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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]

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]

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 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]

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]

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]

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]

Well‐defined supramolecular interactions are a powerful tool to control the stereochemistry of a catalytic reaction. In this paper, we report a novel core motif for fluxional 2,2′‐biphenyl ligands carrying (S)‐amino acid‐derived interaction sites in 5,5′‐position that cause spontaneous enrichment of the Rax rotamer. The process is based on strong non‐covalent interlocking between interaction sites, which causes diastereoselective formation of a supramolecular ligand dimer, in which the axial chirality of the two subunits is dictated by the stereochemical information in the amino acid residues. The detailed structure of the dimer was elucidated by NMR spectroscopy and single‐crystal X‐ray analysis. Three different phosphorus‐based ligand types, namely a bisphosphine, a bisphosphinite and a phosphoramidite were synthesized and characterized. Whereas the first one was found to exist in a strongly weighted equilibrium, the two others each exhibited stereoconvergent behavior transforming into the diastereopure Rax rotamer. Enriched ligands were used in rhodium‐mediated asymmetric hydrogenation reactions of prochiral olefins in which very high enantioselectivities of up to 96:4 were achieved. [ABSTRACT FROM AUTHOR]

Evidence for the surprising formation of polymeric phases under high pressure for conjugated nanohoop molecules was found. This paper represents one of the unique cases, in which the molecular-level effects of pressure in crystalline organic solids is addressed, and provides a general approach based on vibrational Raman spectroscopy combining experiments and computations. In particular, we studied the structural and supramolecular chemistry of the cyclic conjugated nanohoop molecule [5]cyclo- para-phenylene ([5]CPP) under high pressures up to 10 GPa experimentally and up to 20 GPa computationally. The theoretical modeling for periodic crystals predicts good agreements with the experimentally obtained Raman spectra in the molecular phase. In addition, we have discovered two stable polymeric phases that arise in the simulation. The critical pressures in the simulation are too high, but the formation of polymeric phases at high pressures provides a natural explanation for the observed irreversibility of the Raman spectra upon pressure release between 6 and 7 GPa. The geometric parameters show a deformation toward quinonoid structures at high pressures accompanied by other deformations of the [5]CPP nanohoops. The quinonoidization of the benzene rings is linked to the systematic change of the bond length alternation as a function of the pressure, providing a qualitative interpretation of the observed spectral shifts of the molecular phase. [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]

Cooperative effects can be observed in various research areas in chemistry; cooperative catalysis is well-established, the assembly of compounds on surfaces can be steered by cooperative effects, and supramolecular polymerization can proceed in a cooperative manner. In biological systems, cooperativity is observed in protein-protein, protein-lipid and protein-molecule interactions. Synergistic effects are relevant in frustrated Lewis pairs, organic multispin systems, multimetallic clusters and also in nanoparticles. However, a general approach to determine cooperativity in the different chemical systems is currently not known. In the present concept paper it is suggested that, at least for simpler systems that can be described at the molecular level, cooperativity can be defined based on energy considerations. For systems in which no chemical transformation occurs, determination of interaction energies of the whole system with respect to the interaction energies between all individual component pairs (subsystems) will allow determination of cooperativity. For systems comprising of chemical transformations, cooperativity can be evaluated by determining the activation energy of the synergistic system and by comparing this with activation energies of the corresponding subsystems that lack an activating moiety. For more complex systems, cooperativity is generally determined at a qualitative level. [ABSTRACT FROM AUTHOR]

The synthesis of phenanthroline‐containing polymer chains enables the subsequent incorporation of metal‐ions to generate functional macromolecular architectures. Using nitroxide‐mediated polymerization techniques, both polar and non‐polar polymers can be task‐specifically designed, readily extendable for their applications. Phenanthroline‐functionalized polymer chains hold unique potential as a platform for metal‐complexed single‐chain technology or as fluorescent soft matter material. More information can be found in the Full Paper by A.‐N. Unterreiner, P. W. Roesky, C. Barner‐Kowollik, et al. on page 17475. [ABSTRACT FROM AUTHOR]

A Chiral‐at‐Al aluminate can be prepared by the stepwise reaction of two different alcohols with the aluminate anion [EtAl(6‐Me‐2‐py)3]−. The method can also be used to prepare chiral‐at‐ligand aluminates and for the introduction of 3‐py and 4‐py functionalities into the aluminate framework through the selective and controlled substitution of one or two pyridine arms, thereby giving entry to new supramolecular chemistry. The cover represents the formation of such a rare example of a chiral‐at‐aluminum aluminate and it is also a tribute to the oneiric worlds of surrealist painter René Magritte. More information can be found in the Full Paper by R. García‐Rodríguez et al. on page 17019. [ABSTRACT FROM AUTHOR]

