Novel Straightforward Access to a 2,2′-Bipyridine Ligand Bearing Two “(η²-dppe)(η⁵-C₅Me₅)FeCC−” Redox-Active Substituents by Homocoupling of Mononuclear Organoiron(II) 2-Bromopyridyl Synthons

We report in this contribution the synthesis and characterization of the two organoiron(II) (η2-dppe)(η5-C5Me5)FeCC−(5,2-C5H3N-X) compounds (X = Cl, 6a; X = Br, 6b) bearing a pendant halogenated m-pyridyl group. These new functional “metallo-ligands” allow for an original, convenient, and rapid synthetic access to the 2,2′-bipyridine (bipy) ligand (3) bearing two redox-active “(η2-dppe)(η5-C5Me5)FeCC−” organometallic moieties grafted to the 5,5′-positions of bipy via a Pd-catalyzed homocoupling procedure.