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Structural Transformation of ZnII -Dipyridylamide-Based Coordination Frameworks: Hybrid-Ligand and Metal Effects
Biing-Chiau Tzeng1, Tsung-Yi Chang1, Miao-Hsin Tsai1
1Department of Chemistry and Biochemistry, National Chung Cheng University, 168 University Road, Min-Hsiung, Chiayi 62102 (Taiwan).
Abstract:
A series of one-dimensional (1D) double-zigzag ({[Zn(papx)2 (H2 O)2 ](ClO4 )2 }n (x=so 1, sc 3, oc 5, and soc 7) and 2D polyrotaxane ([Zn(papx)2 (ClO4 )2 ]n (x=so 2, sc 4, oc 6, and soc 8) frameworks are synthesized by the reactions of Zn(ClO4 )2 with equimolar amounts of papx (i.e., papso=1/2paps+1/2papo, papsc=1/2paps+1/2papc, papoc=1/2papo+1/2papc, and papsoc=1/3paps+1/3papo+1/3papc; paps=N,N'-bis(pyridylcarbonyl)-4,4'-diaminodiphenyl thioether, papo=N,N'-bis(pyridylcarbonyl)-4,4'-diaminodiphenyl ether, papc=N,N'-(methylenedi-p-phenylene)bispyridine-4-carboxamide). The new frameworks are isolated and characterized by single-crystal and powder X-ray diffraction studies, elemental analysis, and 1 H NMR spectroscopy. In addition, synthesis and structural characterization of 2D polyrotaxane frameworks of [Cu(papx)2 (ClO4 )2 ]n (x=s 9, o 10, and c 11) by the reaction of Cu(ClO4 )2 with the respective dipyridylamide ligands are carried out. Based on the PXRD experiments, upon heating, the double-zigzag frameworks of 1, 3, 5, and 7 undergo structural transformation to give the respective polyrotaxane frameworks of 2, 4, 6, and 8. Moreover, grinding the solid samples of 2, 4, 6, and 8 in the presence of moisture also result in the total conversion back into the double-zigzag frameworks of 1, 3, 5, and 7, respectively. Remarkably, grinding the solid samples of polyrotaxane frameworks of 9 and 10 in the presence of moisture fails to induce a structural transformation process.
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