Oleksandr

A carbonaceous dumbbell was able to spontaneously glue two tubular receptors to form a unique two-wheeled composite through van der Waals interactions, thus forcing the wheel components into contact with each other at the edges. In the present study, two tubular receptors with enantiomeric carbon networks were assembled on the dumbbell joint, and the handedness of the receptors was discriminated, thus leading to the self-sorting of homomeric receptors from a mixture of enantiomeric tubes. The crystal structures of the composites revealed the structural origins of the molecular recognition driven by van der Waals forces as well as the presence of a columnar array of C₁₂₀ molecules in a 1:1 composite.

Leave them to sort themselves out: C₁₂₀ acts as a dumbbell-shaped joint for the assembly of two tubular receptors (see picture). Enantiomeric receptor carbon networks can be discriminated on the basis of the structures of the contacting edges, thus leading to the self-sorting of homomeric receptors from a mixture of enantiomeric tubes.

Poly(ortho ester)s (POEs) are well-known for their surface-eroding properties and hence present unique opportunities for controlled-release and tissue-engineering applications. Their development and wide-spread investigation has, however, been severely limited by challenging synthetic requirements that incorporate unstable intermediates and are therefore highly irreproducible. Herein, the first catalytic method for the synthesis of POEs using air- and moisture-stable vinyl acetal precursors is presented. The synthesis of a range of POE structures is demonstrated, including those that are extremely difficult to achieve by other synthetic methods. Furthermore, application of this chemistry permits efficient installation of functional groups through ortho ester linkages on an aliphatic polycarbonate.

Revival of the poly(ortho ester)s: A facile catalytic method is reported for production of poly(ortho ester)s (POEs) from air- and moisture-stable vinyl acetal precursors. The mild and efficient method is versatile with respect to monomer incorporation, and it allows access to novel materials and side-chain functionalization of a sensitive, degradable polymer backbone.

Despite significant progress in the synthesis of covalent organic frameworks (COFs), reports on the precise construction of template-free nano- and microstructures of such materials have been rare. In the quest for dye-containing porous materials, a novel conjugated framework DPP-TAPP-COF with an enhanced absorption capability up to λ=800 nm has been synthesized by utilizing reversible imine condensations between 5,10,15,20-tetrakis(4-aminophenyl)porphyrin (TAPP) and a diketopyrrolopyrrole (DPP) dialdehyde derivative. Surprisingly, the obtained COF exhibited spontaneous aggregation into hollow microtubular assemblies with outer and inner tube diameters of around 300 and 90 nm, respectively. A detailed mechanistic investigation revealed the time-dependent transformation of initial sheet-like agglomerates into the tubular microstructures.

Rolling up the COFs: Tetraphenylporphyrins and diketopyrrolopyrroles have been incorporated as functional dye components in covalent organic frameworks by means of reversible imine condensations. Upon formation, these crystalline polymers spontaneously self-assemble to form hollow microtubes.

Coupling of K⁺ selective N-(o-iso-propoxy)phenylaza-18-crown-6 with [1,3]dioxolo[4,5-f][1,3]benzo-dioxole ester fluorophore yields a new fluorescent probe for the sensing of K⁺ by increasing the averaged fluorescence decay time (τ_f(av)). This fluorescent tool is a good candidate for a reliable analysis of physiologically relevant K⁺ levels by fluorescence lifetime imaging microscopy (FLIM) in vivo. More information can be found in the Communication by P. Wessig, H.-J. Holdt et al. (DOI: 10.1002/chem.201703799).

Cage compounds are very attractive structures for a wide range of applications and there is ongoing interest in finding effective ways to access such kinds of complex structures, particularly those possessing dynamic adaptive features. Here we report the accessible synthesis of new type of organic cage architectures, possessing two different dynamic bonds within one structure: hydrazones and disulfides. Implementation of three distinct functional groups (thiols, aldehydes and hydrazides) in the structure of two simple building blocks resulted in their spontaneous and selective self-assembly into aromatic cage-type architectures. These organic cages contain up to ten components linked together by twelve reversible covalent bonds. The advantage provided by the presented approach is that these cage structures can adaptively self-sort from a complex virtual mixture of polymers or macrocycles and that dynamic covalent chemistry enables their deliberate disassembly through controlled component exchange.

Doing some remodelling: Multi-component aromatic cages are self-assembled, self-sorted, and reconfigured in aqueous solutions through two simultaneous dynamic covalent reactions, hydrazone and disulfide.

By simple ligand exchange of the cationic transition-metal complexes [(Cp*)M(acetone)₃](OTf)₂ (Cp*=pentamethylcyclopentadienyl and M=Ir or Rh) with pillar[5]arene, mono- and polynuclear pillar[5]arenes, a new class of metalated host molecules, is prepared. Single-crystal X-ray analysis shows that the charged transition-metal cations are directly bound to the outer π-surface of aromatic rings of pillar[5]arene. One of the triflate anions is deeply embedded within the cavity of the trinuclear pillar[5]arenes, which is different to the host–guest behavior of most pillar[5]arenes. DFT calculation of the electrostatic potential revealed that the metalated pillar[5]arenes featured an electron-deficient cavity due to the presence of the electron-withdrawing transition metals, thus allowing encapsulation of electron-rich guests mainly driven by anion–π interactions.

