Co(ii) coordination polymers supported by a benzenetetracarboxylate and bis-pyridyl-bis-amides with different flexibilities

Hydrothermal reactions of Co(CH3COO)(2)center dot 4H(2)O and 1,2,4,5-benzenetetracarboxylic acid (1,2,4,5-H4BTEC) with N,N & PRIME;-bis(3-methylpyridyl)oxalamide (L-1), N,N ' -bis(3-methylpyridyl)adipamide (L-2) and N,N ' -bis(3-methylpyridyl)sebacamide (L-3) afforded [Co(L-1)(0.5)(1,2,4,5-BTEC)(0.5)(H2O)](n), 1, {[Co(L-1)(1,2,4,5-BTEC)(0.5)(H2O)]center dot H2O}(n), 2, {[Co(L-1)(1.5)(1,2,4,5-BTEC)(0.5)(H2O)]center dot 3H(2)O}(n), 3, [Co(L-2)(1,2,4,5-BTEC)(0.5)(H2O)(2)](n), 4, and [Co-3(L-3)(1,2,4,5-BTEC)(1.5)(mu(2)-OH2)(2)](n), 5, which have been structurally characterized by using single crystal X-ray crystallography. Complexes 1, 3 and 5 are 3D frameworks with (4(4)center dot 6(2))(4(6)center dot 6(4))(2)(4(8)center dot 6(6)center dot 8)-4,5,6T11, (6(5)center dot 8)-dmp and (3 center dot 5(2))(2)(3(12)center dot 4(34)center dot 5(20)center dot 6(52)center dot 7 center dot 8)(3(2)center dot 4(2)center dot 5(2))(2) topologies, whereas 2 and 4 are 2D layers with (4 center dot 6(2))(2)(4(2)center dot 6(2)center dot 8(2))-bex and (3(2)center dot 8 center dot 9(2)center dot 10)(2)(3(2)center dot 8(4))-4,4L88, topologies, respectively. The different structural types and the rare 4,4L88 and unique (3 center dot 5(2))(2)(3(12)center dot 4(34)center dot 5(20)center dot 6(52)center dot 7 center dot 8)(3(2)center dot 4(2)center dot 5(2))(2) topologies demonstrate that combination of the flexible bis-pyridyl-bis-amides and the benzenetetracarboxylate ligand under suitable conditions may lead to the formation of complexes with interesting structural diversity. Evaluation of the structural transformations for 1-3 reveals the reversibility and selectivity for 3 and its desolvated counterpart upon water removal and adsorption, indicating the governing role of porosity.