A metal complex represented by the following formula (1):
wherein R 1 to R 6 each independently represent a hydrogen atom or a substituent; Y 1 and Y 2 each independently represent any one of the following groups:
wherein R ± represents a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms; P 1 and P 2 each represent a group of atoms necessary for forming a heterocyclic ring together with Y 1 or Y 2 and the two carbon atoms at a position adjacent to Y 1 or Y 2 ; P 1 and P 2 may be linked to each other to form a ruing; M represents a transition metal element or typical metal element; m represents 1 or 2; X represents a counter ion or a neutral molecule; n represents the number of X's in the complex, and an integer of 0 or more; and Q 1 and Q 2 each independently represent an aromatic heterocyclic group.
