Catalytic consequences of the structural environment and electronics of Ti in grafted Ti-calixarenes

J.M. NOTESTEIN; L. R. ANDRINI; V. I. KALCHENKO; F.G. REQUEJO; A. KATZ; E. IGLESIA

LNLS Highlights

Otro; LNLS Highlights; 2008

Laboratorio Nacional de Luz Sincrotron, LNLS

Calixarenes provide the opportunity for fundamental studies to correlate basic characteristics and properties of molecules and atomic species. In particular because grafted Ti-calixarenes provide Ti centers with varying electron density and coordination but maintain accessible sites (active centers) with uniform structures and unrestricted access to reactants, they allow for a systematic approach in relating oxidation reactivity to Ti 3d occupancy, a descriptor of Lewis acid strength, and Ti coordination. Thus, the relationship between activity, geometry and concepts of electronics in catalysis can be revisited and clarified due to the well-defined nature of these Ti sites, allied to the chemical and local sensitivity of X-ray absorption techniques.