Patent ID: 8512877

Claim:
A compound of Formula 1: wherein each Ar 1 is selected from the group consisting of substituted or unsubstituted C 6 -C 30 aromatic hydrocarbon groups which optionally contain at least one unsaturated aliphatic moiety, C 2 -C 10 unsaturated aliphatic hydrocarbon groups, and substituted or unsubstituted C 2 -C 24 unsaturated heterocyclic groups; R 1 and R 2 are each independently selected from the group consisting of hydrogen, C 6 -C 24 aromatic hydrocarbon groups, and C 6 -C 30 aromatic hydrocarbon groups containing at least one unsaturated aliphatic moiety; and X is selected from the group consisting of carbon, silicon, oxygen and sulfur, provided that when X is carbon or silicon, m is 4 and n is an integer from 1 to 4 and that when X is oxygen or sulfur, m is 2 and n is 1 or 2.