Organometallic Iridium Complex, Light-Emitting Element, Light-Emitting Device, Electronic Device, and Lighting Device

Abstract

An organometallic iridium complex has high emission efficiency and a long lifetime. The iridium complex includes the structure represented by Formula (G1). In the formula, Ar represents a substituted or unsubstituted arylene group having 6 to 13 carbon atoms. R 1 to R 6 independently represent any one of hydrogen and a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and one of R 2 and R 6 represents the alkyl group. X represents a carbon atom or a nitrogen atom, and when X represents a carbon atom, hydrogen or an alkyl group having 1 to 6 carbon atoms is bonded to the carbon atom. A dihedral angle between a ring bonded to R 1 and a phenyl group bonded to R 2 to R 6 is 30° or more and 90° or less. An interior angle of the pyridine/pyrimidine ring facing R 1 is within a range of 118° to 122°.

1 . A compound comprising a structure represented by Formula (G1): 
       
         
           
           
               
               
           
         
         wherein: 
         Ar represents an unsubstituted arylene group having 6 to 13 carbon atoms; 
         R 1  to R 6  independently represent any one of hydrogen and a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms; 
         at least one of R 2  and R 6  represents an alkyl group having 1 to 6 carbon atoms; 
         X represents any one of a carbon atom and a nitrogen atom, the carbon atom having any one of hydrogen and an alkyl group having 1 to 6 carbon atoms; 
         the other of R 2  and R 6  represents hydrogen, or one of R 1  and R 3  to R 5  represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms; 
         a dihedral angle between a ring bonded to R 1  and a phenyl group bonded to R 2  to R 6  is greater than or equal to 30° and less than or equal to 90°; and 
         a dihedral angle between the ring bonded to R 1  and a ring of Ar is greater than or equal to 0° and less than 2°. 
       
     
     
         2 . The compound according to  claim 1 , wherein R 1  represents hydrogen. 
     
     
         3 . The compound according to  claim 1 , wherein one of R 2  and R 6  represents hydrogen. 
     
     
         4 . A light-emitting device comprising the compound according to  claim 1 . 
     
     
         5 . A lighting device comprising the compound according to  claim 4 . 
     
     
         6 . An electronic device comprising the light-emitting device according to claim  4 . 
     
     
         7 . A compound represented by Formula (G5): 
       
         
           
           
               
               
           
         
         wherein: 
         R 1  to R 6  independently represent any one of hydrogen and a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms; 
         R 7  to R 9  each represent hydrogen; 
         at least one of R 2  and R 6  represents an alkyl group having 1 to 6 carbon atoms; 
         X represents any one of a carbon atom and a nitrogen atom, the carbon atom having any one of hydrogen and an alkyl group having 1 to 6 carbon atoms; 
         L represents a monoanionic ligand; 
         the other of R 2  and R 6  represents hydrogen, or one of R 1  and R 3  to R 5  represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms; 
         a dihedral angle between a ring bonded to R 1  and a phenyl group bonded to R 2  to R 6  is greater than or equal to 30° and less than or equal to 90°; 
         a dihedral angle between the ring bonded to R 1  and a phenyl group bonded to R 7  to R 9  is greater than or equal to 0° and less than 2°; and 
         a bond angle denoted by a is greater than or equal to 120° and less than 129°. 
       
     
     
         8 . The compound according to  claim 7 ,
 wherein:   the monoanionic ligand is represented by any one of Formulae (L1) to (L7):   
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         R 71  to R 109  independently represent any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a halogen, a vinyl group, a substituted or unsubstituted haloalkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, and a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms; 
         A 1  to A 3  independently represent any one of nitrogen and carbon bonded to hydrogen or to a substituent R; and 
         the substituent R is any one of an alkyl group having 1 to 6 carbon atoms, a halogen, a haloalkyl group having 1 to 6 carbon atoms, and a phenyl group. 
       
     
     
         9 . The compound according to  claim 7 , wherein R 3  to R 5  represent hydrogen. 
     
     
         10 . The compound according to  claim 7 , wherein R 1  represents hydrogen. 
     
     
         11 . The compound according to  claim 7 , wherein one of R 2  and R 6  represents hydrogen. 
     
     
         12 . A compound represented by Formula (G6): 
       
         
           
           
               
               
           
         
         wherein: 
         R 1 , R 2  and R 6  independently represent any one of hydrogen and a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms; 
         R 7  to R 9  each represent hydrogen; 
         one of R 2  and R 6  represents an alkyl group having 1 to 6 carbon atoms; 
         the other one of R 2  and R 6  represents hydrogen; 
         X represents any one of a carbon atom and a nitrogen atom, the carbon atom having any one of hydrogen and an alkyl group having 1 to 6 carbon atoms; 
         L represents a monoanionic ligand; 
         a dihedral angle between a ring bonded to R 1  and a phenyl group bonded to R 2  and R 6  is greater than or equal to 30° and less than or equal to 90°; 
         a dihedral angle between the ring bonded to R 1  and a phenyl group bonded to R 7  to R 9  is greater than or equal to 0° and less than 2°; and 
         a bond angle denoted by a is greater than or equal to 120° and less than 129°. 
       
     
     
         13 . The compound according to  claim 12 ,
 wherein:   the monoanionic ligand is represented by any one of Formulae (L1) to (L7):   
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         R 71  to R 109  independently represent any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a halogen, a vinyl group, a substituted or unsubstituted haloalkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, and a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms; 
         A 1  to A 3  independently represent any one of nitrogen and carbon bonded to hydrogen or to a substituent R; and 
         the substituent R is any one of an alkyl group having 1 to 6 carbon atoms, a halogen, a haloalkyl group having 1 to 6 carbon atoms, and a phenyl group. 
       
     
     
         14 . A light-emitting device comprising the compound according to  claim 12 . 
     
     
         15 . A lighting device comprising the compound according to  claim 12 . 
     
     
         16 . An electronic device comprising the light-emitting device according to  claim 14 .