Class of organic phosphors based on derivatives of benzimidazoxanthenoisoquinolinone for LED lighting

Abstract

The invention provides a lighting device including a light source configured to generate light source light and a light converter configured to convert at least part of the light source light into visible converter light. The light converter includes a matrix containing a luminescent material based on derivatives of benzimidazoxanthenoisoquinolinone. The lighting device may include a further luminescent material.

Claims

1. A lighting device comprising (a) a light source configured to generate light source light, and (b) a light converter configured to convert at least part of the light source light into visible converter light, wherein the light converter comprises a matrix containing a luminescent material comprising at least an organic phosphor defined by formula IA, and optionally an organic phosphor defined by formula TB: ##STR00005## wherein G1-G12 are independently selected from hydrogen, halogen, R1, OR1, NHR1, and NR2R1, wherein R1 and R2 are independently selected from C1-C18alkyl, C6-C24aryl, and C6-C24heteroaryl, wherein optionally one or more of G1-G12 is covalently linked to the matrix, and wherein when the organic phosphor defined by formula IB is available in the luminescent material, the phosphor defined by formula IB and the phosphor defined by formula IA have a molar ratio of 1B/1A 0.1, wherein at least four of G1-G12 for the organic phosphor IA independently are H, and wherein independently one or more of G2 and G7 for the organic phosphor IA comprise R1 or OR1, with R1 being defined by formula II: ##STR00006## wherein D, E, I, L and M are independently selected from hydrogen, halogen, R3, OR3, NHR3, and NR4R3, and wherein R3 and R4 are independently selected from C1-C18alkyl, C6-C24aryl, and C6-C24heteroaryl.

2. The lighting device according to claim 1, wherein at least ten of G1-G12 independently are H.

3. The lighting device according to claim 1, wherein independently one or more of G2 and G7 for the organic phosphor IA comprise R1 or OR1 and wherein R1 comprises a group defined by formula II: ##STR00007## wherein D, E, I, L and M are H, and wherein at least four of G1, G3, G4, G5, G6, G8, G9, G10, G11 and G12 independently are H.

4. The lighting device according to claim 3, wherein at least eight of G1, G3, G4, G5, G6, G8, G9, G10, G11 and G12 independently are H.

5. The lighting device according to claim 1, wherein the luminescent material comprising a combination of at least two different organic phosphors defined by formulas IA and IA and optionally at least four different organic phosphors defined by formulas IA, IB, IA and IB: ##STR00008## wherein G1-G12 are as defined above, with a molar ratio of IB/1A 0.1 and a molar ratio of IB/1A0.5.

6. The lighting device according to claim 1, wherein the matrix comprises a polymeric material.

7. The lighting device according to claim 1, wherein the matrix comprises an aromatic polyester or a copolymer thereof.

8. The lighting device according to claim 1, wherein one or more of G1, G2, G3, G4, G5, G6, G7, G8, G9, G10, G11, and G12 comprise a covalent link with the matrix.

9. A light converter comprising a matrix containing a luminescent material according to claim 1.

10. A lighting device comprising (a) a light source configured to generate light source light, and (b) a light converter configured to convert at least part of the light source light into visible converter light, wherein the light converter comprises a matrix containing a luminescent material comprising at least an organic phosphor defined by formula IA, and optionally an organic phosphor defined by formula IB: ##STR00009## wherein G1-G12 are independently selected from hydrogen, halogen, R1, OR1, NHR1, and NR2R1, wherein R1 and R2 are independently selected from C1-C18alkyl, C6-C24aryl, and C6-C24heteroaryl, wherein optionally one or more of G1-G12 is covalently linked to the matrix, and wherein when the organic phosphor defined by formula IB is available in the luminescent material, the phosphor defined by formula IB and the phosphor defined by formula IA have a molar ratio of 1B/1A 0.1, wherein one or more of G1-G12 of the organic phosphor IA are independently selected from R1, OR1, NHR1, and NR2R1, wherein one or more of R1 and R2 independently comprise a group defined by formula II: ##STR00010## wherein D, E, I, L and M are independently selected from hydrogen, halogen, R3, OR3, NHR3, and NR4R3, and wherein R3 and R4 are independently selected from C1-C18alkyl, C6-C24aryl, and C6-C24heteroaryl.

11. The lighting device according to claim 10, wherein at least two of D, E, I, L and M are H.

12. A luminescent material comprising at least an organic phosphor defined by formula IA and optionally also an organic phosphor defined by formula IB: ##STR00011## wherein G1-G12 are independently selected from hydrogen, halogen, R1, OR1, NHR1, and NR2R1, wherein R1 and R2 are independently selected from C1-C18alkyl, C6-C24aryl, and C6-C24heteroaryl, and wherein when the organic phosphor defined by formula IB is available in the luminescent material, the phosphor defined by formula IB and the phosphor defined by formula IA have a molar ratio of 1B/1A 0.1, and wherein one or more of G2 and G7 comprises independently a group selected from the group consisting of R1, OR1, NHR1, and NR2R1, and wherein at least four of G1-G12 for the organic phosphor IA independently are H, and wherein independently one or more of G2 and G7 for the organic phosphor IA comprise R1 or OR1, with R1 being defined by formula II; ##STR00012## wherein D, E, I, L and M are independently selected from hydrogen, halogen, R3, OR3, NHR3, and NR4R3, and wherein R3 and R4 are independently selected from C1-C18alkyl, C6-C24aryl, and C6-C24heteroaryl, the luminescent material, comprising an organic phosphor selected from the group consisting of 6,16-diphenyl-8H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[1,2-b]isoquinolin-8-one; 6,16-diphenoxy-8H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[1,2-b]isoquinolin-8-one; 16-phenoxy-8H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[1,2-b]isoquinolin-8-one; 6,16-bis(4-(2,4,4-trimethylpentan-2-yl)phenoxy)-8H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[1,2-b]isoquinolin-8-one; and 16-(4-(2,4,4-trimethylpentan-2-yl)phenoxy)-8H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[1,2-b]isoquinolin-8-one.

