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 req uirement for a better insight into surface organometallic chemistry an d 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 investi gated spectroscopically. However, the use of solvent extraction with o r without surface reactions as a tool for a more precise characterizat ion of these surface species is becoming a new approach. Extraction te sts under various conditions constitute a first probe because the even tual extracted species can be easily characterized by classical method s. Moreover, reactions of the unextracted surface organometallic speci es 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 substant iated by the synthesis of well defined molecular organometallic models and by the investigation of their reactivity.