Direct evidence for interactions between acidic functional groups and silanols in cubic mesoporous organosilicas

A facile one-pot synthesis route for preparation of a well-ordered cubic mesoporous silica SBA-1 functionalized with -COOH functional groups is reported for the first time. The results of 29Si{1H} HETCOR NMR provide direct evidence for the interactions between the carboxylic acid and silanol groups in carboxylic acid functionalized SBA-1. Density functional theory calculations indicate that the T3-Q4-Q3 motif is the favorable framework composition in the material and the carboxylic protons in the T3 species can form hydrogen bonds with the spatially proximate oxygen atom in the Q3 Si-OH species.