PubMed2004
A microporous and an open framework structure, [Cu(2)(pzc)(2)(H(2)O)(2)ReO(4)] (I) and [Cu(pzc)(H(2)O)ReO(4)].2H(2)O (II) (pzc = 2-pyrazinecarboxylate), respectively, have been prepared using hydrothermal methods and characterized using IR, TGA, and X-ray diffraction (I Pnma, No. 62, Z = 4, a = 7.4949(9) A, b = 24.975(3) A, c = 9.141(1) A; II P2(1)/c, No. 14, Z = 4, a = 8.5878(9) A, b = 12.920(1) A, c = 9.741(1) A, beta = 92.830(2) degrees ). I and II crystallize as red and blue solids, respectively, and each contains chains constructed from alternating Cu(pzc)(2)/ReO(4) oxide-bridged metal sites. The bidentate pzc ligand further bridges each -Cu-O-Re-O- chain to adjacent chains, via the Cu sites, to form a 3D net in I, with ellipsoidal channels that are approximately 3.3-4.7 A x 12.5 A, and in II, stacked layers of square nets with H(2)O-filled cavities that are approximately 4.4 x 5.1 A. Local ReO(4)(-) groups, a component of common oxidation catalysts, are directed at the channels and cavities of each structure, respectively. Thermogravimetric analysis indicates that I loses up to 64% of its H(2)O content before decomposition at 225 degrees C, while II loses approximately 100% of its H(2)O content by 265 degrees C.