Basic sites on periodic mesoporous organosilicas investigated by XPS and in situ FTIR of adsorbed pyrrole

Langmuir. 2011 Feb 1;27(3):1181-5. doi: 10.1021/la103814w. Epub 2010 Dec 28.

Abstract

Oxygen sites in ethane-bridged and phenylene-bridged PMOs prepared using neutral templates in acidic conditions are characterized by means of XPS and FTIR spectroscopy of adsorbed pyrrole. Their electron donor ability is observed to be stronger than that of oxygens in pure amorphous silica of MCM-41 type and comparable to that reported for oxygen atoms in some alkali metal exchange zeolites. For pyrrole adsorbed on PMOs double interactions most probably occur, involving both silanols and electron donor sites at the surface. In the case of phenylene-bridged PMO preferential electron donor sites for interaction with pyrrole N-H group are aromatic rings rather than oxygens, as previously observed for adsorbed iodine.