Patent ID: 8323805

Claim:
An emissive compound represented by a formula: wherein R 1 is C 1-30 alkyl, optionally substituted C 6-10 aryl, or C 1-30 O 1-15 ether; R 2 , R 3 , R 4 and R 5 are independently H, C 1-10 alkyl, or C 1-10 alkoxyl; R 6 , R 7 , R 8 , and R 9 are independently H, optionally substituted C 6-30 aryl, C 1-10 alkyl, or C 1-10 alkoxyl; and Z′ is independently NR 10 or O, wherein R 10 is phenyl, phenylmethyl, or (4-halophenyl)methyl.