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Supramolecular nanomaterials  for bulk heterojunction organic solar cells have been designed and constructed through hierarchical organization of hydrogen ‐ bonded rosette assembly of barbituric ‐ acid ‐ conjugated oligothiophene semiconductors. A solar cell using one of the nanomaterials exhibited a power conversion efficiency exceeding 3%. For more details, see the Full Paper by S. Yagai et al. on page 16128 ff. [ABSTRACT FROM AUTHOR]

New linear and networked  fullerene polymeric organizations were synthesized through self ‐ assembly directed by molecular recognition of a biscalix[5]arene and C60. The cover represents the schematic representation of the supramolecular organization processes for the formation of the linear and network fullerene polymers. For more details see the Full Paper by T. Haino et al. on page 16138 ff. [ABSTRACT FROM AUTHOR]

Single crystals of 2D coordination network {Cu2L2 ⋅ (DMF)3(H2O)3}n (1‐DMF) were prepared by reaction of commercial reagents 3‐formyl‐4‐hydroxybenzoic acid (H2L) and Cu(NO3)2 in dimethylformamide (DMF). The single‐crystal structure shows two distinct Cu(II) coordination environments arising from the separate coordination of Cu(II) cations to the carboxylate and salicylaldehydato moieties on the linker, with 1D channels running through the structure. Flexibility is exhibited on solvent exchange with ethanol and tetrahydrofuran, while porosity and the unique overall connectivity of the structure are retained. The activated material exhibits type I gas sorption behaviour and a BET surface area of 950 m2 g−1 (N2, 77 K). Notably, the framework adsorbs negligible quantities of CH4 compared with CO2 and the C2Hn hydrocarbons. It exhibits exceptional selectivity for C2H2/CH4 and C2H2/C2Hn, which has applicability in separation technologies for the isolation of C2H2. [ABSTRACT FROM AUTHOR]

The synthesis of regioisomeric asterisks (5) and (6) incorporating a benzene core with six 1‐naphthylthio or six 2‐naphthylthio arms are reported in search for new materials with optoelectronic properties. The consequences on the extension of a π system surrounding a persulfurated benzene core provide a new avenue to study the structural, photophysical, and chemical properties of such family of all‐organic phosphors. It also diverts the persulfuration mechanism after two radical cyclizations for making a [5]dithiohelicene by‐product (7) and favors dynamic sulfur component exchange reactions surrounding the core. These exchanges convert asterisks (5) and (6), non‐phosphorescent at 20 °C to the highly phosphorescent (4) (ϕ ∼100 %, solid state at 20 °C). For asterisks (5) and (6), the absence of the typical phosphorescence of the per(phenylthio)benzene core in the solid state at 20 °C and the presence of a weak naphthalene‐based phosphorescence at 77 K is attributed to an energy transfer from the triplet state of the persulfurated benzene core to the outer naphthalene moieties, resulting in an antenna system. [ABSTRACT FROM AUTHOR]

The facile assembly of shell-by-shell (SbS)-coated nanoparticles [TiO2PAC16]@shell 1- 7 (PAC16=hexadecylphosphonic acid), which are soluble in water and can be isolated as stable solids, is reported. In these functional architectures, an umpolung of dispersibility (organic apolar versus water) was accomplished by the noncovalent binding of ligands 1- 7 to titania nanoparticles [TiO2PAC16] containing a first covalent coating with PAC16. Ligands 1- 7 are amphiphilic and form the outer second shell of [TiO2PAC16]@shell 1- 7. The tailor-designed dendritic building blocks 3- 5 contain negative and positive charges in the same molecule, and ligands 6 and 7 contain a perylenetetracarboxylic acid dimide (PDI) core ( 6/ 7) as a photoactive reporter component. In the redox and photoactive system [TiO2PAC16]@shell 7, electronic communication between the inorganic core to the PDI ligands was observed. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) are considered excellent materials for the construction of flexible displays due to their nanoscale dimensions and unique physical and chemical properties. By using the recognition properties of 2-ureido-4[1 H]pyrimidinone (UPy), a versatile and simple methodology was demonstrated for the construction of macroscopic structures based on UPy-CNT/polymer composites prepared by a combination of two functionalization approaches: 1) covalent attachment of UPy pendants on the multiwalled CNT surface ( UPy-MWCNTs) and 2) directed self-assembly of UPy-MWCNTs within polymers bearing UPy pendants ( Bis-UPy 1 and Bis-UPy 2) by quadruple complementary DDAA-AADD hydrogen-bond recognition (D=donor, A=acceptor). [ABSTRACT FROM AUTHOR]

Heterometal arrays in molecular aggregations were obtained by the spontaneous and ultrasound-induced gelation of organic liquids containing the chiral, clothespin-shaped trans-bis(salicylaldiminato) d8 transition-metal complexes 1. Heterometallic mixtures of complexes 1 a (Pd) and 1 b (Pt) underwent strict heterochiral aggregation entirely due to the organic shell structure of the clothespin shape, with no effect of the metal cores. This phenomenon provides an unprecedented means of generating highly controlled heterometallic arrangements such as alternating sequences [(+)-Pd(−)-Pt(+)-Pd(−)-Pt ⋅⋅⋅] as well as a variety of single metal-enriched arrays (e.g., [(+)-Pt(−)-Pd(+)-Pd(−)-Pd(+)-Pd(−)-Pd ⋅⋅⋅] and [(+)-Pd(−)-Pt(+)-Pt(−)-Pt(+)-Pt(−)-Pt ⋅⋅⋅]) upon the introduction of an optically active masquerading unit with a different metal core in the heterochiral single-metal sequence. The present method can be applied to form various new aggregates with optically active Pd and Pt units, to allow 1) tuning of the gelation ultrasound sensitivity based on the different hearing abilities of the metal units; 2) aggregation-induced chirality transfer between heterometallic species; and 3) aggregation-induced chirality enhancement. A mechanistic rationale is proposed for these molecular aggregations based on the molecular structures of the units and the morphologies of the aggregates. [ABSTRACT FROM AUTHOR]

