Formation of entangled Co(ii) coordination polymers based on bis-pyridyl-bis-amide and angular dicarboxylate ligands: a structural comparison

Abstract

Reactions of Co(II) salt and N,N′-di(4-pyridyl)sebacoamide (L¹), N,N′-bis(4-pyridylmethyl)bicyclo(2,2,2,)oct-7-ene-2,3,5,6-tetracarboxylic diamide (L²) or N,N′-di(4-pyridyl)adipoamide (L³) with angular dicarboxylate ligands afforded coordination polymers (CPs) {[Co(L¹)(OBA)(H₂O)]·0.5H₂O}_n [H₂OBA = 4,4′-oxybis(benzoic acid)], 1a, {[Co₂(L¹)(OBA)₂]·3DMF}_n, 1b, {[Co(L¹)_0.5(SDA)]·2H₂O}_n (H₂SDA = 4,4′-sulfonyldibenzoic acid), 2a, {[Co₂(L¹)₂(SDA)₂(H₂O)]·2H₂O}_n, 2b, {[Co(L¹)_0.5(MBA)]·H₂O}_n (H₂MBA = diphenylmethane-4,4′-dicarboxylic acid), 3, {[Co(L²)(OBA)]·solvent}_n, 4, {[Co(L²)(SDA)(H₂O)]·solvent}_n, 5, {[Co(L²)(MBA)(H₂O)]·2H₂O}_n, 6, [Co(L²)(HFIPBB)(H₂O)]_n [H₂HFIPBB = 4,4-(hexafluoroisopropylidene)-bis(benzoic acid)], 7, and {[Co(L³)(MBA)]·2H₂O}_n, 8. CPs 1a, 1b, 2a and 2b exhibit a 2D layer with an (8⁴·12²)(8)-22,4L2 topology, a 3-fold interpenetrated 3D net with a (4¹²·6³)-pcu topology, a 2D → 3D inclinedly polycatenated framework with a (4²·6⁸·8·10⁴)(4)₂-2,6L1 topology and a 2-fold interpenetrated 3D framework with a (4⁸·6⁷)-msw topology, respectively, and 3 displays a 2-fold interpenetrated 2D layer with a (4²·6⁸·8·10⁴)(4)₂-2,6L1 topology. CPs 4–6 are 2D layers, showing (6⁴·8·10)(6)-2,4L3, (3⁶·4⁶·5³)-hxl and (4·8²)-fes topologies, respectively, whereas CP 7 displays a 3-fold interpenetrated 3D net with a (4⁵·8)-dmp topology and 8 forms a 1D → 2D polycatenation with a (6³·8²·10)(6)₂-2,2,4C5 topology. A structural comparison of 1–8 indicates that the flexibility of the bis-pyridyl-bis-amide plays an important role in the formation of entangled Co(II) CPs auxiliarily supported by the angular dicarboxylate ligand.