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Supramolecular chemistry has become an interdisciplinary discipline of chemistry, physics, and biology. As a huge subunit of supramolecular compounds, the functional metal–organic supramolecular systems with well‐defined cavities which are able to accommodate size‐suitable guests via benign host‐guest behavior, have been known as "metal–organic molecular containers" (MOMCs) and attracted much attentions for their rich chemical properties and wide potential applications in molecular recognition, catalysis, bio‐medical and other fields. In particular, the MOMCs with flexible backbones exhibit a unique feature both in the aspect of structural construction and applications, due to the free rotation and self‐adaptively of the specific functional groups in the skeletons. In this paper, we review several selected examples of the coordination‐driven metal–organic supramolecular systems from the aspects of self‐assembly construction to the various applications. The self‐assembly strategies, especially the different choice of organic ligands with flexible backbones during the construction, leading to quite diverse configurations compared to the rigid ligands, have been also discussed to show a different perspective of metal–organic system construction. [ABSTRACT FROM AUTHOR]

The construction of diverse and distinctive self‐assembled structures in water, based on the control of the self‐assembly processes of artificial small molecules, has received considerable attention in supramolecular chemistry. Cage‐like perforated vesicles are distinctive and interesting self‐assembled structures. However, the development of self‐assembling molecules that can easily form perforated vesicles remains challenging. This paper reports a lower critical solution temperature (LCST) behavior‐triggered self‐assembly property of a 4‐aminoquinoline (4‐AQ)‐based amphiphile with a tetra(ethylene glycol) chain, in HEPES buffer (pH 7.4). This property allows to form perforated vesicles after heating at 80 °C (> LCST). The self‐assembly process of the 4‐AQ amphiphile can be controlled by heating at 80 °C (> LCST) or 60 °C (< LCST). After cooling to room temperature, the selective construction of the perforated vesicles and nanofibers was achieved from the same 4‐AQ amphiphile. Furthermore, the perforated vesicles exhibited slow morphological transformation into intertwined‐like nanofibers but were easily restored by brief heating above the LCST. [ABSTRACT FROM AUTHOR]

There is an ongoing need for explosive detection strategies to uncover threats to human security including illegal transport and terrorist activities. The widespread military use of the explosive trinitrotoluene (TNT) for landmines poses another particular threat to human health in the form of contamination of the surrounding environment and groundwater. The detection of explosives, particularly at low picogram levels, by using a molecular sensor is seen as an important challenge. Herein, we report on the use of a fluorescent metal-organic framework hydrogel that exhibits a higher detection capability for TNT in the gel state compared with that in the solution state. A portable sensor prepared from filter paper coated by the hydrogel was able to detect TNT at the picogram level with a detection limit of 1.82 ppt (parts per trillon). Our results present a simple and new means to provide selective detection of TNT on a surface or in aqueous solution, as afforded by the unique molecular packing through the metal-organic framework structure in the gel formation and the associated photophysical properties. Furthermore, the rheological properties of the MOF-based gel were similar to those of a typical hydrogel. [ABSTRACT FROM AUTHOR]

Ring‐opening metathesis polymerization (ROMP) of strained macrocycles is a key method to prepare diverse polymers. However, lack of ring strain in most macrocycles is an impediment to polymerization. In this paper, the polymerization/oligomerization of unstrained macrocycles was achieved using a supramolecular approach, leading selectively to cyclic products. Diphenyl thiourea and other guest molecules were used as additives to the ROMP reaction of unstrained macrocycles. An intermediate host‐guest complex leads to the stabilization of the open form of the macrocycle after treatment with Grubbs catalysts, thereby favoring polymerization by inhibiting the ring‐closing reaction back to the monomer. This proof‐of‐concept enables ring‐expansion polymerization of unstrained macrocycles leading to cyclic polymers with molecular weights up to 6700 Da. [ABSTRACT FROM AUTHOR]

EPR spectroscopic evidence for intramolecular electron transfer in anionic N‐substituted naphthalimides to yield persistent diradical anions and intermolecular electron transfer from a variety of carbanions to 6‐bromo‐N‐phenyl‐naphthalimide to yield persistent radical–radical anion pairs was recently claimed in two papers by Zhang et al. In this comment, it is shown that the EPR spectra published in both papers do not agree with the proposed triplet‐state species. Rather, the spectra are due to various doublet‐state radicals, deriving from minor side reactions. The misinterpretations invalidate the general conclusions of the papers. [ABSTRACT FROM AUTHOR]

The interaction between pyridines and the π‐hole of BeH2 leads to the formation of strong beryllium‐bonded complexes. Theoretical investigations demonstrate that the Be−N bonding interaction can effectively regulate the electronic current through a molecular junction. The electronic conductance exhibits distinct switching behavior depending on the substituent groups at the para position of pyridine, highlighting the role of Be−N interaction as a potent chemical gate in the proposed device. The complexes exhibit short intermolecular distances ranging from 1.724 to 1.752 Å, emphasizing their strong binding. Detailed analysis of electronic rearrangements and geometric perturbations upon complex formation provides insights into the underlying reasons for the formation of such strong Be−N bonds, with bond strengths varying from −116.25 to −92.96 kJ/mol. Moreover, the influence of chemical substituents on the local electronic transmission of the beryllium‐bonded complex offers valuable insights for the implementation of a secondary chemical gate in single‐molecule devices. This study paves the way for the development of chemically gateable, functional single‐molecule transistors, advancing the design and fabrication of multifunctional single‐molecule devices in the nanoscale regime. [ABSTRACT FROM AUTHOR]

