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The use of hierarchically structured materials as catalysts has been finding increasing application in the past years. For these catalytic systems, not only the nano‐scale matters: a high degree of order across multiple length scales, along with its control and analytical assessment, is of paramount importance to obtain innovative properties that can find application in catalysis. Most reviews dealing with hierarchically structured materials are concerned with the "bottom‐up" transfer of structural information along the different length scales, with special emphasis on the transmission of chirality. Due to their mesoscale size together with their complex behaviour, these systems are often susceptible to feel the effects of macroscopic forces, that can exert a "top‐down" control of their catalytic properties, so that an external stimulus, acting at the level of the supramolecular architecture of the catalyst, can ultimately determine the outcome of the catalyzed reaction at the molecular level. We review in this paper some recent reports that deal with the experimental implementation of this concept, either by using a mechanical force in a full range direct transmission to the reaction coordinate, or by means of a stepwise relay transmission from the macroscopic level (purely supramolecular chirality) to the nanoscopic one. We focus in this review on these multi‐length scale communication control effects, identifying the different mechanisms that are affecting the catalytic activity. [ABSTRACT FROM AUTHOR]

Supramolecular capsules can be used to change the activity and selectivity of a catalyst through the influence of the second coordination sphere, reminiscent of how enzymes control the selectivity of their processes. In enzymes, this approach is used to also control the enantioselectivity of reactions in which the active catalytic site is often not chiral but the second coordination sphere is. We are interested in the possibility to generate a chiral second coordination sphere around an otherwise achiral transition metal complex for asymmetric catalysis. In this paper we show that the ligand template approach can be used to generate a chiral second coordination sphere around a rhodium complex, which is used in asymmetric hydroformylation. [ABSTRACT FROM AUTHOR]

This paper describes the synthesis and characterization of 21 chiral monodentate ligands L, assembled of three building blocks utilizing amide bonds: a metal binding triphenylphosphine, a chiral cyclic diamine and an additional substituent for fine‐tuning the steric and/or electronic properties. Cis square‐planar metal complexes of RhI and PtII with ML2 stoichiometry have been prepared and characterized by spectroscopic methods (NMR, IR, UV‐Vis, CD) and DFT calculations. A key feature of the metal complexes is a prochiral metal coordination sphere and "backdoor induction" of chirality from a distant chiral source via an outer‐coordination sphere, well‐defined by aromatic stacking and hydrogen‐bonding. The rhodium complexes were used as catalysts in asymmetric hydrogenation of α,β‐dehydroamino acids with excellent yield and selectivity (up to 97 % ee), strongly supporting the "backdoor induction" hypothesis. Chiral information is transmitted from a distant chiral source to the prochiral coordination sphere by means of noncovalent interactions, resulting in up to 97 % ee in asymmetric hydrogenations. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes the peculiar co‐assembly supramolecular polymerization behavior of triphenylamine trisamide derivatives with d‐alanine (T‐ala) or glycine (T‐gly) moieties. Concentration and temperature‐dependent circular dichroism (CD) spectroscopy revealed that the heating curves of co‐assemblies obtained at various molar ratios of T‐ala to T‐gly exhibited two distinct transition temperatures. The first transition was due to the transformation from coiled helical bundles to single helical fibers without handedness. The second was due to a change from typical elongation to nucleation. These phenomena were confirmed by solvent‐dependent decoiling of coiled helical structures and concentration‐dependent morphological analysis. The two transitioning temperatures were dependent on the concentration of T‐ala in the co‐assemblies, suggesting that T‐ala concentration plays an important role in the formation of coiled helical bundles. Our study demonstrated the first observation of two distinct transition temperatures in supramolecular polymers. [ABSTRACT FROM AUTHOR]

Recent investigations of supramolecular polymers based on chiral triphenylene‐2,6,10‐tricarboxamides (TTAs) showed how temperature‐induced changes in solvation can greatly influence the preferred helical conformation of the supramolecular polymers formed. Here, we combine chiral TTA with achiral copolymerization partners to further investigate temperature‐dependent solvation effects. Systematic variation of the system's composition shows clear impacts on the temperature window where the conformational change occurs. Further, simple chain length variations in the achiral comonomer greatly affect the ability to influence the conformational change in the copolymer, while the differences in the properties of the individual homopolymers are rather small. We herein highlight how subtle changes in the monomers can impact the observed copolymer properties drastically; an effect arising from the emerging complexity of multicomponent interactions in supramolecular copolymers with solvent‐solute interactions being more important than typically thought. [ABSTRACT FROM AUTHOR]

