Binuclear metal complexes and electronic devices, in particular organic electroluminescent devices containing said metal complexes

1. A compound of formula (1):

wherein

M is the same or different in each instance and is iridium or rhodium;

D is the same or different in each instance and is C or N, with the proviso that one C and one N are coordinated to each of the two M;

X is the same or different in each instance and is CR or N;

V is the same or different in each instance and is a group of formula (2) or (3):

wherein one of the dotted bonds denotes the bond to the corresponding 6-membered aryl or heteroaryl group in formula (1) and the two other dotted bonds each denote the bonds to the sub-ligands L;

L is the same or different in each instance and is a bidentate monoanionic sub-ligand;

X 1 is the same or different in each instance and is CR or N;

A 1 is the same or different in each instance and is C(R) 2 or O;

A 2 is the same or different in each instance and is CR, P(═O), B, or SiR, with the proviso that, when A 2 =P(═O), B, or SiR, A 1 is O and the A bonded to the A 2 is not —C(═O)—NR′— or —C(═O)—O—;

A is the same or different in each instance and is —CR═CR—, —C(═O)—NR′—, —C(═O)—O—, —CR 2 —CR 2 —, —CR 2 —O—, or a group of formula (4):

wherein the dotted bond denotes the position of the bond of a bidentate sub-ligand L or the corresponding 6-membered aryl or heteroaryl group in formula (1) to this structure and * denotes the position of the linkage of the unit of formula (4) to the central cyclic group;

X 2 is the same or different in each instance and is CR or N or two adjacent X 2 groups together are NR, O, or S, so as to define a five-membered ring, and the remaining X 2 are the same or different in each instance and are CR or N; or two adjacent X 2 groups together are CR or N when one of the X 3 groups in the cycle is N, so as to define a five-membered ring; with the proviso that not more than two adjacent X 2 groups are N;

X 3 is C in each instance or one X 3 group is N and the other X 3 groups in the same cycle are C; with the proviso that two adjacent X 2 groups together are CR or N when one of the X 3 groups in the cycle is N;

R is the same or different in each instance and is H, D, F, Cl, Br, I, N(R 1 ) 2 , CN, NO 2 , OR 1 , SR 1 , COOH, C(═O)N(R 1 ) 2 , Si(R 1 ) 3 , B(OR 1 ) 2 , C(═O)R 1 , P(═O)(R 1 ) 2 , S(═O)R 1 , S(═O) 2 R 1 , OSO 2 R 1 , COO(cation), SO 3 (cation), OSO 3 (cation), OPO 3 (cation) 2 , O(cation), N(R 1 ) 3 (anion), P(R 1 ) 3 (anion), a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, wherein the alkyl, alkenyl, or alkynyl group in each case is optionally substituted by one or more R 1 radicals, wherein one or more nonadjacent CH 2 groups are optionally replaced by Si(R 1 ) 2 , C═O, NR 1 , O, S, or CONR 1 , or an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and is optionally substituted in each case by one or more R 1 radicals; and wherein two R radicals together optionally define a ring system;

R′ is the same or different in each instance and is H, D, a straight-chain alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, wherein the alkyl group in each case is optionally substituted by one or more R 1 radicals and wherein one or more nonadjacent CH 2 groups are optionally replaced by Si(R 1 ) 2 , or an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and is optionally substituted in each case by one or more R 1 radicals;

R 1 is the same or different in each instance and is H, D, F, Cl, Br, I, N(R 2 ) 2 , CN, NO 2 , OR 2 , SR 2 , Si(R 2 ) 3 , B(OR 2 ) 2 , C(═O)R 2 , P(═O)(R 2 ) 2 , S(═O)R 2 , S(═O) 2 R 2 , OSO 2 R 2 , COO(cation), SO 3 (cation), OSO 3 (cation), OPO 3 (cation) 2 , O(cation), N(R 2 ) 3 (anion), P(R 2 ) 3 (anion), a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, wherein the alkyl, alkenyl, or alkynyl group in each case is optionally substituted by one or more R 2 radicals, wherein one or more nonadjacent CH 2 groups are optionally replaced by Si(R 2 ) 2 , C═O, NR 2 , O, S, or CONR 2 , or an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and is optionally substituted in each case by one or more R 2 radicals; wherein two or more R 1 radicals together optionally define a ring system;

