Synthesis, Antioxidant Activity and Fluorescence Properties of Novel Europium Complexes with (E)~2- or 4-hydroxy-N' -[(2-hydroxynaphthalen-l- yl)methylene]benzohydrazide Schiff Base

摘要

Two novel Eu(III) complexes with notable properties have been successfully prepared with hydrazone Schiff base ligands, (E)-2-hydroxy-N'-[(2-hydroxynaphthalen-l-yl)methylene]benzohydrazide (3a) and (E)-4-hydroxy-N-[(2-hydroxynaphthalen-l-yl)methylene]benzohydrazide (3b). DFT, FMO energy and Mulliken charge distribution studies of the ligands allowed us to hypothesize that their HON, >C=O and -OH (naphthyl) groups were involved in coordinating with the Eu~(3+) ion. The eight coordination sites of the Eu~(3+) ion were occupied by the three functional groups of the two ligands (3a or 3b) mentioned above and two water molecules. Similar UV, IR and fluorescence spectra indicated the presence of comparable coordination environments for the Eu~(3+) ion in both complexes. Both the ligands and their complexes exhibited moderate DPPH radical scavenging activity. Moreover, it was found that the Eu(III) complexes exhibited fluorescence properties.