A Single Watson−Crick G·C Base Pair in Water: Aqueous Hydrogen Bonds in Hydrophobic Cavities

Multipocket Cage Enables the Binding of High-Order Bulky and Drug Guests Uncovered by MS Methodology

Achieving high guest loading and multiguest-binding capacity holds crucial significance for advancement in separation, catalysis, and drug delivery with synthetic receptors; however, it remains a challenging bottleneck in characterization of high-stoichiometry guest-binding events. Herein, we describe a large-sized coordination cage (MOC-70-Zn8Pd6) possessing 12 peripheral pockets capable of accommodating multiple guests and a high-resolution electrospray ionization mass spectrometry (HR-ESI-MS)-based method to understand the solution host-guest chemistry. A diverse range of bulky guests, varying from drug molecules to rigid fullerenes as well as flexible host molecules of crown ethers and calixarenes, could be loaded into open pockets with high capacities. Notably, these hollow cage pockets provide multisites to capture different guests, showing heteroguest coloading behavior to capture binary, ternary, or even quaternary guests. Moreover, a pair of commercially applied drugs for the combination therapy of chronic lymphocytic leukemia (CLL) has been tested, highlighting its potential in multidrug delivery for combined treatment.

Biomimetic Hydrogen-Bonded G ⋅ C ⋅ G ⋅ C Quadruplex within a Tetraphenylethene-Based Octacationic Spirobicycle in Water

In biological systems, nucleotide quadruplexes (such as G-quadruplexes) in DNA and RNA that are held together by multiple hydrogen bonds play a crucial functional role. The biomimetic formation of these hydrogen-bonded quadruplexes captured by artificial systems in water poses a significant challenge but can offer valuable insights into these complex functional structures. Herein, we report the formation of biomimetic hydrogen-bonded G ⋅ C ⋅ G ⋅ C quadruplex captured by a tetraphenylethene (TPE) based octacationic spirobicycle (1). The spirobicyclic compound possesses a three-dimensional (3D) crossing dual-cavity structure, which enables the encapsulation of four d(GpC) dinucleotide molecules, thereby realizing 1 : 4 host-guest complexation in water. The X-ray structure reveals that four d(GpC) molecules further form a two-layer G ⋅ C ⋅ G ⋅ C quadruplex with Watson-Crick hydrogen bonds, which are stabilized within the dual hydrophobic cavities of 1 through the cooperative non-covalent interactions of hydrogen bonds, CH⋅⋅⋅π interactions, and hydrophobic effect. Due to the dynamically-rotational propeller chirality of TPE units, 1 with adaptive chirality can further serve as a chiroptical sensor to exhibit opposite Cotton effects with mirror-image CD spectra for the pH-dependent hydrogen-bonded assemblies of d(GpC) including the Watson-Crick G ⋅ C ⋅ G ⋅ C (pH 9.22) and Hoogsteen G ⋅ C+ ⋅ G ⋅ C+ (pH 5.74) quartets through the host-guest chirality transfer in water.

Advancements in nanoscale delivery systems: optimizing intermolecular interactions for superior drug encapsulation and precision release

Nanoscale preparations, such as nanoparticles, micelles, and liposomes, are increasingly recognized in pharmaceutical technology for their high capability in tailoring the pharmacokinetics of the encapsulated drug within the body. These preparations have great potential in extending drug half-life, reducing dosing frequency, mitigating drug side effects, and enhancing drug efficacy. Consequently, nanoscale preparations offer promising prospects for the treatment of metabolic disorders, malignant tumors, and various chronic diseases. Nevertheless, the complete clinical potential of nanoscale preparations remains untapped due to the challenges associated with low drug loading degrees and insufficient control over drug release. In this review, we comprehensively summarize the vital role of intermolecular interactions in enhancing encapsulation and controlling drug release within nanoscale delivery systems. Our analysis critically evaluates the characteristics of common intermolecular interactions and elucidates the techniques employed to assess them. Moreover, we highlight the significant potential of intermolecular interactions in clinical translation, particularly in the screening and optimization of preparation prescriptions. By attaining a deeper understanding of intermolecular interaction properties and mechanisms, we can adopt a more rational approach to designing drug carriers, leading to substantial advancements in the application and clinical transformation of nanoscale preparations. Moving forward, continued research in this field offers exciting prospects for unlocking the full clinical potential of nanoscale preparations and revolutionizing the field of drug delivery.

