Bipyridine-based metal complex and ink composition comprising the same

A bipyridine-based metal complex represented by formula (II) below:

• wherein W1, W2 and W4 are each an atom included in a 4 to 8-membered heteroaryl group or heterocycloalkenyl group;
• W3 is an atom included in a 0 to 8-membered group selected from the group consisting of a cycloalkyl group, a cycloalkenyl group, an aryl group, a heteroaryl group, a heterocycloalkyl group and a heterocycloalkenyl group;
• n is an integer of 0 to 100;
• A1, A2, A3 and A4 represent the same or different coloring agents, and are capable of binding to at least one of W1, W2, W3 and W4;
• i, j, k and m are each independently 0 or 1, wherein i, j, k and m are not all equal to zero;
• when i, j, k and m are each equal to 1, R1, R2, R3 and R4 are linkers;
• when i is zero, R1 is a mono-substituent, or the same or different multi-substituents, and is selected from the group consisting of a hydrogen atom, a halogen atom, a nitro group, —SO3H, —COOH, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C1-C20 heteroalkyl group, a hydroxy group, an amino group, a cyano group, a substituted or unsubstituted C2-C20 alkenyl group, a substituted or unsubstituted C1-C20 alkoxy group, a substituted or unsubstituted C1-C20 alkylsulfonamide group, a substituted or unsubstituted C6-C20 arylsulfonamide group, a substituted or unsubstituted C1-C20 acylamino group, a C1-C20 alkylureido group, a C6-C20 arylureido group, a C2-C20 alkoxycarbonyl group, a C2-C20 alkoxycarbonylamino group, a carbamoyl group, a sulfamoyl group, a sulfo group or its salt, a carboxy group or its salt, a substituted or unsubstituted C1-C20 hydroxyalkyloxyalkyl group, a substituted or unsubstituted C1-C20 dialkylaminoalkyl group, a substituted or unsubstituted C6-C20 pyridylalkyl group, a substituted or unsubstituted C5-C20 pyridyl group, a substituted or unsubstituted C6-C20 imidazolyl group, a hydrazine group, a hydrozone group, a substituted or unsubstituted C1-C20 pyridylalkyl group, a substituted or unsubstituted C6-C20 aryl group, a substituted or unsubstituted C6-C20 arylalkyl group, a substituted or unsubstituted C6-C20 heteroaryl group, C6-C20 heteroarylalkyl group, a substituted or unsubstituted C6-C20 heteroarylalkenyl group, or a substituted or unsubstituted C3-C20 heterocycloalkyl group;
• when j is zero, R2 is selected from the group recited for the R1 where i is zero;
• when k is zero, R3 is selected from the group recited for the R1 where i is zero;
• when m is zero, R4 is selected from the group recited for the R1 where i is zero;
• M is a metal atom of one of groups III to XIV;
• L1 is an anionic ligand;
• L2 is a neutral ligand;
• Z is a counter ion;
• and
• o, p and q are each integers of 0 to 10, wherein o and p are not equal to zero simultaneously.