Themed collection Macrocycle-based Supramolecular Elements

Hai-Bo Yang and Christoph A. Schalley introduce this themed issue on macrocyle-based supramolecular elements.

Non-covalent interactions control the solid-state packing of AuX₄⁻ anions (yellow circles) co-precipitated with different supramolecular elements.

Modification of crown ethers via grafting of functional groups represents a convenient yet underexplored tool.

Light–powered host–guest charge transfer (HGCT) is shown for a coordination cage based on electron-rich phenothiazines, containing an anthraquinone acceptor as guest. Transient absorption spectroscopy and spectroelectrochemistry data is presented.

Polycyclic aromatic hydrocarbon chromophores that show an ideal bipartition between fluorescence and singlet oxygen production have been developed.

Three desired discrete metallomacrocyclic wreaths with four-, five- and six-fold symmetry were successfully realized in a controlled fashion.

The reactivity of the glycine ketimine ester with α,β-unsaturated ketones in the presence of macrocyclic hybrid phase-transfer catalysts under high pressure conditions has been investigated.

The allosteric effect of a new bis(β-cyclodextrin) receptor amounts to a more than 18-fold increase of its binding affinity towards sodium deoxycholate upon addition of a zinc(II) phenanthroline complex as an effector.

A molecular box with an electron-rich cavity, namely naphthobox, was contructed and showed selective binding to planar aromatic cations.

A supramolecular dual-donor artificial light-harvesting system with efficient visible light-harvesting capacity was constructed through the hierarchical self-assembly approach.

A novel supramolecular strategy has been proposed by using a ditopic H-bonded amide macrocycle that is capable of controlling the binding process in response to external stimulus due to its assembly-and-disassembly-induced anion binding.

Three [3]catenanes were fabricated in high efficiency through the self-assembly of a 90° platinum(II) receptor, a flexible bis(4,4′-bipyridinium) donor and a crown ether (DB24C8 or DB30C10).

A precise replacement of one oxygen atom with sulfur allowed a novel thioimidate anion-templated macrocyclization to form a crowded host 2 with the ability to act as a highly selective and sensitive fluorescence probe for hypochlorite (ClO⁻).

A pyrene-functionalized [2]catenane with switchable optical output was constructed through a novel sulfonamide [2]catenane synthesized by a self-templation approach.

All-phenylene molecular spoked wheels, cutouts of graphenylene-3, have been synthesized by intramolecular Yamamoto coupling of the respective dodecabromides.

A novel type of circularly polarized luminescence (CPL) active systems have been constructed via chiral supramolecular polymerization of dicyanostilbene-based monomers.

A new family of supramolecular heparin-based biohybrid metallogels with multiple stimuli-responsive behaviours was constructed through the controlled self-assembly based on three orthogonal interactions within a single system.

Dynamic alkyne metathesis has successfully been employed toward the synthesis of a truxene-based shape-persistent covalent organic polyhedron (COP) with high binding affinity for fullerenes.

Herein, we have designed and synthesized a series of aryl carbazole-based macrocycles and their stable radical cation species and interesting fullerene recognition were systematically investigated.

Insights into how the optoelectronic properties of π-conjugated macrocycles evolve as a result of systematic structural changes are presented, helping to develop structure–property relationships and molecular design guidelines.

The incorporation of a linear D–π–A “push–pull” chromophore synthesized by a Knoevenagel condensation as axle of a rotaxane is reported.

Perylene bisimide cyclophanes, ideal receptors for planar aromatic compounds, act as π–π catalysts by stabilizing shape-complementary stereoinversion transition structures.

Terpenoids, (S)-citronellal, nerol, geraniol and farnesol, were site-selectively adsorbed to binding pockets on the pore surface of a metal-macrocycle framework, and their cyclization reaction was controlled in a confined nanospace.

An efficient, one-step protocol for the enrichment of C₈₄ (up to 86%) directly from a fullerene extract is reported, by utilizing a tetragonal prismatic nanocapsule with a suitable size and shape for selective encapsulation.

