Metal coordination compound and electroluminescence device

A metal coordination compound represented by the following formula (1):

• MLmL′n (1),
• wherein M is L and L′ are mutually different bidentate ligands;
• m is 1, 2 or 3;
• n is 0, 1 or 2 with the proviso that m+n is 3;
• a partial structure MLm is represented by formula (2) shown below and a partial structure ML′n is represented by formula (3), (4) or (5) shown below:
• wherein N and C are nitrogen and carbon atoms, respectively;
• A, A′ and A″ are independently a cyclic group capable of having a substituent and connected to the Ir atom M via the nitrogen atom;
• B, B′ and B″ are independently a cyclic group capable of having a substituent and connected to the Ir atom M via the carbon atom;
• {wherein the substituent denotes a halogen atom, a cyano group, a nitro group, a trialkylsilyl group (of which the alkyl groups are independently a linear or branched alkyl group having 1 to 8 carbon atoms), a linear or branched alkyl group having 1 to 20 atoms (of which the alkyl group can include one or more non-neighboring two or more methylene groups that can be replaced with —O—, —S—, —CO—, —CO—O—, —O—CO—, —CH═CH— or —C≡C— and the alkyl group can include a hydrogen atom that can be replaced with a fluorine atom), or an aromatic cyclic group capable of having a substituent (of which the substituent denotes a halogen atom, a cyano group, a nitro group, a linear or branched alkyl group having 1 to 20 carbon atoms (of which the alkyl group can include one or non-neighboring two or more methylene groups that can be replaced with —O—, —S—, —CO—, —CO—O—, —O—CO—, —CH═CH— or —C≡C— and the alkyl group can include a hydrogen atom that can be replaced with a fluorine atom))},
• A and B, A′ and B′, and A″ and B″ are respectively bonded to each other via a covalent bond;
• and
• A and B, and A′ and B′ are bonded to each other via X and X′, respectively, in which X and X′ are independently a linear or branched alkylene group having 2-10 carbon atoms (of which the alkylene group can include one or non-neighboring two or more methylene groups that can be replaced with —O—, —S—, —CO—, —CO—O—, —O—CO—, —CH═CH— or —C≡C— and the alkylene group can include a hydrogen atom that can be replaced with a fluorine atom);
• and
• E and G are independently a linear or branched alkyl group having 1 to 20 carbon atoms (of which the alkyl group can include a hydrogen atom that can be replaced with a fluorine atom), or an aromatic cyclic group capable of having a substituent {of which the substituent denotes a halogen atom, a cyano group, a nitro group, a trialkylsilyl group (of which the alkyl groups are independently a linear or branched alkyl group having 1 to 8 carbon atoms), or a linear or branched alkyl group having 1 to 20 carbon atoms (of which the alkyl group can include one or non-neighboring two or more methylene groups that can be replaced with —O—, —S—, —CO—, —CO—O—, —O—CO—, —CH═CH— or —C≡C— and the alkyl group can include a hydrogen atom that can be replaced with a fluorine atom)}.