Polyanionic clusters embedded in lattice-type hydrogen bonding networks involving in situ bond activation and coupling of organic cations

Two inorganic-organic supramolecular polyoxometalates, (H(2)chtpy)(2)[SiW12O40] (1) (chtpy = 1,3,4,6-tetra(4-pyridyl) cyclohexane-1,3-diol) and [Co(Hbztpy)(2)]H[AlW12O40]center dot 3H(2)O (2) (bztpy = 1,2,4,5-tetra(4-pyridyl)benzene), have been hydrothermally synthesized and characterized. Both of them consist of complex supramolecular interactions between inorganic polyanions and organic cations. During the formation process of 1 and 2, in situ organic reactions involving C-C coupling through dehydrogenative cyclodimerization of two flexible 1,3-bis(4-pyridyl)propane (bpp) molecules were observed. The tetradentate pyridyl chtpy and bztpy molecules serve as 4-connected nodes to enrich the structural topologies of 1 and 2. The typical centered N-H center dot center dot center dot N (N center dot center dot center dot N = 2.6-2.7 angstrom) hydrogen bonding interactions link the organic cations to form grid-type networks for capturing the pseudo-spherical Keggin-type anions. The pH values of the reaction solutions are important for the intermolecular C-C coupling of the organic molecules, and their transformation mechanisms are discussed.