Supramolecular cations of (m-halogenated-anilinium)(dibenzo[18]crown-6) in Keggin [SMo12O402−] polyoxometallates

Abstract

Four supramolecular cations (m-XAni⁺)(DB[18]crown-6) (X = F, Cl, Br or I; Ani⁺ = anilinium ion; DB[18]crown-6 = dibenzo[18]crown-6) were introduced into crystals of a Keggin [SMo₁₂O₄₀²⁻] polyanion to form [(m-XAni⁺)(DB[18]crown-6)]₂[SMo₁₂O₄₀²⁻]·4CH₃CN (1, 2, 3 or 4 for X = F, Cl, Br or I) through a hydrogen-bonding interaction. Crystals 1, 2, 3 and 4, which were isomorphous to each other, crystallized in the monoclinic space group P2₁/n. Supramolecular cations (m-XAni⁺)(DB[18]crown-6) were constructed by a N–H⁺⋯O hydrogen-bonding interaction. [SMo₁₂O₄₀²⁻] polyoxoanions were infinitely extended in three dimensions through a weak C–H⋯O hydrogen-bonding interaction with DB[18]crown-6. Disorder of the halogen atoms at the meta-position was observed in crystals 1, 2 and 3. The rotational freedom of the (m-XAni⁺) cations was suppressed because of weak interactions with surrounding molecules.