Optical properties and aggregation behavior of environmentally friendly Lanthanum (III) acyl–alaninnate complexes

Abstract

Rare earth organic complex materials have attracted tremendous attention for their intrinsic properties and promising practical applications. It is still a great challenge to realize the rare earth organic complex materials with excellent functional properties and diversified structural states. Here, the amino acid rare earth surfactant complexes of lanthanum octanoyl-alaninate (La(oct-ala)3), lanthanum octanyl-serinate (La(ser-oct)3) and lanthanum octanoyl-phenylalaninate (La(oct-phe)3) were synthesized by the reaction of C11H21NO3, C11H21NO4, C17H26NO3 with LaCl3, respectively. As-synthesized complexes of La(oct-ala)3 and La(oct-phe)3 have high solubility in pure solvent, while the solubility of La(ser-oct)3 is very low in pure solvent. When the concentration of the complex solution is lower than the critical micelle concentration, the dissociation phenomenon of the complex is occurred in the solution. When the concentration of the complex solution is greater than the critical micelle concentration, the dissociated ligand ions and metal ions will associate, which can form micelle aggregates. In addition, the aggregates of the complex gradually shrink to form aggregates of different sizes and sizes as the solvent continues to volatilize. By further heating and cooling, the glassy, crystalline, liquid crystal and other complexes can be obtained. The rare earth organic low molecular complexes formed by the combination of these rare earth ions and amino acid ligands can not only obtain the complexes with high rare earth content, but also have the excellent properties of convenient synthesis, high yield, easy processing, good solubility, low toxicity and high stability, etc., which can play the special physical and chemical functional characteristics of the diversified structure state of rare earth organic molecular materials. Therefore, in present work, the lanthanum complexes as a functional molecular materials have potential applications in many fields.