Magnetic, fluorescence and electric properties of rare earth complexes based on reduced Schiff base carboxylic acid ligand

By regulating the reaction system, two kinds of rare earth complexes [M(L)(HL)(DMF)]n [M = Eu(1), Nd(2), Pr(3) and [M(L)(HL)(H2O)3]n [M = Eu(4), Ho(5), Dy(6), Er(7), Y(8)] with different structures were designed and synthesized based on the reduced Schiff base carboxylic acid ligand [H2L=5-((4-(1H-imidazol-1-yl)benzyl)amino)isophthalic acid]. The crystal structures, electrochemical, magnetic and fluorescence properties of complexes were characterized and discussed. Complexes 1-3 are two-dimensional (2D) framework composed of binuclear [M2O14N2] building unit. Complexes 4-8 are three-dimensional (3D) network structure with ecu topological net. Fluorescence properties of complexes 1 and 4 in the solid state were investigated at room temperature. Magnetic measurements indicate that the 2, 3 and 5-7 exhibit typical antiferromagnetic. Complex 2 has been evaluated as a candidate electrode material for supercapacitors with a maximum specific capacitance is 412.3 F g−1 at a current density of 1 A g−1, and the specific capacitance retention is about 59.4% of the initial capacitance even at 5 A g−1. The excellent rate capability makes it as the best candidate for high capacity supercapacitor electrode material.