Phenyl pyridine-iridium metal complex compounds for organic electroluminescent device and organic electroluminescent device using thereof

A compound represented by the following formula (1):

• wherein R1, R2, R3, R4, R5, R6, R7, and R8 each independently are hydrogen, a straight or branched alkyl group haying 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a halogen group, a substituted or un-substituted aromatic group having 5 to 18 carbon atoms, a cycloalkyl group having 5 to 18 carbon atoms, or an aromatic heterocyclic group of 5 to 18 carbon. atoms containing one or more hetero-atoms selected from the group consisting of N, O and S;
• A1 is a straight or branched alkyl group having 1 to 18 carbon atoms;
• A2 is —COA4;
• A3 is a straight or branched alkyl group having 1 to 18 carbon atoms;
• or A2 and A3 form together a cycloalkanone having 5 to 18 carbon atoms;
• A4 is a straight or branched alkyl group having 1 to 18 carbon atoms;
• is a single bond or double bond;
• and
• Py is a substituted or un-substituted pyridine or isoquinoline.