Coordination of 12-Electron Organometallic Fragments to the Arene Ring of Nonsymmetric Group 10 POCOP Pincer Complexes.
Résumé
A series of heterobimetallic complexes have been prepared in good yields by η6 coordination of [Cp*Ru]+, [CpRu]+, [CpFe]+, and [Cr(CO)3] fragments to the aromatic ring of nonsymmetric Ni(II), Pd(II), and Pt(II) naphthoresorcinate POCOP compounds, and the molecular structures of the new compounds have been unequivocally determined by single-crystal X-ray diffraction crystallography. The reaction is regiospecific, and only coordination at the noncyclometalated ring is observed. The coordination occurs in an orthogonal fashion, and as a consequence, the heterobimetallic species exhibit axial desymmetrization of the pincer fragment, generating molecules with planar chirality. In addition, the electronic properties of the metal center can be tuned by the effect of π coordination of the second metal, as shown by electrochemical studies. The observed specificity of the reaction is discussed and supported with theoretical studies.