13. The luminescent material according to claim 12, comprising 6,16-diphenyl-8H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[1,2-b]isoquinolin-8-one.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

(2) FIGS. 1a-1f schematically depict some embodiments of the lighting device; these drawings are not necessarily on scale;

(3) FIG. 2a-2c show some information on the phosphors according to formulas IA and IB;

(4) FIGS. 3a-3c show a synthesis scheme and a number of luminescent materials made, respectively;

(5) FIG. 4a shows luminescence spectra (at RT) in ethyl acetate of those materials, also in comparison with F083 (state of the art perylene derivative);

(6) FIGS. 4b-4f depict white light luminescence spectra using a blue LED as excitation source, and further the luminescent material in combination with another organic luminescent material (b), a quantum dot material (c) or a red LED (d) (see also the table 2 at the end of the experiments);

(7) FIGS. 5a-5b depicts phosphors 2485A/2485B and 2475A/2475B, respectively; and

(8) FIGS. 6a-6b show normalized luminescence spectra (at RT) of the phosphors of FIGS. 6a-6b in ethyl acetate of those materials (2486=2485A; 2487=2485B; 2485 is the mixture; 2504=2475A; 2505=2475B; 2475 is the mixture. FIG. 6c shows the normalized excitation spectra (at RT) of these organic phosphors.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(9) FIG. 1a schematically depicts a lighting device 1 with a light converter 100, which in this embodiment at least comprises the luminescent material 140 according to formula 1. The luminescent material 140 is in this embodiment embedded in a (polymeric) matrix, such as PET. As can be seen, a remote version is shown, with a non-zero distance d between the luminescent material (in the light converter 100) and the light source(s), indicated with reference(s) 10. The lighting device 1 comprises one or more light sources 10 which are configured to provide light source light 11, especially blue and/or UV light. The lighting device 1 may comprise a plurality of such light sources. When lighting device light, indicated with reference 2, of a white nature is desired, it may be necessary to us an RGB concept, wherein the green and/or yellow color, or at least part thereof, is provided by the green and/or yellow luminescent material 140, and the blue and red light are provided by one or more of the light source and a combination of the light source and another luminescent material, especially the further luminescent material. The further luminescent material is indicated with reference 130, and provides further luminescent material light 131.

(10) The luminescent material 140 according to formula I provides upon excitation by the light source light 11 and/or by emission of one or more other luminescent materials, such as e.g. the further luminescent material light 131, luminescent material light 141. Here, the light converter 100 is remote from the light source 10, and the luminescent material, which is embedded in the light converter 100, is thus also remote. The optional further luminescent material 130 can also be arranged remote, see below, but is by way of example close to the light source 10, such as in a dome and/or as layer on the LED die.

(11) Just by way of example, one light source has been depicted without the further luminescent material 130. However, in another embodiment, all light sources 10 may be configured with at least further luminescent material 130. Also, by way of example three light sources 10 have been depicted. However, more or less than three light sources may be applied.

(12) Note that the light source 10 may provide blue and/or UV light. The further luminescent material 130 may especially, upon excitation (by said light of the light source 10) provide red light. Optionally, the further luminescent material 130 may also provide green and/or yellow light.

(13) FIG. 1a, and other figures, schematically depict a device with a light chamber 170, with an enclosure 171, at least partly enclosing a cavity 172, which has a transmissive part 173. In an embodiment, the transmissive part 173 comprises the light converter 100, or may especially consist of the light converter 100. The surface of the non-transmissive part of the enclosure is indicated with reference 171. At least part of the surface 171 may comprise a reflector, such as a reflective coating.

(14) The light converter 100 provides upon excitation light converter light 111, which at least comprises luminescent material light 141 but may optionally comprise other luminescence light as well (see below). The lighting device light, indicated with reference 2, at least comprises light converter light 111/luminescent material light 141, but may optionally comprise one or more of the light source light 11, further luminescent material light 131, and light of other luminescent materials (not depicted).

(15) FIG. 1b schematically depicts an embodiment wherein the light converter 100 may comprise an upstream layer with further luminescent material 130. Optionally, this may be a light converter comprising two layers comprising the same matrix, but comprising different luminescent materials. The distance of the layer with further luminescent material 130 to the light source is indicated with d1. This distance is in this embodiment non-zero, in contrast to the embodiment schematically depicted in FIG. 1a.

(16) FIG. 1c schematically depicts an embodiment wherein the light converter 100 comprises the further luminescent material 140, e.g. in the form of quantum dots, and the luminescent material 130 according to formula IA. Both the luminescent material 140 and the further luminescent material 130 are in this embodiment embedded in the (remote) light converter, i.e. embedded in the (polymeric) matrix of the light converter 100.

