Synthesis and Properties of Salicyladehyde Salicyhydrazone Derivatives and Their Europium Complexes

Four novel salicyladehyde salicyhydrazone derivatives and their corresponding europium (Eu3+) complexes were synthesized and characterized. The formulas of the complexes were [EuLa-d(NO3)(2)](NO3) center dot H2O. The investigatoin of fluoresence properties of the Eu3+ complexes showed that the salicyladehyde salicyhydrazone derivatives were efficient sensitizers for the fluoresence of Eu3+ ions. The fluorescence intensity of the complex substituted by methyl (-CH3) was the strongest among all the Eu3+ complexes. The exploration of the electrochemical properties of the Eu3+ complexes showed that the introduction of electron-donating groups methyl and methoxyl (-CH3 and -OCH3) could increase the oxidation potential and the highest occupied molecular orbital (HOMO) energy level of the Eu3+ complex; however, the results of introduction of electron-withdrawing group were just opposite.