Tetrakis(4‐aminophenyl)porphyrin (1) and tetrakis(4‐acetamidophenyl)porphyrin (2) were dissolved in water with the incorporation of a polysaccharide (λ‐carrageenan (CGN)) as a water‐solubilizing agent. Although the photodynamic activity of the CGN‐2 complex was considerably lower than that of the CGN‐1 complex, the selectivity index (SI; IC50 in a normal cell/IC50 in a cancer cell) of the CGN‐2 complex was considerably higher than that of the CGN‐1 complex. This is because the photodynamic activity of the CGN‐2 complex was significantly affected by the intracellular uptakes by the normal and cancer cells. During in vivo experiments, the CGN‐2 complex inhibited tumor growth under light irradiation with high blood retention compared with the CGN‐1 complex and Photofrin, which exhibited lower blood retention. This study showed that the photodynamic activity and SI are influenced by substituent groups of arene in the meso‐positions of porphyrin analogs. [ABSTRACT FROM AUTHOR]

A new sensing strategy towards hydrogen peroxide based on metal coordination polyelectrolyte‐driven self‐assembly of alkynylplatinum(II) 2,6‐bis(benzimidazol‐2′‐yl)pyridine (bzimpy) complex was demonstrated. The cationic in situ‐generated Ag(I)–thiocholine coordination polyelectrolytes were shown to induce the supramolecular self‐assembly of anionic low‐energy red‐emissive alkynylplatinum(II) bzimpy complexes via non‐covalent Pt(II)⋅⋅⋅Pt(II), electrostatic and π–π stacking interactions. The presence of hydrogen peroxide was shown to inhibit the formation of coordination polyelectrolytes and the coordination polyelectrolyte‐induced self‐assembly of platinum(II) complexes. The weakening of Pt(II)⋅⋅⋅Pt(II), electrostatic and π–π stacking interactions was supported by UV‐vis absorption, emission, and resonance light scattering (RLS) studies. The present assay was also applied to probe glucose indirectly based on the enzymatic reaction of glucose oxidase on the substrate. Operating in a label‐free manner, together with the low‐energy red emission and large Stokes shift of alkynylplatinum(II) complexes, these features render the proposed design attractive for biological applications. [ABSTRACT FROM AUTHOR]

The field of anion supramolecular chemistry has received more and more attention in recent years. Anions with diverse types and geometries have been widely used for the synthesis of ionic spin crossover (SCO) complexes. This review is devoted to anion effects on the molecular, supramolecular structures and magnetic properties of discrete SCO compounds. Firstly, typical anions used in the synthesis of these compounds are briefly summarized according to their various geometries. This is followed by a collection of representative examples of anion‐based SCO compounds, whose SCO properties are analyzed in terms of supramolecular interactions, geometry and charge of anions. In the third part, anion effects on SCO complexes of different kinds of metal centers and ligands are outlined and finally remarks on the synthesis new type of ionic SCO complexes in the future are described. [ABSTRACT FROM AUTHOR]

Selective binding of chloride over the other most abundant anions in living organisms is pivotal due to its essential role in physiological functions. Herein, we report a template‐free Pd2L4 cage exhibiting high selectivity for medium‐sized halides (i. e. Cl−, Br−) in water owing to the size‐discriminatory nature of the cage cavity. In pure water, this cage displays high selectivity and micromolar affinity for chloride. The cage shows no binding towards other biologically more abundant essential anions such as phosphates, carboxylates, or bicarbonate. This cage shows an unprecedented nanomolar affinity with 1 : 1 binding stoichiometry for chloride in aqueous‐DMSO media. This high affinity was achieved with the best use of traditional hydrogen bonding and electrostatic interactions, as confirmed by single‐crystal X‐ray diffraction analysis. This well‐defined cage sequestrates F− by cleaving a B−F bond in BF4− in a facile manner in a nonpolar solvent or in the presence of excess ligand. This cage also demonstrates capture of the sub‐ppm chloride level that is present in commercial D2O samples. [ABSTRACT FROM AUTHOR]

Three new ligands containing a bicyclo[2.2.2]oct‐7‐ene‐2,3,5,6‐tetracarboxydiimide unit have been used to assemble lantern‐type metal‐organic cages with the general formula [Cu4L4]. Functionalisation of the backbone of the ligands leads to distinct crystal packing motifs between the three cages, as observed with single‐crystal X‐ray diffraction. The three cages vary in their gas sorption behaviour, and the capacity of the materials for CO2 is found to depend on the activation conditions: softer activation conditions lead to superior uptake, and one of the cages displays the highest BET surface area found for lantern‐type cages so far. [ABSTRACT FROM AUTHOR]

The negative homotropic allostery of a triple‐layered trisporphyrin cleft with two guest binding sites is confirmed. The X‐ray crystal structures of the 1 : 2 host‐guest complexes showed that the trisporphyrin accommodated two guest molecules within the cleft through π–π stacking and donor‐acceptor interactions. In solution, 1H NMR and Job plots showed 1 : 2 host‐guest complexes. Isothermal titration calorimetry (ITC) and UV/vis absorption spectroscopy were employed to evaluate the binding constants and cooperativities. The guest binding of the trisporphyrin showed negative cooperativity and non‐cooperativity depending on the structures of the guest molecules. The correlations between the interaction parameters (α) and Hill constants were determined. ITC experiments showed that the host‐guest complexation of trisporphyrin with electron‐deficient guests incurred an enthalpy penalty in the successive guest binding process. DFT calculations revealed that binding of the first guest reduced the electron density of the central porphyrin plane, which led to an energetic penalty that weakened the successive binding process. [ABSTRACT FROM AUTHOR]