A new family of 120° carbazole-based dendritic donors D1- D3 have been successfully designed and synthesized, from which a series of novel supramolecular carbazole-based metallodendrimers with well-defined shapes and sizes were successfully prepared by [2+2] and [3+3] coordination-driven self-assembly. The structures of newly designed rhomboidal and hexagonal metallodendrimers were characterized by multinuclear NMR (1H and 31P) spectroscopy, ESI-TOF mass spectrometry, FTIR spectroscopy, and the PM6 semiempirical molecular orbital method. The fluorescence emission behavior of ligands D1- D3, rhomboidal metallodendrimers R1- R3, and hexagonal metallodendrimers H1- H3 in mixtures of dichloromethane and n-hexane with different n-hexane fractions were investigated. The results indicated that D1- D3 featured typical aggregation-induced emission (AIE) properties. However, different from ligands D1- D3, metallodendrimers R1- R3 and H1- H3 presented interesting generation-dependent AIE properties. Furthermore, evidence for the aggregation of these metallodendrimers was confirmed by a detailed investigation of dynamic light-scattering, Tyndall effect, and SEM. This research not only provides a highly efficient strategy for constructing carbazole-based dendrimers with well-defined shapes and sizes, but also presents a new family of carbazole-based dendritic ligands and rhomboidal and hexagonal metallodendrimers with interesting AIE properties. [ABSTRACT FROM AUTHOR]

We have synthesized a series of triarylamine-cored molecules equipped with an adjacent amide moiety and dendritic peripheral tails in a variety of modes. We show by 1H NMR and UV/Vis spectroscopy that their supramolecular self-assembly can be promoted in solution upon light stimulation and radical initiation. In addition, we have probed their molecular arrangements and mesomorphic properties in the bulk by integrated studies on their film state by using differential scanning calorimetry (DSC), variable-temperature polarizing optical microscopy (VT-POM), variable-temperature X-ray diffraction (VT-XRD), and atomic force microscopy (AFM). Differences in the number and the disposition of the peripheral tails significantly affect their mesomorphic properties associated with their lamellar- or columnar-packed nanostructures, which are based on segregated stacks of the triphenylamine cores and the lipophilic/lipophobic periphery. Such structural tuning is of interest for implementation of these soft self-assemblies as electroactive materials from solution to mesophases. [ABSTRACT FROM AUTHOR]

Two novel types of supramolecular nanocarriers fabricated by the amphiphilic host-guest inclusion complex formed from water-soluble pillar[6]arene ( WP6) and azobenzene derivatives G1 or G2 have been developed, in which G1 is structurally similar to G2 but has an extra phenoxy group in its hydrophobic region. Supramolecular micelles can be initially formed by WP6 with G1, which gradually transform into layered structures with liquid-crystalline properties, whereas stable supramolecular vesicles are obtained from WP6 and G2, which exhibit dual photo- and pH-responsiveness. Notably, the resulting WP6⊃ G2 vesicles can efficiently encapsulate anticancer drug mitoxantrone (MTZ) to achieve MTZ-loaded vesicles, which maintain good stability in a simulated normal physiological environment, whereas in an acid environment similar to that of tumor cells or with external UV irradiation, the encapsulated drug is promptly released. More importantly, cytotoxicity assay indicates that such vesicles have good biocompatibility and the MTZ-loaded vesicles exhibit comparable anticancer activity to free MTZ, especially with additional UV stimulus, whereas its cytotoxicity for normal cells was remarkably reduced. Flow cytometric analysis further confirms that the cancer cell death caused by MTZ-loaded vesicles is associated with apoptosis. Therefore, the dual pH- and UV-responsive supramolecular vesicles are a potential platform for controlled release and targeted anticancer drug delivery. [ABSTRACT FROM AUTHOR]

A poly[(2-ethyl-2-oxazoline)- ran-(2-nonyl-2-oxazoline)] copolymer in combination with hydroxypropylated cyclodextrins has been demonstrated to lead to a supramolecular self-assembly process that results in the formation of kinetically trapped thermoresponsive nanoparticles. Selection of the cyclodextrin type provides control over the nanoparticle phase-transition thermodynamics, thus affording optical temperature sensors with an unprecedented, long-term thermal memory function, which is reversible or irreversible. This research also sheds light onto kinetic and dynamic supramolecular assemblies, thus providing important insight because similar supramolecular processes are at the foundation of living matter. [ABSTRACT FROM AUTHOR]

A new class of L-glutamic gelators, LG12(CH2) nCOOH, containing different lengths of methylene spacer were synthesized. It was found that the gelation ability of these compounds themselves was very weak. However, when another compound, p-xylylenediamine (XEA), was introduced, the gelation ability was improved greatly. In particular, LG12(CH2)10COOH showed super-gelation ability in the presence of XEA, which could immobilize almost all of the solvents except methanol. Moreover, the formed supramolecular gels even could be molded. Interestingly, some supramolecular gels of LG12(CH2) nCOOH and XEA could respond to multiple stimuli, such as heating, shaking, sonication, and acid/base. The studies of CD spectra suggested that the supramolecular chirality induced by self-assembled chiral gelator molecules in gels could be tuned by the length of methylene spacer. In addition, the supramolecular chirality could be regulated as on/off by heating-cooling or external NH3/HCl. This would facilitate the development of dual chiroptical switches by temperature and acid/base. [ABSTRACT FROM AUTHOR]

