Hollow silica nanosphere having functionalized interior surface with thin manganese oxide layer: nanoreactor framework for size-selective Lewis acid catalysisElectronic supplementary information (ESI) available: Additional TEM images and NMR data. See DOI: 10.1039/c0jm02647f

A novel selective nanoscale etching process that generated a well defined hollow nanostructure was developed by treating manganese oxide nanoparticles with a hydroxylamine solution. This selective etching process was used for exploiting a novel method of differentially functionalizing the internal surface of a hollow silica shell with a catalytically active Mn 3 O 4 layer and creating a novel nanoreactor framework. The nanoreactor fabricated by the newly developed method catalyzed the cyanosilylation reactions of various aromatic aldehydes with size and shape selectivity. Moreover, the substrate selectivity in the cyanosilylation reactions was efficiently tuned by modifying the outer silica shell with silane coupling reagents. Nanoscale etching process generated a nanoreactor framework, consisting of a hollow and porous silica shell and a functionalized interior surface with Mn 3 O 4 layer, which catalyzes cyanosilylation reactions with size selectivity.