Aggregation of supramolecular helices, for example through interdigitation of their alkyl side chains or through more directional supramolecular interactions, leads to hierarchical architectures with original structural and chiroptical properties. However, when a chiral monomer (the "sergeant") is introduced as a minor component in these assemblies composed of a majority of achiral monomers (the "soldiers"), it is not clear how the aggregation changes the ability of the sergeant to induce a preferential helicity to the polymer main chain (the so‐called "sergeants‐and‐soldiers" effect). This study reports a detailed investigation of the influence of [Cu(OAc)2⋅H2O] coordination on the structure and chiroptical properties of helical hydrogen‐bonded co‐assemblies composed of a catalytically‐active benzene‐1,3,5‐tricarboxamide (BTA) monomer, acting as the "soldier", and an enantiopure BTA monomer derived from cyclohexylalanine, playing the role of the "sergeant". The copper actually significantly influences the extent of the "sergeants‐and‐soldiers" effect since it acts as a crosslink that induces some chiral defects in the supramolecular helices. These crosslinks appear to be preserved during the catalytic hydrosilylation of 4‐nitroacetophenone. The aggregation of helices through the formation of copper crosslinks is reversible since homochiral single helices are exclusively formed in the case of sergeant‐rich assemblies. The fact that both main chain and side chain aggregation affects the chiroptical properties of supramolecular helices must be considered in the design of elaborated chiral materials. [ABSTRACT FROM AUTHOR]

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. DFT calculations and SCXRD analysis revealed PDs are extremely flexible with adaptive molecular geometries that can be mechanically regulated via crystal packing or host–guest complexation. The excellent donor nature of PDs renders inclusion complexes with the cyclophane bluebox (cyclobis(paraquat‐p‐phenylene)), featuring association constants up to 104 M−1. Additionally, a planarized transition intermediate associated with inversion dynamics of a PD has been preserved in the pseudorotaxane structure with assistances of π⋅⋅⋅π and S⋅⋅⋅π interactions. The hinged structure, excellent redox‐activity, and adaptive nature of PDs could further enable accesses to exotic redox switchable host–guest chemistry and functional materials. [ABSTRACT FROM AUTHOR]

In contrast to the mature predictive frameworks applied to neutral cocrystals, ionic cocrystals, those including an ion pair, are difficult to design. Furthermore, they are generally excluded categorically from studies which correlate specific molecular properties to cocrystal formation, leaving the prospective ionic cocrystal engineer with few clear avenues to success. Herein ammonium nitrate, an energetic oxidizing salt, is targeted for cocrystallization in a potential coformer group selected based on likely interactions with the nitrate ion as revealed in the Cambridge Structural Database; six novel ionic cocrystals were discovered. Molecular descriptors previously identified as being related to neutral cocrystal formation were examined across the screening group but showed no relationship with ionic cocrystal formation. High packing coefficient is shown to be a constant among the successful coformers in the set and is utilized to directly target two more successful coformers, bypassing the need for a large screening group. [ABSTRACT FROM AUTHOR]

Here we describe a photoswitchable iron(III) salen phosphate catalyst, which is able to catalyze the enantiodivergent oxidation of prochiral aryl alkyl sulfides to chiral aryl alkyl sulfoxides. The stable (S)‐axial isomer of the catalyst produced enantioenriched sulfoxides with the (R)‐configuration in up to 75 % e.e., whereas the photoisomerized metastable (R)‐axial isomer of the catalyst favored the formation of (S)‐sulfoxides in up to 43 % e.e. The maximum Δe.e. value obtained in the enantiodivergent sulfoxidation was 118 %, which is identical to the maximum Δe.e. value that was measured in the enantiodivergent epoxidation of alkenes by a related recently described Mn1 catalyst. This iron‐based catalyst broadens the scope of photoswitchable enantiodivergent catalysts and may be used in the future to develop a photoswitchable catalytic system that can write digital information on a polymer chain in the form chiral sulfoxide functions. [ABSTRACT FROM AUTHOR]

Coordination chemistry is a powerful method to synthesize supramolecular cages with distinct features that suit specific applications. This work demonstrates the synthesis of discrete, homochiral FeII2L3 cages via chirality‐driven self‐assembly. Specifically, the installation of chirality – at both the vertices and ligand backbones – allows the formation of discrete, homochiral FeII2L3 cages of different sizes via stereochemical control of the iron(II) centers. We observed that larger cages require multiple chiral centra (chiral ligands and vertices). In contrast, the formation of smaller cages is stereoselective with solely chiral ligands. The latter cages can also be formed from two chiral subcomponents, but only when they have matching chirality. Single‐crystal X‐ray diffraction of these smaller FeII2L3 cages revealed several non‐covalent interactions as a driving force for narcissistic chiral self‐sorting. This expected behavior was confirmed utilizing the shorter ligands in racemic form, yielding discrete, homochiral FeII2L3 cages formed in enantiomeric pairs. [ABSTRACT FROM AUTHOR]

Pentaphosphaferrocenes [CpRFe(η5‐P5)] (Cp*=η5‐C5Me5) (A), Cp"=η5‐C5H3tBu2‐1,3 (B)) are excellent building blocks for polymeric assemblies in supramolecular chemistry in combination with coinage metal salts of weakly coordinating anions such as AgSbF6. Adding rigid aromatic dinitriles ortho/meta/para‐(NC)2C6H4 in a one‐pot reaction between [CpRFe(η5‐P5)] and AgSbF6 leads to various coordination polymers (CPs) by a three‐component self‐assembly. The sterical demand of the differently substituted cyclopentadiene ligands as well as the rigid constitution of the isomeric dinitriles (NC)2C6H4 play a key role in the formation of the isolated CPs. All CPs were characterized by NMR spectroscopy, mass spectrometry, elemental analysis, and single‐crystal X‐ray diffraction. [ABSTRACT FROM AUTHOR]

