Theoretical study of the complexassion of bivalent ions: Mg2+, Zn2+, Cu2+ and Fe2+ by 4-hydroxy-3-(1-phenylpropyl)-2H-chromen-2-one(HPCO), 4-hydroxy-3-(3-oxo-1-phenylbutyl)-2H-chromen-2-one(HOCO) and 4-hydroy-6-(1-phenylbutan-2-yl)-3-(1-phenylpropyl)-2H-pyran-2-one(HPPO) in water and in ethanol

Trace elements ensure the proper functioning of enzymes. Their theoretical study of complexassion shows that: Iron II is not chelated. Mg 2 + , Zn 2 + and Cu 2 + are chelated by HPCO and HOCO. And HPPO chelates only the Mg 2 + and Zn 2 + . Some of the chelates have become diphenols or are assisting in the modification of the chelating structure. The two solvents influence the interaction of HPCO, of HOCO and of HPPO with the metals: Fe 2 + , Mg 2 + , Zn 2 + and Cu 2 + . The transform certain monovalent bonds into divalent bonds and vice versa, or promote or prevent the metal from integrating the structure of the ligand. And NBO calculations show that the donor atoms yield their charge by half or entirely equal to the metal as a function of bond number: monovalent or divalent bond.