Formation and asymmetric catalysis of C- and 8-shaped titania tubes

Two trans-1,2-diaminocyclohexane-derived chiral cationic gelators were synthesized, each of which could self-assemble into ribbons in n-propanol. Titania tubes resembling the letter 'C' and the numeral '8' in the nano- and micro-size range were prepared using the self-assemblies of the gelators as the templates through a sol-gel transcription approach. Field emission electron microscopy images indicated the C- and 8-shaped titania tubes were formed by the adsorption of titania nanoparticles on the edges of the organic nanoribbons. The titania tubes were found to be applicable as asymmetric catalysts. We infer that gelator chirality is imparted on the titania surface at the angstrom level.