A Highly Efficient Single-Chain Metal–Organic Nanoparticle Catalyst for Alkyne–Azide “Click” Reactions in Water and in Cells

We show that copper-containing metal-organic nanoparticles (MONPs) are readily synthesized via Cu(II)-mediated intramolecular cross-linking of aspartate-containing polyolefins in water. In situ reduction with sodium ascorbate yields Cu(I)-containing MONPs that serve as highly efficient supramolecular catalysts for alkyne-azide "click chemistry" reactions, yielding the desired 1,4-adducts at low parts per million catalyst levels. The nanoparticles have low toxicity and low metal loadings, making them convenient, green catalysts for alkyne-azide "click" reactions in water. The Cu-MONPs enter cells and perform efficient, biocompatible click chemistry, thus acting as intracellular nanoscale molecular synthesizers.