Patent ID: 7964743

Claim:
A compound denoted by general formula (1a) or (1b) below: (wherein X denotes carbon, oxygen, sulfur, or nitrogen; Y denotes NR 10 R 11 (wherein R 10 and R 11 each independently denote a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group), OR 12 (wherein R 12 denotes a substituted or unsubstituted alkyl group, or substituted or unsubstituted aryl group), or SR 13 (wherein R 13 denotes a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group); n denotes an integer of from 1 to 3; R 1 to R 8 each independently denote hydrogen, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group).