(17) FIG. 1d schematically depicts an embodiment wherein the transmissive part 173 comprises at least two types of segments, with volumes over 0.25 cm.sup.3, wherein the two types of segments comprise different weight ratios luminescent material and further luminescent material. For instance, first segments only comprise the luminescent material 140 as luminescent material and second segments only comprises further luminescent material 130 as luminescent material. The luminescent material 140 may also in this embodiment be embedded in a (polymeric) matrix, such as PET. Likewise, also the further luminescent material 130 may be embedded in a (polymeric) matrix, such as PET.

(18) FIG. 1e schematically depicts an embodiment wherein the enclosure 170 comprises a transmissive diffuser 160 (as transmissive part 173) and the light converter is applied to at least part of the non-transmissive part of the enclosure 171.

(19) FIG. 1f schematically depicts a reflective configuration. As mentioned above, the luminescent material 140 and optionally the further luminescent material 140 may (both) be embedded in a (polymeric) matrix.

(20) Combinations of embodiments may also be applied, like the segmented light converter of FIG. 1d in combination with or alternative to the light converter(s) shown in the other drawings, such as e.g. 1a, 1b, 1e, 1f.

(21) In FIGS. 1a-1d, the lighting device comprises a light transmissive window, which comprises or consists of the matrix. Hence, the matrix may be applied as light transmissive window. In FIGS. 1e-1f, a transmissive diffuser is used as transmissive window. The transmissive window is used as an envelope, or as part of an envelope. Here, the transmissive window envelopes at least part of the cavity 172. Note that the transmissive window is not necessarily flat. The transmissive window, comprising in embodiments the matrix, may also be curved, like in the embodiment of a TLED or in a retrofit incandescent lamp (bulb).

(22) FIG. 2a shows the (combination of) phosphors according to formula IA and IB, which combination, but at least IA, may be available in the luminescent material as described above in relation to some specific device embodiments. FIG. 2b shows the group with formula II, which may be substituent or which may be part of a substituent (one or more of G1-G12 (in one or more of IA and IB)). Under specific conditions, especially when G9G12 and when G10G11, four different systems may be obtained, as indicated in FIG. 2c, with formulas IA, IA, IB, IB. The luminescent material at least comprises one or more phosphors according to one or more of formula IA and IA, and optionally one or more phosphors according to one or more of formula IB and IB, and optionally one or more other (organic and/or inorganic) phosphors.

EXAMPLES

(23) By way of example, a few syntheses are described below. A synthesis scheme is depicted in FIGS. 3a-3c. Luminescence spectra of those materials, also in comparison with F083 (prior art system), are depicted in FIG. 4a.

(24) Synthesis of 2410 (Mixture of Isomers):

1. 4-(2-nitrophenoxy)-1,8-naphthalic Anhydride 2458

(25) A mixture of 4-bromonaphthalic anhydride (50 g, 180.46 mmol), 2-nitrophenol (50.2 g, 360.92 mmol) and NaOH (13 g, 325.17 mmol) and copper powder (1.9 g) in DMF (1 L) was refluxed for 2 h under nitrogen. The mixture was cooled and poured into aqueous hydrochloric acid (20%, 1 L) and the precipitated solid was filtered, washed with water and recrystallized in AcOH to afford a mixture of starting material and expected compound 2458. Washing of the solid with hot toluene removed the unreacted starting material and afforded after drying under vacuum compound 2458 (11.5 g, 10%) as a beige solid.

2. 4-(2-aminophenoxy)-1,8-naphthalic Anhydride 2459

(26) A suspension of compound 2458 (11.0 g, 32.81 mmol) in 1,4-dioxane (800 mL) under nitrogen atmosphere was warmed to get a clear solution. The mixture was then cooled to 60 C. and 10% Pd/C (2.5 g) was added. The mixture was stirred 20 h at 60 C. under hydrogen atmosphere (balloon) then cooled to 40 C. filtered over a pad of celite and concentrated to give crude compound 2459 (9.5 g, 95%) as a yellow solid used as such in the next step.

3. Benzo[k,l]xanthene-3,4-dicarboxylic Anhydride 2460

(27) A solution of compound 2459 (6.1 g, 19.98 mmol) in AcOH (120 mL) was treated with concentrated hydrochloric acid (5.3 mL) and water (7 mL) at 0-5 C. A solution of sodium nitrite (1.6 g, 23.98 mmol) in water (10 mL) was added drop wise and the mixture was stirred at 0-8 C. for 2 h. The diazonium solution was added portion wise to a boiling solution of hydrated copper(II) sulphate (13.4 g, 53.75 mmol) in water (180 mL) and acetic acid (11 mL) over 30 minutes. After the addition was complete, the mixture was boiled for a further 30 minutes, cooled and filtered. The precipitate obtained was washed with water and recrystallized from DMF to afford the title compound (1.2 g, 21%) as a yellow solid.

4. Mixture of 8H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[1,2-b]isoquinolin-8-one and 7H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[2,1-a]isoquinolin-7-one: 2410

(28) A mixture of 1460 (260 mg, 0.90 mmol) and o-phenylenediamine (215 mg, 1.98 mmol) in propionic acid (30 mL) and was stirred for 20 h at 140 C. The yellow solution became red. The mixture was cooled to room temperature and poured into 5% aqueous hydrochloric acid (30 mL) and the precipitate was collected by filtration, washed with water and recrystallized from DMF. The crystals obtained were washed with methanol and dried to afford the title compounds (mixture of isomers, 270 mg, 83%) as an orange solid poorly soluble at room temperature. (exc) (ethyl acetate)=447 nm and 475 nm. (em) (ethyl acetate) 487 nm and 521 nm. The term (exc) indicates the excitation wavelength (i.e. the wavelength at which is excited); the term (em) indicates the emission wavelength (i.e. the emission wavelength at which the emission is monitored).