Continuous intensification of reaction screening methodologies has required the development of novel high‐throughput analytical technologies. This urge involves also chirality related fields where nowadays novel methods for reliable, fast and effective analysis are developed. Within this field, chiroptical spectroscopies have emerged as promising techniques, in particular when they are combined with stereodynamic probes for optical signal amplification. We report here the synthesis and characterisation of a series of molecular architectures based on a modified tris(2‐pyridylmethyl)amine (TPMA) complex which are able to amplify the electronic CD signal of phenylalanine. The study reports the synthesis of six novel TPMA based supramolecular architectures characterised by the presence of two different metals within the same molecule. Besides the synthesis, the study highlights how mixing metals influences the chiroptical properties of the formed compounds. [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]

Significant advances have been made recently in generating chiral polymer surfaces and materials using a range of methods such as block copolymer self-assembly, layer-by-layer assembly and surface functionalization by polymer brushes. This paves the way for novel chiral materials that can harness and tailor chiral interactions for specific functionalities and properties in a range of biomedical and bioanalytical applications. This paper reviews these advances and speculates on the future of chiral surfaces. © 2013 Society of Chemical Industry [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]

A new family of homochiral silver complexes based on carbophilic interactions with ortho-phenylene ethynylene (o-OPE) scaffolds containing up to two silver atoms are described. These compounds represent a unique class of complexes with chirality at the metal. Chiral induction is based on the inclusion of chiral sulfoxides, which allow efficient transfer of chirality to the helically folded o-OPE, leading to circularly polarized luminescence (CPL)- and vibrational circular dichroism (VCD)-active compounds. In the presence of silver(I) cations, carbophilic interactions dominate, which promote helical structures with a defined helicity. This is one of the very scarce examples of the use of such interactions in the attractive field of abiotic foldamers. The switching event has been extensively studied by using different chiroptical techniques, including circular dichroism, CPL, and VCD, and represents one of the few CPL switches described in the literature. [ABSTRACT FROM AUTHOR]

Supramolecular chirality in a binary mixture of achiral bent-core (BC) and achiral rodlike mesogens was observed. Three different nanosegregated mesophases were determined in the binary system, and meaningful changes in circular dichroism (CD) were detected near the phase-transition temperatures of the rodlike mesogens. The highest CD intensity in the binary system was noted in the nanosegregated mesophase, in which the BC mesogens were in the helical nanofilament (HNF) phase and the rodlike mesogens were in the smectic A phase. The supramolecular chirality in the binary mixture was attributed to the self-assembled hierarchical chiral superstructures. Based on the experimental results, plausible scenarios for the chiral superstructures of the rodlike molecules embedded in the HNF networks are suggested. In addition, a system comprising BC and rodlike molecules doped with a photoresponsive compound exhibited remarkable photoswitching of CD intensity. According to the isothermal photoinduced phase transition of the embedded molecules in BC molecular HNFs, the observed CD intensities can be dynamically and reversibly modulated. Such a material with easily controllable functionality is of considerable interest in the field of materials science. [ABSTRACT FROM AUTHOR]

Invited for the cover of this issue is the group of Mikiji Miyata at Osaka University. The image depicts the concept of supramolecular hidden chirality of hydrogen-bonded networks characterized by advanced graph set analysis. Read the full text of the article at . [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]

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]

Inspired by the signal transduction function of organophosphates in biological systems, bioactive organophosphates were utilized for the first time as chiral nodes to dictate the stereoselective assembly of hydrogen‐bonded anionic cages. Phosphonomycin (antibiotics), tenofovir (antivirals), adenosine monophosphate (natural product, AMP) and clindamycin phosphate (antibiotics) were assembled with an achiral bis‐monourea ligand, thereby leading to the stereoselective formation of quadruple or triple helicates. The extent of the stereoselectivity could be enhanced by either lowering the temperature or adding stronger‐binding cations as templates. With the chiral anionic cages as the host, some enantioselectivity was achieved when binding chiral quaternary ammonium cations. [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]

