Light-emitting element and novel iridium complexes

1. A light-emitting element comprising:

a pair of electrodes; and

at least one organic compound layer comprising a light-emitting layer provided between the electrodes,

the light-emitting layer comprising at least one compound represented by the formula (1):

wherein R 11 represents a substituent, R 12 represents a hydrogen atom or a substituent, Y 11 represents a substituted or unsubstituted nitrogen atom or a substituted or unsubstituted carbon atom, Z 11 represents a linking group, M 11 represents a transition metal ion, L 11 represents a ligand, X 11 represents a counter ion, a bond between Y 11 and a nitrogen atom is a single bond or a double bond, a bond between R 11 and the nitrogen atom is a single bond or a double bond, n 11 represents 0 or 1, n 12 represents 0 or 1, provided that when n 12 is 0, Y 11 and R 11 may be linked together to form a nitrogen-containing hetero ring, m 11 represents an integer of 1 to 3, m 12 represents an integer of 0 to 8, and m 13 represents an integer of 0 to 3, with at least one electron-withdrawing group being contained in the compound represented by the formula (1),

wherein the light-emitting layer comprises a host compound and the compound represented by the formula (1), and the host compound has an energy level of a lowest triplet excited state (T 1 level) of 62 kcal/mol (259 kJ/mol) to 85 kcal/mol (355 kJ/mol) and,

wherein a layer adjacent to the light-emitting layer comprises a compound having an energy level of a lowest triplet excited state (T 1 level) of 62 kcal/mol (259 kJ/mol) to 85 kcat/mol (355 kJ/mol).

2. The light-emitting element of claim 1 , wherein the compound represented by the formula (1) is a compound represented by the formula (2):

wherein Z 21 represents a linking group, L 21 represents a ligand, n 21 represents 0 or 1, in 21 represents an integer of 1 to 3, in 22 represents an integer of 0 to 4, and Q 21 represents atoms necessary for forming a nitrogen-containing hetero ring.

3. The light-emitting element of claim 1 , wherein the compound represented by the formula (1) is a compound represented by the formula (3):

wherein Z 31 represents a linking group, n 31 represents 0 or 1, Q 31 represents atoms necessary for forming a nitrogen-containing hetero ring, and R31, R 32 , R 33 , R 34 , R 35 , R 36 , R 37 and R 38 each independently represents a hydrogen atom or a substituent.

4. The light-emitting element of claim 1 , wherein the electron-withdrawing group has a Hammett's σ value of at least 0.1.

5. The light-emitting element of claim 1 , wherein the electron-withdrawing group is one of a fluorine atom, a trifluoromethyl group, an acetyl group, a methanesulfonyl group, a trifluoroacetyl group, a trifluoromethanesulfonyl group and a cyano group.

6. The light-emitting element of claim 1 , wherein the compound represented by the formula (1) has at least one fluorine atom.

7. The light-emitting element of claim 1 , which comprises a layer comprising a compound having an ionization potential of 5.9 eV or more between a cathode and the light-emitting layer.

8. The light-emitting element of claim 1 , wherein the light-emitting layer comprises a host compound and the compound represented by the formula (1), and the host compound has an energy level of a lowest triplet excited state (Ti level) of 65 kcal/mol (272 kJ/mol) to 80 kcal/inol (334 kJ/mol).

9. The light-emitting element of claim 1 , wherein M 11 represents rhenium ion or ruthenium ion.

10. The light-emitting element of claim 1 , wherein M 11 is iridium ion, m 11 is 2 and m 12 is 1.

11. The light-emitting element of claim 1 , wherein Z 11 represents an alkylene group, an arylene group, a heteroarylene group, a nitrogen-containing heterocyclic linking group, an oxygen atom linking group, a nitrogen atom linking group, a thiocarbonyl linking group, a sulfoxide linking group, a sulfonyl linking group and a linking group composed of a combination of these linking groups.

12. The light-emitting element of claim 1 , wherein Y 11 represents a substituted or unsubstituted nitrogen atom and Y 11 and R 11 may be linked together to form a nitrogen-containing hetero ring when n 12 is 0.

13. A light-emitting element comprising:

a pair of electrodes; and

at least one organic compound layer comprising a light-emitting layer provided between the electrodes,

the light-emitting layer comprising at least one compound represented by the formula (5):

wherein R 511 represents a substituent, R 512 represents a hydrogen atom or a substituent, Y 51 represents a substituted or unsubstituted nitrogen atom or a substituted or unsubstituted carbon atom, Z 51 represents an alkylene group, a heteroarylene group, a nitrogen-containing heterocyclic linking group, an oxygen atom linking group, a nitrogen atom linking group, a thiocarbonyl linking group, a sulfoxide linking group, a sulfonyl linking group and a linking group composed of a combination of these linking groups, M 51 represents a transition metal ion, L 51 represents a ligand that forms at least one bond with a metal and at least one of these bonds is a non-carbon-metal bond, X 51 represents a counter ion, a bond between Y 51 and a nitrogen atom is a single bond or a double bond, a bond between R 511 and the nitrogen atom is a single bond or a double bond, n 51 represents, n 52 represents 0 or 1, provided that when n 52 is 0, Y 51 and R 511 may be linked together to form a nitrogen-containing hetero ring, m 51 represents an integer of 1 to 3, m 52 represents an integer of 0 to 8, and m 53 represents an integer of 0 to 3.

