Phosphorescent metal complex compound radiation emitting component comprising a phosphorescent metal complex compound and method for production of a phosphorescent metal complex compound

Abstract

A phosphorescent metal complex is provided, which comprises a metallic central atom M and at least one ligand coordinated by the metallic central atom M, wherein the one metallic central atom M and the ligand form a six-membered metallacyclic ring. Additionally specified are a radiation-emitting component comprising a metal complex, and a process for preparing the metal complex.

Claims

1. A phosphorescent polynuclear metal complex which comprises at least two metallic central atoms M, that are bonded to one another via at least one bridging bidentate ligand that coordinates by one bonding atom to one central atom and another bonding atom to another central atom, and at least one ligand coordinated by one metallic central atom M, wherein the at least one bridging bidentate ligand is 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine, wherein one of the metallic central atoms M and the ligand form a six-membered metallacyclic ring, wherein the ligand which forms a six-membered metallacyclic ring with the metallic central atom has a tautomerizable unit in the uncoordinated state, wherein the metallic central atom M is selected from a group consisting of Ir, Pt, Au, Re, Rh, Ru, Os, Pd, Ag, Zn, Al and lanthanoids, and wherein the six-membered metallacyclic ring has the structural formula: ##STR00050## where: n=1 to 3, Y=CH, N, P, As, Sb, CR.sub.y, SiR.sub.y, GeR.sub.y, X=N, O, P, As, Sb, R.sub.1, R.sub.2, R.sub.y, R.sub.4 and R.sub.5 are each independently H, unbranched alkyl radicals, branched alkyl radicals, fused alkyl radicals, cyclic alkyl radicals, fully or partly substituted unbranched alkyl radicals, fully or partly substituted branched alkyl radicals, fully or partly substituted fused alkyl radicals, fully or partly substituted cyclic alkyl radicals, alkoxy groups, amines, amides, esters, carbonates, aromatics, fully or partly substituted aromatics, fused aromatics, fully or partly substituted fused aromatics, heterocycles, fully or partly substituted heterocycles, fused heterocycles, fully or partly substituted heterocycles, F and CN, and R.sub.1 and R.sub.5 include a free electron pair when X is O.

2. The complex of claim 1, wherein R.sub.1 and/or R.sub.5 is additionally coordinated to M.

3. The complex of claim 1, wherein at least one of R.sub.1 and R.sub.2, R.sub.2 and R.sub.y, R.sub.y and R.sub.4, R.sub.4 and R.sub.5 are bridged to one another.

4. The complex of claim 3, wherein the six-membered metallacyclic ring has a structural formula selected from a group consisting of compounds of the following structural formula: ##STR00051## where: n=1 to 3, Y=CH, N, P, As, Sb, CR.sub.y, SiR.sub.y, GeR.sub.y, X=N, O, P, As, Sb, X.sub.1, X.sub.2, X.sub.3, X.sub.4, X.sub.5, X.sub.6, X.sub.7 and X.sub.8 are each independently C or, when R.sub.11, R.sub.12, R.sub.3, R.sub.14, R.sub.15, R.sub.6, R.sub.7 or R.sub.8 includes a free electron pair, N, and R.sub.y, R.sub.11, R.sub.12, R.sub.3, R.sub.14, R.sub.15, R.sub.6, R.sub.7 and R.sub.8 are each independently H, unbranched alkyl radicals, branched alkyl radicals, fused alkyl radicals, cyclic alkyl radicals, fully or partly substituted unbranched alkyl radicals, fully or partly substituted branched alkyl radicals, fully or partly substituted fused alkyl radicals, fully or partly substituted cyclic alkyl radicals, alkoxy groups, amines, amides, esters, carbonates, aromatics, fully or partly substituted aromatics, fused aromatics, fully or partly substituted fused aromatics, heterocycles, fully or partly substituted heterocycles, fused heterocycles, fully or partly substituted heterocycles, F and CN.

5. The complex of claim 4, wherein X.sub.1X.sub.5, R.sub.11R.sub.15, X.sub.2X.sub.6, R.sub.12R.sub.6, X.sub.3X.sub.7, R.sub.3R.sub.7, X.sub.4X.sub.8 and R.sub.14R.sub.8.