Macrocyclic hosts with a well‐defined cavity are particularly appealing for supramolecular chemistry, but they are still rare. In this research, we reported a new class of macrocyclic hosts, namely methylene‐bridged naphthotubes, with well‐defined cavities. They were synthesized through TFA‐catalyzed Friedel–Crafts reactions between alkoxy‐substituted bisnaphthalenes and paraformaldehyde. A configurational selection was observed. Three‐membered macrocycles possess a single cavity, while four‐membered macrocycles adopt a double‐cavity conformation or a self‐filling conformation depending on the alkoxy length. The small homologue shows quite strong binding affinities (up to 108 M−1) to organic cations, which is better than structurally similar but flexible macrocycles. This demonstrates the advantage of a well‐defined cavity in molecular recognition. Moreover, these naphthotubes can be used as chirality sensors for chiral organic cations through different chirality transfer mechanisms. [ABSTRACT FROM AUTHOR]

A highly accurate and reliable screening method for enantiomeric excess of amine derivatives in the presence of water is reported. The fluorescence-based screening system has been realized by self-assembly of chiral diol-type dyes (BINOL, VANOL and VAPOL), 2-formylphenylboronic acid, and chiral amines forming iminoboronate esters. The structure and chirality of the amine analytes determine the stability of the diastereomeric iminoboronate esters, which in turn display differential fluorescence. The fluorescence signal reflects the enantiomeric purity of the chiral amines and was utilized in high-throughput arrays. The arrays were able to recognize enantiomeric excess of amines, amino esters, and amino alcohols. In addition to qualitative analysis, quantitative experiments were successfully performed. Studies of the role of additives such as water or citrate were carried out to gain insight into the stability of the iminoboronate esters. It is shown that the above additives destabilize less stable esters while the stable esters remain unchanged. Thus, the presence of water and citrate leads to increased difference between the diastereomeric iminoboronates and contributes to the enantiodiscrimination of the chiral amines. [ABSTRACT FROM AUTHOR]

Chiral head groups have been introduced into water-soluble hydroxyl-terminated nonionic amphiphiles and the impact of the head group stereochemistry on the supramolecular ultrastructures has been studied. Enantiomeric isomers were compared with the achiral meso form and the racemic mixture by means of cryogenic transmission electron microscopy and circular dichroism spectroscopy. Structurally, all amphiphiles are composed of the first-generation hydrophilic polyglycerol head group coupled to a single hydrophobic hexadecyl chain through an amide linkage and diaromatic spacer. The enantiomers aggregate to form twisted ribbons with uniform handedness, whereas the meso stereoisomer and racemic mixture produce elongated assemblies, namely, tubules and platelets, but without a chiral ultrastructure. Simulations on the molecular packing geometries of the stereoisomers indicate different preferential assembly routes that explain the individual supramolecular aggregation behavior. [ABSTRACT FROM AUTHOR]

Molecular capsules composed of amino acid or peptide derivatives connected to resorcin[4]arene scaffolds through acylhydrazone linkers have been synthesized using dynamic covalent chemistry (DCC) and hydrogen-bond-based self-assembly. The dynamic character of the linkers and the preference of the peptides towards self-assembly into β-barrel-type motifs lead to the spontaneous amplification of formation of homochiral capsules from mixtures of different substrates. The capsules have cavities of around 800 Å3 and exhibit good kinetic stability. Although they retain their dynamic character, which allows processes such as chiral self-sorting and chiral self-assembly to operate with high fidelity, guest complexation is hindered in solution. However, the quantitative complexation of even very large guests, such as fullerene C60 or C70, is possible through the utilization of reversible covalent bonds or the application of mechanochemical methods. The NMR spectra show the influence of the chiral environment on the symmetry of the fullerene molecules, which results in the differentiation of diastereotopic carbon atoms for C70, and the X-ray structures provide unique information on the modes of peptide-fullerene interactions. [ABSTRACT FROM AUTHOR]

Keywords: chirality switching; pillar[n]arenes; solvent mixing; supramolecular chemistry; temperature effects Solvent mixing drastically varied the inversion temperature of MUJs, and the temperature-driven chirality switching direction could be critically controlled by mixing the ratios of two solvents. Solvent mixing drastically varied the inversion temperature of MUJs, and the temperature-driven chirality switching direction could be critically controlled by mixing the ratios of two solvents. [Extracted from the article]

