Synthesis of [N-bis(4-methyl benzene-diamino formyl)methyl phosphonic acid] and its europium (III) complex and its application as DNA electrochemical sensor

Abstract

The new tripod ligand [N-bis(4-methyl benzene-diamino formyl)methyl phosphonic acid] and its europium (III) complex (Eu(pic)₃L) have been synthesized and characterized by TG-DSC, IR spectroscopy, UV-vis spectroscopy, elemental and molar conductance analysis. The experimental results show that the ligand forms the 1:1 complex with europium picrate. The results of  UV-vis spectroscopy and cyclic voltammetry indicate that there are intercalation interaction between DNA and Eu(pic)₃L. When the Eu(pic)₃L is regarded as DNA hybridization probe and used in the study of DNA electrochemical sensor, no obvious electrochemical signal response could be found with Eu(pic)₃L under the effect of modified electrodes single-strand DNA testing. However, obvious electrochemical signal response is found when it is under the effect of double-stranded DNA testing. It indicates that the biosensor can discriminate well between the complementary sequences from the base-mismatched and the non-complementary sequences. So Eu(pic)₃L can be used as a biosensor to discriminate between the complementary sequences from the base-mismatched and the non-complementary sequences.