Heteroleptic carbene complexes and the use thereof in organic electronics

Abstract

The present invention relates to heteroleptic complexes comprising a phenylimidazole or phenyltriazole unit bonded via a carbene bond to a central metal atom, and phenylimidazole ligands attached via a nitrogen-metal bond to the central atom, to OLEDs which comprise such heteroleptic complexes, to light-emitting layers comprising at least one such heteroleptic complex, to a device selected from the group consisting of illuminating elements, stationary visual display units and mobile visual display units comprising such an OLED, to the use of such a heteroleptic complex in OLEDs, for example as emitter, matrix material, charge transport material and/or charge blocker.

1 . A heteroleptic complex of the general formula (I) 
       
         
           
           
               
               
           
         
         in which M, A 1 , A 2 , n, m, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13  and R 14  are each defined as follows: 
         M is a metal atom selected from the group consisting of Ir and Pt, 
         A 1 , A 2  are each independently N or C, 
         n, m are each independently 1 or 2, where, if M is Pt, the sum of n and m is 2, or, if M is Ir, the sum of n and m is 3, 
         R 1  is a linear or branched alkyl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 1 to 20 carbon atoms, cycloalkyl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 3 to 20 carbon atoms, substituted or unsubstituted aryl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 5 to 18 carbon atoms and/or heteroatoms, 
         R 2 , R 3  are each independently hydrogen, linear or branched alkyl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 1 to 20 carbon atoms, cycloalkyl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 3 to 20 carbon atoms, substituted or unsubstituted aryl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 5 to 18 carbon atoms and/or heteroatoms, 
         R 4 , R 5 , 
         R 6 , R 7  are each independently hydrogen, substituent with donor or acceptor action, linear or branched alkyl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 1 to 20 carbon atoms, cycloalkyl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 3 to 20 carbon atoms, substituted or unsubstituted aryl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 5 to 18 carbon atoms and/or heteroatoms,
 or 
 R 4  and R 5  or R 5  and R 6  and/or R 6  and R 7  together form a saturated, unsaturated or aromatic carbon ring optionally interrupted by at least one heteroatom and having a total of 5 to 30 carbon atoms or heteroatoms, 
 
         R 8 , R 9  are each independently a free electron pair if A 1  or A 2  is N, or, if A 1  or A 2  is C, hydrogen, linear or branched alkyl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 1 to 20 carbon atoms, cycloalkyl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 3 to 20 carbon atoms, substituted or unsubstituted aryl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 5 to 18 carbon atoms and/or heteroatoms, 
         R 10  linear or branched alkyl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 1 to 20 carbon atoms, cycloalkyl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 3 to 20 carbon atoms, substituted or unsubstituted aryl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 5 to 18 carbon atoms and/or heteroatoms 
         R 11 , R 12 , 
         R 13 , R 14  are each independently hydrogen, substituent with donor or acceptor action, linear or branched alkyl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 1 to 20 carbon atoms, cycloalkyl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 3 to 20 carbon atoms, substituted or unsubstituted aryl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl radical optionally interrupted by at least one heteroatom, optionally bearing at least one functional group and having 5 to 18 carbon atoms and/or heteroatoms,
 or 
 R 11  and R 12  or R 12  and R 13  and/or R 13  and R 14  together form a saturated, unsaturated or aromatic carbon ring optionally interrupted by at least one heteroatom and having a total of 5 to 30 carbon atoms and/or heteroatoms 
 
         and/or 
         R 1  and R 14  together form a saturated or unsaturated, linear or branched bridge optionally comprising heteroatoms, aromatic units, heteroaromatic units and/or functional groups and having a total of 1 to 30 carbon atoms and/or heteroatoms, to which a substituted or unsubstituted, five- to eight-membered ring comprising carbon atoms and/or heteroatoms, preferably a six-membered aromatic ring, is optionally fused, 
         and/or 
         if A 1  is C, R 7  and R 8  together form a saturated or unsaturated, linear or branched bridge optionally comprising heteroatoms, aromatic units, heteroaromatic units and/or functional groups and having a total of 1 to 30 carbon atoms and/or heteroatoms, to which a substituted or unsubstituted, five- to eight-membered ring comprising carbon atoms and/or heteroatoms, preferably a six-membered aromatic ring, is optionally fused. 
       