The intriguing dual-emission behavior of p- dimethylaminobenzonitrile (DMABN) and the identity of the associated excited states is, arguably, the most extensively investigated and also controversially discussed molecule- specific phenomenon of modern photochemistry. We have now found a new, third fluorescence band when DMABN is encapsulated within the water-soluble molecular container cucurbit[8]uril (CB8). It is centered between the previously observed emissions and assigned to the elusive excimer emission from DMABN through 1:2 CB8:DMABN complex formation. Heating of the CB8 ⋅(DMABN)2 complex from 0 to 100 °C results in the dissociation of the ternary complex and restoration of the dual-emission properties of the monomer. Alternatively, monomer emission can be obtained by selecting cucurbit[7]uril (CB7), a host homologue that is too small to accommodate two DMABN molecules, or by introducing ethyl instead of methyl groups at the amino terminus of the aminobenzonitrile guest. [ABSTRACT FROM AUTHOR]

Two enantiomerically pure 9,9′-spirobifluorene-based bis(pyridine) ligands 1 and 2 were prepared to study their self-assembly behavior upon coordination to cis-protected palladium(II) ions. Whereas the sterically more demanding ligand, 2, gave rise to the expected dinuclear metallosupramolecular M2L2 rhombi, the sterically less demanding ligand, 1, acts as a template to give rise to a homochiral metallosupramolecular M4L4 catenane. [ABSTRACT FROM AUTHOR]

Switchable Anion Receptor The conformation of bispyrrolylbenzene anion receptor can be controlled by a proper anionic stimuli. Addition of fluoride anion gradually changes the conformation of this receptor. It was demonstrated that switchability of this building block allowed it to act as INHIBIT and NAND molecular logic gates using fluoride and dihydrogenphosphate anions as inputs and UV/Vis or fluorescence readout, respectively. For more information, see the Full Paper by J. Jurczak et al. on page 12790 ff. [ABSTRACT FROM AUTHOR]

Multichromophoric systems capable of operating as light ‐ harvesting antennae have recently been attracting increasing attention. In their Full Paper on page 10661 ff., M. Gingras, G. Bergamini et al. describe the synthesis, characterization, and metal ‐ ion coordination of a multichromophoric tetra(terpyridine) ligand that can be used to make new supramolecular systems with tailor ‐ made photophysical properties and aggregation states. [ABSTRACT FROM AUTHOR]

Advanced graph set analysis has been proposed by incorporating a concept of symmetry into conventional graph set analysis. Based on the advanced graph set analysis, handedness determinations were demonstrated on supramolecular hidden chirality of three types of hydrogen‐bonded networks, 0D‐cubic, 1D‐ladder, and 2D‐sheet networks, by characterizing the symmetric properties of their component ring‐type hydrogen‐bonded networks formed by primary ammonium carboxylates. For more details see the Full Paper by I. Hisaki, M. Miyata et al. on page 2478 ff. [ABSTRACT FROM AUTHOR]

A series of  bis(benzimidazole)pyridine (BBP)‐containing compounds have been synthesized and structurally characterized. Their birefringence values (Δn) were determined, ranging from Δn=0.08(1) to a very high 0.69(3), illustrating the effect on the measurable birefringence of the crystal quality, growth direction and structural alignment of the anisotropic BBP building blocks as described by V. E. Williams, D. B. Leznoff et al. in their Full Paper on page 16572 ff. [ABSTRACT FROM AUTHOR]

The shortest possible C70 peapods were formed in a size‐ and orientation‐selective manner from C70 and either [10]cycloparaphenylene (CPP) or [11]CPP as 1:1 complexes. C70 exists in two distinct orientations inside the CPP cavity, namely “lying” and “standing”, depending on the size of the CPP. The interaction between [10]CPP and the short axis of C70 is isotropic, but that between [11]CPP and C70 is anisotropic, involving the radial deformation of [11]CPP to an ellipsoidal shape. This “induced‐fit” occurred due to the radically elastic character of the CPPs and maximized the van der Waals interactions with the long axis of C70. For more details, see the Full Paper by S. Yamago et al. on page 14061 ff. [ABSTRACT FROM AUTHOR]

Molecular assemblies that change photoluminescence color in response to thermal or mechanical stimulation without dissociation into the monomeric states in water are described herein. A dumbbell-shaped amphiphilic compound forms micellar molecular assemblies in water and exhibits yellow photoluminescence derived from excimer formation of the luminescent core, which contains a 2,6-diethynylanthracene moiety. Annealing of the aqueous solution induces a photoluminescence color change from yellow to green ( λem, max=558→525 nm). The same photoluminescence color change is also achieved by rubbing the yellow-photoluminescence-emitting molecular assemblies adsorbed on glass substrates with cotton wool in water. The observed green photoluminescence is ascribed to micelles that are distinct from the yellow-photoluminescence-emitting micelles, on the basis of transmission electron microscopy observations, atomic force microscopy observations, and dynamic light scattering measurements. We examined the relationship between the structure of the molecular assemblies and the photophysical properties of the anthracene derivative in water before and after thermal or mechanical stimulation and concluded that thermal or mechanical stimuli-induced slight changes of the molecular-assembled structures in the micelles result in the change in the photoluminescence color from yellow to green in water. [ABSTRACT FROM AUTHOR]