(29) See also FIGS. 3a, 3c (2410) and 4a (87(2410)).

(30) Synthesis of 2441 (Mixture of Isomers):

1. 6-chloro-2-(2,6-diisopropylphenyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione (2368)

(31) A mixture of 4-chloronaphthalic anhydride (10 g, 43.0 mmol) and 2,6-diisopropylaniline (16.2 mL, 86 mmol) in AcOH (300 mL) was refluxed overnight. The mixture was cooled and poured into water. The precipitate was collected by filtration, washed with water and dried under vacuum. Purification by column chromatography on SiO.sub.2 (DCM/heptane=2:1) gave 7.5 g (44%) of pure compound 2368.

2. 4-(2-nitrophenoxy)-N-(2,6-diisopropylphenyl)-1,8-naphthalimide (2369)

(32) A mixture of 2368 (7.5 g, 19.1 mmol), 2-nitrophenol (13.5 g, 34.4 mmol) and K.sub.2CO.sub.3 (5.3 g, 38.2 mmol) in NMP (300 mL) was stirred at 90 C. under nitrogen overnight. The mixture was cooled and poured into a mixture of AcOH (150 mL) and ice-water. After 5 minutes, 2 N HCl (200 mL) was added and the mixture was extracted with toluene (4). The combined organic layers were washed with water and brine, dried (Na.sub.2SO.sub.4), filtered and concentrated. Purification by column chromatography on SiO.sub.2 (DCM/heptane=1/1 to 2:1) gave 6.7 g (71%) of pure compound 2369 as a white solid.

3. 4-(2-aminophenoxy)-N-(2,6-diisopropylphenyl)-1,8-naphthalimide (2370)

(33) A solution of compound 2369 (5.7 g, 11.5 mmol) in a mixture of THF (60 mL) and MeOH (50 mL) under nitrogen atmosphere was warmed to get a clear solution. The mixture was then cooled to room temperature and 10% Pd/C (2 g) was added. The mixture was stirred 2 h at room temperature under hydrogen atmosphere (balloon) then filtered over a pad of celite and concentrated. Purification by column chromatography on SiO.sub.2 (DCM) gave 4.9 g (90%) of pure compound 2370 as a yellow solid.

4. 2-(2,6-diisopropylphenyl)-1H-xantheno[2,1,9-def]isoquinoline-1,3(2H)-dione (2363)

(34) A solution of compound 2370 (5.1 g, 11.0 mmol) in AcOH (80 mL) was treated with hydrochloric acid (1.5 M, 21 mL) and sodium nitrite (3.0 g, 43.9 mmol in 20 mL water) at 0 C. After 60 minutes, a solution of CuSO.sub.4.5H.sub.2O (11.24 g, 45.0 mmol) in water (130 mL) was added. The mixture was refluxed for another 0.5 h and then allowed to cool. The precipitated yellow solid was filtered, washed with water and dried under vacuum. Purification by column chromatography on SiO.sub.2 (DCM/heptane=1/1 to 2:1) gave 850 mg (17%) of pure compound 2363 as a yellow solid. M+H=448.1. .sub.max (ethyl acetate)=421 nm, =25500 and 444 nm =21300. (em) (ethyl acetate) 460 nm and 490 nm.

5. 5,11-dibromo-2-(2,6-diisopropylphenyl)-1H-xantheno[2,1,9-def]isoquinoline-1,3(2H)-dione (2404)

(35) Bromine (2.7 mL, 53.64 mmol) was added to a solution compound 2363 (2 g, 4.47 mmol) in CHCl.sub.3 (160 mL) under nitrogen. The mixture was stirred at 60 C. for 5 h cooled to room temperature and concentrated. The various brominates products were separated by column chromatography (SiO.sub.2, eluent: toluene/DCM 1/1 to 2/1). Compound 2404 (1.8 g, 66%) was obtained as a yellow solid.

6. 2-(2,6-diisopropylphenyl)-5,11-diphenyl-1H-xantheno[2,1,9-def]isoquinoline-1,3(2H)-dione (2401)

(36) Compound 2404 (500 mg, 0.83 mmol), phenylboronic acid (810 mg, 6.64 mmol), Pd(PPh.sub.3).sub.4 (40 mg, 0.03 mmol) and Na.sub.2CO.sub.3 (265 mg, 2.50 mmol) were added to a degassed mixture of EtOH (1 mL), benzene (15 mL) and water (2 mL) under nitrogen. The mixture was reacted at 80 C. overnight. The reaction was quenched by addition of water and extracted with DCM (3). The combined organic layer was washed with water, brine, dried (Na.sub.2SO.sub.4), filtered and concentrated under reduced pressure. The crude solid was purified by column chromatography (SiO.sub.2, eluent: DCM/heptane 2/1). Compound 2401 (490 mg, 98%) was obtained as a yellow solid. M+H=600.3. .sub.max (ethyl acetate)=435 nm, =17700 and 455 nm, =15600. (em) (ethyl acetate) 489 nm and 516 nm.

