Applications of chalcogen containing iron carbonyl clusters: Examination of self-assembled films and homogeneous carbonylation catalysis of methanol
Guzman-Jimenez, Ilse Yolanda
Whitmire, Kenton H.
Doctor of Philosophy
Thin films have been prepared via the solution-phase-self-assembly of organometallic chalcogen-containing cluster compounds onto the surface of gold and characterized. The following anionic complexes were used as thin films precursors: [Fe3(CO)9E]2- and [HFe3(CO)9E]-, where E = S, Se, Te. The films were generated by adsorption from organic solvents (e.g., methanol, acetonitrile, acetone, and dichloromethane) onto evaporated gold and were characterized by ellipsometry, polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS), X-ray diffraction (XRD), atomic force microscopy (AFM), quartz crystal microbalance (QCM), and X-ray photoelectron spectroscopy (XPS). [Et4N]2[Fe3(CO)9E] catalyzes the carbonylation of methanol to form methyl formate under moderate CO pressures (600--1200 psi) between 50 and 90°C. A detailed kinetic analysis of this system is reported. [Fe3(CO)9E]- selectively carbonylates methanol to methyl formate in a homogeneus reaction which first order dependent in cluster concentration, quasi second order dependent in pressure of CO. The reaction appears to be almost independent of the [OCH 3-]total at values of [OCH3 -]total ≤ 3 x 10-3 M, but at higher concentrations it appears to be first order dependence in [OCH3-]total. This system affords the opportunity to compare the effects of different main group heteroatoms in a homogeneous series.