Covalent Folding of Fluorinated Polyphenylene by Sulfur Fluorine Annulative Substitution.

We report that fluorinated polyphenylene P50 undergoes folding-like sulfur fluorine annulative substitution (SFAS) to form a well-defined tubular helix H50. This is achieved with atomic precision in an exceptionally efficient manner, involving the simultaneous transformation of 98 C-F bonds with the yield per reaction site approaching 99.9 %.

A compact chemically driven [2]catenane rotary motor operated through alternate pumping and discharging.

Here we present a compact and precise [2]catenane rotary motor that functions with a single recognition site, capable of achieving a 360° directional rotation powered by chemical fuels. The motor is propelled by an acid-base fueled benzimidazolium pumping cassette and deemed the smallest (molecular weight ∼ 994 Da) catenane rotary motor to date. It can effectively undergo a 180° rotation by transitioning the [24]crown-6 ether (24C6) from the benzimidazolium site to the less favorable alkyl moiety through sequential deprotonation, slipping, and re-protonation operations, generating a meta stable co-conformer.

Engineering Nanobelt Structure via Sulphur and Oxygen Doping: Synthesis, Structural Characterization, and Complexation with Fullerenes.

This study explores the synthesis, structural characterization, and host-guest interactions of heteroatom bridged nanobelts, focusing on a cyclothianthrene nanobelt and a fused nanobelt incorporating thianthrene and phenoxathiin. Utilizing a cyclization-followed-by-bridging synthetic approach, both molecular belts were successfully synthesized, and their structures confirmed through NMR and MALDI-TOF-MS analysis. Crystallographic studies revealed that the cyclothianthrene nanobelt adopts an octagonal column-like conformation, while the hybrid belt forms an oval tub-shaped shape, both exhibiting distinct assembly motifs.

Fabrication of Azacrown Ether-Embedded Covalent Organic Frameworks for Enhanced Cathode Performance in Aqueous Ni-Zn Batteries.

Crown ethers (CEs), known for their exceptional host-guest complexation, offer potential as linkers in covalent organic frameworks (COFs) for enhanced performance in catalysis and host-guest binding. However, their highly flexible conformation and low symmetry limit the diversity of CE-derived COFs. Here, we introduce a novel C-symmetrical azacrown ether (ACE) building block, tris(pyrido)[18]crown-6 (TPy18C6), for COF fabrication (ACE-COF-1 and ACE-COF-2) via reticular synthesis.

A π-extended molecular belt with selective binding capability for fullerene C.

A molecular belt incorporating naphthalene moieties, featuring an ellipsoidal cavity, was precisely engineered through bottom-up synthesis. Its pre-arranged geometry exhibits excellent complementarity to fullerene C, resulting in remarkable selective binding ability ( = 1.3 × 10 M) for C compared to C ( = 176 M), forming a 1 : 1 complex.

Advancements and strategic approaches in catenane synthesis.

Catenanes, a distinctive category of mechanically interlocked molecules composed of intertwined macrocycles, have undergone significant advancements since their initial stages characterized by inefficient statistical synthesis methods. Through the aid of molecular recognition processes and principles of self-assembly, a diverse array of catenanes with intricate structures can now be readily accessed utilizing template-directed synthetic protocols. The rapid evolution and emergence of this field have catalyzed the design and construction of artificial molecular switches and machines, leading to the development of increasingly integrated functional systems and materials.

Cyclization of an Achiral Flipping Panel to Homochiral Tubes Exhibiting Circularly Polarized Luminescence.

Macrocyclization of the bendable 2,7-dimethoxythianthrene with methylene linkages afforded a pair of homochiral macrocycles featuring a hex-nut-like geometry. Their structures were fully characterized by NMR spectroscopy, mass spectrometry, and single-crystal X-ray diffraction analysis. Their stable planar chirality facilitates efficient resolution of the pair of enantiomers which could be readily derivatized.

ProBox: A Rigid yet Dynamic Cyclophane Capable of Adaptive and Redox-Switchable Host-Guest Binding.

