Preparation and characterization of nanosilica copper (II) complexes of amino acids

The frequent use of traditional copper-based microbicides has led to the growing risk of toxicity to non-target organisms in the environment. In this work, nanosilica was conjugated with copper(II) complexes of L-glutamate (or glycine) to develop novel copper-based microbicides with good microbicidal activity, systemicity and desired safety to plant, and the obtained nanosilica-L-glutamate copper complexes (Silica-Glu-Cu) and nanosilica-glycine copper complexes (Silica-Gly-Cu) were characterized and evaluated by FT-IR, SEM, TEM, and XPS. The results showed that Silica-Glu-Cu and Silica-Gly-Cu exhibited satisfactory activities and long effective periods against Phytophthora capsica and Botrytis cinereal and could move upward and downward freely in cucumber seedlings. Moreover, Silica-Glu-Cu increased the fresh weights of cucumber and wheat seedlings by 0.4-6.4% at the concentrations of 50-200 mg/L of copper. Thus, the novel copper-based microbicides can reduce the frequency of using copper-based bactericides and phytotoxicity to plants.