Metal complex compound

A metal complex compound represented by the following Formula I or II ##STR10## wherein at least one of X and Y is substituted aryl having a substituent independently selected from hydroxyl, mercapto, acylamino, having an electron withdrawing group as a substituent, alkylsulfonamido, arylsulfonamido, alkoxy, alkylthio, and alkylamino;

• when one of X and Y is said substituted aryl, another of X and Y is heterocyclic, which may have an alkyl group or a halogen atom as a substituent, hydrogen, or a group of non-metal atoms;
• Z is substituted aryl having a substituent selected from hydroxyl, amino, alkyl substituted amino, alkoxy, anilino, acylamino, add alkylsulfonamido, at the para-position thereof;
• and M is Ni.sup.2+ ion or its salt, Cu.sup.2+ ion or its salt, Co.sup.2+ ion or its salt, Zn.sup.2+ ion or its salt, Fe.sup.2+ ion or its salt, Pd.sup.2+ ion or its salt, or Pt.sup.2+ ion or its salt.