The syntheses of two novel mechanically chiral rotaxanes containing urea and squaramide motifs (in yields of 33 % and 22 %, respectively) are presented. 1H NMR spectroscopic titrations reveal shuttling of the macrocycle – detectable by modulation of the expression of mechanical chirality in the NMR spectrum – is possible through the addition of achiral chloride anions, a process which is reversed by the addition of sodium cations. [ABSTRACT FROM AUTHOR]

The synthesis of iodine(I) complexes with either benzoimidazole or carbazole‐derived sp2N‐containing Lewis bases is described, as well as their corresponding silver(I) complexes. The addition of elemental iodine to the linear two‐coordinate Ag(I) complexes produces iodine(I) complexes with a three‐center four‐electron (3c–4e) [N−I−N]+ bond. The 1H and 1H‐15N HMBC NMR studies unambiguously confirm the formation of the complexes in all cases via the [N−Ag−N]+→[N−I−N]+ cation exchange, with the 15N NMR chemical shift change between 94 to 111 ppm when compared to the free ligand. The single crystal X‐ray crystallographic studies on eight I+ complexes revealed highly symmetrical [N−I−N]+ bonds with I−N bond distances of 2.21–2.26 Å and N−I−N angles of 177–180°, whilst some of the corresponding Ag+ complexes showed a clear deviation from linearity with N−Ag−N angles of ca. 150° and Ag−N bond distances of 2.09–2.18 Å. [ABSTRACT FROM AUTHOR]

We report the synthesis, gelation abilities and aggregation‐induced, blue‐shifted emission (AIBSE) properties of two minimalistic diketopiperazine‐based gelators. Despite containing a highly insoluble luminophore that makes up more than half of their respective molecular masses, efficient hydrogelation by multiple stimuli for one and efficient organogelation for the other compound are reported. Insights into the aggregation and gelation properties were gained through examination of the photophysical and material properties of selected gels, which are representative of the different modes of gelation. The synthesis of the gelators is highly modular and based on readily available amino acid building blocks, allowing the efficient and rapid diversification of these core structures and fine‐tuning of gel properties. [ABSTRACT FROM AUTHOR]

A linear double pyridinium‐terminated thread comprising a central chalcone moiety is shown to provide two independent binding sites with similar affinity for cucurbit[7]uril (CB7) macrocycles in water as judged from NMR, UV‐Visible and fluorescence spectroscopies. Association results in [2] and [3]pseudorotaxanes, which are both pH and photosensitive. Switching from the neutral chalcone to the cationic flavylium form upon irradiation at 365 nm under acidic conditions provided an enhanced CB7 association (K1:1 increases from 1.2×105 M−1 to 1.5×108 M−1), limiting spontaneous on‐thread cucurbituril shuttling. This co‐conformational change in the [2]pseudorotaxane is reversible in the dark with kobs=4.1×10−4 s−1. Threading the flavylium moiety into CB7 leads to a dramatic increase in the fluorescence quantum yield, from 0.29 in the free axle to 0.97 in the [2]pseudorotaxane and 1.0 in the [3]pseudorotaxane. [ABSTRACT FROM AUTHOR]

Cationic cyclophanes are widely used in a variety of applications in supramolecular chemistry and materials science. In this work the authors systematically study the integration of electron‐rich diboron units with BII atoms into polycationic cyclophanes with viologen‐like electron‐acceptor units. They also report a first hexacationic cage‐compound in which three diboron units connect two tris(4‐pyridyl)triazine acceptor units. Moreover, di‐ and tetracationic open‐structure compounds, in which one diboron unit connects two bispyridyl groups, were synthesized and the properties compared to those of the corresponding closed structures (cyclophanes). The combination of diboron electron‐donor units and bi‐ or oligopyridyl electron‐acceptor units leads to intriguing optical and redox properties. [ABSTRACT FROM AUTHOR]

Host‐guest complexes between native cyclodextrins (α‐, β‐ and γ‐CD) and hybrid Lindqvist‐type polyoxovanadates (POVs) [V6O13((OCH2)3C−R)2]2– with R = CH2CH3, NO2, CH2OH and NH(BOC) (BOC = N‐tert‐butoxycarbonyl) were studied in aqueous solution. Six crystal structures determined by single‐crystal X‐ray diffraction analysis revealed the nature of the functional R group strongly influences the host–guest conformation and also the crystal packing. In all systems isolated in the solid‐state, the organic groups R are embedded within the cyclodextrin cavities, involving only a few weak supramolecular contacts. The interaction between hybrid POVs and the macrocyclic organic hosts have been deeply studied in solution using ITC, cyclic voltammetry and NMR methods (1D 1H NMR, and 2D DOSY, and ROESY). This set of complementary techniques provides clear insights about the strength of interactions and the binding host‐guest modes occurring in aqueous solution, highlighting a dramatic influence of the functional group R on the supramolecular properties of the hexavanadate polyoxoanions (association constant K1:1 vary from 0 to 2 000 M−1) while isolated functional organic groups exhibit only very weak intrinsic affinity with CDs. Electrochemical and calorimetric investigations suggest that the driving force of the host‐guest association involving larger CDs (β‐ and γ‐CD) is mainly related to the chaotropic effect. In contrast, the hydrophobic effect supported by weak attractive forces appears as the main contributor for the formation of α‐CD‐containing host‐guest complexes. In any cases, the origin of driving forces is clearly related to the ability of the macrocyclic host to desolvate the exposed moieties of the hybrid POVs. [ABSTRACT FROM AUTHOR]

