Heterocyclic complexes are widely exiting in nature, and their applications are also widely. It is not only the main ingredients of natural medicines, but also the main ingredients of the man-made compounds, such as medicine, dye, material and pesticide, etc. Heterocyclic complexes are one of the important organic reagents which owning strong chelate capacity in the analytical chemistry, and thus they are widely used to determine the inorganic ions. Those complexes, which own the planar and aromatic rings, ...