Indenyl and indacenyl ligands in homo and heterobimetallic complexes

Metal atoms that are held in close proximity exhibit unique properties and many ligands have been tested for their ability to coordinate two or more transition metals in an effort to search for new chemical and physical properties. During the last decade, extensive studies have been conducted on a series of heterobimetallic indenyl complexes of Cr(O) and Rh(I). The mutual effect of the two metal units, viz. Cr(CO)(3) and RhI2 [L-2 = COD, NBD, (CO)(2)], anti coordinated to the same planar bridging ligand influences both the reactivity and the catalytic activity of the two metals. Some insight into the dependence of the mutual effects on the stereochemistry of the bimetallic complexes may be provided by the availability of pairs of pure syn and anti bimetallic stereoisomers of rigid bridging ligands. Reported here are the preliminary results concerning the synthesis of syn and anti homobimetallic s-indacene-diide-[RhL2](2) complexes.