Multisite anion receptors HAT(CN)6 and [M(CN)4]2− stack under the regime of anion–π interactions to create the platform for a sponge‐like behavior and anion → receptor charge transfer. More information can be found in the Full Paper by R. Podgajny et al. on page 16302. [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]

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]

A bifunctional MOF for selective CO2 capture and efficient aqueous‐phase sensing of 2,4,6‐trinitrophenol (TNP) has been rationally designed and synthesized. Owing to the presence of basic (−NH2) functionalized pore surface, the MOF exhibits selective adsorption of CO2 with a high value of heat of adsorption (Qst = 46.5 kJ mol−1) which is about 10 kJ mol−1 higher than that of the analogues MOF without −NH2 functionality. Further, the MOF shows highly selective, aqueous‐phase sensing of TNP over other competing NACs. The observed selectivity of MOF for CO2 capture and sensing of TNP has been correlated to the stronger interaction of the guest molecules with the basic −NH2 groups in the 1D channels, unveiled from the DFT calculations. For more information see the Full Paper by C. M. Nagaraja et al. on page 16204 ff. [ABSTRACT FROM AUTHOR]

Simple particle counting cannot in general be reliably employed to predict the observed architecture as DFT analysis shows that vibrational contributions to entropy dominate and may significantly influence the preferred architecture. However, simple particle counting, which predicts triangles over squares, is seen to be correct here, and DFT confirms the triangles are energetically favored over the corresponding squares. Image kindly created by Michael Crawford (Dunedin). More information can be found in the Full Paper by A. L. Garden, S. Brooker et al. on page 14193. [ABSTRACT FROM AUTHOR]

Owing to the electron‐donating and ‐accepting nature of corroles (Corr) and phthalocyanines (Pc), respectively, we designed and developed two novel covalently linked Corr‐Pc conjugates. The synthetic route allows the preparation of the target conjugates in satisfying yields. Comprehensive steady‐state absorption, fluorescence, and electrochemical assays enabled insights into energy and electron‐transfer processes upon photoexcitation. Coordinating a pyridine‐appended subphthalocyanine (SubPc) to the Pc of the conjugate sets up the ways and means to realize the first example of an array composed by three different porphyrinoids, which drives a cascade of energy and charge‐transfer processes. Importantly, the SubPc assists in stabilizing the charge‐separated state, that is, one‐electron oxidized Corr and the one electron‐reduced Pc, upon photoexcitation by means of a reductive charge transfer to the SubPc. To the best of our knowledge, this is the first case of an intramolecular oxidation of a Corr within electron‐donor–acceptor conjugates by means of just photoexcitation. Moreover, the combination of Corr, Pc, and SubPc guarantees panchromatic absorption across the visible range of the solar spectrum, with the SubPc covering the „green gap" that usually affects porphyrinoids. [ABSTRACT FROM AUTHOR]

A triquinoline cationic moiety (TQ⋅H+) has recently been designed as a novel molecular unit for supramolecular chemistry. In addition to some useful features, TQ⋅H+ has strong electron‐acceptor properties, which renders the molecular cation a unique element in nanochemistry. TQ⋅H+ is found to form complexes with coronene (COR) and cycloparaphenylene (CPP). In this work, we report a computational study of photoinduced electron transfer in supramolecular complexes TQ⋅H+‐COR, TQ⋅H+⊂[12]CPP and (TQ⋅H+‐COR)⊂[12]CPP. The electron‐transfer rates are estimated by using the semi‐classical approach. The results are compared with the data previously obtained for a structurally similar inclusion complex Li+@C60⊂[10]CPP. In particular, we found a red solvatochromic shift for charge‐shift bands in the TQ⋅H+‐complexes unlike a blueshift showed by Li+@C60⊂[10]CPP. This distinction is explored in terms of electronic and structural features of the systems. [ABSTRACT FROM AUTHOR]