     
     
         2 . A heteroleptic complex according to  claim 1 , wherein M, A 1 , A 2 , n, m, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13  and R 14  are each defined as follows:
 M is Ir,   A 1 , A 2  is C,   n, m are each independently 1 or 2, where the sum of n and m is 3,   R 1  is a linear or branched alkyl radical having 1 to 20 carbon atoms, substituted or unsubstituted aryl radical having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl radical having 5 to 18 carbon atoms and/or heteroatoms,   R 2 , R 3  are each independently hydrogen, linear or branched alkyl radical having 1 to 20 carbon atoms, substituted or unsubstituted aryl radical having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl radical having 5 to 18 carbon atoms and/or heteroatoms,   R 4 , R 5 ,   R 6 , R 7  are each hydrogen
 or 
   R 4  and R 5  or R 5  and R 6  or R 6  and R 7  together form a saturated, unsaturated or aromatic ring optionally interrupted by at least one heteroatom and having a total of 5 to 30 carbon atoms and/or heteroatoms,   R 8 , R 9  are each hydrogen,   R 10  is a linear or branched alkyl radical having 1 to 20 carbon atoms, substituted or unsubstituted aryl radical having 6 to 30 carbon atoms, and   R 11 , R 12 ,   R 13 , R 14  are each independently hydrogen or linear or branched alkyl radical having 1 to 20 carbon atoms,   and/or   R 1  and R 14  together form a saturated or unsaturated, linear or branched bridge optionally comprising heteroatoms, aromatic units, heteroaromatic units and/or functional groups and having a total of 1 to 30 carbon atoms and/or heteroatoms, to which a substituted or unsubstituted, five- to eight-membered ring comprising carbon atoms and/or heteroatoms, preferably a six-membered aromatic ring, is optionally fused,   and/or   R 7  and R 8  together form a saturated or unsaturated, linear or branched bridge optionally comprising heteroatoms, aromatic units, heteroaromatic units and/or functional groups and having a total of 1 to 30 carbon atoms and/or heteroatoms, to which a substituted or unsubstituted, five- to eight-membered ring comprising carbon atoms and/or heteroatoms, preferably a six-membered aromatic ring, is optionally fused.   
     
     
         3 . A heteroleptic complex according to  claim 1 , wherein M, A 1 , A 2 , n, m, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13  and R 14  are each defined as follows:
 M is Ir,   A 1 , A 2  are each N or C, where A 1 =N when A 2 =C and A 1 =C when A 2 =N   n, m are each independently 1 or 2, where the sum of n and m is 3,   R 1  is a linear or branched alkyl radical having 1 to 20 carbon atoms, substituted or unsubstituted aryl radical having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl radical having 5 to 18 carbon atoms and/or heteroatoms,   R 2 , R 3  are each independently hydrogen, linear or branched alkyl radical having 1 to 20 carbon atoms, substituted or unsubstituted aryl radical having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl radical having 5 to 18 carbon atoms and/or heteroatoms,   R 4 , R 5 ,   R 6 , R 7  are each hydrogen   or   R 4  and R 5  or R 5  and R 6  or R 6  and R 7  together form a saturated, unsaturated or aromatic ring optionally interrupted by at least one heteroatom and having a total of 5 to 30 carbon atoms and/or heteroatoms,   R 8 , R 9  are each independently a free electron pair if A 1  or A 2  is N, or, if A 1  or A 2  is C, hydrogen, linear or branched alkyl radical having 1 to 20 carbon atoms, substituted or unsubstituted aryl radical having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl radical having 5 to 18 carbon atoms and/or heteroatoms,   R 10  linear or branched alkyl radical having 1 to 20 carbon atoms, substituted or unsubstituted aryl radical having 6 to 30 carbon atoms, and   R 11 , R 12 ,   R 13 , R 14  hydrogen or linear or branched alkyl radical having 1-20 carbon atoms   and/or   R 1  and R 14  together form a saturated or unsaturated, linear or branched bridge optionally comprising heteroatoms, aromatic units, heteroaromatic units and/or functional groups and having a total of 1 to 30 carbon atoms and/or heteroatoms, to which a substituted or unsubstituted, five- to eight-membered ring comprising carbon atoms and/or heteroatoms, preferably a six-membered aromatic ring, is optionally fused,   and/or   if A 1  is C, R 7  and R 8  together form a saturated or unsaturated, linear or branched bridge optionally comprising heteroatoms, aromatic units, heteroaromatic units and/or functional groups and having a total of 1 to 30 carbon atoms and/or heteroatoms, to which a substituted or unsubstituted, five- to eight-membered ring comprising carbon atoms and/or heteroatoms, preferably a six-membered aromatic ring, is optionally fused.   
     