The first confacial pentaoctahedron comprised of transition metal ions namely ZnIIFeIIIAFeIIIBFeIIIAZnII has been synthesized by using a dinucleating nonadentate ligand. The face‐sharing bridging mode enforces short ZnII⋅⋅⋅FeIIIA and FeIIIA⋅⋅⋅FeIIIB distances of 2.83 and 2.72 Å, respectively. Ab‐initio CASSCF/NEVPT2 calculations provide significant negative zero‐field splittings for FeIIIA and FeIIIB with |DA|>|DB| with the main component along the C3 axis. Hence, a spin‐Hamiltonian comprised of anisotropic exchange, zero‐field, and Zeeman term was employed. This allowed by following the boundary conditions from the theoretical results the simulation in a theory‐guided parameter determination with Jxy=+0.37, Jz=−0.32, DA=−1.21, EA=−0.24, DB=−0.35, and EB=−0.01 cm−1 supported by simulations of high‐field magnetic Mössbauer spectra recorded at 2 K. The weak but ferromagnetic FeIIIAFeIIIB interaction arises from the small bridging angle of 84.8° being at the switch from anti‐ to ferromagnetic for the face‐sharing bridging mode. [ABSTRACT FROM AUTHOR]

Two major hurdles in NP‐based catalysis are the aggregation of the NPs and their recycling. Immobilization of NPs onto a 2D support is the most promising strategy to overcome these difficulties. Herein, amphiphilicity‐driven self‐assembly of galactose‐hexaphenylbenzene‐based amphiphiles into galactose‐decorated 2D nanosheet is reported. The extremely dense decoration of reducing sugar on the surface of the sheets is used for the in situ synthesis and immobilization of ultrafine catalytically active AgNPs by using Tollens' reaction. The potential of the system as a catalyst for the reduction of various nitroaromatics is demonstrated. Enhanced catalytic activity is observed for the immobilized AgNPs when compared to the corresponding discrete AgNPs. Recovery of the catalytic system from the reaction mixture by ultrafiltration and its subsequent recycling for several cycles without dropping its activity is shown. This is the first report demonstrating the in situ synthesis and immobilization of ultrafine AgNPs onto a 2D nanosheet that exhibits excellent catalytic performance for the reduction of nitroaromatics. [ABSTRACT FROM AUTHOR]

We investigate the gas-phase chemistry of noncovalent complexes of [10]cycloparaphenylene ([10]CPP) with C60 and C70 by means of atmospheric pressure photoionization and electrospray ionization mass spectrometry. The literature-known [1: 1] complexes, namely [10]CPP⊃C60 and [10]CPP⊃C70, are observed as radical cations and anions. Their stability and charge distribution are studied using energy-resolved collision-induced dissociation (ER-CID). These measurements reveal that complexes with a C70 core exhibit a greater stability and, on the other hand, that the radical cations are more stable than the respective radical anions. Regarding the charge distribution, in anionic complexes charges are exclusively located on C60 or C70, while the charges reside on [10]CPP in the case of cationic complexes. [2: 1] complexes of the ([10]CPP2 ⊃C60/70)+ ⋅/- ⋅ type are observed for the first time as isolated solitary gas-phase species. Here, C60 -based [2: 1] complexes are less stable than the respective C70 analogues. By virtue of the high stability of cationic [1: 1] complexes, [2: 1] complexes show a strongly reduced stability of the radical cations. DFT analyses of the minimum geometries as well as molecular dynamics calculations support the experimental data. Furthermore, our novel gas-phase [2: 1] complexes are also found in 1,2-dichlorobenzene. Insights into the thermodynamic parameters of the binding process as well as the species distribution are derived from isothermal titration calorimetry (ITC) measurements. [ABSTRACT FROM AUTHOR]

CLICK‐chemistry has become a universal route to covalently link organic molecules functionalized with azides and alkynes, respectively. Here, we report how CLICK‐chemistry can be used to attach oligoaromatic organic moieties to Dawson‐type polyoxometalates. In step one, the lacunary Dawson anion [α2‐P2W17O61]6− is functionalized with phosphonate anchors featuring peripheral azide groups. In step two, this organic‐inorganic hybrid undergoes microwave‐assisted CLICK coupling. We demonstrate the versatility of this route to access a series of Dawson anions covalently functionalized with oligoaromatic groups. The supramolecular chemistry and aggregation of these systems in solution is explored, and we report distinct changes in charge‐transfer behavior depending on the size of the oligoaromatic π‐system. [ABSTRACT FROM AUTHOR]

Three C3 symmetric macrolactams were very efficiently cyclized from their linear precursors. Adequately located substituents are responsible for the enhancement of reactivity that is not observed in the unsubstituted parent. DFT calculations show that the properly folded cyclization precursor, the reactive conformer, is more populated than other conformers, leading to a decrease of free energy of activation. The crystal structure of the ring substituted with three very bulky esters indicates that tubular stacking is preserved. [ABSTRACT FROM AUTHOR]

The self‐assembly of 2,5‐diformylpyrrole, tris(2‐aminoethyl)amine, and silver(I) yielded, depending on the size and basicity of the anion, new cascade complexes or plenates, that is, cryptates incorporating Agnn+ clusters. The nature of the product was counterion‐dependent, and its formation was either driven by cascade anion binding or by argentophilic interactions stabilizing the cluster within the cavity. The reaction of plenates with tetrabutylammonium halides resulted in the protonation‐coupled replacement of the Ag33+ with anion(s), yielding cascade cryptates. [ABSTRACT FROM AUTHOR]

Appending functional groups to the exterior of Zn4L4 self‐assembled cages allows gated control of anion binding. While the unfunctionalized cages contain aryl groups in the ligand that can freely rotate, attaching inert functional groups creates a "doorstop", preventing rotation and slowing the guest exchange rate, even though the interiors of the host cavities are identically structured. The effects on anion exchange are subtle and depend on multiple factors, including anion size, the nature of the leaving anion, and the electron‐withdrawing ability and steric bulk of the pendant groups. Multiple exchange mechanisms occur, and the nature of the external groups controls associative and dissociative exchange processes: these bulky groups affect both anion egress and ingress, introducing an extra layer of selectivity to the exchange. Small changes can have large effects: affinities for anions as similar as PF6− and SbF6− can vary by as much as 400‐fold between identically sized cavities. [ABSTRACT FROM AUTHOR]