6. The complex of claim 4, wherein at least one of R.sub.11 and R.sub.12, R.sub.12 and R.sub.3, R.sub.3 and R.sub.14, R.sub.14 and R.sub.y, R.sub.y and R.sub.8, R.sub.15 and R.sub.6, R.sub.6 and R.sub.7 or R.sub.7 and R.sub.8 are bridged to one another.

7. The complex of claim 3, wherein the six-membered metallacyclic ring has a structural formula selected from a group consisting of compounds of the following structural formula: ##STR00052## where: n=1 to 3, Y=CH, N, P, As, Sb, CR.sub.y, SiR.sub.y, GeR.sub.y, X=N, O, P, As, Sb, X.sub.1, X.sub.2, X.sub.5 and X.sub.6 are each independently C or, when R.sub.11, R.sub.12, R.sub.15 or R.sub.6 includes a free electron pair, N, X.sub.3 and X.sub.7 are each S, and R.sub.y, R.sub.11, R.sub.12, R.sub.15 and R.sub.6 are each independently H, unbranched alkyl radicals, branched alkyl radicals, fused alkyl radicals, cyclic alkyl radicals, fully or partly substituted unbranched alkyl radicals, fully or partly substituted branched alkyl radicals, fully or partly substituted fused alkyl radicals, fully or partly substituted cyclic alkyl radicals, alkoxy groups, amines, amides, esters, carbonates, aromatics, fully or partly substituted aromatics, fused aromatics, fully or partly substituted fused aromatics, heterocycles, fully or partly substituted heterocycles, fused heterocycles, fully or partly substituted heterocycles, F and CN.

8. The complex of claim 7, wherein X.sub.1X.sub.5, R.sub.11R.sub.15, X.sub.2X.sub.6, R.sub.12R.sub.6, and X.sub.3X.sub.7.

9. The complex of claim 7, wherein R.sub.11 and R.sub.12 and/or R.sub.15 and R.sub.6 are bridged to one another.

10. The complex of claim 3, wherein the six-membered metallacyclic ring has a structural formula selected from a group consisting of compounds of the following structural formula: ##STR00053## where: n=1 to 3, Y=CH, N, P, As, Sb, CR.sub.y, SiR.sub.y, GeR.sub.y, X.sub.1, X.sub.2, X.sub.3 and X.sub.4 are each independently CR or N, and R.sub.y and R are each independently H, unbranched alkyl radicals, branched alkyl radicals, fused alkyl radicals, cyclic alkyl radicals, fully or partly substituted unbranched alkyl radicals, fully or partly substituted branched alkyl radicals, fully or partly substituted fused alkyl radicals, fully or partly substituted cyclic alkyl radicals, alkoxy groups, amines, amides, esters, carbonates, aromatics, fully or partly substituted aromatics, fused aromatics, fully or partly substituted fused aromatics, heterocycles, fully or partly substituted heterocycles, fused heterocycles, fully or partly substituted heterocycles, F and CN.

11. The complex of claim 1, wherein the tautomerizable unit has a structural unit which is selected from C(H,R.sub.y) or N(H), and connects an electron-deficient and an electron-rich aromatic.

12. The complex of claim 1, wherein the six-membered metallacyclic ring has a structural formula selected from a group consisting of compounds of the following structural formula: ##STR00054## where: n=1 to 3, Y=CH, N, P, As, Sb, CR.sub.y, SiR.sub.y, or GeR.sub.y, X and X are each independently N, O, P, As or Sb, R.sub.1, R.sub.2, R.sub.4, R.sub.y, R.sub.5 are each independently selected from H, unbranched alkyl radicals, branched alkyl radicals, fused alkyl radicals, cyclic alkyl radicals, fully or partly substituted unbranched alkyl radicals, fully or partly substituted branched alkyl radicals, fully or partly substituted fused alkyl radicals, fully or partly substituted cyclic alkyl radicals, alkoxy groups, amines, amides, esters, carbonates, aromatics, fully or partly substituted aromatics, fused aromatics, fully or partly substituted fused aromatics, heterocycles, fully or partly substituted heterocycles, fused heterocycles, fully or partly substituted heterocycles, F and CN, and R.sub.1 together with R.sub.2 and XC, and R.sub.4 together with R.sub.5 and XC, form at least one aromatic ring each.