Multicomponent metallo‐supramolecular assembly allows the rational combination of different building blocks. Discrete multifunctional hosts with an accessible cavity can be prepared in a non‐statistical fashion. We employ our shape‐complementary assembly (SCA) method to achieve for the first time integrative self‐sorting of heteroleptic PdII cages showing guest‐tunable circularly polarized luminescence (CPL). An enantiopure helicene‐based ligand (M or P configuration) is coupled with a non‐chiral emissive fluorenone‐based ligand (A or B) to form a series of Pd2L2L′2 assemblies. The modular strategy allows to impart the chiral information of the helicenes to the overall supramolecular system, resulting in CPL from the non‐chiral component. Guest binding results in a 4‐fold increase of CPL intensity. The principle offers potential to generate libraries of multifunctional materials with applications in molecular recognition, enantioselective photo‐redox catalysis and information processing. [ABSTRACT FROM AUTHOR]

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

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

Inspired by biological systems, supramolecular polymers have emerged over the past three decades as an important way to form functional structures with potential to tune the internal order and dynamics and to create materials with the potential for responsiveness, reconfigurability, and recyclability. We focus here on several recent examples of ordered supramolecular polymers with a significant extent of internal order that results in crystalline molecular packing, or with dynamics that allow them to undergo structural reconfiguration. These examples highlight the spectrum of molecular mobility that the noncovalently bound constituents can experience. These materials have found interesting functions in their interaction with chiral biological systems and in their ability to form materials with interesting optoelectronic and photocatalytic behavior. [ABSTRACT FROM AUTHOR]

The precise positioning of functional groups about the inner space of abiotic hosts is a challenging task and of interest for developing more effective receptors and catalysts akin to those found in nature. To address it, we herein report a synthetic methodology for preparing basket‐like cavitands comprised of three different aromatics as side arms with orthogonal esters at the rim for further functionalization. First, enantioenriched A (borochloronorbornene), B (iodobromonorbornene), and C (boronorbornene) building blocks were obtained by stereoselective syntheses. Second, consecutive A‐to‐B and then AB‐to‐C Suzuki–Miyaura (SM) couplings were optimized to give enantioenriched ABC cavitand as the principal product. The robust synthetic protocol allowed us to prepare (a) an enantioenriched basket with three benzene sides and each holding either tBu, Et, or Me esters, (b) both enantiomers of a so‐called "spiral staircase" basket with benzene, naphthalene, and anthracene groups surrounding the inner space, and (c) a photo‐responsive basket bearing one anthracene and two benzene arms. [ABSTRACT FROM AUTHOR]

While controlling the chirality and modulating the helicity is a challenging task, it attracts great research interest for gaining a better understanding of the origin of chirality in nature. Herein, structurally similar azobenzene (Azo) vinyl monomers were designed in which the alkyl chains comprised the chiral stereocenter with different achiral tail lengths. Combining the synchronous polymerization, supramolecular stacking and self‐assembly, the multiple chiroptical inversion of the Azo‐polymer supramolecular assemblies can be modulated by the tail length and DP of Azo blocks during in situ polymerization. The DP‐, UV light‐, temperature‐, aging time‐dependent chiroptical properties and liquid‐crystalline (LC) characterization indicated that the amorphous‐to‐LC phase transition and biphasic LC interconversion allow the transcription of intra‐chain π–π stacking, inter‐chain H‐ and J‐aggregation, thereby controlling the dynamic multiple reversal of supramolecular chirality. [ABSTRACT FROM AUTHOR]

Main observation and conclusion: Circularly polarized luminescent (CPL) materials with intense emission and high luminescence dissymmetry factor (glum) are highly desirable for their promising applications in communication technologies, nanotechnologies, innovative materials, etc. Motivated by benefits in supramolecular chemistry and aggregation‐induced emission (AIE) materials for the development of advanced luminescent materials, herein, we report a new class of CPL‐active AIE luminogens (AIEgens) by incorporating the p‐terphenylene (TP) with chiral alkoxyl chains. Aggregation‐induced emission and supramolecular chirality have been realized by hierarchical self‐assembly of these TP cored coil‐rod‐coil molecules under the synergistic effect of π‐π stacking, hydrogen bonding and van der Waals forces. Helical nanofibers with length up to several microns and tunable handedness in different condensed states, such as in poor solvents, thin films and gel states are produced, which exhibit strong CPL signals (glum) of ca. 10–2 and fluorescence quantum yields up to 56.7%. The well‐defined one‐component self‐assembly of AIEgens from a concise molecular design is expected to pave a general avenue to fabricate chiroptical materials with both strong emission and high glum, which would be practically important for advanced modern technologies. [ABSTRACT FROM AUTHOR]