Besides their widespread use in coordination chemistry, 2,2'‐bipyridines are known for their ability to undergo cis–trans conformational changes in response to metal ions and acids, which has been primarily investigated at the molecular level. However, the exploitation of such conformational switching in self‐assembly has remained unexplored. In this work, the use of 2,2'‐bipyridines as acid‐responsive conformational switches to tune supramolecular polymerization processes has been demonstrated. To achieve this goal, we have designed a bipyridine‐based linear bolaamphiphile, 1, that forms ordered supramolecular polymers in aqueous media through cooperative aromatic and hydrophobic interactions. Interestingly, addition of acid (TFA) induces the monoprotonation of the 2,2'‐bipyridine moiety, leading to a switch in the molecular conformation from a linear (trans) to a V‐shaped (cis) state. This increase in molecular distortion along with electrostatic repulsions of the positively charged bipyridine‐H+ units attenuate the aggregation tendency and induce a transformation from long fibers to shorter thinner fibers. Our findings may contribute to opening up new directions in molecular switches and stimuli‐responsive supramolecular materials. [ABSTRACT FROM AUTHOR]

Halogen and hydrogen bonding were compared in the solid state, solution, and gas phase in three series of halogen ‐ bonded complexes derived from p ‐ substituted pyridine derivatives and 3 N ‐ halosuccinimides (iodo ‐ , bromo ‐ , and chloro ‐ ; NIS, NBS, and NCS) and an equivalent series of hydrogen ‐ bonded complexes of succinimide. The bond energies for the halogen bonds increase with the basicity of the base and Lewis acidity of the halogen, while the hydrogen bond energies are intermediate between those in complexes of NIS and NBS. More information can be found in the Full Paper by V. Stilinović, et al. on page 5244 ff. [ABSTRACT FROM AUTHOR]

NMR analysis reveals that quartet assemblies formed by a guanosine building block in solution can transform into a mixture of quartet (Q) and ribbon (R) ‐ like assemblies after solvent evaporation. Our results demonstrate that the existence of a stable supramolecular structure in solution or in the solid state may not reflect its stability and integrity in another phase. More information can be found in the Full Paper by S. P. Brown et al. on page 2315 ff. [ABSTRACT FROM AUTHOR]

With the largest cavity in the cucurbituril family, cucurbit[10]uril (CB[10]) has been utilized to make supramolecular assemblies by host – guest ‐ enhanced charge ‐ transfer interactions. Two packed “sandwiches” have been assembled by forming a 1:2:1 or 1:1:1 complex between CB[10] and viologen derivatives and an electron ‐ rich molecule in water. Amazingly, as a known building block for the construction of molecular machines, blue box can be encapsulated within CB[10]. By threading a guest through the cavities of both blue box and CB[10], a supramolecular “Russian doll” architecture has been built up. More information can be found in the Full Paper by L. Isaacs, S. Liu et al. on page 17612 ff. [ABSTRACT FROM AUTHOR]

Due to the widespread application of carbon nanotube (CNT)-based materials in nanomedicine, it is nowadays of paramount importance to unravel at the atomistic level of detail the structural properties of such bioconjugates in order to rationalize and predict the effect exerted by the graphitic framework on the bio-active counterpart. In this paper, we report for the first time all-atom explicit solvent molecular dynamics (MD) simulations investigating the structural and dynamic properties of a noncovalent bioconjugate in which the monoclonal Cetuximab antibody (Ctx) is adsorbed on a CNT surface. Upon selection of the three most representative adsorption modes as obtained by docking studies, force-field MD and DFT simulations unambiguously showed that hydrophobic interactions mainly govern the adsorption of the protein on the graphitic surface. Two main adsorption poses have been predicted: a pose-fab ( p-fab) and pose-fc ( p-fc) (fab = fragment antigen binding region; fc = fragment crystallizable region), the former being favored with small-diameter tubes (≤40 Å). In all the predicted poses, the secondary structure of Ctx is largely unaffected by the presence of the graphitic surface and, consistently with previous literature studies, our simulations reveal that positively charged amino acidic residues, such as Lys and Arg, predominantly contribute to the stabilization of the CNT⋅Ctx complex acting like surfactants. The predicted structural models are consistent with the experimental data, for which the immobilization of the antibody on CNTs does not disrupt the structural and recognition properties of the Ctx, consequently supporting the reliability of the used bioconjugation strategy for engineering stable and responsive hybrid nanomaterials for therapeutic applications. Moreover, a remarkable structural similarity of Ctx with antibodies of different isotypes suggests that in principle the CNT framework can interact in the same manner with all antibodies currently used in clinical applications. [ABSTRACT FROM AUTHOR]