The detection of nucleotides is of crucial importance because they are the basic building blocks of nucleic acids. Scorpiand-based polyamine receptors functionalized with pyridine or anthracene units are able to form stable complexes with nucleotides in water, based on coulombic, π-π stacking, and hydrogen-bonding interactions. This behavior has been rationalized by means of an exploration with NMR spectroscopy and DFT calculations. Binding constants were determined by potentiometry. Fluorescence spectroscopy studies have revealed the potential of these receptors as sensors to effectively and selectively distinguish guanosine-5′-triphosphate (GTP) from adenosine-5′-triphosphate (ATP). [ABSTRACT FROM AUTHOR]

Iodination has long been employed as a successful labelling strategy to gain structural insights into proteins and other biomolecules via several techniques, including Small Angle X‐ray Scattering, Inductively Coupled Plasma Mass Spectrometer (ICP‐MS), and single‐crystal crystallography. However, when dealing with smaller biomolecular systems, interactions driven by iodine may significantly alter their self‐assembly behaviour. The engineering of amyloidogenic peptides for the development of ordered nanomaterials has greatly benefitted from this possibility. Still, to date, iodination has exclusively been applied to aromatic residues. In this work, an aliphatic bis‐iodinated amino acid was synthesized and included into a custom pentapeptide, which showed enhanced fibrillogenic behaviour. Peptide single crystal X‐ray structure and powder X‐ray diffraction on its dried water solution demonstrated the key role of iodine atoms in promoting intermolecular interactions that drive the peptide self‐assembly into amyloid fibrils. These findings enlarge the library of halogenated moieties available for directing and engineering the self‐assembly of amyloidogenic peptides. [ABSTRACT FROM AUTHOR]

Inspired by the rigidified architecture of 'picket‐fence' systems, we propose a strategy utilizing strain to impose intramolecular tension in already peripherally overcrowded structures leading to selective atropisomeric conversion. Employing this approach, tuneable shape‐persistent porphyrin conformations were acquired exhibiting distinctive supramolecular nanostructures based on the orientation of the peripheral groups. The intrinsic assemblies driven by non‐covalent bonding interactions form supramolecular polymers while encapsulating small molecules in parallel channels or solvent‐accessible voids. The developed molecular strain engineering methodologies combined with synthetic approaches have allowed the introduction of the pivalate units creating a highly strained molecular skeleton. Changes in the absorption spectrum indicated the presence of severe steric repulsions between the peripheral groups which were confirmed by single crystal X‐ray analysis. To release the steric strain introduced by the peripheral units, thermal equilibration strategies were used to selectively convert the most abundant atropisomer to the desirable minor one. [ABSTRACT FROM AUTHOR]

Bifunctional, trinuclear complexes with high recycling potential in the synthesis of organic carbonates from oxiranes and carbon dioxide are described in the Full Paper on page 2641 ff. by A. W. Kleij et al. This supramolecular approach towards catalyst immobilization and recycling is highly promising, as demonstrated in a typical reaction that requires both Lewis acid and nucleophilic activation; the recycling potential of one of these complexes was found to be superior to the commonly used binary‐type catalysts that comprise both (but separate) components [ABSTRACT FROM AUTHOR]

We describe herein the synthesis of a triptycene-based surfactant designed with the ability to solubilise single-walled carbon nanotubes (SWNTs) and C60 in water through non-covalent interactions. Furthermore, an amphiphilic naphthalene-based surfactant with the same ability to solubilise SWNTs and C60 has also been prepared. The compounds synthesised were designed with either two ionic or non-ionic tails to ensure a large number of supramolecular interactions with the solvent, thereby promoting strong solubilisation. The surfactants produced stable suspensions in which the SWNTs are dispersed and the surfactant/SWNT complexes formed are stable for more than one year. UV/Vis/NIR absorption spectroscopy, TEM and AFM were employed to probe the solubilisation properties of the dispersion of surfactants and SWNTs in water. [ABSTRACT FROM AUTHOR]

The synergistic functioning of redox‐active components that emerges from prototypical 2,2′‐di(N‐methylpyrid‐4‐ylium)‐1,1′‐biphenyl is described. Interestingly, even if a trans conformation of the native assembly is expected, due to electrostatic repulsion between cationic pyridinium units, we demonstrate that cis conformation is equally energy‐stabilized on account of a peculiar LUMO (SupLUMO) that develops through space, encompassing the two pyridiniums in a single, made‐in‐one‐piece, electronic entity (superelectrophoric behavior). This SupLUMO emergence, with the cis species as superelectrophore embodiment, originates in a sudden change of electronic structure. This finding is substantiated by insights from solid state (single‐crystal X‐ray diffraction) and solution (NOE NMR and UV‐vis‐NIR spectroelectrochemistry) studies, combined with electronic structure computations. Electrochemistry shows that electron transfers are so strongly correlated that two‐electron reduction manifests itself as a single‐step process with a large potential inversion consistent with inner creation of a carbon‐carbon bond (digital simulation). Besides, absence of reductive formation of dimers is a further indication of a preferential intramolecular reactivity determined by the SupLUMO interaction (cis isomer pre‐organization). The redox‐gated covalent bond, serving as electron reservoir, was studied via atropisomerism of the reduction product (VT NMR study). The overall picture derived from this in‐depth study of 2,2′‐di(N‐methylpyrid‐4‐ylium)‐1,1′‐biphenyl proves that trans and cis species are worth considered as intrinsically sharply different, that is, as doubly‐electrophoric and singly‐superelectrophoric switchable assemblies, beyond conformational isomerism. Most importantly, the through‐space‐mediated SupLUMO may come in complement of other weak interactions encountered in Supramolecular Chemistry as a tool for the design of electroactive architectures. [ABSTRACT FROM AUTHOR]

