Bis(cyclopentadienyl)chromium and Bis(cyclopentadienylvanadium) Composites of Mesoporous Niobium Oxide with Pseudo-One-Dimensional Organometallic Wires in the Pores

Abstract

New composites of mesoporous niobium oxide with mixed oxidation state bis(cyclopentadienyl)vanadium and -chromium phases in the pores were synthesized and characterized by X-ray powder diffraction, nitrogen adsorption, UV, electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), and superconducting quantum interference device magnetometry. The XPS and EPR revealed that the walls of the mesostructure in both composites were reduced and that the organometallic had retained its structural integrity as a combination of neutral and cationic metallocene species. The conductivity of these materials ranged from 10-4 to 10-6 Ω-1 cm-1 and was attributed to the mixed oxidation state organometallic phase since previous studies showed that the reduced niobium oxide mesostructure is inherently insulating. The Hubbard model involving the bandwidth and the Hubbard potential was invoked using electron affinities, ionization potentials, and bandwidths of the organometallic species to verify the model ...