Entanglement in Co(ii) coordination networks: polycatenation from single net to 2-fold and 3-fold interpenetrated nets

Abstract

The synthesis, structures and properties of six coordination networks based on N,N′-di(4-pyridyl)suberoamide (L) and angular dicarboxylate ligands, {[Co(L)(MBA)]·2H₂O}_n (H₂MBA = diphenylmethane-4,4′-dicarboxylic acid), 1, {[Co(L)_0.5(MBA)]·CH₃OH}_n, 2, [Co(L)_0.5(MBA)]_n, 3, {[Co₂(L)(OBA)₂]·7CH₃OH}_n [H₂OBA = 4,4′-oxybis(benzoic acid)], 4, {[Co(L)(hfipbb)]·2H₂O}_n [H₂hfipbb = 4,4′-(hexafluoroisopropylidene)bis(benzoic acid)], 5, and {[Co(L)(SDA)]·H₂O}_n (H₂SDA = 4,4′-sulfonyldibenzoic acid), 6, are reported. Complex 1 is a 1D → 2D polycatenane derived from the helical channels, whereas both complexes 2 and 3 show 2D layers with the (4²·6⁸·8·10⁴)(4)₂-2,6L1 topology, which are further entangled to form a 2-fold 2D → 2D interpenetration network and a 2D → 3D inclined polycatenation network, respectively, and complex 4 shows a 3-fold 3D → 3D interpenetration network with the (4¹²·6³)-pcu topology. The unusual topological features of 5 and 6 consist of 2- and 3-fold interpenetrated layers with the (4⁴·6²)-sql topology, which are further catenated to the two such adjacent sheets in parallel and uniform fashions to give 2D → 3D polycatenated networks. Complexes 1, 5 and 6 represent unique examples that the angular dicarboxylate ligands show significant effect on the degree of interpenetration of polycatenation coordination networks with interpenetrating modes. The CO₂ capture is preferable to N₂ and H₂ in the gas sorption for the desolvated product of 4.