Prevalence of the external surface over the internal pores in the spontaneous generation of tetrathiafulvalene radical cation incorporated in the novel delaminated ITQ-2 zeolite

ITQ-2 is a novel delaminated zeolite whose crystalline sheets (2.5 nm depth ) define a large external surface (similar to 720 g(-1)) having 12-membered ring (MR) open cups together with a reduced microporosity due to a 10 MR c hannel system. This feature is the reverse of that of classical zeolites (i .e., much larger internal area compared to the external surface). Herein, w e have used tetrathiafulvalene and triphenylamine to probe the capability o f layered ITQ-2 zeolite to generate persistent organic radical cations comp ared to conventional Y, mordenite and ZSM-5 zeolites as well as to Al/MCM-4 1 (3.2 nm diameter) and amorphous silica-alumina. By selective silylation o f the external cups, it has been found that formation of a significant conc entration of persistent organic radical cations in ITQ-2 is a property that occurs within the open cups of the external surface rather than inside the 10 MR pores.