Catalytic Inhibition of Base-Mediated Reactivity by a Self-Assembled Metal-Ligand Host

Spacious M4 L6 tetrahedra can act as catalytic inhibitors for base-mediated reactions. Upon adding only 5 % of a self-assembled Fe4 L6 cage complex, the conversion of the conjugate addition between ethylcyanoacetate and β-nitrostyrene catalyzed by proton sponge can be reduced from 83 % after 75 mins at ambient temperature to <1 % under identical conditions. The mechanism of the catalytic inhibition is unusual: the octacationic Fe4 L6 cage increases the acidity of exogenous water in the acetonitrile reaction solvent by favorably binding the conjugate acid of the basic catalyst. The inhibition only occurs for Fe4 L6 hosts with spacious internal cavities: minimal inhibition is seen with smaller tetrahedra or Fe2 L3 helicates. The surprising tendency of the cationic cage to preferentially bind protonated, cationic ammonium guests is quantified via the comprehensive modeling of spectrophotometric titration datasets.

Nano-injectable pH/NIR-responsive hydrogel for chemo-photothermal synergistic drug delivery

Conventional cancer treatments are highly toxic and ineffective; therefore, it is essential to develop less toxic and minimally invasive treatment methods. A pH/Near Infra-red (NIR) dual-responsive, nano-injectable smart hydrogel was fabricated by incorporating CuS nanoparticles into the hydrogel networks formed by a random copolymer of N-isopropylacrylamide (NIPAM) and double-bond functionalized uracil. Microstructural characterizations of synthesized polymer and hydrogels were carried out using transmission electron microscope (TEM), scanning electron microscope (SEM), nuclear magnetic resonance (NMR) and fourier transform infrared spectroscopy (FT-IR). Multiple hydrogen bonding interactions between uracils function as physical cross-linking points to construct the network structure of the polymeric nanogel without the addition of additional cross-linking agents, ensuring the material's safety. The amino group on the structure of uracil gives the uracil-modified polymeric hydrogel excellent pH responsiveness. Notably, as a temperature-responsive material, poly (N-isopropylacrylamide) (PNIPAM) nanogel solution can achieve in situ gel formation (within 100 s at 37°C) above its lower critical solution temperature (LCST), granting injectability to polymeric solutions. Moreover, using a hierarchical construction strategy, the variable loading of DOX and CuS was achieved. First, a heterogeneous system was created by encapsulating doxorubicin (DOX) inside the nanogel via hydrophobic and π-π stacking interactions, followed by the introduction of CuS nanoparticles as photosensitizers outside of the nanogels. Due to the presence of CuS nanoparticles, the gel is able to convert NIR light into local heat to enhance the destruction of tumor cells while simultaneously achieving rapid in situ gel formation. The in situ-forming hydrogel showed promising tissue biocompatibility. The in vitro antitumor test demonstrated the capacity of the nanocomposite hydrogel for chemo-photothermal synergistic therapy. Therefore, this prepared platform has the potential to become a safe and effective, smart-responsive drug carrier for chemotherapy and PTT synergy, a minimally invasive material for tumor treatment.

Water-Soluble Metallo-Supramolecular Nanoreactors for Mediating Visible-Light-Promoted Cross-Dehydrogenative Coupling Reactions

Water-soluble metallo-supramolecular cages with well-defined nanosized cavities have a wide range of functions and applications. Herein, we design and synthesize two series of metallo-supramolecular octahedral cages based on the self-assembly of two congeneric truxene-derived tripyridyl ligands modified with two polyethylene glycol (PEG) chains, i.e., monodispersed tetraethylene glycol (TEG) and polydispersed PEG-1000, with four divalent transition metals (i.e., Pd, Cu, Ni, and Zn). The resulting monodispersed cages C1-C4 are fully characterized by electrospray ionization mass spectrometry (ESI-MS), nuclear magnetic resonance (NMR) spectroscopy, and single-crystal X-ray diffraction. The polydispersed cages C5-C8 display good water solubilities and can act as nanoreactors to mediate visible-light-promoted C(sp³)-C(sp²) cross-dehydrogenative coupling reactions in an aqueous phase. In particular, the most robust Pd(II)-linked water-soluble polydispersed nanoreactor C5 is characterized by ESI-MS and capable of mediating the reactions with the highest efficiencies. Detailed host-guest binding studies in conjunction with control studies suggest that these cages could encapsulate the substrates simultaneously inside its hydrophobic cavity while interacting with the photosensitizer (i.e., eosin Y).

