Synthesis, antioxidant activity and fluorescence properties of novel europium complexes with (E)-2- or 4-hydroxy-N'-[(2-hydroxynaphthalen-1-yl) methylene]benzohydrazide schiff base

Abstract

Two novel Eu(III) complexes with notable properties have been successfully prepared with hydrazone Schiff base ligands, (E)-2-hydroxy-N'-[(2- hydroxynaphthalen-1-yl)methylene]benzohydrazide (3a) and (E)-4-hydroxy- N'-[(2-hydroxynaphthalen-1-yl)methylene]benzohydrazide (3b). DFT, FMO energy and Mulliken charge distribution studies of the ligands allowed us to hypothesize that their HC=N, >C=O and -OH (naphthyl) groups were involved in coordinating with the Eu3+ ion. The eight coordination sites of the Eu3+ 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 Eu3+ 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. © 2005 KCSNET.