Rim-modified pillarplexes are prepared by a macrocycle-templated synthesis strategy. They exhibit a shape-adaptive behaviour and complementary H-bonding, showing that rim modification can modulate the flexibility and functionality of the cavitand.

Kinked tetraaldehyde building blocks lead in condensation reactions with diamines to pumpkin shaped cages – the cucurbitimines.

Using macrocyclic DB24C8 as a new kind of host molecule for a pseudorotaxane ligand, actinide-linked crown ether-based coordination polyrotaxanes, UCER-1 and UCER-2, that are linked by two different uranyl nodes, have been synthesised for the first time.

2-D Sheets from macrocycle assembly undergoes reversible lengthwise division in response to temperature change.

Here, we report a novel [2]pseudorotaxane based on perbromoethylated pillar[5]arene/imidazolium iodide ionic liquid ion-pair recognition and this pseudorotaxane shows supramolecular interaction induced LCST behavior in solution.

Dual-stimuli pseudorotaxane switches: Threaded complexes dissociate upon deprotonation or oxidation. A mechanical bond changes the influence of a ‘speed bump’ on the outcome of a switching event.

A series of clover-like supramolecular structures were designed and synthesized using a combination of Ru–Zn, Ru–Co, Ru–Mn or Ru–Ni metal ions. These structures with distinct redox properties may have further applications as functional materials.

Three luminescent tetranuclear macrocycles are obtained selectively, applying coordination-driven supramolecular processes to the reaction of 3,3′-bipyridine ligand with in situ formed Cu(I) bimetallic units bearing a coordination angle of ca. 120°.

Fluorescent mono-phosphonate calix[4]pyrrole cavitands display selectivity in amino acids' sensing.

A novel spiroborate-based double-stranded hetero-helicate is selectively formed through donor–acceptor interactions between the central electron-rich porphyrin and electron-deficient naphthalene diimide units.

By varying the metal/ligand ratio, either dinuclear triple helicate or mononuclear pincer can be stereo-selectively obtained from the same chiral ligand. Their catalytic properties have been demonstrated with the asymmetric FC alkylation reactions.

A novel method utilising sodium cation templation between a pyridinium bridged calix[4]diquinone macrocycle and a pyridine-N-oxide functionalised macrocycle precursor motif is used for the construction of a mechanically interlocked ion-pair.

Macrocycles bearing a variety of functional groups give access to a wide range of synthetic methods for further derivatisation or preparation of more complex structures such as mechanically interlocked molecules or polymeric materials.

A pair of radial [4]catenane isomers interlocked with two CB[6]s and one β-CD is reported. Due to the different positions of the tightly bound CB[6]s, shuttling dynamics of the β-CD between the two biphenyl stations are different in the isomers.

An azobenzene-bridged perylene bisimide cyclophane was designed and synthesized, which showed reversible fluorescence intensity switching under light-irradiation due to cooperative adjustments of PBI–PBI and PBI–Azo interactions.

Schiff-base macrocycles interact with ammonium-based guests to form threaded pseudorotaxanes or unthreaded external complexes, and tautomerize in the process.

A controllable and efficient template-driven strategy for the rational construction of polyimidazolium macrocycles has been developed.

A M₈L₂ metalla-cage constructed through coordination-driven self-assembly from a quinonato bis-ruthenium complex and an electron-rich tetrathiafulvalene (TTF) tetrapyridyl ligand is depicted.

The tubular aqueous assembly of dinucleobase amphiphilic monomers endowed with anionic, neutral or cationic groups is investigated under diverse conditions.

An α-CD component enhanced the anion recognition ability of the urea moiety and the deprotonation of the phenol moiety in the axle component in orientationally isomeric [2]rotaxanes with the OH groups on the wide rim of the α-CD, respectively.

An abnormal flexible O-coordinated zwitterion ligand L shows self-adaptive conformation behaviour in chemical self-assembly. Two trefoil knots were obtained with C-shaped ligand L and two novel 1D chains were obtained with Z-shaped ligand L.

A facile method by utilizing the host–guest interaction of Q[n]s for the catalytic fabrication of CDs with high emitting qualities and a tunable particle size from a single organic precursor in water with high output has been demonstrated.