7. 5,11-diphenylisochromeno[6,5,4-mna]xanthene-1,3-dione (2456)

(37) To a solution of compound 2401 (1.20 g, 2.00 mmol) in tBuOH (60 mL) and 1,4-dioxane (15 mL) was added powder KOH (1.12 g, 20.00 mmol). The mixture was refluxed for 4 h. The yellow solution became reddish after a few minutes. The solution was cooled to room temperature and poured into AcOH (60 mL). After 2 minutes, 2 N aqueous HCl (300 mL) was added. The orange precipitate was collected by filtration, first washed with water then with heptane and Et2O to remove most of the unreacted starting material and 2,6-diisopropylaniline. The precipitate was stirred in refluxing AcOH (70 mL) for 10 minutes and concentrated. The residue was coated on silica gel and purified by column chromatography (SiO2, eluent: DCM/Heptane 2/1 to remove remaining starting material then with DCM/Heptane 4/1 to 1/0). Compound 2456 (40 mg, 41%) was obtained as an orange solid. Fractions containing starting material 2401 were combined and purified by column chromatography (SiO2, eluent: DCM/Heptane 2/1) to give pure recovered compound 2401 (255 mg, 21%).

8. Mixture of 6,16-diphenyl-8H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[1,2-b]isoquinolin-8-one and 5,15-diphenyl-7H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[2,1-a]isoquinolin-7-one (2441)

(38) A mixture of 2456 (30 mg, 0.068 mmol) and o-phenylenediamine (36.8 mg, 0.34 mmol) in AcOH (10 mL) and 1,4-dioxane (5 mL) was refluxed for 6 h. The yellow solution became red. The mixture was cooled to room temperature and concentrated. The red solid obtained was triturated in MeOH (50 mL), collected by filtration on a glass filter, washed again with MeOH to remove excess of o-phenylenediamine and some other impurities then washed with heptane and dried under vacuum. Compound 2441 (mixture of isomers, 30 mg, 86%) was obtained as an orange-red solid. M+H=513.6. .sub.max (chloroform)=461 nm, =27400 and 488 nm, =29800. (em) (ethyl acetate) 502 nm and 535 nm.

(39) See also FIGS. 3b/3c (2441) and 4a (101 (2441)).

(40) Synthesis of 2442 (Mixture of Isomers):

1. 2-(2,6-diisopropylphenyl)-5,11-diphenoxy-1H-xantheno[2,1,9-def]isoquinoline-1,3(2H)-dione (2436)

(41) A mixture of 2404 (2.0 g, 3.3 mmol), phenol (10.0 g, 16.5 mmol) and Cs2CO3 (6.4 g, 19.8 mmol) in degased 1,4-dioxane (1560 mL) was stirred at 90 C. under nitrogen for 1 h. Then, a mixture of Cu(I)I (314 mg, 1.65 mmol) and N,N-dimethylglycine (510 mg, 495 mmol) in 1,4-dioxane (4 mL) was added and the reaction mixture was stirred at 90 C. under nitrogen overnight. The mixture was cooled to room temperature and the solvent removed under reduced pressure. The residue was dissolved in DCM and SiO2 was added. The DCM was removed under reduced pressure and the product coated on silica was poured on top of a column chromatography for purification (SiO2, eluent: DCM/heptane 1/1). The compound was washed with hot heptane in a glass filter and dried under vacuum. Compound 2436 (1.0 g, 48%) was obtained as a yellow solid.

2. 5,11-diphenoxyisochromeno[6,5,4-mna]xanthene-1,3-dione (2457)

(42) To a solution of compound 2436 (390 mg, 0.62 mmol) in tBuOH (20 mL) and 1,4-dioxane (5 mL) was added powder KOH (348 mg, 6.20 mmol). The mixture was refluxed for 4 h. The yellow solution became reddish after a few minutes. The solution was cooled to room temperature and poured into AcOH (50 mL). After 2 minutes, 2 N aqueous HCl (150 mL) was added. The orange precipitate was collected by filtration, first washed with water then with heptane and Et.sub.2O to remove most of the unreacted starting material 2436 and 2,6-diisopropylaniline. The precipitate was stirred in refluxing AcOH (50 mL) for 10 minutes and concentrated. The residue was coated on silica gel and purified by column chromatography (SiO.sub.2, eluent: DCM/Heptane 2/1 to remove remaining starting material then with DCM/Heptane 4/1 to 1/0). Compound 2457 (135 mg, 46%) was obtained as an orange solid.

3. Mixture of 6,16-diphenoxy-8H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[1,2-b]isoquinolin-8-one and 5,15-diphenoxy-7H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[2,1-a]isoquinolin-7-one (2442)

(43) A mixture of 2457 (135 mg, 0.286 mmol) and o-phenylenediamine (36.8 mg, 0.34 mmol) in AcOH (50 mL) and 1,4-dioxane (15 mL) was refluxed for 6 h. The yellow solution became red. The mixture was cooled to room temperature and concentrated. The red solid obtained was triturated in MeOH (60 mL), collected by filtration on a glass filter, washed again with MeOH to remove excess of o-phenylenediamine and some other impurities then washed with heptane and dried under vacuum. Compound 2442 (mixture of isomers, 132 mg, 85%) was obtained as an orange-red solid. M+H=545.2. .sub.max (chloroform)=463 nm, =40500 and 485 nm, =47200. (em) (ethyl acetate) 508 nm and 540 nm.

