Stabilized Copper(I) Oxide Nanoparticles Catalyze Azide‐Alkyne Click Reactions in Water

Abstract

Abstract A novel form of polyvinylpyrrolidone (PVP) coated copper(I) oxide nanoparticle (Cu 2 O‐NP) was prepared and used to catalyze azide‐alkyne click reactions in water under aerobic conditions. The nanoparticles were well dispersed in aqueous solutions and have a size of 20±10 nm, as determined by transmission electron microscope (TEM). Inductively coupled plasma (ICP), X‐ray powder diffraction (XRD), and X‐ray photoelectron spectroscopy (XPS) analyses demonstrated that the main content of Cu 2 O‐NP is copper(I). The cytotoxicity of it was evaluated by an in vitro 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay and its catalytic efficiency for azide‐alkyne click reactions was studied in water and organic solvents at physiological temperatures. Our results indicate that Cu 2 O‐NP is more efficient in catalytic reactions in water for both aliphatic and aromatic azides and alkynes and less toxic than the commonly used CuSO 4 /reductant catalyst systems.