A Half-Sandwich Rhodium(III) Complex with 4-Bromo-N-(1-Pyrenylidene)Aniline: Regioselective Cyclorhodation of the 1-Pyrenyl Group

Abstract

Reaction of [RhCp^*Cl₂]₂ (Cp^* = pentamethylcyclopentadienyl anion), 4-bromo-N-(1-pyrenylidene)aniline (Hpyan, H represents a proton of the 1-pyrenyl ring) and CH₃CO₂Na in 1:2:6 mole ratio in dichloromethane provides the half-sandwich, cyclometallated rhodium(III) complex [RhCp^*(pyan)Cl]. X-ray crystallographic study confirms the bidentate 1-pyrenyl ortho-C and azomethine-N coordination mode of (pyan)⁻and the half-sandwich ‘piano-stool’ structure of [RhCp^*(pyan)Cl]. In dichloromethane, the diamagnetic, redox active complex displays a metal-centred oxidation at E_1/2 = 1.14 V (versus Ag/AgCl).