Spin state isomerism and molecular magnetism from site-specifically substituted bis(indenyl) transition metal complexes

Abstract

This work focuses on bis(indenyl) complexes of vanadium, chromium, manganese and iron. Specifically, spin-state manipulations of the complexes were attempted by the variation of ligand substituents in number, type, and position on the indenyl rings. The spin states of the resulting organometallic species were probed via magnetic susceptibility measurements in solution and in the solid state. Characterization of these complexes in the solid state by x-ray crystallography was essential to the determination of their preference for a specific rotational conformation. In certain cases the rotational conformation of the rings, and consequently the molecule’s symmetry, was directed by sterically bulky substituents. Studies of the molecules’ reactivity with small molecular gases (e.g., N₂, H₂, CO, C₂H₄, and NO) were investigated as functions of the symmetry, spin-state, and metal center.