Assembly and post-modification of a metal-organic nanotube for highly efficient catalysis.

A metal-organic nanotube (MONT) was synthesized by linking up the bent organic ligands and the tetra-coordinated zinc cations under mild conditions. Structural analysis revealed that the MONT has a very large exterior wall diameter of 4.91 nm and an interior channel diameter of 3.32 nm. Interlocking of the nanotubes gives rise to a 3D chiral framework containing 1D helical cylindered channels with diameter of 2.0 nm. The MONT has very interesting property by synergizing the functionality of nanotubes, metal-organic frameworks (MOFs), and N-heterocyclic carbenes (NHCs). The dye adsorption experiments demonstrate that the channels of the MONTs are accessible to large reagents typically used for catalysis. The postmodification of the MONT can be easily operated by unmarking the imidazolium moieties in the channel walls, which was conducted as a highly active heterogeneous catalyst for Suzuki-Miyaura and Heck coupling reactions, hydrogenation of olefins and nitrobenzene, while the constituent elements are less efficient for these reactions under the same conditions.