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While oxidized pillar[5]arenes with 1-5 benzoquinone units are known, very few examples of oxidized pillar[6]arenes have been reported. We describe here the synthesis, characterization and electrochemical behavior of a series of macrocyclic hosts prepared by the stepwise oxidation of 1,4-diethoxypillar[6]arene, resulting in high-yield and high-purity isolation of two constitutional isomers for each macrocycle, in which two, three or four 1,4-diethoxybenzene units are replaced by benzoquinone residues. A careful structural comparison with their counterparts in the pillar[5]arene framework indicates that the geometries of the macrocycles are better described as non-Euclidean hyperbolic hexagons and elliptic pentagons, respectively. A comprehensive computational study to determine anisotropic induced current density (ACID) allows us to visualize and quantify through-space and through-bond communication pathways along the macrocyclic belt. Experimental and simulated voltammetric data, as well as UV-vis spectra, of the new macrocycles afford insights into the various electronic communication pathways in these compounds.

The use of cucurbit[8]uril as a molecular host has emerged in the chemical literature as a reliable strategy for the creation of dynamic chemical systems, owing to its ability to form homo‐ and heteroternary complexes in aqueous media with appropriate molecular switches as guests. In this manner, CB[8]‐based supramolecular switches can be designed in a predictable and modular fashion, through the selection of appropriate guests able to condition the redox, photochemical, or pH‐triggered behavior of tailored multicomponent systems. Furthermore, CB[8] allows the implementation of dual/triple and linear/orthogonal stimuli‐dependent properties into these molecular devices by a careful selection of the guests. This versatility in their design gives these supramolecular switches great potential for the rational development of new materials, in which their function is not only determined by the custom‐made stimuli‐responsiveness, but also by the transient aggregation/disaggregation of homo‐ or heteromeric building blocks.

Der molekulare Wirt Cucurbit[8]uril kann in wässrigen Medien homo‐ und heteroternäre Komplexe mit molekularen Schaltern als Gastspezies bilden und gilt in der chemischen Literatur zunehmend als zuverlässiges System zum Erzeugen dynamischer chemischer Systeme. Durch Auswählen geeigneter Gastspezies kann das Redox‐, photochemische oder pH‐ausgelöste Verhalten von Mehrkomponentensystemen konditioniert werden, so dass supramolekulare Schalter auf CB[8]‐Basis vorhersehbar und modular entworfen werden können. Zudem können mit CB[8] durch sorgfältige Auswahl der Gastspezies dual/dreifach und linear/orthogonal stimuliabhängige Eigenschaften für diese molekularen Funktionseinheiten verwirklicht werden. Die vielseitigen Designmöglichkeiten verleihen diesen supramolekularen Schaltern ein enormes Potential für die rationale Entwicklung neuer Materialien, bei denen die Funktion nicht nur durch die maßgeschneiderte Ansprechbarkeit durch Reize bestimmt wird, sondern auch durch die vorübergehende Aggregation/Disaggregation homo‐ oder heteromerer Baueinheiten.

The self‐assembly in aqueous solution of the well‐known cyclophane, cyclobis(paraquat‐p‐phenylene) (BB⁴⁺), and two cucurbit[7]uril (CB7) hosts around a simple hydroquinol‐based, diamine guest (GH₂²⁺) was investigated by¹H NMR and electronic absorption spectroscopies, electrospray mass spectrometry and DFT computations. The formation of a quaternary supramolecular assembly [GH₂²⁺⋅BB⁴⁺⋅ (CB7)₂] was shown to be a very efficient process, which takes place not only because of the attractive forces between each of the hosts and the guest, but also because of the lateral interactions between the hosts in the final assembly. This complementary set of attractive interactions results in clear cooperative binding effects that help overcome the entropic barriers for multiple component assembly.