(44) See also FIGS. 3b/3c (2442) and 4a (102 (2442)).

(45) Synthesis of 2464 (Mixture of Isomers):

1. 2-(2,6-diisopropylphenyl)-5-bromo-11-phenoxy-1H-xantheno[2,1,9-def]isoquinoline-1,3(2H)-dione (2405)

(46) A mixture of 2404 (1.4 g, 2.31 mmol), phenol (1.2 g, 12.75 mmol) and K.sub.2CO.sub.3 (2.2 g, 15.92 mmol) in NMP (60 mL) was stirred at 90 C. under nitrogen overnight. Then, the contents of the flask were poured into a cold 20% acetic acid solution in water. After 5 minutes, 2 N aqueous HCl was added and stirred for 10 minutes and the precipitated solid was filtered, washed neutral with warm water and vacuum dried at 60 C. The residue was coated on silica gel and purified by column chromatography (SiO.sub.2, eluent: DCM/Heptane 1/1 to 2/1). Compound 2405 (1.1 g, 76%) was obtained as a yellow solid.

2. 2-(2,6-diisopropylphenyl)-11-phenoxy-1H-xantheno[2,1,9-def]isoquinoline-1,3(2H)-dione (2389)

(47) To a clear solution of compound 2405 (600 mg, 0.97 mmol) in THF (80 mL) and MeOH (10 mL) under nitrogen was added 10% Pd/C (100 mg) and the reaction was placed under hydrogen atmosphere with a balloon. The mixture was stirred at 30 C. overnight and then filtered over Celite. The crude solid was purified by column chromatography (SiO.sub.2, eluent: toluene/DCM 3/2). Compound 2389 (540 mg, 98%) was obtained as a yellow solid.

3. 11-phenoxyisochromeno[6,5,4-mna]xanthene-1,3-dione (2464)

(48) To a solution of compound 2389 (2.0 g, 3.71 mmol) in tBuOH (110 mL) and 1,4-dioxane (30 mL) was added powder KOH (2.1 g, 37.10 mmol). The mixture was refluxed for 1 h. The yellow solution became orange after a few minutes. The solution was cooled to room temperature and poured into AcOH (100 mL). After 2 minutes, 2 N aqueous HCl (300 mL) was added. The orange precipitate was collected by filtration, first washed with water then with heptane and Et.sub.2O to remove most of the unreacted starting material 2389 and 2,6-diisopropylaniline. The precipitate was stirred in refluxing AcOH (70 mL) for 10 minutes and concentrated. The residue was coated on silica gel and purified by column chromatography (SiO.sub.2, eluent: DCM/Heptane 2/1 to remove remaining starting material then with DCM/Heptane 4/1 to 1/0). Compound 2646 (600 mg, 42%) was obtained as an yellow-orange solid. Fractions containing starting material 2389 were combined and purified by column chromatography (SiO.sub.2, eluent: DCM/Heptane 2/1) to give pure recovered compound 2646 (600 mg, 42%).

4. Mixture of 16-phenoxy-8H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[1,2-b]isoquinolin-8-one and 5-phenoxy-7H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[2,1-a]isoquinolin-7-one (2463)

(49) A suspension of 2464 (600 mg, 1.58 mmol) and o-phenylenediamine (853 mg, 7.89 mmol) in AcOH (100 mL) and 1,4-dioxane (20 mL) was refluxed for 16 h. The yellow suspension became an orange clear solution then an orange precipitate was formed. The mixture was cooled to room temperature and concentrated. The red solid obtained was triturated in MeOH (70 mL), collected by filtration on a glass filter, washed again with MeOH (450 mL) to remove excess of o-phenylenediamine and some other impurities then washed with heptane and dried under vacuum. Compound 2463 (mixture of isomers, 680 mg, 93%) was obtained as an orange solid. M+H=452.9.2. .sub.max (chloroform)=455 nm, =30900 and 481 nm, =33700. (em) (ethyl acetate) 496 nm and 529 nm.

(50) See also FIGS. 3b/3c (2463) and 4a (111 (2463)).

(51) Further materials were made, of which the structure formulas are indicated in FIGS. 5a and 5b.

Synthesis of a Mixture of 6,16-bis(4-(2,4,4-trimethylpentan-2-yl)phenoxy)-8H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[1,2-b]isoquinolin-8-one and 5,15-bis(4-(2,4,4-trimethylpentan-2-yl)phenoxy)-7H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[2,1-a]isoquinolin-7-one (2475)

(52) This compound was made in the same manner as described for the synthesis of 2442, but replacing phenol by 4-(2,4,4-trimethylpentan-2-yl)phenol.

(53) Compound 2475 was obtained as an orange-red solid. M+H=769.4. .sub.max (ethyl acetate)=456 nm, =23900 and 479 nm, =27700. (em) (ethyl acetate) 510 nm and 542 nm.

Separation of 2475 into its Isomers 6,16-bis(4-(2,4,4-trimethylpentan-2-yl)phenoxy)-8H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[1,2-b]isoquinolin-8-one (2475A) and 5,15-bis(4-(2,4,4-trimethylpentan-2-yl)phenoxy)-7H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[2,1-a]isoquinolin-7-one (2475B)

(54) Mixture 2475 (300 mg) was poured on top of a chromatography column (SiO.sub.2). Elution with DCM/Heptane 2/1 gave a first fraction containing 2475A (yellow DCM solution). After evaporation 175 mg of 2475A was obtained as orange solid. (em) (ethyl acetate) 510 nm. Further elution afforded a fraction containing 2475B (orange DCM solution). After evaporation 100 mg of 2475B was obtained as a red solid. (em) (ethyl acetate) 561 nm.

