Extended OrganicInorganic Hybrids Based on Dawson and Double-Dawson-Type Polyoxometalates

The reaction between K12[H2P2W12O48] and CuCl2 in a NaCl aqueous solution assisted with organoamines (1,2-ethylenediamine (en), 1,6-hexamethylene diamine (hn), or both) leads to the isolation of three compounds: K4Na10[α1-CuP2W17O60(OH)]2·∼58H2O (1), Na2[H2en][H2hn]0.5[Cu(en)2]4.5[α1-CuP2W17O60(OH)]2·∼43H2O (2), and Na3[H2hn]2.5[α1-P2W17O60Cu(OH)2]·∼14H2O (3). The polyoxoanion [α1-CuP2W17O60(OH)]214− in 1 and 2 exhibits a double-Dawson-type polyoxoanion that consists of two α1-type mono-Cu-substituted WellsDawson anions, which can be synthesized by both the conventional aqueous solution method and the hydrothermal technique. Furthermore, the double-Dawson-type polyoxoanions in 2 are linked by the [Cu(en)2]2+ bridges to form 2-D networks, which are further packed into a 3-D supramolecular porous framework via extensive hydrogen bonding interactions, exhibiting two types of tunnels (A and B). Compound 3 possesses a 3-D supramolecular framework with 1-D tunnels constructed from the α1-type mono-Cu-substituted WellsDawson anion. The magnetic studies of compounds 1 and 2 indicate that weak antiferromagnetic interactions exist in these two compounds.