     
         4 . A heteroleptic complex according to  claim 1 , wherein M, A 1 , A 2 , n, m, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13  and R 14  are each defined as follows:
 M is Ir,   A 1  is C,   A 2  is N or C,   n, m are each independently 1 or 2, where the sum of n and m is 3,   R 1  is a linear or branched alkyl radical having 1 to 20 carbon atoms, substituted or unsubstituted aryl radical having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl radical having 5 to 18 carbon atoms and/or heteroatoms,   R 2 , R 3  are each independently hydrogen, linear or branched alkyl radical having 1 to 20 carbon atoms, substituted or unsubstituted aryl radical having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl radical having 5 to 18 carbon atoms and/or heteroatoms,   R 4 , R 5 ,   R 6  are each independently hydrogen, linear or branched alkyl radical having 1 to 20 carbon atoms, substituted or unsubstituted aryl radical having 6 to 30 carbon atoms,   R 7 , R 8  together form an unsaturated C 2  bridge, to which a substituted or unsubstituted, five- to eight-membered ring comprising carbon atoms and/or heteroatoms, may be fused,   R 9  is a free electron pair if A 2  is N or, if A 2  is C, hydrogen, linear or branched alkyl radical having 1 to 20 carbon atoms, substituted or unsubstituted aryl radical having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl radical having 5 to 18 carbon atoms and/or heteroatoms,   R 10  is a linear or branched alkyl radical having 1 to 20 carbon atoms, substituted or unsubstituted aryl radical having 6 to 30 carbon atoms, and   R 11 , R 12 ,   R 13 , R 14  are each independently hydrogen or linear or branched alkyl radical having 1 to 20 carbon atoms,   and/or   R 1  and R 14  together form a saturated or unsaturated, linear or branched bridge optionally comprising heteroatoms, aromatic units, heteroaromatic units and/or functional groups and having a total of 1 to 30 carbon atoms and/or heteroatoms, to which a substituted or unsubstituted, five- to eight-membered ring comprising carbon atoms and/or heteroatoms, preferably a six-membered aromatic ring, is optionally fused.   
     
     
         5 . A heteroleptic complex according to any of  claims 1  to  4 , wherein R 1  is an aryl radical which has 6 to 30 carbon atoms and is substituted in the ortho,ortho′ positions in each case by a linear or branched alkyl radical having 1 to 10 carbon atoms. 
     
     
         6 . A heteroleptic complex according to any of  claims 1  to  5 , wherein R 1  and R 14  together form a saturated or unsaturated, linear or branched bridge optionally comprising heteroatoms, aromatic units, heteroaromatic units and/or functional groups and having a total of 1 to 30 carbon atoms and/or heteroatoms, to which a substituted or unsubstituted, five- to eight-membered ring comprising carbon atoms and/or heteroatoms, preferably a six-membered aromatic ring, is optionally fused. 
     
     
         7 . A heteroleptic complex according to any of  claims 1  to  5 , wherein R 4  and R 5 , R 5  and R 6  or R 6  and R 7  together form a cycle of the general formula (IIa) or (IIb) 
       
         
           
           
               
               
           
         
       
     
     
         8 . A heteroleptic complex according to any of  claims 1  to  7  with the specified definitions of M, A 1 , A 2 , n, m, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13  and R 14 , which has one of the following configurations IIIa, IIIb, IVa or IVb: 
       
         
           
           
               
               
           
         
       
     
     
         9 . A process for preparing a heteroleptic complex according to any of  claims 1  to  8  by
 contacting at least one precursor compound comprising the metal M and the at least one ligand which, in the complexes of the general formula (I), is attached to M via noncarbene bonds with at least one ligand which, in the complexes of the general formula (I), is attached to M via at least one carbene bond, or the ligand precursor thereof, for example a corresponding imidazolium salt, 
 or 
 by contacting at least one precursor compound comprising the metal M and a ligand which, in the complexes of the general formula (I), is bonded to M via at least one carbene bond with at least one ligand which, in the complexes of the general formula (I), is attached to M via noncarbene bonds. 
 
     
     
         10 . An OLED comprising at least one heteroleptic complex according to any of  claims 1  to  8 . 
     
     
         11 . An OLED comprising a heteroleptic complex according to any of  claims 1  to  8 , and at least one compound of the formula (X) 
       
         
           
           
               
               
           
         
         In which 
         T is NR 57 , S, O or PR 57 , preferably S or O, more preferably O; 
         R 57  is aryl, heteroaryl, alkyl, cycloalkyl or heterocycloalkyl; 
         Q′ is —NR 58 R 59 , —P(O)R 60 R 61 , —PR 62 R 63 , —S(O) 2 R 64 , —S(O)R 65 , —SR 66  or —OR 67 , preferably —NR 58 R 59 ; more preferably 
       
       
         
           
           
               
               