Host‐guest interactions are of paramount importance in supramolecular chemistry and in a wide range of applications. Particularly well known is the ability of cucurbit[n]urils (CB[n]) to selectively host small molecules. We show that the charge transfer and complexation capabilities of CB[n] are retained on the surface of 2D transition metal dichalcogenides (TMDs), allowing the development of efficient electrochemical sensing platforms. We unveil the mechanisms of host‐guest recognition between the MoS2‐CB[8] hybrid interface and melatonin (MLT), an important molecular regulator of vital constants in vertebrates. We find that CB[8] on MoS2 organizes the receptor portals perpendicularly to the surface, facilitating MLT complexation. This advantageous adsorption geometry is specific to TMDs and favours MLT electro‐oxidation, as opposed to other 2D platforms like graphene, where one receptor portal is closed. This study rationalises the cooperative interaction in 2D hybrid systems to improve the efficiency and selectivity of electrochemical sensing platforms. [ABSTRACT FROM AUTHOR]

This Full Paper reports the formation of silver (Ag) NPs within spatially resolved two‐component hydrogel beads, which combine a low‐molecular‐weight gelator (LMWG) DBS‐CONHNH2 and a polymer gelator (PG) calcium alginate. The AgNPs are formed through in situ reduction of AgI, with the resulting nanoparticle‐loaded gels being characterised in detail. The antibacterial activity of the nanocomposite gel beads was tested against two drug‐resistant bacterial strains, often associated with hospital‐acquired infections: vancomycin‐resistant Enterococcus faecium (VRE) and Pseudomonas aeruginosa (PA14), and the AgNP‐loaded gels showed good antimicrobial properties against both types of bacteria. It is suggested that the gel bead format of these AgNP‐loaded hybrid hydrogels makes them promising versatile materials for potential applications in orthopaedics or wound healing. [ABSTRACT FROM AUTHOR]

Mechanical grinding/milling can be regarded as historically the first technology for changing the properties of matter. Mechanically activated molecular units (mechanophores) can be present in various structures: polymers, macromolecules, or small molecules. However, only polymers have been reported to effectively transduce energy to mechanophores, which induces breakage of covalent bonds. In this paper, a second possibility is presented—molecular capsules as stress‐sensitive units. Mechanochemical encapsulation of fullerenes in cystine‐based covalent capsules indicates that complexation takes place in the solid state, despite the fact that the capsules do not possess large enough entrance portals. By using a set of solvent‐free MALDI (sf‐MALDI) and solid‐state NMR (ss‐NMR) experiments, it has been proven that encapsulation proceeds during milling and in this process hydrazones and disulfides get activated for breakage, exchange, and re‐forming. The capsules are porous and therefore prone to collapse under solvent‐free conditions and their conformational rigidity promotes the collapse by the breaking of covalent bonds. [ABSTRACT FROM AUTHOR]

We present here the synthesis of a novel fluorescent actinide polyrotaxane compound URCP1 through the utilization of an end‐cutting pseudorotaxane precursor with only the cucurbit[6]uril (CB[6]) macrocyclic components acting as linking struts. The non‐coordinating guest motif in the obtained polyrotaxane, with increased freedom and structural flexibility, can display intriguing temperature‐triggered conformational variations inside the cavity of CB[6], which was clearly evidenced by crystallographic snapshots at different temperatures. Notably, this observation of temperature‐triggered structural dynamics in URCP1 represents the first report of actinide polyrotaxane with such feature in solid‐state. Moreover, URCP1 has a high photoluminescence quantum yield (PLQY) of 49.8 %, comparable to other luminescent uranyl compounds, and can work as a fluorescent probe to selectively detect Fe3+ over other eight competing cations in aqueous solution, with the limit of detection being as low as 4.4×10−3 ppm. [ABSTRACT FROM AUTHOR]

The so far missing parent compound of the large family of pentaphosphaferrocenes [CpFe(η5‐P5)] (1 b) was synthesized by the thermolysis of [CpFe(CO)2]2 with P4 using the very high‐boiling solvent diisopropylbenzene. It was comprehensively characterized by, inter alia, NMR spectroscopy, single crystal X‐ray structure analysis, cyclic voltammetry and DFT computations. Moreover, its coordination behavior towards CuI halides was explored, revealing the unprecedented 2D polymeric networks [{CpFe(η5:1:1:1:1‐P5)}Cu2(μ‐X)2]n (2 a: X=Cl, 2 b: X=Br) and [{CpFe(η5:1:1‐P5)}Cu(μ‐I)]n (3) and even the first cyclo‐P5‐containing 3D coordination polymer [{CpFe(η5:1:1‐P5)}Cu(μ‐I)]n (4). The sandwich complex 1 b can also be incorporated in nano‐sized supramolecules based on [Cp*Fe(η5‐P5)] (1 a) and CuX (X=Cl, Br, I): [CpFe(η5‐P5)]@[{Cp*Fe(η5‐P5)}12(CuX)20‐n] (5 a: X=Cl, n=2.4; 5 b: X=Br, n=2.4; 5 c: X=I, n=0.95). Thereby, the formation of the CuI‐containing fullerene‐like sphere 5 c is found for the first time. [ABSTRACT FROM AUTHOR]

