On the activation of PhICl2 with pyridine

Abstract

It has been previously proposed that pyridines can activate PhICl₂ by displacing a chloride and forming the [PhI(Pyr)(Cl)]⁺ cation as a reactive intermediate. Here we show that pyridine does not displace chloride, but rather forms a weak complex with the iodine via halogen bonding along the C–I bond axis. This interaction is interrogated by NMR, structural, charge density, and theoretical investigations, which all indicate that pyridine does not activate PhICl₂ as proposed.