. . . . . "each of R1, R2, R3, R4 and R5, which are the same or different, when taken alone, represents hydrogen, nitro, cyano, a halogen such as fluorine, chlorine, bromine or iodine, an alkoxy preferably having 1 to about 8 carbon atoms, a substituted or unsubstituted alkyl having 1 to about 8 carbon atoms in the alkyl group, a substituted or unsubstituted carbocyclic or heterocyclic aromatic ring group ha" .