14. The light-emitting element of claim 13 , wherein the compound represented by the formula (5) is a compound represented by the formula (6):

wherein Z 61 has the same meaning as Z 51 , L 61 represents a ligand that forms at least one bond with a metal and at least one of these bonds is a non-carbon-metal bond, n 61 represents 1, m 61 represents an integer of 1 to 3, m 62 represents an integer of 0 to 4, and Q 61 represents atoms necessary for forming a nitrogen-containing hetero ring.

15. The light-emitting element of claim 13 , wherein L 51 represents a ligand which is attached to a metal atom with at least one atom selected from the group consisting of a nitrogen atom, an oxygen atom, a sulfur atom and a phosphorus atom.

16. The light-emitting element of claim 13 , wherein L 51 represents a bidentate ligand forming a non-carbon-metal bond.

17. The light-emitting element of claim 13 , wherein L 5 represents a bidentate ligand which is attached to a metal with two nitrogen atoms.

18. The light-emitting element of claim 7 , wherein the bidentate ligand is selected from bipyridyl, phenanthroline, pyrazolyl pyridine, benzimidazolyl pyridine and pyromethene.

19. The light-emitting element of claim 13 , wherein L 51 represents a bidentate ligand which is attached to a metal with a nitrogen atom and an oxygen atom.

20. The light-emitting element of claim 19 , wherein the bidentate ligand is picolinic acid or 2-hydroxymethylpyridine.

21. The light-emitting element of claim 13 , wherein L 51 represents a bidentate ligand which is attached to a metal with two oxygen atoms.

22. The light-emitting element of claim 21 , wherein the bidentate ligand is acetyl acetone or acetyl.

23. A light-emitting element comprising:

a pair of electrodes; and

at least one organic compound layer comprising a light-emitting layer provided between the electrodes,

the light-emitting layer comprising at least one compound represented by the formula (5):

wherein R 511 represents a substituent, R 512 represents a hydrogen atom or a substituent, Y 51 represents a substituted or unsubstituted nitrogen atom or a substituted or unsubstituted carbon atom, Z 51 represents a linking group, M 51 represents a transition metal ion, L 51 represents a bidentate ligand which is attached to a metal with two nitrogen atoms, X 51 represents a counter ion, a bond between Y 51 and a nitrogen atom is a single bond or a double bond, a bond between R 511 and the nitrogen atom is a single bond or a double bond, n 51 represents 0 or 1, n 52 represents 0 or 1, provided that when n 52 is 0, Y 51 and R 511 may be linked together to form a nitrogen-containing hetero ring, m 51 represents an integer of 1 to 3, m 52 represents an integer of 1 to 8, and m 53 represents an integer of 0 to 3.

24. A light-emitting element according to claim 23 , wherein the bidentate ligand is selected from bipyridyl, phenanthroline, pyrazolyl pyridine, benzimidazolyl pyridine and pyromethene.

25. A light-emitting element comprising:

a pair of electrodes; and

at least one organic compound layer comprising a light-emitting layer provided between the electrodes,

the light-emitting layer comprising at least one compound represented by the formula (5):

wherein R 511 represents a substituent, R 512 represents a hydrogen atom or a substituent, Y 51 represents a substituted or unsubstituted nitrogen atom or a substituted or unsubstituted carbon atom, Z 51 represents a linking group, M 51 represents a transition metal ion, L 51 represents a bidentate ligand which is attached to a metal with a nitrogen atom and an oxygen atom wherein the bidentate ligand is picolinic acid or 2-hydroxymethylpyridine , X 51 represents a counter ion, a bond between Y 51 and a nitrogen atom is a single bond or a double bond, a bond between R 511 and the nitrogen atom is a single bond or a double bond, n 51 represents 0 or 1, n 52 represents 0 or 1, provided that when n 52 is 0, Y 511 and R 511 may be linked together to form a nitrogen-containing hetero ring, m 51 represents an integer of 1 to 3, m 52 represents an integer of 1 to 8, and in 53 represents an integer of 0 to 3.

26. A light-emitting element comprising:

a pair of electrodes; and

at least one organic compound layer comprising a light-emitting layer provided between the electrodes,

the light-emitting layer comprising at least one compound represented by the formula (5):

wherein R 511 represents a substituent, R 512 represents a hydrogen atom or a substituent, Y 51 represents a substituted or unsubstituted nitrogen atom or a substituted or unsubstituted carbon atom, Z 51 represents a linking group, M 51 represents a transition metal ion, L 51 represents a bidentate ligand which is attached to a metal with two oxygen atoms, X 51 represents a counter ion, a bond between Y 51 and a nitrogen atom is a single bond or a double bond, a bond between R 511 and the nitrogen atom is a single bond or a double bond, n 51 represents 0 or 1, n 52 represents 0 or 1, provided that when n 52 is 0, Y 51 and R 511 may be linked together to form a nitrogen-containing hetero ring, m 51 represents an integer of 1 to 3, in 52 represents an integer of 1 to 8, and m 53 represents an integer of 0 to 3.

27. A light-emitting element according to claim 26 , wherein the bidentate ligand is acetyl acetone or acetyl.

28. A light-emitting element comprising:

a pair of electrodes; and

at least one organic compound layer comprising a light-emitting layer provided between the electrodes,

the light-emitting layer comprising at least one compound represented by formula (7):

wherein R 70 , R 71 , R 72 and R 79 each independently represents a hydrogen atom or a substituent, L 71 represents a ligand forming a non-carbon-metal bond and each bond between the ligand L 71 and the metal Ir is a non-carbon metal bond, m 71 represents an integer of 1 to 3, and m 72 represents an integer of 0 to 4.