Cavity filling: A simple yet highly efficient approach gives pillar[5]arene hosts with metalated π-surfaces. The metalated pillar[5]arenes have an electron-deficient cavity owing to the presence of the electron-withdrawing transition-metal moieties, thus allowing the encapsulation of anion guests via anion–π interactions.

Polymeric VesiclesB. P. Bastakoti and J. Perez-Mercader show in their Communication on page 12086 ff., how the oscillatory Belousov–Zhabotinsky reaction can be used to synthesize self-assembling giant polymeric vesicles in one pot.

Self-assembly of Cu(NO₃)₂⋅3 H₂O and di(3-pyridylmethyl)amine (dpma) with addition of different acids (HNO₃, HOAc, HCl, HClO₄, HOTf, HPF₆, HBF₄, and H₂SO₄) afforded a family of anion-templated tetragonal metallocages with a cationic prismatic structure of [(Gⁿ⁻)⊂{Cu₂(Hdpma)₄}]⁽⁸⁻ⁿ⁾⁺ (Gⁿ⁻=NO₃⁻, PF₆⁻, SiF₆²⁻) with different ligating anions/solvents (NO₃⁻, Cl⁻, ClO₄⁻, OTf⁻, H₂O) outside the cage. Systematic competitive experiments have rationalized the tendency of anion templation towards the formation of metallocages [(Gⁿ⁻)⊂{Cu₂(Hdpma)₄}]⁽⁸⁻ⁿ⁾⁺ as occurring in the order SiF₆²⁻≈PF₆⁻>NO₃⁻>SO₄²⁻≈ClO₄⁻≈BF₄⁻. This sequence is mostly elucidated by shape control over size selectivity and electrostatic attraction between the cationic {Cu₂(Hdpma)₄}⁸⁺ host and the anionic guests. In addition, these results have also roughly ranked the anion coordination ability in the order Cl⁻, ClO₄⁻, OTf⁻>NO₃⁻>BF₄⁻, CH₃SO₄⁻. Magnetic studies of metallocages 1 t and 2–4 suggest that the fitted magnetic interaction, being weakly magnetically coupled overall, is interpreted as a result of the combination of intracage ferromagnetic coupling integrals and intercage antiferromagnetic exchange; both contributions are very weak and comparable in strength.

Metallocage preference of anion templation: The findings of the anion-templated metallocages have approximately rationalized the capacity of anions to act as templates: SiF₆²⁻ ≈ PF₆⁻ > NO₃⁻ > SO₄²⁻ ≈ ClO₄⁻ ≈ BF₄⁻, which could mostly be elucidated by their shape selectivity over electrostatic attraction, coordination interactions, and size (see scheme).

In living systems processes like genome duplication and cell division are carefully synchronized through subsystem coupling. If we are to create life de novo, similar control over essential processes such as self-replication need to be developed. Here we report that coupling two dynamic combinatorial subsystems, featuring two separate building blocks, enables effector-mediated control over self-replication. The subsystem based on the first building block shows only self-replication, whereas that based on the second one is solely responsive toward a specific external effector molecule. Mixing the subsystems arrests replication until the effector molecule is added, resulting in the formation of a host–effector complex and the liberation of the building block that subsequently engages in self-replication. The onset, rate and extent of self-replication is controlled by the amount of effector present.

An effector molecule triggers self-replication in a mixed dynamic combinatorial library constructed from two coupled subsystems, the first devoted to effector recognition and the second to self-replication. The approach is modular and allows for quantitative control over the self-replication process.

Chirality-driven self-sorting is envisaged to efficiently control functional properties in supramolecular materials. However, the challenge arises because of a lack of analytical methods to directly monitor the enantioselectivity of the resulting supramolecular assemblies. Presented herein are two fluorescent core-substituted naphthalene-diimide-based donor and acceptor molecules with minimal structural mismatch and they comprise strong self-recognizing chiral motifs to determine the self-sorting process. As a consequence, stereoselective supramolecular polymerization with an unprecedented chirality control over energy transfer has been achieved. This chirality-controlled energy transfer has been further exploited as an efficient probe to visualize microscopically the chirality driven self-sorting.

To the core: Presented herein are two fluorescent core-substituted naphthalene-diimide-based donor and acceptor molecules with minimal structural mismatch, and they comprise self-recognizing chiral motifs to facilitate the self-sorting process. Visual discrimination of the stereoselective self-sorted and co-assembled supramolecular polymers is presented by using chirality-controlled energy transfer.