13. The complex of claim 12, wherein one of the aromatic rings formed with R.sub.5 and R.sub.4 and R.sub.1 and R.sub.2 is electron-rich, and the other aromatic ring is electron-deficient.

14. The complex of claim 12, wherein Y is CR.sub.y, SiR.sub.y, or GeR.sub.y, and wherein R.sub.4 and R.sub.y and/or R.sub.y and R.sub.2 are bridged.

15. A radiation-emitting component comprising: a substrate; a first electrode layer on the substrate; at least one organic emitting layer on the first electrode layer; and a second electrode layer on the organic emitting layer, wherein the organic emitting layer comprises a phosphorescent metal complex of claim 1.

16. The component of claim 15, wherein the phosphorescent metal complex is present in a matrix material.

17. The component of claim 15, which on application of a voltage emits light of a color selected from a group consisting of deep blue, light blue, blue-green and green.

18. The component of claim 15, wherein the substrate and the first electrode layer are transparent.

Description

BRIEF DESCRIPTION OF TUE DRAWINGS

(1) FIG. 1 shows the schematic side view of a radiation-emitting component.

(2) FIG. 2 shows a photoluminescence spectrum of a metal complex compared to a conventional metal complex.

(3) FIGS. 3a to j show photoluminescence spectra for various metal complexes.

(4) FIG. 4 shows a) the absorption spectrum and b) the photoluminescence emission spectrum of tris(dipyridylimine)iridium(III).

(5) FIG. 5 shows a) the absorption spectrum and b) the photoluminescence emission spectrum of tris(di-1,2,4-benzotriazin-3-ylmethine)iridium(III).

DETAILED DESCRIPTION OF THE DRAWINGS

(6) Examples of compounds which have a carbine ligand are shown in formula 24. For all compounds shown here, for example, M may be Ir when n=3. When n=2 and M=Lr, an additional ligand, for example a picolinate anion, phenylpyridine and 2-phenylimidazole, is then also present. Analogously, when n=1 and M=Ir, two additional ligands are also present.

(7) ##STR00029## ##STR00030##

(8) Examples of compounds which have a ligand with one electron-deficient and one electron-rich aromatic ring are shown in formula 25. The central atom here is Ir; further central atoms are equally suitable.

(9) ##STR00031## ##STR00032##

(10) Examples of compounds which are binuclear are given hereinafter.

(11) Formula 26 shows examples of a binuclear compound with Pt as central atoms and 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine (a) and pyrazole (b) as bridging ligands, where, for R, substituents according to the statements made above are selected from H, unbranched alkyl radicals, branched alkyl radicals, fused alkyl radicals, cyclic alkyl radicals, fully or partly substituted unbranched alkyl radicals, fully or partly substituted branched alkyl radicals, fully or partly substituted fused alkyl radicals, fully or partly substituted cyclic alkyl radicals, alkoxy groups, amines, amides, esters, carbonates, aromatics, fully or partly substituted aromatics, fused aromatics, fully or partly substituted fused aromatics, heterocycles, fully or partly substituted heterocycles, fused heterocycles, fully or partly substituted heterocycles, F and CN.

(12) ##STR00033##

(13) Formula 27 shows examples of compounds with Ir as central atoms, 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine (a) and pyrazole (b) as bridging ligands, where either two bridging ligands and two ligands on each Ir, or four bridging ligands and one ligand on each Ir, may be present. R may be selected analogously to formula 26.

(14) ##STR00034## ##STR00035##

(15) The structural formulae shown in the formulae 26a and 27a may also have NCN units as bridging ligands, which are integrated into a five-membered, six-membered or seven-membered ring, or which are substituted without ring formation.

(16) FIG. 1 shows the schematic side view of a radiation-emitting component. On a substrate 1, which is made of glass, for example, is arranged a first electrode layer 2 which is, for example, transparent and made of ITO (indium tin oxide). On this electrode layer 2 is arranged a hole injection layer 3, on which in turn is arranged a hole transport layer 4. On the hole transport layer 4 is arranged an organic active layer, the organic emitting layer 5, on which are arranged a hole blocking layer 6, an electron transport layer 7 and an electron injection layer 8. On the electron injection layer 8 is arranged a second electrode layer 9, for example a metal electrode.