Synthesis of a Mixture of 16-(4-(2,4,4-trimethylpentan-2-yl)phenoxy)-8H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[1,2-b]isoquinolin-8-one and 5-(4-(2,4,4-trimethylpentan-2-yl)phenoxy)-7H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[2,1-a]isoquinolin-7-one (2485)

(55) This compound was made in the same manner as described for the synthesis of 2463, but replacing phenol by 4-(2,4,4-trimethylpentan-2-yl)phenol.

(56) Compound 2485 was obtained as an orange solid. M+H=574.8. .sub.max (ethyl acetate)=448 nm, =27000 and 473 nm, =29500. (em) (ethyl acetate) 498 nm and 531 nm.

Separation of 2485 into its Isomers 16-(4-(2,4,4-trimethylpentan-2-yl)phenoxy)-8H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[1,2-b]isoquinolin-8-one (2485A) and 5-(4-(2,4,4-trimethylpentan-2-yl)phenoxy)-7H-benzo[3,4]isochromeno[7,8,1-def]benzo[4,5]imidazo[2,1-a]isoquinolin-7-one (2485B)

(57) Mixture 2485 (330 mg) was poured on top of a chromatography column (SiO.sub.2). Elution with DCM/Heptane 3/1 gave a first fraction containing 2485A (yellow DCM solution). After evaporation 195 mg of 2485A was obtained as an orange solid. .sub.max (ethyl acetate)=448 nm, =31500 and 473 nm, =32500. (em) (ethyl acetate) 498 nm and 530 nm.

(58) Further elution with DCM afforded a fraction containing 2485B (orange DCM solution). After evaporation 120 mg of 2485B was obtained as a red solid. .sub.max (ethyl acetate)=475 nm, =31500 and 473 nm, =18100. (em) (ethyl acetate) 547 nm.

(59) The lifetime of 2410 and other systems in a PET (polyethylene terephthalate) film was tested by measuring the lifetime under illumination with blue light at 0.5-7 W/cm.sup.2 at 60 C. The concentration and the thickness of the layers were set so that the transmission of blue light was 90%.

(60) The lifetime is determined as 10% luminescence reduction extrapolated to the conditions for a TLED (0.016 W/cm.sup.2 blue and a temperature of 60 C. in air) assuming a linear dependence of the decay rate on the flux density. In the case of F083 a lifetime of about 100 hours was estimated while new compound 2410 showed a lifetime of about 12500 hours. This means an increase in lifetime of about 125 times.

(61) Lifetime of organic yellow emitting molecules in a PET matrix (in hours at which 10% has bleached at an exposure of 0.016 W/cm.sup.2 blue and a temperature of 60 C. in air), see table 1:

(62) TABLE-US-00001 TABLE 1 Lifetime measurements Compound Lifetime (hrs) F083 50-200 F170 150-400 Solvent yellow 98 400-650 2410A + 2410B 12500 2441A + 2441B 12500 2442A + 2442B 17000 2463A + 2463B 21000 2475A + 2475B 13000 2485A + 2485B 18000

(63) It appears that phenoxy substituted compounds have a longer lifetime. Further, it appears that G2 substitution may have an even stronger lifetime enhancement effect than G7 substituted compounds.

(64) Matrices than PET (or PET analogues) provide in general worse results. PETG and PET especially provide stable luminescent systems.

Examples of White Blends

Example 1

(65) Emission of various organic molecules excited by blue LED can be combined to produce white light. Herein, the emission from the molecules depicted in FIG. 3a (material 2410, see FIGS. 3a/4a) and N,N-Bis(2,6-diisopropylphenyl)-1,6,7,12-tetraphenoxyperylene-3,4:9,10-tetracarboxdiimide; CAS nr. 123174-58-3, also known as F305 (from BASF)), were combined with blue light to obtain white light with a spectrum shown in FIG. 4b. Such a white light can be produced showing the following values shown in the table below.

Example 2

(66) In this example the emission from the molecules depicted in FIG. 3a (material 2410, see FIG. 3a/4a) is combined with blue light and also with emission from a quantum dot with a emission maximum at 615 nm to obtain white light with a spectrum shown in FIG. 4c, and with values as shown in the table below.

Example 3

(67) In this example the emission from the molecules depicted in FIG. 3a (material 2410, see FIG. 3a/4a) is combined with blue light and also with emission from a red LED with a emission maximum at 615 nm to obtain white light with a spectrum shown in FIG. 4d, and with values as shown in the table below.

Example 4

(68) In this example the emission from the molecules depicted in FIG. 3a (material 2441, see FIG. 3c/4a) is combined with blue light and also with emission from a red luminescent material F305 to obtain white light with a spectrum shown in FIG. 4e, and with values as shown in the table below.

Example 5

(69) In this example the emission from the molecules depicted in FIG. 3a (material 2442, see FIGS. 3c/4a) is combined with blue light and also with emission from a red luminescent material F305 to obtain white light with a spectrum shown in FIG. 4f, and with values as shown in the table below.

