Composition containing a metal complex and organic compound, and light-emitting element using said compound

1. A composition comprising a metal complex represented by the following formula (1), and an organic compound, wherein a difference between an absolute value of a lowest unoccupied molecular orbital energy level of the metal complex and an absolute value of a lowest unoccupied molecular orbital energy level of the organic compound as calculated by a computational scientific approach wherein calculations are performed by a density functional method at B3LYP level with LANL2DZ basis function for the central metal atom and 6-31 g*basis function for atoms other than the central metal atom using Gaussian03 quantum chemical calculation program is less than 0.40 eV:

wherein M is a metal atom of ruthenium, rhodium, palladium, osmium, iridium, or platinum, and R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , and R 8 each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an alkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, an arylalkylthio group, an acyl group, an acyloxy group, an amide group, an acid imide group, an imine residue, a substituted amino group, a substituted silyl group, a substituted silyloxy group, a substituted silylthio group, a substituted silylamino group, a monovalent heterocyclic group, a heteroaryloxy group, a heteroarylthio group, an arylalkenyl group, an arylalkynyl group, a substituted carboxyl group, or a cyano group, or R 3 and R 4 , or R 5 and R 6 may be bonded to form a ring, wherein R 3 is not a monovalent heterocyclic group, provided that R 2 is a hydrogen atom and R 7 is a group represented by the following formula (2-7):

wherein R′ is a hydrogen atom, a halogen atom, and alkyl group, an alkoxy group, an alkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, an arylalkylthio group, an acyl group, an acyloxy group, an amide group, an acid imide group, an imine residue, a substituted amino group, a substituted silyl group, a substituted silyloxy group, a substituted silylthio group, a substituted silylamino group, a monovalent heterocyclic group, a heteroaryloxy group, a heteroarylthio group, an arylalkenyl group, an arylalkynyl group, a substituted carboxyl group, or a cyano group; and a plurality of R′ may be the same or different,

m is an integer of 1 to 3, and n is an integer of 0 to 2; a moiety represented by the following formula (3):

represents a monoanionic bidentate ligand; and R x and R y are atoms bonded to the metal atom M and each independently represent a carbon atom, an oxygen atom, or a nitrogen atom.

2. The composition according to claim 1 , wherein the organic compound is a compound represented by the following formula (A′):

wherein Ar y1 , Ar y2 , and Ar y3 each independently represent an aryl group or a monovalent heterocyclic group; Z 6 to Z 8 each independently represent a carbon atom or a nitrogen atom, provided that at least two of Z 6 to Z 8 are nitrogen atoms; and when any of Z 6 to Z 8 is a carbon atom, a hydrogen atom bonded to the carbon atom may be replaced by a substituent,

or a compound having a residue of the foregoing compound.

3. The composition according to claim 2 , wherein the compound having a residue of a compound represented by the formula (A′) is a compound having a divalent group represented by the following formula (A):

wherein Ar x1 and Ar x2 represent an arylene group or a divalent heterocyclic group; and Ar y3 and Z 6 to Z 8 are as defined above.

4. The composition according to claim 2 , wherein the Z 6 to the Z 8 are nitrogen atoms.

5. The composition according to claim 3 , wherein the compound having a divalent group represented by the formula (A) is a polymer compound having a divalent group represented by the formula (A) as a repeating unit.

6. The composition according to claim 5 , wherein the polymer compound having a divalent group represented by the formula (A) as a repeating unit further has a repeating unit represented by the following formula (B):

—(Ar 2 )—  (B)

wherein Ar 2 represents an arylene group which may have a substituent, or a divalent heterocyclic group which may have a substituent.

7. The composition according to claim 1 , wherein the metal complex represented by the formula (1) is a metal complex represented by the following formula (1a):

wherein M, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , and R 8 , and m are as defined above.

8. The composition according to claim 1 , wherein the M is a platinum atom or an iridium atom.

9. The composition according to claim 1 , showing phosphorescence emission in which at least one peak wavelength of a photoluminescence emission spectrum is 550 nm to 800 nm.

10. The composition according to claim 1 , comprising a solvent or a dispersion medium.

11. A film comprising a composition according to claim 1 .

12. A device comprising a composition according to claim 1 .

13. The device according to claim 12 , wherein the device is a light-emitting device.

14. A surface light source comprising a device according to claim 13 .

15. A light comprising a device according to claim 13 .

16. A compound having a residue of a metal complex represented by the following formula (1), and a residue of an organic compound, wherein a difference between an absolute value of a lowest unoccupied molecular orbital energy level of the metal complex and an absolute value of a lowest unoccupied molecular orbital energy level of the organic compound as calculated by a computational scientific approach wherein calculations are performed by a density functional method at B3LYP level with LANL2DZ basis function for the central metal atom and 6-31 g*basis function for atoms other than the central metal atom using Gaussian03 quantum chemical calculation program is less than 0.40 eV:

wherein M is a metal atom of ruthenium, rhodium, palladium, osmium, iridium, or platinum, and R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , and R 8 each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an alkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, an arylalkylthio group, an acyl group, an acyloxy group, an amide group, an acid imide group, an imine residue, a substituted amino group, a substituted silyl group, a substituted silyloxy group, a substituted silylthio group, a substituted silylamino group, a monovalent heterocyclic group, a heteroaryloxy group, a heteroarylthio group, an arylalkenyl group, an arylalkynyl group, a substituted carboxyl group, or a cyano group, or R 3 and R 4 , or R 5 and R 6 may be bonded to form a ring, wherein R 3 is not a monovalent heterocyclic group, provided that R 2 is a hydrogen atom and R 7 is a group represented by the following formula (2-7):

wherein R′ is a hydrogen atom, a halogen atom, and alkyl group, an alkoxy group, an alkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, an arylalkylthio group, an acyl group, an acyloxy group, an amide group, an acid imide group, an imine residue, a substituted amino group, a substituted silyl group, a substituted silyloxy group, a substituted silylthio group, a substituted silylamino group, a monovalent heterocyclic group, a heteroaryloxy group, a heteroarylthio group, an arylalkenyl group, an arylalkynyl group, a substituted carboxyl group, or a cyano group; and a plurality of R′ may be the same or different,

m is an integer of 1 to 3, and n is an integer of 0 to 2; a moiety represented by the following formula (3):

represents a monoanionic bidentate ligand; and R x and R y are atoms bonded to the metal atom M and each independently represent a carbon atom, an oxygen atom, or a nitrogen atom.