Metal complexes

A monometallic compound comprising a hexadentate tripodal ligand wherein three bidentate part-ligands, which may be identical or different, are coordinated to a metal selected from the group consisting of ruthenium, osmium, rhodium and iridium, and the three bidentate part-ligands are linked to one another via a bridge of formula (1):

• wherein
• the dashed bonds are the direct bonds from the bidentate part-ligands to the structure of formula (1);
• X1 is on each occurrence, identically or differently, CR2 or O;
• X2 is on each occurrence, identically or differently, CR, P═O, B, or Si, which is optionally substituted, with the proviso that, when X2 is P═O, B, or Si, which is optionally substituted, X1 is O;
• and wherein substituents optionally present on X1 and X2 optionally define an aliphatic or heteroaliphatic ring system with themselves or with one another;
• X3 is on each occurrence, identically or differently, —CR═CR—, —CR═N—, —CR—NR″—, —C(═O)—O—, —C(═O)—NR″—, —C(═O)—S—, —C(═S)—O—, —C(═S)—S—;
• R is on each occurrence, identically or differently, H, D, F, Cl, Br, I, N(R1)2, CN, NO2, OR1, SR1, COOH, C(═O)N(R1)2, Si(R1)3, B(OR1)2, C(═O)R1, P(═O)(R1)2, S(═O)R1, S(═O)2R1, OSO2R1, a straight-chain alkyl group having 1 to 20 C atoms or an alkenyl or alkynyl group having 2 to 20 C atoms or a branched or cyclic alkyl group having 3 to 20 C atoms, wherein the alkyl, alkenyl, or alkynyl group in each case is optionally substituted by one or more radicals R1, wherein one or more non-adjacent CH2 groups are optionally replaced by R1C═CR1, C═C, Si(R1)2, C═O, NR1, O, S, or CONR1, or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which in each case is optionally substituted by one or more radicals R1;
• and wherein two or more radicals R which are bonded to X1 and/or X2 optionally define an aliphatic or heteroaliphatic ring system with one another;
• and wherein two radicals R when X3 is —CR═CR— optionally define an aliphatic, heteroaliphatic, aromatic, or heteroaromatic ring system with one another;
• and wherein radicals R and R″ when X3 is —CR—NR″— define a heteroaromatic ring system with one another;
• R″ is on each occurrence, identically or differently, H, D, a straight-chain alkyl group having 1 to 20 C atoms or a branched or cyclic alkyl group having 3 to 20 C atoms or an alkenyl group having 2 to 20 C atoms, wherein the alkyl or alkenyl group in each case is optionally substituted by one or more radicals R1 and wherein one or more non-adjacent CH2 groups are optionally replaced by Si(R1)2, or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which in each case is optionally substituted by one or more radicals R′;
• R1 is on each occurrence, identically or differently, H, D, F, Cl, Br, I, N(R2)2, CN, NO2, OR2, SR2, Si(R2)3, B(OR2)2, C(═O)R2, P(═O)(R2)2, S(═O)R2, S(═O)2R2, OSO2R2, a straight-chain alkyl group having 1 to 20 C atoms or an alkenyl or alkynyl group having 2 to 20 C atoms or a branched or cyclic alkyl group having 3 to 20 C atoms, wherein the alkyl, alkenyl, or alkynyl group in each case is optionally substituted by one or more radicals R2, wherein one or more non-adjacent CH2 groups are optionally replaced by R2C═CR2, C≡C, Si(R2)2, C═O, NR2, O, S, or CONR2, or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which in each case is optionally substituted by one or more radicals R2;
• wherein a plurality of substituents R1 optionally define an aliphatic, heteroaliphatic, aromatic, or heteroaromatic ring system with one another;
• furthermore, the groups R or R substituted with R1 optionally form a ring system, and groups R and R1 optionally form a ring system with one another;
• R2 is on each occurrence, identically or differently, H, D, F, or an aliphatic, aromatic, and/or heteroaromatic organic radical having 1 to 20 C atoms, wherein one or more H atoms are optionally replaced by F;
• and
• wherein the bidentate part-ligands are selected, identically or differently on each occurrence, from the group consisting of structures of formulae (L-1), (L-2), (L-3), and (L-4):
• wherein
• the dashed bond is the direct bond from the part-ligand to the bridge of formula (1);
• CyC is, identically or differently on each occurrence, an optionally substituted aryl or heteroaryl group having 5 to 14 aromatic ring atoms, which is coordinated to the metal via a carbon atom and which is connected to CyD via a covalent bond;
• CyD is, identically or differently on each occurrence, an optionally substituted heteroaryl group having 5 to 14 aromatic ring atoms, which is coordinated to the metal via a nitrogen atom or via a carbene carbon atom and which is connected to CyC via a covalent bond;
• and
• wherein a plurality of the optional substituents optionally defines a ring system with one another;
• and
• the three bidentate ligands are optionally cyclised by a further bridge, in addition to the bridge of formula (1), to define a cryptate.