R 2 is the same or different in each instance and is H, D, F, or an aliphatic, aromatic, or heteroaromatic organic radical having 1 to 20 carbon atoms, wherein one or more hydrogen atoms is also optionally replaced by F;

cation is the same or different in each instance and is selected from the group consisting of proton, deuteron, alkali metal ions, alkaline earth metal ions, ammonium, tetraalkylammonium, and tetraalkylphosphonium; and

anion is the same or different in each instance and is selected from the group consisting of halides, carboxylates R 2 —COO − , cyanide, cyanate, isocyanate, thiocyanate, thioisocyanate, hydroxide, BF 4 − , PF 6 − , B(C 6 F 5 ) 4 − , carbonate, and sulfonates.

2. The compound of claim 1 , wherein both metals M are Ir(III) and the compound is uncharged.

3. The compound of claim 1 , wherein the compound is selected from the group consisting of structures of formulae (1a′) and (1b′):

wherein the radicals R explicitly shown are each the same or different in each instance and are selected from the group consisting of H, D, F, CH 3 , and CD 3 .

4. The compound of claim 1 , wherein the group of the formula (2) is the same or different in each instance and is selected from the group consisting of structures the formulae (5) through (8) and the group of formula (3) is the same or different in each instance and is selected from the group consisting of structures of formulae (9) through (13):

5. The compound of claim 1 , wherein the group of formula (2) is the same or different in each instance and is selected from the group consisting of structures of formula (5′) and wherein the group of formula (3) is the same or different in each instance and is selected from the group consisting of structures of formulae (9′) or (9″):

6. The compound of claim 1 , wherein A is the same or different in each instance and is selected from the group consisting of —C(═O)—O—, —C(═O)—NR′—, and a group of formula (4), wherein the group of formula (4) is selected from the group consisting of structures of formulae (14) through (38):

7. The compound of claim 1 , wherein the group of formula (2) is the same or different in each instance and is selected from the group consisting of structures of formulae (2a) through (2m) and wherein the group of formula (3) is the same or different in each instance and is selected from the group consisting of structures of formulae (3a) through (3m):

8. The compound of claim 1 , wherein V is the same or different in each instance and is selected from the group consisting of structures of formulae (5a″) and (5a′″):

9. The compound of claim 1 , wherein the bidentate sub-ligands L are the same or different in each instance and are selected from the group consisting of structures of formulae (L-1), (L-2), and (L-3):

wherein

the dotted bond denotes the bond of the sub-ligand L to the group of formula (2) or (3);

CyC is the same or different in each instance and is a substituted or unsubstituted aryl or heteroaryl group which has 5 to 14 aromatic ring atoms and coordinates to M via a carbon atom and is bonded to CyD via a covalent bond;

CyD is the same or different in each instance and is a substituted or unsubstituted heteroaryl group which has 5 to 14 aromatic ring atoms and coordinates to M via a nitrogen atom or via a carbene carbon atom and is bonded to CyC via a covalent bond; and

wherein two or more of the substituents together optionally define a ring system.

10. A process for preparing the compound of claim 1 comprising reacting the ligand with metal alkoxides of formula (57), with metal ketoketonates of formula (58), with metal halides of formula (59), with metal carboxylates of formula (60), or with iridium or rhodium compounds bearing both alkoxide and/or halide and/or hydroxyl and also ketoketonate radicals:

wherein

Hal is F, Cl, Br, or I; and

the iridium or rhodium reactants are optionally in the form of hydrates.

11. A formulation comprising at least one compound of claim 1 and at least one solvent.

12. An electronic device comprising at least one compound of claim 1 .

13. The electronic device of claim 12 , wherein the electronic device is an organic electroluminescent device and wherein the compound of formula (1) is present in the electroluminescent device as an emitting compound in one or more emitting layers.