(17) On application of a voltage between first and second electrode layers 2, 9, current flows through the component and photons are released in the emission layer 5 and leave the component in the form of light, for example through the first electrode layer 2 and the substrate 1. Alternatively, it is also possible for the second electrode layer 9 to additionally or solely have a transparent configuration, and for the light to leave the component through both electrode layers or only through the second electrode layer.

(18) The emission layer 5 comprises metal complexes according to the above statements, which may be embedded in a matrix.

(19) FIG. 2 shows a comparison of photoluminescence spectra of two metal complexes with a six-membered metallacyclic ring, which differ by the affinity of the ligand for the central atom, ((phenylpyridyl).sub.2Ir(dipyridylamine) and (phenylpyridyl).sub.2Ir(acetylacetonate)). The wavelength in nm is plotted against the relative intensity I.sub.rel. It is evident that, as a result of the introduction of the more nucleophilic aza-analogous 1,3-diketone ligand 2,2-dipyridylamine, a shift of the light emitted to shorter wavelengths by about 10 nm takes place. The breadth of the spectra is obtained as a result of the heterolepticity of the complexes; the five-membered metallacycles emit above 500 nm; the increasing influence of the component (2,2-dipyridyl-amine) which forms the more affinitive six-membered metallacycles intensifies the emission of blue light (wavelengths less than 500 nm).

(20) (Phenylpyridyl).sub.2Ir(dipyridylamine) can be prepared from (phenylpyridyl).sub.2Ir(acetylacetonate), for example, by heating (phenylpyridyl).sub.2Ir(acetylacetonate) with the equivalent amount of dipyridylamine in ethoxyethanol for 1 to 2 min until the orange color changes to yellow. After cooling, the product is filtered off with suction and washed with methanol. This reaction takes place with a yield of 95%. The reaction shows that the formation of a six-membered metallacyclic ring with a tautomerizable unit of the ligand, which forms an aza-analogous 1,3-diketonate complex with the central atom, is energetically favored owing to the increased nucleophilicity.

(21) Alternatively, (phenylpyridyl).sub.2Ir(dipyridylamine) can be prepared by boiling 0.1 mmol (107 mg) of (phenyl-pyridine)di--chloroiridium(III) complex, 0.2 mmol (35 mg) of dipyridylamine and 0.2 mmol (168 mg) of sodium bicarbonate in 20 ml of ethoxyethanol at reflux in a 100 ml flask for 30 min. In the course of this, yellow product precipitates out, which is filtered off with suction and washed with methanol (75% yield).

(22) Working examples for preparation of transition complexes and metal complexes are given hereinafter.

Synthesis of di(-chloro)bis[(phenylpyridino)-platinum(II)]=compound 1

(23) ##STR00036##

(24) 12 mmol (4.98 g) of potassium tetrachloroplatinate are dissolved in 24 ml of hot degassed water and cooled again with vigorous stirring. In the course of this, the potassium tetrachloroplatinate precipitates out as a fine suspension. A solution of 12 mmol (1.86 g) of phenylpyridine in 72 ml of ethoxyethanol is added dropwise to this suspension. The suspension is heated to 70 C., which increasingly forms a dark green precipitate. To precipitate the crude product, the suspension is blanketed with 30 ml of water and stirred after approx. 2 h. The crude product is filtered off with suction and washed repeatedly with a water/alcohol mixture (10:1). At this point, the product becomes air-stable. Subsequently, it is dried under reduced pressure for approx. 20 h. Different batches exhibit a yellow to green color in the solid according to the proportion of impurities. However, the crude product can be used for the further experiments without further purification.

(25) Yield: 3.56 g (77.2%)

Synthesis of di(-chloro)bis[(2,4-difluorophenyl-pyridino)platinum(II)]=compound 2

(26) ##STR00037##

(27) 7.23 mmol (3 g) of potassium tetrachloroplatinate are dissolved in 14 ml of hot degassed water and cooled to 30 C. with vigorous stirring. In the course of this, the potassium tetrachloroplatinate precipitates out as a fine suspension. A solution of 7.23 mmol (1.387 g) of 2,4-difluorophenylpyridine in 42 ml of ethoxyethanol is slowly added dropwise to this suspension. The suspension is heated to 70 C. for approx. 20 h, in the course of which a yellow-green precipitate increasingly forms. After cooling to room temperature, the crude product is precipitated by blanketing the suspension with 30 ml of water and stirring it after approx. 2 h. The yellow-green crude product is filtered off with suction and washed repeatedly with a water/alcohol mixture (10:1). Dry. in a desiccator under reduced pressure for approx. 20 h.