Herein, we report an achiral anthracene‐based tetracationic nanotube (1⋅4Cl−) that shows two levels of supramolecular chirality: namely, conformationally adaptive host–guest complexation with nucleoside triphosphates (e.g. ATP, GTP, CTP, and UTP) and twisted packing of the chiral host–guest complexes in water. Interestingly, achiral 1⋅4Cl− exhibits chiral recognition for ATP/GTP and CTP/UTP through structural transformation of its intramolecular M‐ and P‐twisted conformation as the first level of supramolecular chirality, which leads to adaptive chirality with opposite CD responses. Furthermore, the formation of chiral M‐1⋅4Cl−⊃ATP can promote an intermolecular P‐twisted dimeric packing of anthracene rings as the second level of supramolecular chirality to achieve assembled chirality with strong circularly polarized luminescence arising from the excimer ((+)‐CPL, glum≈10−2) in water. [ABSTRACT FROM AUTHOR]

Keywords: supramolecular chemistry; host-guest systems; molecular recognition; helicate; chirality EN supramolecular chemistry host-guest systems molecular recognition helicate chirality 2 2 1 01/06/21 20210104 NES 210104 B The molecular recognition b of a water-soluble calix[4]arene triple metallohelicate is reported. Chiral guest molecules were encapsulated within the cavity surrounded by the calixarene cavities, resulting in one-handed helical conformations. Small guest molecules such as 1,4-dimethyl-1,4-diazoniabicyclo[2.2.2]octane and I N i -methyl quinuclidinium ion were accommodated within the cavity to form 1: 2 host-guest complexes in a cooperative manner. [Extracted from the article]

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

Most metallo‐supramolecular assemblies of low nuclearity adopt simple topologies, with bridging ligands spanning neighboring metal centers in a direct fashion. Here we contribute a new structural motif to the family of host compounds with low metal count (two) that consists of a pair of doubly‐interlocked, Figure‐eight‐shaped subunits, also termed "lemniscates". Each metal is chelated by two chiral bidentate ligands, composed of a peptidic macrocycle that resembles a natural product with two pyridyl‐terminated arms. DFT calculation results suggest that dimerization of the mononuclear halves is driven by a combination of 1) Coulomb interaction with a central anion, 2) π‐stacking between intertwined ligand arms and 3) dispersive interactions between the structure's compact inner core bedded into an outer shell composed of the cavitand‐type macrocycles. The resulting cage‐like architecture was characterized by NMR, MS and X‐ray structure analyses. This new mechanically bonded system highlights the scope of structural variety accessible in metal‐mediated self‐assemblies composed of only a few constituents. [ABSTRACT FROM AUTHOR]

Di‐2,7‐naphthihexaphyrin(1.1.1.1.1.1), a non‐aromatic carba‐analogue of the hexaphyrin(1.1.1.1.1.1), incorporating two built‐in 2,7‐naphthylene moieties was synthesized as two separate, conformationally locked stereoisomers. Both conformers followed complex protonation pathways involving structurally different species, which can be targeted under kinetic and thermodynamic control. The neutralization of the ultimate dicationic product, accessible from both stereoisomers of the free base, allowed to realize the complex conformational switching cycle involving six structurally different species. [ABSTRACT FROM AUTHOR]

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

The syntheses of novel amphiphilic 5,5′,6,6′‐tetrachlorobenzimidacarbocyanine (TBC) dye derivatives with aminopropanediol head groups, which only differ in stereochemistry (chiral enantiomers, meso form and conformer), are reported. For the achiral meso form, a new synthetic route towards asymmetric cyanine dyes was established. All compounds form J aggregates in water, the optical properties of which were characterised by means of spectroscopic methods. The supramolecular structure of the aggregates is investigated by means of cryo‐transmission electron microscopy, cryo‐electron tomography and AFM, revealing extended sheet‐like aggregates for chiral enantiomers and nanotubes for the mesomer, respectively, whereas the conformer forms predominately needle‐like crystals. The experiments demonstrate that the aggregation behaviour of compounds can be controlled solely by head group stereochemistry, which in the case of enantiomers enables the formation of extended hydrogen‐bond chains by the hydroxyl functionalities. In case of the achiral meso form, however, such chains turned out to be sterically excluded. [ABSTRACT FROM AUTHOR]

