Achievement

Alex Tucker-Schwartz (Garrell group) has developed a simple approach for immobilizing TEMPO, an organic oxidant, on iron oxide superparamagnetic nanoparticles (SPNs), using metal-oxide chelating phosphonates and azide/alkyne "click" chemistry. The SPNs have excellent magnetic response and efficiently catalyze the oxidation of a wide range of primary and secondary alcohols to aldehydes, ketones, and lactones under either aerobic acidic Mn(II)/Cu(II) oxidizing Minisci conditions, or basic NaOCl Anelli conditions, with good to excellent substrate conversions and product selectivities. Immobilizing TEMPO though a phosphonate linker allows the particles to withstand acidic oxidizing environments with minimal catalyst leaching. The good stability of the linker and simplicity of the catalyst immobilization method make it an attractive approach for tethering catalysts that operate under neutral or acidic conditions to oxide supports, to form magnetically separable catalysts.