New types of hybrid solids of tetravanadate polyanions and cucurbituril

Abstract

Three inorganic–organic hybrid solids based on tetravanadate polyanions, {V₄O₁₂}⁴⁻ and cucurbituril, Me₁₀Q[5] and Q[5], namely (NH₄)₄[(V₄O₁₂)·(Me₁₀Q[5]@0.5H₂O)₂]·∼13H₂O (1), Li₄(H₂O)₅[(V₄O₁₂)·(Me₁₀Q[5]@H₂O)₂]·∼20H₂O (2), and Na₄(H₂O)₂[(V₄O₁₂)·(Q[5])₂]·∼15H₂O (3), have been synthesized under hydrothermal conditions. In the structure of compound 1, two {Me₁₀Q[5]@0.5H₂O} moieties connect to one {V₄O₁₂}⁴⁻ cluster through an NH₄⁺ counter-cation to form a trimer unit, which further forms a three-dimensional (3D) supramolecular architecture via extensive hydrogen bonds (H-bonds). Compound 2 contains a one-dimensional (1D) covalently bonded chain structure built by alternate {Me₁₀Q[5]@H₂O} moieties and {Li₂O₄(H₂O)₃}²⁺ dimer units. The anionic {V₄O₁₂}⁴⁻ units bond to every another {Li₂O₄(H₂O)₃}²⁺ dimer unit sitting on the chain through multi-uncoordinated water molecules via H-bonds. Compound 3 is built from {V₄O₁₂}⁴⁻ clusters, Q[5], and sodium cations into a two-dimensional (2D) covalent wavy structure, showing interesting connection between the building units, which is packed into 2D through plentiful H-bonds. It has been found that the cations dramatically affect the coordination of the tetravanadate polyanion and cucurbituril.