Coordination polymers constructed from alkali metal ions and (HO)10cucurbit[5]uril

Abstract

Three novel coordination polymers {[K(H₂O)](NO₃⊂C₃₀H₂₈N₂₀O₂₀)[K(η²-NO₃)]}Cl(H₃O)₂²⁺·7H₂O (1), {[Rb₃(μ₂-H₂O)(μ₃-H₂O)(H₂O)₅SO₄]⁺(H₂O⊂C₃₀H₂₉N₂₀O₂₀)}Cl(H₃O)⁺·2H₂O (2), [Cs₂(H₂O⊂C₃₀H₂₆N₂₀O₂₀)]SO₄²⁻(H₃O)₄⁴⁺ (3), were obtained by reactions of the corresponding alkali metal salts with an organic macrocyclic ligand perhydroxycucurbit[5]uril, (HO)₁₀Q[5], and their structures were determined by single-crystal X-ray diffraction studies. The results revealed that, in complexes 1 and 3, the (HO)₁₀Q[5] ligands are interlinked into two-dimensional networks through coordination of their carbonyl groups and hydroxy groups to the alkali metal ions (K⁺ and Cs⁺) in between, while in complex 2, the carbonyl groups and hydroxy groups of the (HO)₁₀Q[5] ligands are coordinated by the Rb⁺ ions to form an acclivitous ‘ladder’ structure. Furthermore, solid-state packing of the complexes 1 and 3 shows the formation of open channels occupied by counterions and non-coordinating water molecules. The thermogravimetric analysis (TGA) of complex 1 was characterized.