Designing Molecules for Metal−Metal Electronic Communication:  Synthesis and Molecular Structure of the Couple of Heterobimetallic Isomers [η⁶-(2-Ferrocenyl)indene]-Cr(CO)₃and [η⁶-(3-Ferrocenyl)indene]-Cr(CO)₃

The heterobinuclear isomers [eta(6)-(2-ferrocenybindene]-Cr(CO)(3) (1) and [eta(6)-(3-/errocenyl)indene]-Cr(CO)(3) (2) have been prepared and the crystal structure determination showed that the Fe(C5H5) and Cr(CO)(3) groups in the two molecules are disposed in different conformations with respect to the Cp-indene bridging ligand, cisoid in 1 and transoid in 2. Preliminary electrochemical (CV) and spectroscopic (IR and near-IR) results obtained for the corresponding monooxidized 1(+) and 2(+) demonstrate the existence of stronger electronic coupling in 1(+) than in 2(+).