| Abstract: Reactions of MgCO3/BaCO3 and 1,2,3,4,5,6-cyclohexanehexacarboxylic acid hydrate (H6LⅠ·H2O) (cis-chair conformation LⅠ: a,e,a,e,a,e) resulted in formation of two three-dimensional coordination polymers [Mg3(LⅡ)(H2O)6] (1) and [Ba2(H2LⅡ)( μ2-H2O)2] (2) (trans-chair conformation LⅡ: e,e,e,e,e,e) under hydrothermal condition and were characterized by elemental analysis and IR. X-ray diffraction crystal structure analysis shows that 1 crystallizes in trigonal system , space group R3 with a=1.439 3(2) nm, c=1.459 7(4) nm, β=120.00°, V=2.618 7(10) nm3, Z=18; and 2 crystallizes in monoclinic system, space group C2/c with a=1.676 4(2) nm, b=0.909 5(1) nm, c=1.000 1(1) nm, β=105.991(2)°, V=1.465 9(2) nm3, Z=4. Complex 1 is a highly symmetrical network bridged by the trans-chair conformation LⅡ ligand. In complex 2, the cis-chair H6LⅠ ligand transformed to the partly deprotoned trans-chair H2LⅡ ligand, which bridged the Ba atoms to generate a porous 3D framework with 1D channels, which are filled with the coordinated water molecules. In the two complexes, both of the flexible cyclohexanehexacarboxylate ligands adopt the trans-chair conformation LⅡ, illustrating that the conformation LⅡ can be stabilized by the coordination with alkaline earth Mg(Ⅱ)/Ba(Ⅱ) through hydrothermal syntheses. CCDC: 755551, 1; 755552, 2. |