(70) TABLE-US-00002 TABLE 2 White blends Lumen equivalent (Lm/W) CCT (K) CRI R9 Example 1 (blue + 2410 + F305) 311 3550 92 11 Example 2 (blue + 2410 + QDs) 350 3665 92 30 Example 3 (blue + 2410 + Red LED) 350 3700 90 44 Example 4 (blue + 2441 + F305) 290 3300 84 94 Example 5 (blue + 2442 + F305) 290 3500 85 93

(71) Hence, referring toamongst othersFIGS. 3A, 3b(C), 3C(A), 3C(B), 5A, 5B, the invention also provides in an embodiment luminescent material comprising a combination of at least two organic phosphors selected from the group consisting of (combinations): (i) 2410A+2410B, (ii) 2441A+2441B, (iii) 2442A+2442B, (iv) 2463A+2463B, (v) 2475A+2475B, and (vi) 2485A+2485B. The phrase 2410A+2410B and similar phrases refers to the combination of the isomers. Hence, the luminescent materials as described herein especially comprises a combination of two (related) isomers, and optionally more than one of such combination, such as e.g. a combination of 2410A+2410B and 2475A+2475B, etc. Hence, in embodiment the luminescent material comprises combinations of two isomers, (the combinations) selected from the above indicated six groups. The sets of isomers are depicted in the above mentioned drawings; the general formulas are amongst others indicated in FIG. 2A.

(72) As indicated above, we found after separation of the two isomers from the mixture that the one derived from structure 2410A has excellent spectral properties in the yellow region and a high quantum yield, exceeding 0.9. The other isomer derived from 2410B exhibits an emission in the orange region with a relatively low quantum yield. Thus the use of the first isomer leads to lamps with higher efficiency. Especially in the case when the rather soluble derivates 2475 and 2485 (see FIGS. 5a-5b) are used, separation by column chromatography may be executed. In all cases the first fraction contains the derivative with good spectral properties and high quantum yield. After further elution the other isomer could be isolated.

(73) We separated mixture 2485 into isomers 2485A and 2485B. The first isomer that was isolated by column chromatography was 2485A. In order to determine the structure of 2485A exactly, a CH 3 band coupling NMR spectrum was taken that showed such a coupling between the doublet of H.sup.B and the carbon of the carbonyl moiety. Thus derivatives of 2410A are the compounds that are obtained as first fraction from the chromatographic separation. In the same way mixture 2475 was separated in its two isomers by column chromatography (FIG. 5b). FIGS. 6a-6b show the normalized emission spectra of 2485, 2485A and 2485B and of 2475, 2475A and 2475B in ethyl acetate. Compounds 2485B and 2475B are clearly not yellow but orange emitters. Furthermore, the PLQE (photo luminescence quantum efficiency) of these range emitters (structure II, derived from 2410B) is rather low as shown in the table II. These values will of course also affect the PLQE of the mixtures 2475 and 2485.

(74) TABLE-US-00003 TABLE II optical and lifetime data on mixtures and pure components Life- Number Structure G2 G7 PLQE time 2485 mix C.sub.8H.sub.17C.sub.6H.sub.4O H 0.68 11 Khr 2485A I (A) C.sub.8H.sub.17C.sub.6H.sub.4O H 0.90 17 Khr 2485B II (B) C.sub.8H.sub.17C.sub.6H.sub.4O H 0.46 18 Khr 2475 mix C.sub.8H.sub.17C.sub.6H.sub.4O C.sub.8H.sub.17C.sub.6H.sub.4O 0.77 13 Khr 2475A I (A) C.sub.8H.sub.17C.sub.6H.sub.4O C.sub.8H.sub.17C.sub.6H.sub.4O 0.90 10 Khr 2475B II (B) C.sub.8H.sub.17C.sub.6H.sub.4O C.sub.8H.sub.17C.sub.6H.sub.4O 0.52 23 Khr

(75) The structures I (derived from 2410A) on the other hand have a good spectrum and a high quantum yield. We therefore suggest the use of the following organic phosphor isomers and its derivatives or similarities in phosphor converted LED applications as (green/yellow) emitters as defined by formula IA, wherein for instance G1-G12 are independently hydrogen, a linear or branched alkyl group or oxygen-containing alkyl group C.sub.nH.sub.2n+1O.sub.m, n being an integer from 1 to 16 and m<n/2 or 0, fluorine, chlorine, or Y, OY or NRY. R being an alkyl or aryl group. D,E,I,L and M are H, F, Cl, a linear or branched alkyl group or oxygen-containing alkyl group C.sub.nH.sub.2n+1O.sub.m, n being an integer from 1 to 16 and m<n/2 or 0; especially minimally two of these groups are hydrogen atoms. Especially, minimally 4 of the groups G1-G8 are hydrogen atoms. Further, one or more of G1-G12, especially one, may also contain a covalent link to a polymer backbone in case of incorporation in a polymer.

(76) We tested the lifetime of the molecules in a PET (polyethylene terephthalate) film by measuring the lifetime under illumination with blue light at 4.1/W/cm2 at 60 C. The concentration and the thickness of the layer were set so that the transmission of blue light was 90%.

(77) The lifetime is estimated as 10% reduction under conditions for a TLED (0.016 W/cm.sup.2 blue and a temperature of 60 C. in air). In the case of F083 a lifetime of about 150 hours was estimated while compounds 2485A and 2475A showed a lifetime of more than 10000 hours. This means an increase in lifetime of about 60 times while having good spectral properties and high quantum yield. Normalized emission and excitation spectra of the 2485 and 2475 isomers are shown in FIGS. 6a-6c.