Macrocycles containing 1,1′-ferrocenyldiselenolato ligands on group 4 metallocenes

Abstract

Macrocyclic [Fe(η⁵-C₅H₄Se)₂M(η⁵-C₅H₄R)₂]₂ [M = Ti (1), Zr (2), Hf (3), R = H; and M = Zr (4), Hf (5), R = ^tBu] were prepared and characterized by ⁷⁷Se NMR spectroscopy and the crystal structures of 1–3 and 5 were determined by single-crystal X-ray diffraction. The crystal structure of 4 is known and the complex is isomorphous with 5. 1–5 form mutually similar macrocyclic tetranuclear complexes in which the alternating Fe(C₅H₄Se)₂ and M(C₅H₄R)₂ centers are linked by selenium bridges. The thermogravimetric analysis (TGA) of 1–3 under a helium atmosphere indicated that the complexes undergo a two-step decomposition upon heating. The final products were identified using powder X-ray diffraction as Fe_xMSe₂, indicating their potential as single-source precursors for functional materials.