Supramolecular crystals having one-dimensional (1d) columnar structures were constructed by using supramolecules based on tst-DCH[18]crown-6 (tst-DCH = trans-syn-trans-dicyclohexano). In the crystal of (Ani⁺)(tst-DCH[18]crown-6)[Ni(dmit)₂]⁻ (1) and (m-FAni⁺)(tst-DCH[18]crown-6)[Ni(dmit)₂]⁻ (2) (Ani⁺ = anilinium⁺, m-FAni⁺ = m-fluoroanilinium⁺, dmit²⁻ = 2-thioxo-1,3-dithiole-4,5-dithiolate), the tst-DCH[18]crown-6 formed supramolecular cations with Ani⁺ and m-FAni⁺, respectively, through N–H⋯O hydrogen bonds. The planar conformation of tst-DCH[18]crown-6 molecules in the crystals provided bidirectional hydrogen bonding from the upper and lower side of the molecule that were the driving forces for the construction of the 1d supramolecular architecture. The results provided a method to control arrangements of crown ether-based supramolecules in 1d columns that could be used for channels and/or molecular nanomachines such as molecular rotators.

Supramolecular cations formed by monoprotonated pyridazinium cations and cis-anti-cis-dicyclohexano[18]-crown-6 (DCH[18]-crown-6) or dibenzo[18]-crown-6 (DB[18]-crown-6) were introduced into [Ni(dmit)₂]⁻ salts (where dmit²⁻ = 2-thione-1,3-dithiole-4,5-dithiolate). X-ray crystal structure analysis of (pyridazinium⁺)(DCH[18]-crown-6)[Ni(dmit)₂]⁻ (1) revealed a chair-type conformation of the DCH[18]-crown-6 moiety. A V-shaped conformation of the DB[18]-crown-6 moiety was observed in (pyridazinium⁺)(DB[18]-crown-6)₂[Ni(dmit)₂]⁻(H₂O)₂ (2). Nitrogen atoms in the pyridazinium cations interacted with the oxygen atoms of the DCH[18]-crown-6 and DB[18]-crown-6 through N–H⁺∼O hydrogen bonds, forming 1 : 1 and 1 : 2 supramolecular structures, respectively. Sufficient space for molecular motions of the pyridazinium cations, namely flip-flop and in-plane rotations, exists in salt 1. Disorder in nitrogen atoms was observed by X-ray analysis, indicating dynamic motion of the pyridazinium cation, namely flip-flop motion and in-plane motion. A potential energy calculation further supported the possibility of dynamic motion of cations in the crystal. By contrast, the flip-flop motion of the pyridazinium group in salt 2 is restricted by the two nearest-neighbouring DB[18]-crown-6 molecules. Weak antiferromagnetic intermolecular interactions between the [Ni(dmit)₂]⁻ anions in the two-dimensional layers of salt 1 were observed, resulting in alternating antiferromagnetic Heisenberg chain-type magnetic susceptibility. Quasi-one-dimensional intermolecular interactions between the [Ni(dmit)₂]⁻ anions were observed in salt 2, whose magnetic behaviour followed the Bonner–Fisher model.

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 [SMo₁₂O₄₀ ²⁻] polyanion to form [(m-XAni⁺)(DB[18]crown-6)]₂[SMo₁₂O₄₀ ²⁻]·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. [SMo₁₂O₄₀ ²⁻] 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.