Structural and spin diversity of M(indenyl)2 transition-metal complexes: a DFT investigation

Abstract

Full geometry optimization has been carried out for all the low-energy isomers of M(indenyl)₂ (M = Sc–Ni, Y–Mo, Re, Ru–Pd). Depending on the electron-richness of the molecule, indenyl adopts various hapticities, some of them involving full or partial coordination of the C₆ ring. Our results suggest that a judicious choice of substituents on the ligands should lead to the stabilization of η⁶-coordinated indenyl ligands. Indenyl is also shown to be quite flexible with respect to the spin ground state. Substituted iron and nickel bis-indenyl species should be characterizable in their triplet state. Thus, both from the point of view of coordination and the metal spin ground state, indenyl and cyclopentadienyl appear to behave quite differently.