Flexible porphyrin covalent cages behave as allosteric receptors and control guest encapsulation through large conformational changes. In the closed state, the cage cavity is restricted preventing guest molecules to be captured. Coordination of silver ions to the allosteric sites switches the cage to an open state allowing for the encapsulation of guest molecules. For more details, see the Full Paper by K. Rissanen, V. Heitz and co‐workers on page 1481 ff. [ABSTRACT FROM AUTHOR]

A dual‐cavity host, with six terminal alkynes at the periphery of its two fused cavitands, is obtained at the gram scale by following straightforward synthetic protocols. This structurally unique and multivalent cavitand can be efficiently clicked to carbohydrates, polymers, or small functional molecules. The stage is thus set for exploring the preparation of novel multivalent drugs and nanostructured soft materials. More information can be found in the Full Paper by J. D. Badjić et al. on page 1242. [ABSTRACT FROM AUTHOR]

A self‐sorting network comprising six different hydrogen bonding‐motifs is presented. Detailed analysis of the pairwise molecular recognition behavior of each hydrogen‐bonding motif by NMR spectroscopy, single‐crystal studies, and DFT allowed the construction of cascades exploiting integrative and non‐integrative narcissistic and social self‐sorted product distributions. Multiple distinct pathways within the network could be created depending on the presence or absence of different components. More information can be found in the Full Paper by C. Fonseca Guerra, A. J. Wilson, et al. on page 785. [ABSTRACT FROM AUTHOR]

Lipid–porphyrin conjugates are considered as promising building blocks for supramolecular structures with multifunctional properties such as those required for anticancer photodynamic therapy. The Full Paper by A. Makky et al. on page 19179 ff. describes the synthesis of two new lipid‐porphyrin conjugates by coupling chlorophyll‐a derivative, pheophorbide‐a, to natural phospholipids. These conjugates exhibited self‐assembling properties, high loading rate in liposomes membranes, interesting optical behavior and promising photodynamic activity with better selectivity in vitro to esophageal squamous cell carcinoma relative to normal cells. [ABSTRACT FROM AUTHOR]

Ternary‐component crystals with guest‐dependent photofunctions, such as crystallization‐induced enhanced emission, intermolecular charge‐transfer emission, and room‐temperature phosphorescence emission under UV‐light irradiation, have been designed. The single‐crystal X‐ray structure determination of eight different guest crystals was performed, and the structure–property relationships at a molecular level were studied. The findings provide important guidelines for the future design of novel optoelectronic organic materials. More information can be found in the Full Paper by T. Ono, Y. Hisaeda et al. on page 17487. [ABSTRACT FROM AUTHOR]

From the reaction of manganese halides with the chiral Schiff bases obtained by condensation of o‐vanillin and (R)‐ or (S)‐phenylglycinol, 11 complexes based on pentanuclear cages with trigonal bipyramidal [MnIIMnIII3M′] (M′=NaI, CaII, MnII) or enneanuclear [MnIIMnIII6NaI2] cores were synthesized. Structural, supramolecular chirality, and optical properties were explored. The magnetic properties of related systems were reviewed, and the magnetic response of the new systems was rationalized to the bond parameters. Mirror, mirror: A family of chiral clusters with [MnIIMnIII3M′] or [MnIIMnIII6NaI2] cores (see figure) was obtained from enantiomerically pure Schiff bases. Structural characteristics, optical properties, and magnetic response were studied for these complexes. [ABSTRACT FROM AUTHOR]

The self‐assembly properties of nine low‐molecular‐weight gelators (LMWGs) based on bile acid alkyl amides were studied in detail. Based on the results, the number of hydroxyl groups attached to the steroidal backbone plays a major role in the gelation, although the nature of the aliphatic side chain also modulates the gelation abilities. Of the 50 gel systems studied, 35 are based on lithocholic acid and 15 on cholic acid derivatives. The deoxycholic acid derivatives did not form any gels. The gelation occurred primarily in aromatic solvents and the gels manifested typical fibrous or spherical morphologies. The 13C cross‐polarized magic angle spinning (CPMAS) NMR spectra measured on the crystalline materials and the corresponding wet organogels were analogous, suggesting that the chemical environments, that is, the intermolecular interactions found in the two materials were similar. The single‐crystal X‐ray structures of all nine bile‐acid amide derivatives studied revealed very similar molecular conformations in the solid state and gave insights into the possible intermolecular interactions in the gel state. A detailed study on the self‐assembly properties of nine low‐molecular‐weight gelators based on bile acid alkyl amides resulted in 50 gel systems, 35 of which were based on lithocholic acid and 15 on cholic acid derivatives. Deoxycholic acid derivatives did not form gels. Gelation was observed in aromatic solvents and the gels showed typical fibrous or spherical morphologies. Solid‐state NMR and single‐crystal XRD investigations gave insights into the possible intermolecular interactions in the gel. [ABSTRACT FROM AUTHOR]