A chiral electrochemically responsive molecular universal joint (EMUJ) was synthesized by fusing a macrocyclic pillar[6]arene (P[6]) to a ferrocene‐based side ring. A single crystal of an enantiopure EMUJ was successfully obtained, which allowed, for the first time, the definitive correlation between the absolute configuration and the circular dichroism spectrum of a P[6] derivative to be determined. The self‐inclusion and self‐exclusion conformational change of the EMUJ led to a chiroptical inversion of the P[6] moiety, which could be manipulated by both solvents and changes in temperature. The EMUJ also displayed a unique redox‐triggered reversible in/out conformational switching, corresponding to an occupation/voidance switching of the P[6] cavity, respectively. This phenomenon is an unprecedented electrochemical manipulation of the capture and release of guest molecules by supramolecular hosts. [ABSTRACT FROM AUTHOR]

Supramolecular chirality, generated by the asymmetric assembly of chiral or achiral molecules, has attracted intense study owing to its potential to offer insights into natural biological structures and its crucial roles in advanced materials. The optical activity and stacking pathway of building molecules both greatly determine the chirality of the whole supramolecular structure. The flexibility of supramolecular structures makes their chirality easy to modulate through abundant means. Adjustment of the molecular structure or packing mode, or external stimuli that act like a finger gently pushing toy bricks, can greatly change the chirality of supramolecular assemblies. The dynamic regulation of chiral nanostructures on the intramolecular, intermolecular, and external levels could be regarded as the modulatory essence in numerous strategies, however, this perspective is ignored in most reviews in the literature. Herein, therefore, we focus on the ingenious dynamic modulation of chiral nanostructures by these factors. Through dynamic modulation with changes in chiroptical spectroscopy and electron microscopy, the mechanism of formation of supramolecular chirality is also elaborated. [ABSTRACT FROM AUTHOR]

A chiral, octahedral M12L12 cage, which is charge neutral and contains an internal void of about 2000 Å3, is reported. The cage was synthesised as an enantiopure complex by virtue of amino‐acid‐based dicarboxylate ligands, which assemble around copper paddlewheels at the vertices of the octahedron. The cage persists in solution with retention of the fluorescence properties of the parent acid. The solid‐state structure contains large pores both within and between the cages, and displays permanent porosity for the sorption of gases with retention of crystallinity. Initial tests show some enantioselectivity of the cage towards guests in solution. [ABSTRACT FROM AUTHOR]

Directional self‐assembly of uncharged molecules in water is a major challenge in supramolecular chemistry. Herein, it is demonstrated that peptide‐based cavitands wrap around a hydrophobic core (fullerene C60) by a combination of the hydrophobic effect and hydrogen‐bonding interactions to form highly ordered three‐component complexes in water that resemble the molten‐globule stage of protein folding. The complexes were characterized by DOSY NMR spectroscopy, small‐angle X‐ray scattering, and circular dichroism, and their structures were confirmed by X‐ray crystallography. Enhancement of the CD signals by nearly one order of magnitude and increased hydrolytic stability of hydrazone bonds of the complexes relative to the nonassembled species were observed. In contrast, DMSO and DMSO/water mixtures were found to be highly disintegrative for these complexes. Interestingly, some cavitands can only be synthesized in the presence of the hydrophobic template followed by disassembly of the complexes. Highly competitive: Directional self‐assembly of uncharged molecules in water is a major challenge in supramolecular chemistry. In this work, a combination of hydrogen bonding and the hydrophobic effect allows peptide‐based cavitands to wrap around a C60 fullerene core to form well‐ordered noncovalent chiral assemblies in a highly competitive environment involving intermolecular and intramolecular interactions with water and charged substituents, respectively. [ABSTRACT FROM AUTHOR]

The chirality of supramolecular polymeric materials is subtly affected by a delicate balance among various non‐covalent interactions, the details of which are inadequately understood. Now, a fine balance of intermolecular interactions, including closed‐shell metal–metal, dispersive and electrostatic interactions, is used to direct the delicate orientation of monomeric building blocks, thereby achieving the successful preparation of different nanostructures with distinct supramolecular chirality. Moreover, kinetically trapped and thermodynamically stable aggregates were monitored over time in the supramolecular polymerization of cationic PtII complexes. The dynamic self‐assembly process can be successfully controlled by modifying the counteranion and solvent composition. A chiral doping approach can also be used to induce the chirality of an achiral PtII complex at the supramolecular level. The chirality transfer process and the pathway complexity of a series of chiral pincer‐type PtII complexes are described. A chiral doping approach can be used to induce the chirality of an achiral PtII complex at the supramolecular level. [Pt]=PtII complex; counteranion X−. [ABSTRACT FROM AUTHOR]

