Extraction methods and surface reactions as a convenient methodology for the characterization of surface organometallic species

The characterization of the nature of surface species is a primary requirement for a better insight into surface organometallic chemistry and therefore heterogeneous catalytic processes. To date, the structures of organometallic species formed on the surface of inorganic supports (e.g. mainly oxides such as SiO2, Al2O3, TiO2, MgO) have been investigated spectroscopically. However, the use of solvent extraction with or without surface reactions as a tool for a more precise characterization of these surface species is becoming a new approach. Extraction tests under various conditions constitute a first probe because the eventual extracted species can be easily characterized by classical methods. Moreover, reactions of the unextracted surface organometallic species with specific reagents may lead to products which can be extracted and characterized as well by classical methods. This approach can give an indirect evidence of the nature of the unextracted organometallic surface species. The nature of surface species can be further substantiated by the synthesis of well defined molecular organometallic models and by the investigation of their reactivity.