The nature, concentration, and location of cationic lanthanum species in faujasite-type zeolites (zeolite X, Y and ultrastabilized Y) have been studied in order to understand better their role in hydrocarbon activation. By combining detailed physicochemical characterization and DFT calculations, we demonstrated that lanthanum cations are predominantly stabilized within sodalite cages in the form of multinuclear OH-bridged lanthanum clusters or as monomeric La3+ at the SI sites. In high-silica faujasites (Si/Al = 4), monomeric [La(OH)]2+ and [La(OH)2]+ species were only found in low concentrations at SII sites in the supercages, whereas the dominant part of La3+ is present as multinuclear OH-bridged cationic aggregates within the sodalite cages. Similarly, in the low-silica (Si/Al = 1.2) La–X zeolite, the SI′ sites were populated by hydroxylated La species in the form of OH-bridged bi- and trinuclear clusters. In this case, the substantial repulsion between the La3+ cations confined within the small sodalite cages induces the migration of La3+ cations into the supercage SII sites. The uniquely strong polarization of hydrocarbon molecules sorbed in La–X zeolites is caused solely by the interaction with the accessible isolated La3+ cations.     «

The nature, concentration, and location of cationic lanthanum species in faujasite-type zeolites (zeolite X, Y and ultrastabilized Y) have been studied in order to understand better their role in hydrocarbon activation. By combining detailed physicochemical characterization and DFT calculations, we demonstrated that lanthanum cations are predominantly stabilized within sodalite cages in the form of multinuclear OH-bridged lanthanum clusters or as monomeric La3+ at the SI sites. In high-silica fa...     »

ISI Document Delivery No.: 839UG Times Cited: 3 Cited Reference Count: 57 Schuessler, Florian Pidko, Evgeny A. Kolvenbach, Robin Sievers, Carsten Hensen, Emiel J. M. van Santen, Rutger A. Lercher, Johannes A. Pidko, Evgeny/A-7811-2008; van Santen, Rutger/B-4771-2013; Hensen, Emiel /B-4973-2013 Pidko, Evgeny/0000-0001-9242-9901; Idecat The authors would like to thank Dr. Gabriele Raudaschl-Sieber for supporting the NMR experiment and Prof. Gary Haller for in depth discussion. We also gratefully acknowledge the financial support in the framework of IDECAT for exchange visits between collaborating partners. NWO-NCF (SH-170-11) is acknowledged for providing access to the computational facilities. 3 Amer chemical soc Washington     «

ISI Document Delivery No.: 839UG Times Cited: 3 Cited Reference Count: 57 Schuessler, Florian Pidko, Evgeny A. Kolvenbach, Robin Sievers, Carsten Hensen, Emiel J. M. van Santen, Rutger A. Lercher, Johannes A. Pidko, Evgeny/A-7811-2008; van Santen, Rutger/B-4771-2013; Hensen, Emiel /B-4973-2013 Pidko, Evgeny/0000-0001-9242-9901; Idecat The authors would like to thank Dr. Gabriele Raudaschl-Sieber for supporting the NMR experiment and Prof. Gary Haller for in depth discussion. We also gratefull...     »