| Abstract: Hydrothermal reaction of pyridine-2,4,6-tricarboxylic acid (2,4,6-pytaH3), 4-amino-3,5-bis(4-pyridyl)-1,2,4-triazole (4,4′-abpt) and CoCl2 under different pH conditions generated two coordination polymers [Co(2,4,6-pytaH)(4,4′-abpt)(H2O)] (1) and [Co1.5(2,4,6-pyta)(4,4′-abpt)(H2O)3]·3.5H2O (2). Complex 1 was synthesized under 2,4,6-pytaH3 acid environment and 2,4,6-pytaH3 was partly deprotoned into 2,4,6-pytaH2-, while 2 was reacted under NaOH basic solution and 2,4,6-pytaH3 was completely deprotoned into 2,4,6-pyta3-. Complex 1 contains a one-dimensional (1D) Co-carboxylate chain, while 2 exhibits a two-dimensional (2D) grid-like coordination layer with (4,4) network topology. The three-dimensional (3D) supramolecular networks of 1 and 2 are further constructed through π-π stacking and fruitful hydrogen-bonding (H-bonding) of inter-layers and inter-chains, respectively. X-ray diffraction crystal structure analysis shows that 1 crystallizes in monoclinic system, space group P21/n, a=0.961 30(10) nm, b=0.632 09(6) nm, c=3.372 9(4) nm, β=95.104(2)°, V=2.041 3(4) nm3, Z=4; and 2 crystallizes in monoclinic system, space group P21/c, a=1.795 2(2) nm, b=0.729 62(8) nm, c=2.078 7(2) nm, β=112.323(2)°, V=2.518 6(5) nm3, Z=4. Thermal stability of 2 was measured in N2 atmosphere. CCDC: 784916, 1; 784915, 2. |
