Tuning the electronic structure and hydrophilicity of Prussian-blue type catalysts by incorporation of alklypyrazinium bromides, for enhanced activity

Prussian blue (PB) type material, a historical metal coordination material, is widely used in batteries, catalyst, and for energy storage. However, the scarcity of active sites and its immutable structure limit further applications. Herein, we propose a ligand substitution strategy to tune the electronic structure and hydrophilicity of the PB-type material, involving Fe(CN) 5 as a cyanide precursor, to catalyze epoxidation of olefins . The catalytic performance can be significantly promoted for styrene oxide in the presence of a CoFe PB analog that includes decylpyrazinium bromide (named CoFe-10). Kinetic studies on styrene epoxidation with CoFe-10 show a low activation energy of 27.2 kJ/mol. In addition, mechanistic investigation, coupled to electron paramagnetic resonance (EPR) measurements, suggests that the CoOOC(CH 3 ) 3 adduct is the reactive species for epoxidation of styrene. This study provides an effective strategy to synthesize unprecedented PB-type material and extend its application.