           
         
         
           wherein 
           R 68 , R 69  are each independently alkyl, cycloalkyl, heterocycloalkyl, aryl or heteroaryl; preferably methyl, carbazolyl, dibenzofuryl or dibenzothienyl; 
           y, z are each independently 0, 1, 2, 3 or 4, preferably 0 or 1; 
           R 55 , R 56  are each independently alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, SiR 70 R 71 R 72 , a group Q′ or a group with donor or acceptor action; 
           a″ 0, 1, 2, 3 or 4; 
           b′ 0, 1, 2 or 3; 
           R 58 , R 59  together with the nitrogen atom form a cyclic radical which has 3 to 10 ring atoms and may be unsubstituted or substituted by one or more substitutents selected from alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl and a group with donor or acceptor action and/or may be fused to one or more further cyclic radicals having 3 to 10 ring atoms, where the fused radicals may be unsubstituted or substituted by one or more substituents selected from alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl and a group with donor or acceptor action; 
           R 70 , R 71 , R 72 , R 60 , R 61 , R 62 , R 63 , R 64 , R 65 , R 66 , R 67  are each independently aryl, heteroaryl, alkyl, cycloalkyl or heterocycloalkyl, 
           or 
           two units of the general formula (X) are bridged by a linear or branched, saturated or unsaturated bridge, optionally interrupted by at least one heteroatom, by a bonding or by O. 
         
       
     
     
         12 . OLED according to  claim 11  comprising at least one compound of formula (XI) or (XI*) 
       
         
           
           
               
               
           
         
         wherein 
         T is NR 57 , S, O or PR 57 ; 
         R 57  is aryl, heteroaryl, alkyl, cycloalkyl or heterocycloalkyl; 
         Q′ is —NR 58 R 59 , —P(O)R 60 R 61 , —PR 62 R 63 , —S(O) 2 R 64 , —S(O)R 65 , —SR 66  or —OR 67 ; 
         R 70 , R 71 , R 72  are each independently aryl, heteroaryl, alkyl, cycloalkyl, heterocycloalkyl, wherein of at least one of the radicals R 70 , R 71 , R 72  comprises at least two carbon atoms or OR 73 , 
         R 55 , R 56  are each independently alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, a group Q or a group with donor or acceptor action; 
         a′, b′ are for the compound of formula (XI): each independently 0, 1, 2, 3; for the compound of formula (XI*) a′ is 0, 1, 2 and bis′ 0, 1, 2, 3, 4; 
         R 58 , R 59  together with the nitrogen atom form a cyclic radical which has 2 to 10 ring atoms and may be unsubstituted or substituted by one or more substitutents selected from alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl and a group with donor or acceptor action and/or may be fused to one or more further cyclic radicals having 3 to 10 ring atoms, where the fused radicals may be unsubstituted or substituted by one or more substituents selected from alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl and a group with donor or acceptor action; 
         R 73  is independently SiR 74 R 75 R 76 , aryl, heteroaryl, alkyl, cycloalkyl or heterocycloalkyl, optionally substituted with a group OR 77    
         R 77  is independently SiR 74 R 75 R 76 , aryl, heteroaryl, alkyl, cycloalkyl or heterocycloalkyl, 
         R 60 , R 61 , R 62 , R 63 , R 64 , R 65 , R 66 , R 67 , R 74 , R 75 , R 76  
 are each independently aryl, heteroaryl, alkyl, cycloalkyl or heterocycloalkyl, 
 
         or 
         two units of the general formulae (XI) and/or (XI*) are bridged by a linear or branched, saturated or unsaturated bridge, optionally interrupted by at least one heteroatom or by O, wherein said bridge is bonded in the general formulae (XI) and/or (XI*) each time instead of R 71  to the Si-atoms. 
       
     
     
         13 . OLED according to  claim 12 , wherein in the compounds of the general formulae (XI) or (XI*) R 70  and/or R 71  and/or R 72  are aromatic units of the general formulae (XIi) and/or (XIi*) 
       
         
           
           
               
               
           
         
         wherein R 55 , R 56 , Q′, T, a′ and b′ have the same meanings as in  claim 12 . 
       
     
     
         14 . A light-emitting layer comprising at least one heteroleptic complex according to any of  claims 1  to  8 . 
     
     
         15 . An OLED comprising a light-emitting layer according to  claim 14 . 
     
     
         16 . The OLED according to any of  claim 10  to  13  or  15 , which comprises an electron-transporting layer comprising at least two different materials, of which at least one material should be electron-conductive. 
     
     
         17 . The OLED according to  claim 16 , wherein the electron-transporting layer comprises at least one phenanthroline derivative. 
     
     
         18 . The OLED according to  claim 16 , wherein the electron-transporting layer comprises at least one phenanthroline derivative and at least one alkali metal hydroxyquinolate complex. 
     
     
         19 . A device selected from the group consisting of illuminating elements, stationary visual display units and mobile visual display units, comprising at least one OLED according to any of  claims 10  to  13  or  15  to  18 . 
     
     
         20 . The use of a heteroleptic complex according to any of  claims 1  to  8  in OLEDs. 
     
     
         21 . The use according to  claim 20 , wherein the heteroleptic complexes are used as emitter, matrix material, charge transport material and/or charge blocker.