Patent ID: 8207330

Claim:
A compound represented by the following General Formula (I): where R 1 to R 8 each represent a hydrogen atom, a halogen atom, a carboxyl group, a carboxylic acid ester group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted alkyl group; wherein at least one of X 1 and X 3 is a phenyl group having, as a substitutent, an alkyl group, an alkoxy group, a trifluoromethyl group, a nitro group, a cyano group or a carboxylic acid ester group, or a substituted or unsubstituted pyridinyl group, with the proviso that when only one of X 1 and X 3 is the phenyl group or the pyridinyl group, the other is a hydrogen atom or a halogen atom; and at least one of X 2 and X 4 is a substituent represented by (a) or (b) given below, with the proviso that when only one of X 2 and X 4 is the substitutent, the other is a hydrogen atom or a halogen atom, where R 11 represents an alkyl group or an alkoxy group, R 9 and R 10 each represent a hydrogen atom, an alkyl group or a substituted or unsubstituted phenyl group, and n is an integer of 1 or 2, where R 12 and R 13 each represent a hydrogen atom, an alkyl group or a substituted or unsubstituted phenyl group; and M represents two hydrogen atoms or a divalent, trivalent or tetravalent metal atom which may have an oxygen atom or a halogen atom.