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 E1/2 = 1.14 V (versus Ag/AgCl).