Extended organic-inorganic hybrids based on Dawson and double-Dawson-type polyoxometalates.

The reaction between K 12[H 2P 2W 12O 48] and CuCl 2 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: K 4Na 10[alpha 1-CuP 2W 17O 60(OH)] 2. approximately 58H 2O ( 1), Na 2[H 2en][H 2hn] 0.5[Cu(en) 2] 4.5[alpha 1-CuP 2W 17O 60(OH)] 2. approximately 43H 2O ( 2), and Na 3[H 2hn] 2.5[alpha 1-P 2W 17O 60Cu(OH) 2]. approximately 14H 2O ( 3). The polyoxoanion [alpha 1-CuP 2W 17O 60(OH)] 2 (14-) in 1 and 2 exhibits a double-Dawson-type polyoxoanion that consists of two alpha 1-type mono-Cu-substituted WellsDawson 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 alpha 1-type mono-Cu-substituted WellsDawson anion. The magnetic studies of compounds 1 and 2 indicate that weak antiferromagnetic interactions exist in these two compounds.