%

TABLE-US-00007 Ex. Ligand Metal complex IrL1 L1 [00335] IrL2 L2 [00336] IrL3 L3 [00337] IrL4 L4 [00338] IrL5 L5 [00339] IrL6 L6 [00340] IrL7 L7 [00341] IrL8 L8 [00342] IrL9 L9 [00343] IrL10 L10 [00344] IrL11 L11 [00345] IrL100 L100 [00346] IrL101 L101 [00347] IrL102 L102 [00348] IrL103 L103 [00349] IrL104 L104 [00350] IrL105 L105 [00351] IrL106 L106 [00352] IrL107 L107 [00353] IrL108 L108 [00354] IrL109 L109 [00355] IrL110 L110 [00356] IrL111 L111 [00357]

[0187] In an analogous manner, it is possible to prepare the metal complexes which follow from the corresponding ligands, which can be prepared by the process detailed above:

##STR00358## ##STR00359## ##STR00360## ##STR00361## ##STR00362## ##STR00363## ##STR00364## ##STR00365## ##STR00366## ##STR00367## ##STR00368## ##STR00369## ##STR00370## ##STR00371## ##STR00372## ##STR00373## ##STR00374## ##STR00375## ##STR00376## ##STR00377## ##STR00378## ##STR00379## ##STR00380## ##STR00381## ##STR00382## ##STR00383## ##STR00384## ##STR00385## ##STR00386## ##STR00387##

[0188] The above-described Ir complexes can be used as triplet emitters (triplet dopants, phosphorescent dopants) in organic electronic devices, especially in organic light-emitting devices (OLEDs). The exact use of the Ir complexes and the exact construction of the OLEDs of this kind is disclosed in WO 2016/124304 using structurally similar compounds. The Ir complexes depicted above emit light in the green, yellow to red spectral region (about 500-650 nm) with good to very good external quantum efficiencies EQE (about 18%-30% EQE) with a long component lifetime LT (LT50@1000 cd/m.sup.2 typically >>500 000 h).