Intriguing I2 Reduction in the Iodide for Chloride Ligand Substitution at a Ru(II) Complex: Role of Mixed Trihalides in the Redox Mechanism

Reaction of [Ru(CNtBu)4(Cl)2] and I2 affords the 1D species {[Ru(CNtBu)4(I)2]·I2}n, where the Cl- ligands have been substituted by I- ligands. The result is intriguing in the absence of any suitable reducing agent for I2. Reaction intermediates prompt the possible separation of ICl with a zerovalent Cl atom. The implied electron transfer over a trihalide foreshadows the dynamic behaviour of halogen bonding in solution, as corroborated by a theoretical analysis.