Preparation of solid state samples of a transition metal coordination compound for synchrotron radiation photoemission studies

The aim of this research is to identify a sample preparation method suitable to study transition metal complexes by photoemission spectroscopy with synchrotron radiation as X-ray source, even in the case the compound is not evaporable. Solid phase samples of W(CO)4(dppe) (dppe = 1,2-bis(diphenylphosphino)ethane) have been prepared according to different methods and their synchrotron radiation XPS spectra have been measured. Spectra acquired from samples prepared by spin coating show core level peaks only slightly broader than the spectrum taken from UHV evaporated samples. Moreover, in these samples also the reproducibility of the Binding Energies values is excellent. The dependence of the spin coating technique on parameters such as solvent and concentration of the solution, spinning speed and support material have been studied. The same preparation method has also allowed the acquisition of valence band spectra, of which main peaks are clearly resolved. The results suggest that the use of spin coating technique may allow to reveal small differences in core level binding energies due to ligand substitution.