| abstract |
A metal complex comprising the following first ligand, and tautomers thereof, are provoded. X represents O or S. The group G represents a tricyclic aromatic group or a tetracyclic aromatic group. The group A represents a monocyclic aza-aromatic group or a bicyclic aza-aromatic group. R 1 nrepresents unsubstituted or mono-substituted to the maximum possible number of substituents. Each R 1 nsubstituent is selected from the group consisting of halogen, alkyl, alkoxy, aryl, aralkyl, heteroaryl, and combinations thereof. |