Hybrid gel beads based on combining a low‐molecular‐weight gelator (LMWG) with a polymer gelator (PG) demonstrate an enhanced ability to self‐propel in water, with the LMWG playing an active role. Hybrid gel beads were loaded with ethanol and shown to move in water owing to the Marangoni effect changes in surface tension caused by the expulsion of ethanol – smaller beads move farther and faster than larger beads. Flat shapes of the hybrid gel were cut using a "stamp" – circles moved the furthest, whereas stars showed more rotation on their own axes. Comparing hybrid LMWG/PG gel beads with PG‐only beads demonstrated that the LMWG speeds up the beads, enhancing the rate of self‐propulsion. Self‐assembly of the LMWG into a "solid‐like" network prevents its leaching from the gel. The LMWG also retains its own unique function – specifically, remediating methylene blue pollutant dye from basic water as a result of noncovalent interactions. The mobile hybrid beads accumulate this dye more effectively than PG‐only beads. Self‐propelling gel beads have potential applications in removal/delivery of active agents in environmental or biological settings. The ability of self‐assembling LMWGs to enhance mobility and control removal/delivery suggests that adding them to self‐propelling systems can add significant value. [ABSTRACT FROM AUTHOR]

The excimer fluorescence bands derived from J-type aggregates of the naphthalene in the nanotubes vary according to the different inner diameters. Keywords: aggregation; amphiphiles; nanotubes; self-assembly; supramolecular chemistry EN aggregation amphiphiles nanotubes self-assembly supramolecular chemistry 12449 12449 1 09/03/21 20210901 NES 210901 B Supra-typed molecules b composed of a pyridine-based amphiphile complexed with 1,5-, 1,6-, 2,6-, or 2,7-dihydroxy naphthalene self-assemble in water to form nanotubes. Cover Feature: Self-Assembly of a Pyridine-Based Amphiphile Complexed with Regioisomeric Dihydroxy Naphthalenes into Supramolecular Nanotubes with Different Inner Diameters (Chem. Eur. J. 49/2021). [Extracted from the article]

Cages, peptides, phosphorylation, supramolecular chemistry, tyrosine kinases Keywords: cages; peptides; phosphorylation; supramolecular chemistry; tyrosine kinases EN cages peptides phosphorylation supramolecular chemistry tyrosine kinases 9462 9462 1 07/05/21 20210702 NES 210702 B The modulation of the activity of tyrosine kinases (TK) b is an appealing topic of current research. [Extracted from the article]

Cover Feature: Photoresponsive Binding Dynamics in High-Affinity Cucurbit[8]uril-Dithienylethene Host-Guest Complexes (Chem. Eur. J. 37/2021) Keywords: inclusion complexes; diarylethenes; kinetics; photochemistry; supramolecular chemistry EN inclusion complexes diarylethenes kinetics photochemistry supramolecular chemistry 9463 9463 1 07/05/21 20210702 NES 210702 B Photoresponsive binding kinetics b was achieved in cucurbit[8]uril-dithienylethene host-guest complexes. Inclusion complexes, diarylethenes, kinetics, photochemistry, supramolecular chemistry. [Extracted from the article]

A novel pyrrolopyrrole azadipyrrin (Janus‐PPAD) with Janus duality was synthesized by a Schiff base–forming reaction of diketopyrrolopyrrole. The orthogonal interactions of the hydrogen‐bonding ketopyrrole and metal‐coordinating azadipyrrin moieties in Janus‐PPAD enabled the metal ions to be arranged at regular intervals: zinc(II) and cobalt(II) coordination provided metal‐coordinated Janus‐PPAD dimers, which can subsequently form hydrogen‐bonded one‐dimensional arrays both in solution and in the solid state. The supramolecular assembly of the zinc(II) complex in solution was investigated by 1H NMR spectroscopy based on the isodesmic model, in which a binding constant for the elongation of assemblies is constant. Owing to the tetrahedral coordination, in the solid state, the cobalt(II) complex exhibited a slow magnetic relaxation due to the negative D value of −27.1 cm−1 with an effective relaxation energy barrier Ueff of 38.0 cm−1. The effect of magnetic dilution on the relaxation behavior is discussed. The relaxation mechanism at low temperature was analyzed by considering spin lattice interactions and quantum tunneling effects. The easy‐axis magnetic anisotropy was confirmed, and the relevant wave functions were obtained by ab initio CASSCF calculations. [ABSTRACT FROM AUTHOR]

A pyridine‐based amphiphile complexed with 1,5‐, 1,6‐, 2,6‐, or 2,7‐dihydroxy naphthalene self‐assembled in water to form nanotubes with inner diameters of 46, 38, 24, 18, and 11 nm in which the naphthalene molecules formed J‐type aggregates. In contrast, the amphiphile complexed with 1,2‐, 1,3‐, 1,4‐, 1,7‐, 1,8‐, or 2,3‐dihydroxy naphthalene formed nanofibers in which the naphthalene molecules formed H‐type aggregates. The inner diameter of the nanotubes strongly depended on the regioisomeric dihydroxy naphthalene. UV–vis, fluorescence, infrared spectroscopy, X‐ray diffraction analysis, and differential scanning calorimetry showed that nanotubes with smaller inner diameters had weaker intermolecular hydrogen bonds between the tilted amphiphiles complexed with the naphthalene molecules within the membrane walls and showed larger Stokes shifts in the excimer fluorescence of the naphthalene moiety. These findings should be useful not only for fine‐tuning the inner diameters of supramolecular nanotubes but also for controlling the aggregation states of functional aromatic molecules to generate nanostructures with useful optical and electronic properties in water. [ABSTRACT FROM AUTHOR]