Postfunctionalization of the aluminate anion [EtAl(6‐Me‐2‐py)3]− (1) (2‐py=2‐pyridyl) with alkoxide ligands can be achieved by the selective reactions of the lithium salt 1 Li with alcohols in the appropriate stoichiometry. This method can be used to introduce 3‐ and 4‐py functionality in the form of 3‐ and 4‐alkoxymethylpyridyl groups, while maintaining the integrity of the aluminate framework, thereby giving entry to new supramolecular chemistry. Chirality can be introduced either by using a chiral alcohol as a reactant or by the stepwise reaction of 1 Li with two different nonchiral alcohols. The latter route has allowed the synthesis of a rare example of a chiral‐at‐aluminium aluminate. Deconstructing the scorpionate: Postfunctionalization of the aluminate anion [EtAl(6‐Me‐2‐py)3]− (2‐py=2‐pyridyl) with alkoxide ligands can be used to incorporate different functionalities (see figure), introducing supramolecular chemistry and chirality, either at the ligand or at the Al centre. [ABSTRACT FROM AUTHOR]

The ordering of organic molecules in a supramolecular self‐assembly determines their physical, chemical, and photonic properties. Here, we report the aggregation of two achiral naphthalene diimides (NDIs), in which phenyl moieties are linked to the NDI core via a urea subunit, leading to chiral supramolecular assemblies in THF/methylcyclohexane. Circular dichroism spectroscopic analysis of twisted ribbons deposited from solutions indicated a mixture of left‐ and right‐handed nanostructures for one NDI, whereas only left‐handed structures were observed for the other one. Furthermore, this study also shows the effect of large atoms such as iodine on the self‐assembly process, which governs and controls the helicity of the produced microstructures. The supramolecular assemblies were characterized by UV/Vis, fluorescence emission, CD, SEM, and XRD techniques. Inspired by Mother Nature: A synthesis of two naphthalene diimides (NDIs) bearing urea functionalities is reported. These diimides assembled into supramolecular chiral helical superstructures in THF/methylcyclohexane with varying ratios. The self‐assembly was driven by the hydrogen bonding induced by the urea subunit, π–π stacking interactions between the NDI aromatic core and van der Waals interactions between alkyl chains. The left‐handed twisted supramolecular structures were confirmed by circular dichroism and SEM. [ABSTRACT FROM AUTHOR]

Synthesis of the first enantiomerically pure chiral bambusurils is reported. The bambusurils were prepared on the gram scale without using any chromatography techniques. The bambusurils formed supramolecular complexes with all tested chiral carboxylates including amino acids and drug molecules with the enantioselectivity ranging from 1.1 to 3.2. Macrocyclization of glycoluril diastereomers leads to enantiomerically pure chiral bambusurils with the ability to recognize biologically relevant carboxylate anions. [ABSTRACT FROM AUTHOR]

Chirabite‐AR was employed to differentiate enantiomers of the axially chiral cyclotriveratrylene (CTV)‐derived macrocyclic lactam with baseline separation of most of the proton NMR resonances enabling enantiomeric purity determination of this supramolecular scaffold. Attachment of menthyloxy acetic acid as a chiral auxiliary to the CTV‐Beckmann derived lactam afforded diastereomers that were enriched to a ratio of 87:13, as confirmed by both 1H NMR and single‐crystal X‐ray diffraction. Basic hydrolysis of the enriched diastereomeric mixture proceeded with rapid bowl inversion to yield racemic CTV‐lactam as confirmed by Chirabite‐AR NMR analysis. Density functional theory (DFT) calculations (M06 2X/6‐31G*) were performed on the crown and saddle conformers of the CTV‐lactam. [ABSTRACT FROM AUTHOR]

Construction of single-component supramolecular triangle and unprecedented spontaneous resolution of pairs of intertwined supramolecular 31- and 32-double helices by the self-assembly of achiral 2-(iodoethynyl)pyridine and its derivatives have been achieved through intermolecular ethynyl C- I····N halogen bonds in the crystalline state. Fine-tuning of the molecular structure of the achiral monomer and choice of solvents for crystallization have a dominant effect on the resultant supramolecular architectures. [ABSTRACT FROM AUTHOR]