(28) Yield: 2.36 g (78%)

(29) Compounds 1 and 2 show the synthesis of a transition complex with selection of ligands which form five-membered metallacyclic rings with the central atom.

Synthesis of di(-chloro)bis[(dipyridylamino)-platinum(II)]=compound 3

(30) ##STR00038##

(31) 3 mmol (1.245 g) of potassium tetrachloroplatinate are dissolved in 6 ml of hot degassed water and cooled to 30 C. with vigorous stirring. In the course of this, the potassium tetrachloroplatinate precipitates out as a fine suspension. A solution of 3 mmol (0.514 g) of dipyridylamine in 45 ml of ethoxyethanol is slowly added dropwise to this suspension. The suspension is heated to 70 C. for approx. 20 h, in the course of which a cream-colored precipitate increasingly forms. After cooling to room temperature, the crude product is precipitated by blanketing the suspension with 40 ml of water and stirring it after approx. 2 h. The crude product is filtered off with suction and washed repeatedly with a water/alcohol mixture (10:1). Dry in a desiccator under reduced pressure for approx. 20 h.

(32) Yield: 1 g (83%).

(33) Compound 3 shows an example of a metal complex which forms a six-membered metallacyclic ring with the ligand.

Synthesis of bis[(dipyridylamino)platinum(II)]=compound 4

(34) ##STR00039##

(35) 3 mmol (1.245 g) of potassium tetrachloroplatinate are dissolved in 6 ml of hot degassed water and cooled to 30 C. with vigorous stirring. In the course of this, the potassium tetrachloroplatinate precipitates out as a fine suspension. A solution of 6 mmol (1.027 g) of dipyridylamine in 40 ml of ethoxyethanol is slowly added dropwise to this suspension. The suspension is heated to 70 C. for approx. 20 h, in the course of which a yellow precipitate increasingly forms. After cooling, the mixture is admixed twice with 50 ml each time of water and heated with stirring in order to extract the product. The water phase is removed and concentrated by rotary evaporation, and the yellow product is taken up in methanol and filtered in order to remove the potassium chloride formed. Then draw off the methanol under reduced pressure.

(36) Yield: 1.37 g (85%)

(37) This compound can be detected by means of mass spectrometry.

(38) Compound 4 shows a mononuclear metal complex in which the central atom forms six-membered metallacyclic rings with the ligands. FIGS. 3a, b, c and d show photo-luminescence spectra of this compound in different dilutions. With increasing dilution, the emission maximum shifts from approx. 398 nm to 345 nm.

Synthesis of bis[(difluorophenylpyridino)platinum(II)]=compound 5

(39) ##STR00040##

(40) 2.41 mmol (1 g) of potassium tetrachloroplatinate are suspended in 8 ml of degassed water with vigorous stirring. A solution of 5.3 mmol (1.013 g) of 2,4-di-fluorophenylpyridine in 24 ml of ethoxyethanol is added to this suspension. The suspension is heated to 80 C. for approx. 20 h, in the course of which a dark green precipitate increasingly forms. After cooling to room temperature, the crude product is precipitated by blanketing the suspension with 15 ml of water and stirring it after approx. 2 h. The crude product is filtered off with suction and washed repeatedly with a water/alcohol mixture (10:1). At this point, the product becomes air-stable. Subsequently, it is dried under reduced pressure for approx. 20 h.

(41) Yield: 0.935 g (92%)

(42) Compound 5 shows a mononuclear metal complex in which the central atom forms five-membered metallacyclic rings with the ligands.