Anion receptors can be used to transport ions across lipid bilayers, which has potential for therapeutic applications. Synthetic bicarbonate transporters are of particular interest, as defects in transmembrane transport of bicarbonate are associated with various diseases. However, no convenient method exists to directly observe bicarbonate transport and study the mechanisms involved. Here, an assay is presented that allows the kinetics of bicarbonate transport into liposomes to be monitored directly and with great sensitivity. The assay utilises an encapsulated europium(III) complex, which exhibits a large increase in emission intensity upon binding bicarbonate. Mechanisms involving CO2 diffusion and the dissipation of a pH gradient are shown to be able to lead to an increase in bicarbonate concentration within liposomes, without transport of the anion occurring at all. By distinguishing these alternative mechanisms from actual bicarbonate transport, this assay will inform the future development of bicarbonate transporters. [ABSTRACT FROM AUTHOR]

Poly(ethylene oxide)s (PEOs) are useful polymers with good water solubility, biological compatibility, and commercial availability. PEOs with various end groups were threaded into pillar[5]arene rings in a mixture of water and methanol to afford pseudopolyrotaxanes. Corresponding polyrotaxanes were also constructed by capping COOH‐terminated pseudopolyrotaxanes with bulky amines, in which multiple hydrogen bonds involving the pillar[5]arene OH groups were critically important to prevent dethreading. The number of threaded ring components could be rationally controlled in these materials, providing a simple and versatile method to tune the mechanical and thermal properties. Specifically, a polyrotaxane with a high‐molecular‐weight axle became elastic upon heating above the melting point of PEOs and exhibited temperature‐dependent shape memory property because of the topological confinement and crosslinked hydrogen bonds. [ABSTRACT FROM AUTHOR]

A [2]rotaxane built around a multi‐responsive bis‐acridinium macrocycle has been synthesized. Structural investigation has confirmed the interlocked nature of the molecule, and MD simulations illuminated its conformational dynamics with atomic resolution. Both halochromic and redox‐switching properties were explored to shed light on the mechanical response and electronic changes that occur in the bis‐acridinium [2]rotaxane. The topology of the rotaxane led to different mechanical behaviors upon addition of hydroxide ions or reduction that were easily detected by UV/Vis spectroscopy and electrochemistry. [ABSTRACT FROM AUTHOR]

Stabilization of chiral propeller conformations in triaryl compounds is challenging due to generally low racemization barriers. Nonetheless, it was recently found that chiral conformational preferences can be induced to triaryl boranes by incorporating point‐chiral alkylether chains to the aryl blades and subsequently locking the structure with ammonia. A four‐point interaction, meaning that the cooperative effects of Lewis‐adduct formation and three hydrogen bonds, was proposed as stabilizing mechanism. Herein, it was shown that three such strong interactions suffice to introduce a preferential propeller handedness. Although DFT calculations predict no noteworthy preferences for either P‐ or M‐chiral propellers for some of the investigated triarylborane–amine adducts that were prepared with chiral primary amines, vibrational circular dichroism (VCD) spectroscopic characterizations revealed that there is indeed a measurable excess of one propeller handedness. Furthermore, the steric demand of the amine was found to play a key role in the induction process and especially in preventing blade rotations. [ABSTRACT FROM AUTHOR]

Iodine capture is of great significance for disposal of the hazardous radioactive iodine. CTX[P(O)Ph], one kind of censer‐shaped macrocycle cyclotrixylohydroquinoylene (CTX) derivatives, was applied as an efficient iodine adsorbent. It showed satisfactory iodine adsorption capacity in vapor phase and could be reused without obvious adsorption capacity loss. Besides, the adsorbent could also uptake iodine in water. Fortunately, two iodine loading CTX[P(O)Ph] crystal structures were obtained under different conditions to explore the mechanism of iodine adsorption. This work provides a relatively rare example of iodine adsorption by macrocycle. It is promising that the results with crystal information might be meaningful for exploring and designing new kinds of iodine adsorbents. [ABSTRACT FROM AUTHOR]

Dynamic control of molecular photoluminescence offers chemical solutions to designing functional emissive materials. Although stimuli‐switchable molecular luminescent systems are well established, how to encode these dynamic emissive systems with a "timing" feature, that is, time‐dependent luminescent properties, remains challenging. This Concept aims to summarize the design principles of dynamic timing molecular photoluminescent systems by discussing the state‐of‐the‐art of this topic and the shaping of fabrication strategies at both the molecular and supramolecular levels. An outlook and perspectives are given to outline the future opportunities and challenges in the rational design and potential applications of these smart emissive systems. [ABSTRACT FROM AUTHOR]

The ability to use bio‐inspired building blocks in the assembly of novel supramolecular frameworks is at the forefront of an exciting research field. Herein, we present the first polyproline helix to self‐assemble into a reversibly porous, crystalline, supramolecular peptide framework (SPF). This framework is assembled from a short oligoproline, adopting the polyproline II conformation, driven by hydrogen‐bonding and dispersion interactions. Thermal activation, guest‐induced dynamic porosity and enantioselective guest inclusion have been demonstrated for this novel system. The principles of the self‐assembly associated with this SPF will be used as a blueprint allowing for the further development of helical peptide linkers in the rational design of SPFs and metal‐peptide frameworks. [ABSTRACT FROM AUTHOR]

The globular and monocationic guest molecule trimethyl‐azaphosphatrane (AZAP, a protonated Verkade superbase) was shown to form a host:guest 1 : 1 complex with the cucurbit[10]uril (CB[10]) macrocycle in water. Molecular dynamics calculations showed that CB[10] adopts an 8‐shape with AZAP occupying the majority of the internal space, CB[10] contracting around AZAP and leaving a significant part of the cavity unoccupied. This residual space was used to co‐include planar and monocationic co‐guest (CG) molecules, affording heteroternary CB[10]⋅AZAP⋅CG complexes potentially opening new perspectives in supramolecular chemistry. [ABSTRACT FROM AUTHOR]