Chlorination of 3‐methyl‐5‐phenyl‐1,2‐tellurazole‐2‐oxide yielded the λ4Te dichloro derivative. Its crystal structure demonstrates that the heterocycle retains its ability to autoassociate by chalcogen bonding (ChB) forming macrocyclic tetramers. The corresponding Te⋅⋅⋅O ChB distances are 2.062 Å, the shortest observed to date in aggregates of this type. DFT−D3 calculations indicate that while the halogenated molecule is stronger as a ChB donor it also is a weaker ChB acceptor; the overall effect is that the ChBs in the chlorinated homotetramer are not significantly stronger. However, partial halogenation or scrambling selectively yield the 2 : 2 heterotetramer with alternating λ4Te and λ2Te centers, which calculations identified as the thermodynamically preferred arrangement. [ABSTRACT FROM AUTHOR]

The selective recognition of tyrosine residues in peptides is an appealing approach to inhibiting their tyrosine kinase (TK)‐mediated phosphorylation. Herein, we describe pseudopeptidic cages that efficiently protect substrates from the action of the Src TK enzyme, precluding the corresponding Tyr phosphorylation. Fluorescence emission titrations show that the most efficient cage inhibitors strongly bind the peptide substrates with a very good correlation between the binding constant and the inhibitory potency. Structural insights and additional control experiments further support the proposed mechanism of selective supramolecular protection of the substrates. Moreover, the approach also works in a completely different kinase‐substrate system. These results illustrate the potential of supramolecular complexes for the efficient and selective modulation of TK signaling. [ABSTRACT FROM AUTHOR]

Keywords: photoactive systems; pillar[5]arene; rotaxanes; stopper exchange; supramolecular chemistry EN photoactive systems pillar[5]arene rotaxanes stopper exchange supramolecular chemistry 8408 8408 1 06/12/21 20210610 NES 210610 B Rotaxane building blocks with pentafluorophenyl ester stoppers b have been efficiently prepared and their treatment with various nucleophiles provided a wide range of rotaxanes with amide, ester or thioester stoppers. This new strategy also gave easy access to a photoactive rotaxane incorporating a fulleropillar[5]arene moiety and two Bodipy stoppers. [Extracted from the article]

Spherical assemblies of the type [PdnL2n]2n+ can be obtained from PdII salts and curved N‐donor ligands, L. It is well established that the bent angle, α, of the ligand is a decisive factor in the self‐assembly process, with larger angles leading to complexes with a higher nuclearity, n. Herein, we report heteroleptic coordination cages of the type [PdnLnL′n]2n+, for which a similar correlation between the ligand bent angle and the nuclearity is observed. Tetranuclear cages were obtained by combining [Pd(CH3CN)4](BF4)2 with 1,3‐di(pyridin‐3‐yl)benzene and ligands featuring a bent angle of α=120°. The use of a dipyridyl ligand with α=149° led to the formation of a hexanuclear complex with a trigonal prismatic geometry; for linear ligands, octanuclear assemblies of the type [Pd8L8L′8]16+ were obtained. The predictable formation of heteroleptic PdII cages from 1,3‐di(pyridin‐3‐yl)benzene and different dipyridyl ligands is evidence that there are entire classes of heteroleptic cage structures that are privileged from a thermodynamic point of view. [ABSTRACT FROM AUTHOR]

After extensive studies of 1D and 2D skeletal carbo‐mers based on C8 π‐conjugating dialkynylbutatriene units (DABs: ∼C≡C−(R)C=C=C=C(R)−C≡C∼) bridging sp or sp2 centers in carbo‐butene, carbo‐xylylene or carbo‐benzene derivatives, 3D versions are envisaged through carbo‐barrelenes and partially reduced derivatives thereof where two or three DAB blades span a bridge between sp3 carbinol vertices or ether thereof. For R=Ph, stable representatives were synthesized through a pivotal [6]pericyclynedione, and extensively characterized by spectroscopic, electrochemical and crystallographic methods. Density functional theory calculations allow detailed analysis of structural and electronic features of the 7 Å high C26 barrel‐shaped molecules, and show that they can behave as cages for ionic species. Beyond aesthetical concerns, the results could open prospects of applications in host‐guest supramolecular chemistry and single molecule charge transport. [ABSTRACT FROM AUTHOR]

Stable pillar[5]arene‐containing [2]rotaxane building blocks with pentafluorophenyl ester stoppers have been efficiently prepared on a multi‐gram scale. Reaction of these building blocks with various nucleophiles gave access to a wide range of [2]rotaxanes with amide, ester or thioester stoppers in good to excellent yields. The rotaxane structure is fully preserved during these chemical transformations. Actually, the addition‐elimination mechanism at work during these transformations totally prevents the unthreading of the axle moiety of the mechanically interlocked system. The stopper exchange reactions were optimized both in solution and under mechanochemical solvent‐free conditions. While amide formation is more efficient in solution, the solvent‐free conditions are more powerful for the transesterification reactions. Starting from a fullerene‐functionalized pillar[5]arene derivative, this new strategy gave easy access to a photoactive [2]rotaxane incorporating a C60 moiety and two Bodipy stoppers. Despite the absence of covalent connectivity between the Bodipy and the fullerene moieties in this photoactive molecular device, efficient through‐space excited state interactions have been evidenced in this rotaxane. [ABSTRACT FROM AUTHOR]

