Facile Arene Ligand Exchange in p‑Cymene Ruthenium(II) Complexes of Tertiary P‑Chiral Ferrocenyl Phosphines

Half-sandwich arene–metal complexes are commonly used for specific applications. Herein, we report facile arene ligand exchange reactions of two ruthenium­(II) complexes of tertiary P-stereogenic ferrocenyl phosphines. By mild photochemical activation, the displacement of p-cymene and subsequent tethering by η⁶-coordination of the terminal phenyl ring of a biphenylyl-substituted ferrocenyl phosphine were enabled. Furthermore, the spontaneous p-cymene displacement in a 2-methoxyphenyl-containing ferrocenyl phosphine and ensuing coordination of the ligand as a P,O chelate were examined. For both reactions, theoretical calculations of the general course of the reaction confirmed the experimental findings. The ease of the controlled arene displacement reported here can offer new pathways for the synthesis and design of novel tailor-made catalysts.