The synthesis of a functionally rigid [2]rotaxane incorporating pi-electron rich 1,5-disubstituted naphthalene (NP) ring systems, encircled by the pi-electron deficient tetracationic cyclophane, cyclobis(paraquat-p-phenylene), is described; in the solid state, the molecules of this donor-acceptor [2]rotaxane line themselves up in parallel pi-pi stacks of alternating NP ring systems and bipyridi...

In the title compound, C(12)H(14)N(2) (2+)·2Cl(-), the 4,4'-dimethyl-2,2'-bipyridinium cation is essentially planar (r.m.s. deviation for all non-H atoms = 0.004 Å) and is located on a crystallographic inversion centre. The cations and chloride anions lie in planes parallel to (111) and are connected by N-H⋯Cl and C-H⋯Cl hydrogen bonds.

We have developed a synthetic approach to the self-assembly of [2]-, [3]-, and [4]rotaxanes, incorporating bis-p-phenylene-34-crown-10 as the ring component(s) surrounding bipyridinium-based dumbbell-shaped components bearing dendritic stoppers at both ends. As a result of the hydrophobic dendritic framework, these [n]rotaxanes are soluble in a wide range of organic solvents, despite the polyca...

The title compound, C(10)H(10)N(2) (2+)·C(10)H(8)O(4) (2-), has inversion centres located at the geometric centres of the 1,4-phenyl-enediacetate anion and 4,4'-bipyridinium cation. The anions and cations are connected by N-H⋯O hydrogen bonds, forming one-dimensional supra-molecular chains, which inter-act with each other via π-π inter-actions [centroid-centroid distance = 3.938 (2) Å], buildin...

We report a pH-controllable molecular switch whose switching can be monitored by the naked eye; this system involves the formation of a complex between a [2]rotaxane--featuring dibenzylammonium and 4,4'-bipyridinium stations--and a TTF-side-walled molecular clip.