Rational design of peptides for biomimetic palladium nanoparticle catalysis with Suzuki and Heck coupling in ethanol

Abstract

Peptide-mediated nanoparticle synthesis has been shown as an environmentally friendly way to synthesize highly reactive nanocatalysts. Previous studies have shown that peptides are capable of controlling the size and shape of metal nanoparticles made from Pd, Au, Pt, and Ag. These studies revealed that the sequence of the amino acids is critically important to optimize the performance as nanocatalysts. However, these peptide-mediated formations of nanoparticles are limited to aqueous solvents. There is a need for such optimized catalysts in organic solvents. For this, a palladium-binding peptide was modified to contain hydrophobic sequences to improve the stability and reactivity in organic solvents. Palladium nanoparticles were synthesized using the modified peptides in ethanol and used as catalysts in Suzuki and Heck coupling at a catalytic loading of 0.05 mol% at room temperature or 80 °C. The location of the hydrophobic region was found to be pivotal for increased reactivity.