Facile preparation of π-arene complexes of ruthenium [(η5-C5Me5)Ru(arene)]X including a π-pyridine and the first π-furan derivatives

Abstract

Zinc reduction of (Cp*RuCl₂)_n(Cp*=η⁵-C₅Me₅) in tetrahydrofuran or acetone affords ‘(Cp*RuCl)_n’ which reacts smoothly with arenes with or without KPF₆, even at –50 °C, to give the π-complexes [Cp*Ru(arene)]X (arene = benzene, 3-methylthiophene, pyridine, 2,6-lutidine, 3,5-lutidine, or furan) including the first detected π-furan complex in solution and a rare example of a π-pyridine complex; the latter is proposed as a model for pyridine co-ordination in hydrodenitrogenation reactions, however, the mode of pyridine co-ordination is highly dependent on the polarity of the solvent.