Synthesis of di(-pyrazolato)bis[(phenylpyridino)-platinum(II)]=compound 6

(43) ##STR00041##

(44) 0.65 mmol (0.5 g) of di(-chloro)bis[(phenylpyridino)-platinum(II)] (compound 1) are suspended in 25 ml of dichloromethane. At the same time, 1.3 mmol (88.5 mg) of pyrazole and 1.3 mmol (70.23 mg) of sodium methoxide are likewise suspended in 15 ml of dichloromethane. Both suspensions are stirred for approx. 1 h, and then pyrazole suspension is added to the di(-chloro)bis[(phenylpyridino)platinum(II)]suspension. The mixture is stirred at room temperature for approx. 48 h. After 48 h, the mixture is filtered through a P4 frit and washed repeatedly with dichloromethane. The solution is concentrated under reduced pressure. Subsequently, the substance is washed twice with methanol and dried under reduced pressure.

(45) Yield: 234 mg (43.3%)

(46) FIG. 3e shows the photoluminescence spectrum of the compound 6, with an emission maximum at 488 nm and 522 nm.

Synthesis of di(-pyrazolato)bis[(2,4-difluorophenyl-pyridino)platinum(II)]=compound 7

(47) ##STR00042##

(48) 1.04 mmol (874 mg) of di(-chloro)bis[(2,4-difluoro-phenylpyridino)platinum(II)](compound 2) are suspended in 10 ml of dichloromethane. A mixture of 2.078 mmol (112.2 mg) of sodium methoxide and 2.078 mmol (141.3 mg) of pyrazole, suspended in 40 ml of dichloromethane, is slowly added dropwise thereto. The greenish reaction mixture is stirred at room temperature for 48 h. Subsequently, the mixture is filtered through a frit and washed through with dichloromethane. The filtrate is concentrated and the yellow product obtained is washed twice with hot methanol and once with pentane. Dry under reduced pressure.

(49) Yield: 662 mg (71%)

(50) FIG. 3f shows the photoluminescence spectrum of compound 7, with an emission maximum at 470 nm and 501 nm.

Synthesis of di(-hpp)bis[(phenylpyridino)platinum (II)]=compound 8

(51) ##STR00043##

(52) 0.39 mmol (0.3 g) of di(-chloro)bis[(phenylpyridino)-platinum(II)](compound 1) are suspended in 25 ml of dichloromethane. At the same time, 0.78 mmol (108.6 mg) of Hhpp and 0.78 mmol (42.13 mg) of sodium methoxide are suspended in 20 ml of dichloromethane. Both suspensions are cooled to 70 C. with stirring, and then Hhpp suspension is added to the di(1-chloro)bis[(phenylpyridino)platinum(II)]suspension. The mixture is stirred at room temperature for approx. 48 h. After 48 h, the mixture is filtered through a P4 frit and washed through repeatedly with dichloro-methane. The solution is concentrated under reduced pressure. Subsequently, the substance is washed with pentane. However, the pentane extraction shows the same result in the photoluminescence spectrum as the washed product.

(53) Yield: virtually quantitative

(54) This compound can be detected by means of mass spectrometry.

(55) FIG. 3g shows the photoluminescence spectrum of compound 8, with an emission maximum at 498 nm and 531 nm.

Synthesis of di(-hpp)bis[(2,4-difluorophenyl-pyridine)platinum(II)]=compound 9

(56) ##STR00044##

(57) 1.19 mmol (1 g) of di(-chloro)bis[(2,4-difluorophenyl-pyridino)platinum(II)](compound 2) are suspended in 20 ml of dichloromethane and cooled to 70 C. A mixture of 2.377 mmol (128.4 mg) of sodium methoxide and 2.377 mmol (330.9 mg) of Hhpp, suspended in 40 ml of dichloromethane and likewise cooled to 70 C., is slowly added dropwise thereto. The greenish reaction mixture is stirred at room temperature for 48 h, in the course of which the mixture turns brownish. Subsequently, it is filtered through a frit and washed through with dichloromethane. The filtrate is concentrated to obtain a brownish-beige product. A fraction extracted with ether gives the same PL spectrum as the crude product.

(58) Yield: virtually quantitative

(59) FIG. 3h shows the photoluminescence spectrum of compound 9, with an emission maximum at 473 nm and 501 nm.

