119Sn Mössbauer and X-ray photoelectron studies of novel tin oxide pillared laponite formed under ambient conditions from aryltin precursors. Rapid intercalation reactions using microwave heating

Abstract

119Sn Mössbauer spectroscopy studies have shown that attempts to intercalate three aryltin compounds [Ph 3SnCl, (Ph 3Sn) 2O, Ph 2SnCl 2] into the synthetic smectite clay laponite under ambient conditions result in the formation of tin(IV) oxide pillared clays. The Mössbauer data indicate that the effectiveness of conversion to tin oxide pillars is in the order: Ph 3SnCl > (Ph 3Sn) 2O, Ph 2SnCl 2. The organic product of the pillaring reaction is benzene and has been identified by 13C MASNMR spectroscopy as trapped in the pillared lattice. The new materials are novel since the pillaring was achieved via neutral precursors rather than by sacrificial reaction of the exchanged cation. The intercalation/pillaring reactions are much more rapid (5 min) when carried out in Teflon containers in a simple domestic microwave oven. Combined 119Sn Mössbauer and X-ray photoelectron spectroscopic studies (XPS) suggest that, in the microwave experiments, Ph 3SnCl has a higher initial affinity for the clay surface than (Ph 3Sn) 2O but that the chloride undergoes hydrolysis on the surface once sorbed. Evidence for the considerable mobility of Mg 2+ within the laponite lattice during microwave heating is presented.