Honeycomb supramolecular frameworks of organic-inorganic hybrid cluster composed of cation radical and Keggin-type polyoxometalate

Keggin-type phosphomolybdic acid (H3PMo12O40) promoted the formation of a cation radical of tetra(thienylthio)-tetrathiafulvalene (TT-TTF), consequently resulting in a cation radical complex (TT-TTF)(+center dot)] (3)[(PMo12O40)(3-)](CH2Cl2), which shows self-assembly in solution and forms microtubes. The molecular level structure of the microtube is evaluated by X-ray diffraction analysis, which reveals that the microtube is produced via various non-covalent interactions in the hierarchical assembly process: the electrostatic interactions between (TT-TTF)(+center dot) and (PMo12O40)(3-) afford an organic-inorganic hybrid triangular nanocluster (TT-TTF)(+center dot)(3)[(PMo12O40)(3-)] as the building block; the strong p-p interactions between (TT-TTF)(+center dot) result in the cluster-based two-dimensional honeycomb nanosheet; the van der Waals forces between the nanosheets lead to the propagation along the third direction to form a three-dimensional supramolecular framework possessing nano-sized channels.