Five isostructural microporous supramolecular architectures prepared by H‐bonded assembly between the hexa‐anionic complex [Zr2(Ox)7]6− (Ox=oxalate, (C2O4)2−) and tripodal cations (H3‐TripCH2‐R)3+ with R=H, CH3, OH and OBn (Bn=CH2Ph) are reported. The possibility to obtain the same structure using a mixture of tripodal cations with different R group (R=OH and R=CH3) has also been successfully explored, providing a unique example of three‐component H‐bonded porous framework. The resulting SPA‐1(R) materials feature 1D pores decorated by R groups, with apparent pore diameters ranging from 3.0 to 8.5 Å. Influence of R groups on the sorption properties of these materials is evidenced through CO2 and H2O vapor sorption/desorption experiments, as well as with I2 capture/release experiments in liquid media. This study is one of the first to demonstrate the possibility of tuning the porosity and exerting precise control over the chemical functionalization of the pores in a given H‐bonded structure, without modifying the topology of the reference structure, and thus finely adjusting the sorption characteristics of the material. [ABSTRACT FROM AUTHOR]

As hydrogen bonded frameworks are held together by relatively weak interactions, they often form several different frameworks under slightly different synthesis conditions and respond dynamically to stimuli such as heat and vacuum. However, these dynamic restructuring processes are often poorly understood. In this work, three isoreticular hydrogen bonded organic frameworks assembled through charge‐assisted amidinium⋅⋅⋅carboxylate hydrogen bonds (1C/C, 1Si/C and 1Si/Si) are studied. Three distinct phases for 1C/C and four for 1Si/C and 1Si/Si are fully structurally characterized. The transitions between these phases involve extreme yet recoverable molecular‐level framework reorganization. It is demonstrated that these transformations are related to water content and can be controlled by humidity, and that the non‐porous anhydrous phase of 1C/C shows reversible water sorption through single crystal to crystal restructuring. This mechanistic insight opens the way for the future use of the inherent dynamism present in hydrogen bonded frameworks. [ABSTRACT FROM AUTHOR]

Synthesis of robust covalent macrocycles/cages via multiple amide‐bond forming reaction is highly challenging and generally it needs multistep reactions. One‐pot reaction of appropriate di‐/tri‐acyl chloride with a diamine generally results polymers or oligomers instead of discrete architectures. To overcome this limitation, a strategy is reported here using dynamic imine chemistry for facile construction of imine‐based macrocycle and cage upon treatment of a diamine with di‐ and tri‐aldehydes respectively, followed by post‐synthesis one‐step conversion of imine bonds to amides to form the desired robust macrocycle and cage containing multiple amide bonds. While the macrocycle was found to form aggregates in DMSO, the cage was intact without any aggregation. Six amide groups in the confined pocket of the cage made it an ideal receptor for selective binding of fluoride with very high selectivity (∼3× ${\times }$ 103 fold) over chloride, and it was silent towards other halides, phosphate, and other oxyanions. [ABSTRACT FROM AUTHOR]

Construction of lanthanide heterometallic complex is important for engineering multifunction molecular containers. However, it remains a challenge because of the similar ionic radii of lanthanides. Herein we attempt to prepare chiral lanthanide heterometallic tetrahedra. Upon crystallization with a mixture of [Eu2L3] and [Ln2L3] (Ln=Gd, Tb and Dy) helicates, a mixture of heterometallic EunLn'4‐n(L6) (n=0–4) tetrahedra was prepared. Selective formation of heterometallic tetrahedron was observed as MS deconvolution results deviated from statistical results. The formation of heterometallic tetrahedron was found to be sensitive to ionic radii as well as the ratio of the two helicates used in the crystallization. [ABSTRACT FROM AUTHOR]

Abstract: Detection of nitroaromatics at ultralow concentration is a major security concern in defense, forensics, and environmental science. To this end, a new triarylamine‐cored dendritic gelator (OGR) was synthesized, which produced thermoreversible, thixotropic, and fluorescent gels in n‐octanol. On gelation, both π–π* transitions and the emission peak of the gelator show redshifts with a 4.5‐fold increase of fluorescence intensity in the gel state indicating J‐aggregation. The nitrogen lone‐pair electrons of OGR make it a donor, and electron transfer occurs to acceptor nitroaromatics causing fluorescence quenching, which is further promoted due to its acidity. The Stern–Volmer rate constants measured for different nitroaromatics showed that it senses picric acid (PA) best. The contact‐mode technique with OGR‐treated paper strips can allow naked‐eye detection of PA under UV light down to 10−11  m concentration within 30 s. Reusability of the gel is achieved by treating OGR@PAx with NaOH solution. Impedance spectroscopic results indicated a decrease of both charge‐transport resistance and Warburg impedance on successive addition of PA. The limits of detection of PA determined from fluorescence and impedance measurements match well. Thus, the OGR gel is a reusable, low‐cost, specific sensor for PA by naked‐eye colorimetric, fluorescence, and impedance techniques. [ABSTRACT FROM AUTHOR]

The formation of supramolecular structural units through self‐assembly is a powerful method to design new architectures and materials endowed with specific properties. With the aim of adding a group of versatile tectons to the toolkit of crystal engineers, we have devised and synthesised four new V‐shaped building blocks characterised by an aryl acetylene scaffold comprising three substituted pyridine rings connected by two triple bonds. The judicious choice of different substituents on the pyridine rings provides these tectons with distinctive steric, electrostatic and self‐assembly properties, which influence their crystal structures and their ability to form co‐crystals. Co‐crystals of the tectons with tetraiododifluorobenzene were obtained both via traditional and mechanochemical crystallisation strategies, proving their potential use in crystal engineering. The energetic contributions of the supramolecular interactions at play in the crystal lattice have also been evaluated to better understand their nature and strength and to rationalise their role in designing molecular crystals. [ABSTRACT FROM AUTHOR]