Synthesis of di(-hpp)bis[(dipyridylamino)platinum(II)]=compound 10

(60) ##STR00045##

(61) 1.25 mmol (1 g) of di(-chloro)bis[(dipyridylamino)-platinum(II)](compound 3) are suspended in 10 ml of dichloromethane and cooled to 70 C. A mixture of 2.496 mmol (134.8 mg) of sodium methoxide and 2.496 mmol (347.4 mg) of Hhpp, suspended in 35 ml of dichloromethane and likewise cooled to 70 C., is slowly added dropwise thereto. In the course of this, the reaction mixture turns yellow. The mixture is left to react at room temperature with stirring for 48 h. Thereafter, the substance is filtered through a P4 frit and washed through repeatedly with dichloromethane. The filtrate is concentrated and dried under reduced pressure.

(62) Yield 1.04 g (83%)

(63) This compound can be detected by means of mass spectrometry.

(64) FIG. 3i shows the photoluminescence spectrum of compound 10, with an emission maximum at 463 nm.

Synthesis of di(-pyrazolato)bis[(dipyridylamino)-platinum(II)]=compound 11

(65) ##STR00046##

(66) 0.21 mmol (0.17 g) of di(v-chloro)bis[(dipyridylamino)-platinum(II)](compound 3) are suspended in 15 ml of dichloromethane. At the same time, 0.42 mmol (28.9 mg) of pyrazole and 0.42 mmol (22.9 mg) of sodium methoxide are suspended in 10 ml of dichloromethane. Both suspensions are stirred for approx. 1 h, and then the pyrazole suspension is added to the di(g-chloro)bis[(dipyridylamino)platinum(II)]suspension. The mixture is stirred at room temperature for approx. 48 h. The color of the mixture is intense yellow. After 48 h, the substance is filtered through a P4 frit and washed through repeatedly with dichloromethane. The solution glows bright green under UV light (384 nm). It is subsequently dried under reduced pressure.

(67) Yield: 0.03 g (16.4%)

(68) FIG. 3j shows the photoluminescence spectrum of compound 11, with an emission maximum at 524 nm.

(69) According to the abovementioned synthesis methods, metal complexes of the formula 28 are also preparable.

(70) ##STR00047##

(71) A further example of metal complexes is tris(dipyridyl-amine)iridium(III) (formula 29). This can be prepared, for example, as follows: dipyridylamine and iridium acetylacetonate are initially charged in glycol in a stoichiometric ratio and heated at reflux under inert gas for 12 h. Subsequently, the reaction mixture is admixed with water and the Ir derivative is extracted by means of chloroform. The chloroform phase is concentrated and then the product is precipitated by adding methanol.

(72) ##STR00048##

(73) FIG. 4a shows the absorption spectrum (absorption A against wavelength in nm) of tris(dipyridylimine)iridium(III). A double peak is evident around 300 nm.

(74) FIG. 4b shows the PL emission spectrum (intensity I against wavelength in nm) of the tris(dipyridyl-imine)iridium(III) complex. A single peak is evident at approx. 430 nm.

(75) A further example of a metal complex is tris(di-1,2,4-benzotriazin-3-ylmethine)iridium(III) (formula 30), which can be prepared as follows: dibenzo-1,2,4-triazin-3-ylmethane and iridium acetylacetonate are initially charged in a stoichiometric ratio in glycol and heated at reflux under inert gas for 15 h. Subsequently, the reaction mixture is admixed with water and the Ir derivative is extracted by means of chloroform. The chloroform phase is concentrated and then the product is precipitated by adding methanol.

(76) ##STR00049##

(77) FIG. 5a shows the absorption spectrum (absorption A against wavelength in nm) of tris(di-1,2,4-benzo-triazin-3-ylmethine)iridium(III). A peak is evident at approx. 280 nm.

(78) FIG. 5b, finally, shows a PL emission spectrum (intensity I against wavelength in nm) of the tris(di-1,2,4-benzotriazin-3-ylmethine) iridium(III) complex; a peak is evident at approx. 420 nm.

(79) The embodiments shown in FIGS. 1 to 5 and the working examples can be varied as desired. It should also be taken into account that the invention is not restricted to the examples, but permits further configurations not detailed here.

(80) The scope of protection of the invention is not limited to the examples given hereinabove, The invention is embodied in each novel characteristic and each combination of characteristics, which includes every combination of any features which are stated in the claims, even if this feature or combination of features is not explicitly stated in the examples.