APPLICATION OF X-RAY PHOTOELECTRON SPECTROSCOPY TO POLYMER SUPPORTED AND HOMOGENEOUS TRANSITION METAL CATALYSTS (RHODIUM, POLYSTYRENE)

X-ray Photoelectron Spectroscopy has been applied to the study of triphenylphosphine, bipyridine, chlorotris(triphenylphosphine)rhodium(I) and bipyridine tetracarbonyltungsten(O) supported on thin crosslinked polystyrene films. During this study it was found that the triphenylphosphine and chlorotris(triphenylphosphine)rhodium(I) were usually air sensitive on the surface of the polymer. Chemical evidence was found to support the contention that long lived radicals within the polymer were responsible for the air sensitivity of these films. Spectroscopic and chemical evidence of radicals within crosslinked polystyrene beads also supported the notion of a radical oxidation of the ligand and complexes. Some of these radicals could be generated photochemically, however, the vast majority of the radicals were formed by chemical processes during the functionalization of the polymers.; A methodology was also described for the examination of a homogeneous transition metal catalyst. This method uses substrates containing long hydrocarbon tails to reduce the volatility of any intermediate complexes in the XPS vacuum system. The XPS samples were prepared by dipping a film of polyethylene or polystyrene into a solution of the long chain containing substrate and the catalyst of interest. With the use of polyethylene, all complexes within the solution can be observed. However, with the use of polystyrene, only complexes interacting with the long chain containing substrate could be observed. This methodology was applied to the decarbonylation of acyl chlorides by chlorotris(triphenylphosphine)rhodium(I). All of the known complexes from this reaction were observed by XPS and confirmed by comparison with authentic samples.; This methodology was also used to identify an active olefin metathesis species by XPS from the oxotetrachlorotungsten(IV)/2 eq. ethylaluminum dichloride catalyst system. The ring opening olefin metathesis of a cyclic olefin was used to build a long hydrocarbon tail on the active catalyst. This species was converted to a new complex which by XPS was very similar to known oxoalkylidene complexes.