Synthesis of Dichlorophosphinenickel(II) Compounds and Their Catalytic Activity in Suzuki Cross-Coupling Reactions: A Simple Air-Free Experiment for Inorganic Chemistry Laboratory

Abstract

In this experiment, students perform an air-free synthesis of three dichlorophosphinenickel(II) compounds, NiCl2(PPh3)2, NiCl2(PCy3)2, and NiCl2(DPPE), using NiCl2·6H2O and the appropriate phosphine as the precursors. These colorful nickel compounds are air-sensitive in solution, but are stable toward air once isolated in the solid form. The synthesized nickel products will be utilized in a catalytic Suzuki cross-coupling reaction between phenylboronic acid and 1-bromo-4-(trifluoromethyl)benzene. The formation of the desired product, 4-(trifluoromethyl)biphenyl, is observed and determined quantitatively by 19F{1H} NMR spectroscopy. The effect of the phosphine ligands on the formation of the nickel products and their catalytic activity will also be determined.