The modular structure of metal–organic framework nanosheets (MONs) provides a convenient route to creating two‐dimensional materials with readily tuneable surface properties. Here, the liquid exfoliation of two closely related layered metal–organic frameworks functionalised with either methoxy‐propyl (1) or pentyl (2) pendent groups intended to bestow either hydrophilic or hydrophobic character to the resulting nanosheets is reported. Exfoliation of the two materials in a range of different solvents highlighted significant differences in their dispersion properties, as well as their molecular and nanoscopic structures. Exchange or loss of solvent was found to occur at the labile axial position of the paddle‐wheel based MONs and DFT calculations indicated that intramolecular coordination by the oxygen of the methoxy‐propyl pendant groups may take place. The nanoscopic dimensions of the MONs were further tuned by varying the exfoliation conditions and through "liquid cascade centrifugation". Aqueous suspensions of the nanosheets were used as sensors to detect aromatic heterocycles with clear differences in binding behaviour observed and quantified. Two metal–organic frameworks functionalised with either hydrophilic or hydrophobic alkyl‐ether side chains were synthesised and exfoliated in a wide range of solvents. The concentration, structure and dimensions of the resulting nanosheets were investigated. [ABSTRACT FROM AUTHOR]

The design, synthesis, and characterization of a new multifunctional supramolecular assembly based on a photoactive glycosylated porphyrin and covalently attached monofunctionalized cucurbit[7]uril (CB7) are reported. To obtain the target supramolecular assembly, azido‐functionalized tetraphenylporphyrin (TPP) was used as a building block. TPP was first glycosylated by copper‐catalyzed azide‐alkyne cycloaddition (CuAAC) reaction, then a monopropargyloxy‐functionalized‐CB7 unit was conjugated to glycosylated TPP with a second CuAAC reaction. The host–guest chemistry of the assembly was investigated by 1H NMR experiments to establish the availability of the CB7 as a host. The imidazole‐based guest, which is known to have high affinity toward CB7, was observed to form inclusion complex with CB7. It was also demonstrated that this supramolecular assembly can serve as an efficient photosensitizer for the generation of singlet oxygen. Sugar‐coated assemblies: A new multifunctional supramolecular assembly was synthesized by clicking an azide functionalized photoactive glycosylated porphyrin with monopropargyloxy functionalized cucurbit[7]uril (CB7). This supramolecular assembly can serve as a host to bind with guests and an efficient photosensitizer for the generation of singlet oxygen (see figure). [ABSTRACT FROM AUTHOR]

The stepwise evolution of curved multifarene structures from planar precursors is demonstrated, highlighting three architectural design elements: 1) employment of various aromatic units, 2) changing the hybridization of the linking atoms from sp2 to sp3, and 3) rigidification of the system by the introduction of five‐membered rings. Similar design elements have been employed to transform graphene sheets into curved carbon structures. Specifically, the stepwise synthetic evolution of multifarene[2+2], which has a curved, quite rigid structure, begins with a planar, tetraimine precursor, conversion to pairs of vicinal diamines, and the transformation of these pairs to cyclic thiourea groups. This process was probed by NMR spectroscopy and X‐ray crystallography. Since varying the carbonylation conditions resulted in carbamates or thiocarbamates rather than the urea or thiourea isomers, the isomeric interconversion was studied both experimentally and by DFT computations. The carbamate versus urea preference was found to reflect either kinetic or thermodynamic control, respectively. Molecular design: The stepwise evolution of curved multifarene structures from planar precursors and an increased extent of curvature have been demonstrated (see figure). [ABSTRACT FROM AUTHOR]

A combination of1H NMR, 2D diffusion NMR spectroscopy, electrospray ionization travelling wave ion‐mobility mass spectrometry, small‐angle X‐ray scattering, and molecular modelling allowed the unambiguous characterization of an original covalent polyoxometalate‐based molecular triangle. More details of this fascinating chemistry can be found in the Full Paper by G. Izzet and co‐workers on page 19010 ff. [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]