η6-Coordination of a Ruthenium(II) Organometallic Fragment to the Arene Ring of N,C,N-Pincer Metal Complexes
摘要:
Stable heterobimetallic complexes of the type [MX(NCN)Ru(C5R5)](+) (R = H or Me), where the phenylene ring of an NCN-pincer ligand coordinates first to a-platinum or palladium center via a a-bond, and second to a ruthenium organometallic fragment via a g-bond, are synthesized in a single step involving electrophilic attack of a cationic Ru species on the aryl metal complex. X-ray crystal structures and solution NMR agree on the simultaneous presence of orthogonal eta(6) - and eta(1)-coordination axes. Pt-195 NMR and electrochemistry show that the eta(6)-coordinated ruthenium fragment has a strong electron-withdrawing effect on the pincer metal, which leads to a diminished nucleophilicity of the platinum center toward electrophiles such as SO2.