A yrlodithiin-derived -like cyclophane (), featuring an adaptive geometry with stimuli-responsiveness, was designed and successfully constructed. The dynamic and foldable dithiin subunit endowed the cyclophane with a compressible cavity which can transform from a hex-nut geometry to a nearly rectangular box upon complexing guests with various sizes and shapes. The resulting pseudorotaxane complexes could be dethreaded via electrochemical oxidation.

Molecular Hinges by Fusion of Pyrrole and Dithiin: Synthesis, Structure, Redox Chemistry and Host-Guest Complexation of Dipyrrolo-1,4-dithiins.

A series of novel hinge-like molecules, namely dipyrrolo-1,4-dithiins (PDs), were prepared and fully characterized by NMR, UV/vis, cyclic voltammogram, ESR, and single crystal X-ray diffraction (SCXRD) analysis. The lateral fusion of pyrroles with 1,4-dithiins has led to not only retained key features of a dithiin, but also enhanced redox-activity with increased susceptibility to radical cations via redox or chemical oxidation. Stabilization of their radicals are observed for the N,N-tert-butyl or N,N-triphenylmethyl PD as evidenced by ESR measurements.

Docking rings in a solid: reversible assembling of pseudorotaxanes inside a zirconium metal-organic framework.

An unprecedented zirconium metal-organic framework featuring a T-shaped benzimidazole strut was constructed and employed as a sponge-like material for selective absorption of macrocyclic guests. The neutral benzimidazole domain of the as-synthesized framework can be readily protonated and fully converted to benzimidazolium. Mechanical threading of [24]crown-8 ether wheels onto recognition sites to form pseudorotaxanes was evidenced by solution nuclear magnetic resonance, solid-state fluorescence, and infrared spectroscopy.

2D and 3D metal-organic frameworks constructed with a mechanically rigidified [3]rotaxane ligand.

A mechanically interlocked [3]rotaxane was newly designed, synthesized, and employed as a ligand for constructing metal-organic frameworks (MOFs). The nano-confinement by macrocycles forces the soft bis-isophthalate axle into a pseudo-rigid conformation and coordinates to zinc(II) ions, affording a two- or three-dimensional MOF under controlled conditions. The 2D MOF exhibits a neutral framework with a periodic puckering sheet structure, while an anionic framework with a topology was observed for the 3D MOF.

Precise Control of Radial Catenane Synthesis via Clipping and Pumping.

An unprecedented molecular pumping cassette was designed and implemented for the construction of molecular necklaces, that is, radial []catenanes. The mechanism was fully confirmed on a model [2]pseudorotaxane, and the novel clipping-followed-by-pumping strategy was used to prepare a series of []catenanes ( = 2-5). A pair of [3]catenane diastereomers sequentially threaded with two different wheels was also accomplished.

A Tubular Belt and a Möbius Strip with Dynamic Joints: Synthesis, Structure, and Host-Guest Chemistry.

Two unprecedented isomeric macrocycles, a tubular belt and a Möbius strip, with thianthrene joints have been constructed through a one-step cyclization reaction. Both structures are fully characterized by NMR spectroscopy, mass spectrometry, and single-crystal X-ray diffraction. A complexation study reveals that the tubular belt is a container for electron deficient guests.

A self-assembled ML truncated square and its application as a container for fullerenes.

An unprecedented bisthianthrene dipyridyl ligand was designed and synthesized for coordination driven self-assembly. The combination of this conformationally dynamic linker with a 90° convergent metal corner exclusively afforded a novel ML truncated square-like metallamacrocycle. The single crystal X-ray structure reveals a belt-shaped geometry with a cavity diameter of 13.

Sulphur-Embedded Hydrocarbon Belts: Synthesis, Structure and Redox Chemistry of Cyclothianthrenes.

Cyclothianthrenes, a series of sulphur-embedded hydrocarbon belts proposed a decade ago, were successfully constructed through a stepwise bottom-up synthesis. The belt [6]cyclothianthrene ([6]CT) is the smallest and most strained member of the family yet reported. Both [6]CT and [8]CT are the first examples of cyclothianthrene characterized by single crystal X-ray diffraction.

Fluorescence emission enhancement of a T-shaped benzimidazole with a mechanically-interlocked 'suit'.

