Bottom-Up Construction of Mesoporous Nanotubes from 78-Component Self-Assembled Nanobarrels

Segmental and continuous hexagonal-packed mesoporous metal-organic nanotubes (MMONTs) with outside diameters of up to 4.5 nm and channel sizes of 2.4 nm were hierarchically constructed by a rational multicomponent self-assembly process involving starting from [L2Pd2(NO3)2] (L=o-phenanthroline or 2,2'-bipyridine) and 4-pyridinyl-3-pyrazole. An unprecedented crystallization-driven cross-linking between discrete nanobarrel building units by spontaneous loss of the capping ligands to form infinite nanotubes was observed. Such a barrel-to-tube transformation provides new possibilities for the fabrication of MMONTs using the solution bottom-up approach.