Structural transformations in cobalt(II) coordination polymers constructed from flexible N,N′-bis(3-pyridylmethyl)sebacoamide and benzene-1,3,5-tricarboxylic acid

Hydro(solvo)thermal reactions of cobalt(n) salts, N,N'-bis(3-pyridylmethyl)sebacoamide (L), and benzene-1,3,5-tricarboxylic acid (1,3,5-H3BTC) in water afforded {[Co(L)(1,3,5-HBTC)]center dot H2O}(n) 1 and {[Co-2(L)(2)(1,3,5-HBTC)(2)(H2O)(4)]center dot 9H(2)O}(n) 2, whereas those in MeOH and MeOH/H2O gave {[Co-3 (L)(1,3,5-BTC)(2)(CH3OH)(5)]center dot 5CH(3)OH}(n) 3 and {[Co-1.5(L)(0.5)(1,3,5-BTC)(CH3OH)(H2O)(3)]center dot H2O}(n) 4, respectively, which have been structurally characterized by using single-crystal X-ray diffraction. Complex 1 displays a two-dimensional (2D) network with the {4(2)center dot 6(7)center dot 8}{4(2)center dot 6}-3,5L2 topology, and complexes 2 and 3 are three-dimensional (3D) frameworks with the (6(5)center dot 8)-cds topology and a new topology with a point symbol of {5 center dot 6 center dot 7}{5 center dot 6 center dot 8}(2){5(2)center dot 6(2)center dot 7 center dot 8(2)center dot 9(3)}, respectively, while 4 shows a 2D layer with the {6(3)}-hcb topology, demonstrating that the concentration of the reagent and the solvent system are important in determining the structural diversity. Irreversible structural transformations from 1 to 3 and 2 to 3 under hydro(solvo)thermal conditions are observed and discussed, showing that the flexible nature of the spacer ligands is important in promoting the structural transformations.

Automated summary

Hydro(solvo)thermal reactions of cobalt(n) salts, organic ligands, and solvent systems have been studied, resulting in the synthesis of four different coordination compounds. The structures of these compounds have been characterized using single-crystal X-ray diffraction. The experimental results demonstrate the significant influence of reaction conditions on structural diversity.