The analysis of crystal structures of SF5‐ or SF4‐containing molecules revealed that these groups are often surrounded by hydrogen or other fluorine atoms. Even though fluorine prefers F⋅⋅⋅H over F⋅⋅⋅F contacts, the latter appeared to be important in many compounds. In a significant number of datasets, the closest F⋅⋅⋅F contacts are below 95 % of the van der Waals distance of two F atoms. Moreover, a number of repeating structural motifs formed by contacts between SF5 groups was identified, including different supramolecular dimers and infinite chains. Among SF4‐containing molecules, the study focused on SF4Cl compounds, including the first solid‐state structure analyses of these reactive species. Additionally, electrostatic potential surfaces of a series of Ph‐SF5 derivatives were calculated, pointing out the substituent influence on the ability of F⋅⋅⋅X contact formation (X=F or other electronegative atom). Interaction energies were calculated for different dimeric arrangements of Ph‐SF5, which were extracted from experimental crystal structure determinations. [ABSTRACT FROM AUTHOR]

Urea, which has both hydrogen bond acceptor and donor moieties, is an ideal structure for a supramolecular synthon. Various supramolecules having ureido group(s) have been widely developed. This article summarizes recent developments of urea derivatives that exhibit various functions: i) supramolecular capsules that form discrete urea–urea intermolecular hydrogen bonds, ii) supramolecular polymers that form continuous urea–urea intermolecular hydrogen bonds, iii) supramolecular gels that form continuous urea–urea intermolecular hydrogen bonds, iv) artificial host molecules based on the molecular recognition ability of the ureido group, and v) catalytic reactions developed by utilizing the molecular recognition ability of the ureido group. [ABSTRACT FROM AUTHOR]

Although chiral nanostructures have been fabricated at various structural levels, the transfer and amplification of chirality from molecules to supramolecular self‐assemblies are still puzzling, especially for heterochiral molecules. Herein, four series of C2‐symmetrical dipeptide‐based derivatives bearing various amino acid sequences and different chiralities are designed and synthesized. The transcription and amplification of molecular chirality to supramolecular assemblies are achieved. The results show that supramolecular chirality is only determined by the amino acid adjacent to the benzene core, irrespective of the absolute configuration of the C‐terminal amino acid. In addition, molecular chirality also has a significant influence on the gelation behavior. For the diphenylalanine‐based gelators, the homochiral gelators can be gelled through a conventional heating–cooling process, whereas heterochiral gelators form translucent stable gels under sonication. The racemic gels possess higher mechanical properties than those of the pure enantiomers. All of these results contribute to an increasing knowledge over control of the generation of specific chiral supramolecular structures and the development of new optimized strategies to achieve functional supramolecular organogels through heterochiral and racemic systems. [ABSTRACT FROM AUTHOR]

Synthetic stimuli responsive supramolecular polymers attract increasing interest for their ability to mimic the unique properties of natural assemblies. Here we focus on the well‐studied benzene‐1,3,5‐tricarboxamide (BTA) motif, and substitute it with two (S)‐3,7‐dimethyloctyl groups and an azobenzene photoswitch. We demonstrate the UV (λ=365 nm) induced depolymerisation of the helical hydrogen‐bonded polymers in methylcyclohexane (MCH) through circular dichroism and UV‐vis spectroscopy in dilute solution (15 μm), and NMR and iPAINT super‐resolution microscopy in concentrated solution (300 μm). The superstructure can be regenerated after thermal depolymerization, whilst repeated depolymerisation can be reversed without degradation by irradiating at λ=455 nm. Molecular dynamics simulations show that the most energetically favourable configuration for these polymers in MCH is a left‐handed helical network of hydrogen‐bonds between the BTA cores surrounded by two right‐handed helices of azobenzenes. The responsiveness to two orthogonal triggers across a broad concentration range holds promise for use in, for example, photo‐responsive gelation. [ABSTRACT FROM AUTHOR]

Despite their apparent similarity, framework materials based on tetraphenylmethane and tetraphenylsilane building blocks often have quite different structures and topologies. Herein, we describe a new silicon tetraamidinium compound and use it to prepare crystalline hydrogen bonded frameworks with carboxylate anions in water. The silicon‐containing frameworks are compared with those prepared from the analogous carbon tetraamidinium: when biphenyldicarboxylate or tetrakis(4‐carboxyphenyl)methane anions were used similar channel‐containing networks are observed for both the silicon and carbon tetraamidinium. When terephthalate or bicarbonate anions were used, different products form. Insights into possible reasons for the different products are provided by a survey of the Cambridge Structural Database and quantum chemical calculations, both of which indicate that, contrary to expectations, tetraphenylsilane derivatives have less geometrical flexibility than tetraphenylmethane derivatives, that is, they are less able to distort away from ideal tetrahedral bond angles. [ABSTRACT FROM AUTHOR]

A new supramolecular paradigm is presented for reliable capture and co‐precipitation of haloauric acids (HAuX4) from organic solvents or water. Two classes of acyclic organic compounds act as complementary receptors (tectons) by forming two sets of directional non‐covalent interactions, (a) hydrogen bonding between amide (or amidinium) NH residues and the electronegative X ligands on the AuX4−, and (b) electrostatic stacking of the electron deficient Au center against the face of an aromatic surface. X‐ray diffraction analysis of four co‐crystal structures reveals the additional common feature of proton bridged carbonyls as a new and predictable supramolecular design element that creates one‐dimensional polymers linked by very short hydrogen bonds (CO⋅⋅⋅OC distance <2.5 Å). Two other co‐crystal structures show that the amidinium‐π⋅⋅⋅XAu interaction will reliably engage AuX4− with high directionality. These acyclic compounds are very attractive as co‐precipitation agents within new "green" gold recovery processes. They also have high potential as tectons for controlled self‐assembly or co‐crystal engineering of haloaurate composites. More generally, the supramolecular paradigm will facilitate the design of next‐generation receptors or tectons with high affinity for precious metal square planar coordination complexes for use in advanced materials, nanotechnology, or medicine. [ABSTRACT FROM AUTHOR]

