Copper coordination polymers from cavitand ligands: hierarchical spaces from cage and capsule motifs, and other topologies

Abstract

The cyclotriveratrylene-type ligands (±)-tris(iso-nicotinoyl)cyclotriguaiacylene L1 (±)-tris(4-pyridylmethyl)cyclotriguaiacylene L2 and (±)-tris{4-(4-pyridyl)benzyl}cyclotriguaiacylene L3 all feature 4-pyridyl donor groups and all form coordination polymers with Cu^I and/or Cu^II cations that show a remarkable range of framework topologies and structures. Complex [Cu^I₄Cu^II_1.5(L1)₃(CN)₆]·CN·n(DMF) 1 features a novel 3,4-connected framework of cyano-linked hexagonal metallo-cages. In complexes [Cu₃(L2)₄(H₂O)₃]·6(OTf)·n(DMSO) 2 and [Cu₂(L3)₂Br₂(H₂O)(DMSO)]·2Br·n(DMSO) 3 capsule-like metallo-cryptophane motifs are formed which linked through their metal vertices into a hexagonal 2D network of (4³.12³)(4².12²) topology or a coordination chain. Complex [Cu₂(L1)₂(OTf)₂(NMP)₂(H₂O)₂]·2(OTf)·2NMP 4 has an interpenetrating 2D 3,4-connected framework of (4.6².8)(6².8)(4.6².8²) topology with tubular channels. Complex [Cu(L1)(NCMe)]·BF₄·2(CH₃CN)·H₂O 5 features a 2D network of 6³ topology while the Cu^II analogue [Cu₂(L1)₂(NMP)(H₂O)]·4BF₄·12NMP·1.5H₂O 6 has an interpenetrating (10,3)-b type structure and complex [Cu₂(L2)₂Br₃(DMSO)]·Br·n(DMSO) 7 has a 2D network of 4.8² topology. Strategies for formation of coordination polymers with hierarchical spaces emerge in this work and complex 2 is shown to absorb fullerene-C₆₀ through soaking the crystals in a toluene solution.