A fluorescent T-shaped benzimidazole was successfully designed and interlocked in a bicyclic macrocycle to form a suit[1]ane through supramolecular templated-synthesis. Compared with the bare fluorophore, suit[1]ane requires nearly two times the concentration to initialize the aggregation-caused quenching effect in solution. Furthermore, an 8-fold higher solid-state fluorescence quantum yield (21.

Erratum: One-Step Construction of Hydrophobic MOFs@COFs Core-Shell Composites for Heterogeneous Selective Catalysis.

[This corrects the article DOI: 10.1002/advs.201802365.

Exploring the dynamics of Zr-based metal-organic frameworks containing mechanically interlocked molecular shuttles.

Zr(iv) metal-organic frameworks (MOFs) UiO-68 and PCN-57, containing triphenylene dicarboxylate (TPDC) and tetramethyl-triphenylene dicarboxylate (TTDC) linkers, respectively, were doped with an H-shaped tetracarboxylate linker that contains a [2]rotaxane molecular shuttle. The new MOFs, UWDM-8 and UWDM-9, contain a [2]rotaxane crossbar spanning the tetrahedral cavities of the fcu topology while the octahedral cavities remain empty. C solid-state NMR (SSNMR) spectra and solution H NMR spectra verified that the [2]rotaxanes were included as designed.

Highly Emissive Perylene Diimide-Based Metallacages and Their Host-Guest Chemistry for Information Encryption.

Here we report two highly emissive perylene diimide (PDI)-based metallacages and explore their complexation with polycyclic aromatic hydrocarbons, such as pyrene, triphenylene, and perylene. The fluorescence quantum yields of metallacages exceed 90% and their binding constants with perylene can reach as high as 2.41 × 10 M in acetonitrile.

Heteroatom-bridged molecular belts as containers.

Hoop-shaped or belt-like molecules have been fascinating not only due to their challenging synthesis, but also unique physical and chemical properties. The incorporation of heteroatoms (N, O, S, etc.) into these belts could alter both molecular structures and electronic properties which will lead to versatile applications, from advanced host-guest systems to functional materials.

One-Step Construction of Hydrophobic MOFs@COFs Core-Shell Composites for Heterogeneous Selective Catalysis.

The exploration of novel porous core-shell materials is of great significance because of their prospectively improved performance and extensive applications in separation, energy conversion, and catalysis. Here, mesoporous metal-organic frameworks (MOFs) NH-MIL-101(Fe) as a core generate a shell with mesoporous covalent organic frameworks (COFs) NUT-COF-1(NTU) by a covalent linking process, the composite NH-MIL-101(Fe)@NTU keeping retentive crystallinity with hierarchical porosity well. Importantly, the NH-MIL-101(Fe)@NTU composite shows significantly enhanced catalytic conversion and selectivity during styrene oxidation.

Ring-through-ring molecular shuttling in a saturated [3]rotaxane.

Mechanically interlocked molecules such as rotaxanes and catenanes comprise two or more components whose motion relative to each other can be controlled. A [2]rotaxane molecular shuttle, for example, consists of an axle bearing two recognition sites and a single macrocyclic wheel that can undergo a to-and-fro motion along the axle-shuttling between the recognition sites. The ability of mechanically interlocked molecules to undergo this type of large-amplitude change is the core mechanism behind almost every interlocked molecular switch or machine, including sophisticated mechanical systems such as a molecular elevator and a peptide synthesizer.

Influence of axle length on the rate and mechanism of shuttling in rigid H-shaped [2]rotaxanes.

A series of [2]rotaxane molecular shuttles was prepared containing a dibenzo[24]crown-8 () wheel and a rigid H-shaped axle with varying track lengths between recognition sites; from 7.4 to 20.3 Å as defined by 1-4 phenyl rings or a naphthyl group.

Stepwise engineering of pore environments and enhancement of CO/R22 adsorption capacity through dynamic spacer installation and functionality modification.

Through stepwise post-synthetic spacer insertion and click reactions, six Zr-MOFs with different types and amounts of functional groups have been constructed based on proto-MOF PCN-700. Their gas adsorption capacities and selectivities have been greatly improved and finely tuned, demonstrating the combinatorial effect of pore surface modification and pore space partition.