Atropisomerism is a fundamental feature of substituted biaryls resulting from rotation around the biaryl axis. Different stereoisomers are formed due to restricted rotation about the single bond, a situation often found in substituted porphyrins. Previously NMR determination of porphyrin atropisomers proved difficult, if not almost impossible to accomplish, due to low resolution or unresolvable resonance signals that predominantly overlapped. Here, we shed some light on this fundamental issue found in porphyrinoid stereochemistry. Using benzenesulfonic acid (BSA) for host‐guest interactions and performing 1D, 2D NMR spectroscopic analyses, we were able to characterize all four rotamers of the nonplanar 5,10,15,20‐tetrakis(2‐aminophenyl)‐2,3,7,8,12,13,17,18‐octaethylporphyirin as restricted H‐bonding complexes. Additionally, X‐ray structural analysis was used to investigate aspects of the weak host–guest interactions. A detailed assignment of the chemical signals suggests charge‐assisted complexation as a key to unravel the atropisomeric enigma. From a method development perspective, symmetry operations unique to porphyrin atropisomers offer an essential handle to accurately identify the rotamers using NMR techniques only. [ABSTRACT FROM AUTHOR]

Cover Feature: Triaxially Woven Hydrogen-Bonded Chicken Wires of a Tetrakis(carboxybiphenyl)ethene (Chem. Eur. J. 71/2020) Keywords: hydrogen bonds; interpenetration; mechanochromism; supramolecular chemistry; tetraarylethenes EN hydrogen bonds interpenetration mechanochromism supramolecular chemistry tetraarylethenes 16950 16950 1 12/21/20 20201218 NES 201218 B A porous hydrogen-bonded organic framework b (HOF) composed of triaxially woven chicken wires of tetra-topic carboxylic acid is reported. The HOF shows mechanochromic behavior in terms of fluorescence color and quantum efficiency. [Extracted from the article]

Reported here is the synthesis and self‐assembly characterization of [n.n]paracyclophanes ([n.n]pCps, n=2, 3) equipped with anilide hydrogen bonding units. These molecules differ from previous self‐assembling [n.n]paracyclophanes ([n.n]pCps) in the connectivity of their amide hydrogen bonding units (C‐centered/carboxamide vs. N‐centered/anilide). This subtle change results in a ≈30‐fold increase in the elongation constant for the [2.2]pCp‐4,7,12,15‐tetraanilide ([2.2]pCpNTA) compared to previously reported [2.2]pCp‐4,7,12,15‐tetracarboxamide ([2.2]pCpTA), and a ≈300‐fold increase in the elongation constant for the [3.3]pCp‐5,8,14,17‐tetraanilide ([3.3]pCpNTA) compared to previously reported [3.3]pCp‐5,8,14,17‐tetracarboxamide ([3.3]pCpTA). The [n.n]pCpNTA monomers also represent the reversal of a previously reported trend in solution‐phase assembly strength when comparing [2.2]pCpTA and [3.3]pCpTA monomers. The origins of the assembly differences are geometric changes in the association between [n.n]pCpNTA monomers—revealed by computations and X‐ray crystallography—resulting in a more favorable slipped stacking of the intermolecular π‐surfaces ([n.n]pCpNTA vs. [n.n]pCpTA), and a more complementary H‐bonding geometry ([3.3]pCpNTA vs. [2.2]pCpNTA). [ABSTRACT FROM AUTHOR]

Macroscopic supramolecular assembly (MSA) is a new concept in supramolecular science with a focus on interfacial assembly of macroscopic building blocks, which has largely extended the applicable materials of supramolecular assembly and provided new solutions to fabricating tissue scaffolds, soft devices, etc. The precision of the assembled structures is of great interest; unlike molecular assemblies, MSA precision is highly dependent on the matching degree of assembled surfaces because of the large interactive area and group number, which result in remarkably increased kinetic possibilities and metastable assemblies. This Concept introduces the principle, history, and development of MSA, elaborates the low‐precision challenge in MSA, summarizes the strategies for precise MSA based on the different thermodynamic stability of precise/imprecise structures and control over assembly kinetics, and finally demonstrates the applications of precise MSA structures in advanced manufacture such as tissue scaffolds. [ABSTRACT FROM AUTHOR]

The understanding and the application of reversible covalent reactions and coordination chemistry together with the proper design of the molecular frameworks, allow to achieve not only well‐defined output architectures but also different grades of complex behavior. In this work, the dynamic nature of the helical systems offers an additional level of complexity by combining self‐sorting on two levels: 1) the build‐up of the ligand strand constituents from their components through dynamic covalent chemistry; 2) the assembly of the helicates from the ligands and the metal cations through dynamic metallo‐supramolecular chemistry. The information encoded in the ligands constituent molecule was read differently (and accurately at the same time) by metal cations that varied in the coordination algorithms. It enabled the selective formation of a specific type of helicates from a wide library of helicates formed by the possible combination of subcomponents. Ligands containing dynamic tridentate and/or bidentate binding motifs in the same strand were studied to explore the helicates self‐assembly with appropriate metal cations. [ABSTRACT FROM AUTHOR]

The reaction in basic media of manganese chloride with Schiff bases derived from the condensation of o‐vanillin with different chiral/racemic aminoalcohols yielded in a family of complexes in which the nuclearity, symmetry and magnetic behavior is controlled by changing the position of the chiral carbon. Chiral and racemic clusters with [MnIII6MnIINaI], [MnIII6MnII2NaI2] and [MnIII3MnIINaI] metallic core have been structurally and magnetically characterized. The racemic clusters with an odd number of chiral ligands exhibit the anomalous mixing of ligands with different conformation. Related racemic compounds have been reviewed. [ABSTRACT FROM AUTHOR]