Abstract: Supramolecular containers featuring both high catalytic activity and high enantioselectivity represent a design challenge of practical importance. Herein, it is demonstrated that a chiral octahedral coordination cage can be constructed by using twelve enantiopure Mn(salen)‐derived dicarboxylic acids as linear linkers and six Zn4‐p‐tert‐butylsulfonylcalix[4]arene clusters as tetravalent four‐connected vertices. The porous cage features a large hydrophobic cavity (≈3944 Å3) decorated with catalytically active metallosalen species and is shown to be an efficient and recyclable asymmetric catalyst for the oxidative kinetic resolution of racemic secondary alcohols and the epoxidation of olefins with up to >99 % enantiomeric excess. The cage architecture not only prevents intermolecular deactivation and stabilizes the Mn(salen) catalysts but also encapsulates substrates and concentrates reactants in the cavity, resulting in enhanced reactivity and enantioselectivity relative to the free metallosalen catalyst. [ABSTRACT FROM AUTHOR]

Homochiral helicates were prepared through subcomponent self-assembly with a C2-symmetric chiral building block based on a 6,6'-substituted 1,1'-bi-2-naphthol (BINOL) scaffold. The resulting complexes were analysed through a broad variety of NMR spectroscopy experiments, high-resolution mass spectrometry, CD and UV/Vis spectroscopy and single- crystal X-ray diffraction. As proven by these experiments, the self-assembly occurs through a completely diastereoselective and narcissistic self-sorting manner to form homochiral Fe2L3 helicates. The stereochemistry of the metal centres is directed by the axial chirality of the BINOL-based backbone; the (M)-configured ligand forms the (Δ,Δ) complex, and the (P)-configured ligand forms the (Λ,Λ) complex. [ABSTRACT FROM AUTHOR]

The first synthetic molecular trefoil knot was prepared in the late 1980s. However, it is only in the last few years that more complex small-molecule knot topologies have been realized through chemical synthesis. The steric restrictions imposed on molecular strands by knotting can impart significant physical and chemical properties, including chirality, strong and selective ion binding, and catalytic activity. As the number and complexity of accessible molecular knot topologies increases, it will become increasingly useful for chemists to adopt the knot terminology employed by other disciplines. Here we give an overview of synthetic strategies towards molecular knots and outline the principles of knot, braid, and tangle theory appropriate to chemistry and molecular structure. [ABSTRACT FROM AUTHOR]

The design of new cyclic pseudopeptides of the sequence 2:1-[α/aza]-hexamers, which contain aza-amino acid motifs, has gained much prominence to be involved in several potential applications. X-ray, FTIR, and NMR spectroscopy studies showed the ability of this series to adopt β-turn conformation in solid state, whereas in solution an equilibrium between the monomeric states (stabilized by β-turns through intramolecular hydrogen bonds), and supramolecular construction (stabilized by intermolecular hydrogen bonds and p-p stacking) predominates. Furthermore, both homo- and heterochiral 2:1- [α/aza]-cyclohexamers 3 and 4, respectively, can self-assemble into organized 3D structures with increases in concentration that favor the supramolecular construction in which the macrocyles are stacking over each other and stabilized by several non-covalent intermolecular interactions. [ABSTRACT FROM AUTHOR]

Supramolecular chirality was observed in a charge-transfer (CT) complex formed by self-assembly of β-cyclodextrin-linked pyrene and adamantane-linked pyromellitic diimide in water. In the complex, the pyrene-pyromellitic diimide CT interaction is reinforced several-fold by the strong β-cyclodextrin-adamantane inclusion binding interaction, as confirmed by 1H NMR, absorption, fluorescence and isothermal titration calorimetry studies. The CT complex exhibited high stability, as inferred from the temperature-dependent absorption and NMR studies. The CT absorption band exhibited a positive Cotton effect indicative of supramolecular chirality for the complex. Twisted fibres were observed in TEM, AFM, and SEM experiments. A mechanism involving synergistic binding interactions leading to 2D sheets, followed by twisting of the sheet, is proposed for the formation of twisted fibres. This system offers a chance to investigate a combination of supramolecular CT and supramolecular chirality and explore their synergistic effects. [ABSTRACT FROM AUTHOR]