Patent ID: 8084624

Claim:
A compound represented by: where X 1 and X 2 are independently a calcogen atom, n is an integer in a range of 1 to 3, and R 1 and R 2 are independently a halogen, a C 1 -C 18 alkyl, a halogenated C 1 -C 18 alkyl, a C 1 -C 18 alkyloxy, a C 1 -C 18 alkylthio, an aryl, or an aryl having at least one substituent selected from the group consisting of a halogen, a C 1 -C 18 alkyl, a halogenated C 1 -C 18 alkyl, a C 1 -C 18 alkyloxy, and a C 1 -C 18 alkylthio wherein the calcogen atom is a sulfur atom, a selenium atom, or tellurium atom.