Tailored Supramolecular Cage for Efficient Bio-Labeling

Fluorescent chemosensors are powerful imaging tools used in a broad range of biomedical fields. However, the application of fluorescent dyes in bioimaging still remains challenging, with small Stokes shifts, interfering signals, background noise, and self-quenching on current microscope configurations. In this work, we reported a supramolecular cage (C_A) by coordination-driven self-assembly of benzothiadiazole derivatives and Eu(OTf)₃. The C_A exhibited high fluorescence with a quantum yield (QY) of 38.57%, good photoluminescence (PL) stability, and a large Stokes shift (153 nm). Furthermore, the CCK-8 assay against U87 glioblastoma cells verified the low cytotoxicity of C_A. We revealed that the designed probes could be used as U87 cells targeting bioimaging.

A Cavity-Tailored Metal-Organic Tetrahedral Nanocage and Gas Adsorption Property

Porous organometallic nanomaterials are a new class of materials based on a three-dimensional structure. They have excellent applications in different fields, but their applications in gas storage and separation have not been fully developed. CO₂ adsorption storage and hydrocarbon separation has been a challenging industrial problem. Several typical molecular adsorbents have been used to study the separation, but the problems of long-term stability, high selectivity and synthetic complexity of these adsorbents remain to be solved. Here, we have designed and synthesized tetrahedral metal supramolecular nanocage with custom cavities based on the unique rigid structure of triptycene derivatives. Using the unique discrete porous structure of tetrahedral metal nanocages, the gas adsorption and separation performance of the metal supramolecular nanocage was investigated. By analyzing the adsorption and desorption isotherms and the multi-component competitive adsorption curves, we noticed that the tetrahedral supramolecular nanocages had good CO₂ storage capacity and good separation capacity for C₂H₂/CO₂ and C₂H₂/N₂. All these indicate that porous organic metal nanomaterials are expected to be a new energy saving separation material.

CH-π Multi-Interaction-Driven Recognition and Isolation of Planar Compounds in a Spheroidal Polyaromatic Cavity

π-π Interactions are established as a powerful supramolecular tool, whereas the usability of CH-π interactions has been rather limited so far. Here we present (i) selective binding of planar polyaromatics and (ii) effective isolation of planar metal complexes by a polyaromatic capsule, utilizing multiple CH-π interactions. In the spheroidal cavity, one molecule of large and medium-sized polyaromatic molecules (i. e., coronene and pyrene) is exclusively bound from mixtures bearing the same number of aromatic CH groups. Theoretical studies reveal that multiple host-guest CH-π interactions (up to 32 interactions) are the predominant driving force for the observed selectivity. In addition, one molecule of planar metal complexes (i. e., porphine and bis(acetylacetonato) Cu(II) complexes) is quantitatively bound by the capsule through aromatic and aliphatic CH-π multi-interactions, respectively. The ESR and theoretical studies demonstrate the isolation capability of the capsular framework and an unusual polar environment in the polyaromatic cavity.

Hyper-CEST NMR of metal organic polyhedral cages reveals hidden diastereomers with diverse guest exchange kinetics

Guest capture and release are important properties of self-assembling nanostructures. Over time, a significant fraction of guests might engage in short-lived states with different symmetry and stereoselectivity and transit frequently between multiple environments, thereby escaping common spectroscopy techniques. Here, we investigate the cavity of an iron-based metal organic polyhedron (Fe-MOP) using spin-hyperpolarized 129Xe Chemical Exchange Saturation Transfer (hyper-CEST) NMR. We report strong signals unknown from previous studies that persist under different perturbations. On-the-fly delivery of hyperpolarized gas yields CEST signatures that reflect different Xe exchange kinetics from multiple environments. Dilute pools with ~ 104-fold lower spin numbers than reported for directly detected hyperpolarized nuclei are readily detected due to efficient guest turnover. The system is further probed by instantaneous and medium timescale perturbations. Computational modeling indicates that these signals originate likely from Xe bound to three Fe-MOP diastereomers (T, C3, S4). The symmetry thus induces steric effects with aperture size changes that tunes selective spin manipulation as it is employed in CEST MRI agents and, potentially, impacts other processes occurring on the millisecond time scale.

The Research of G-Motif Construction and Chirality in Deoxyguanosine Monophosphate Nucleotide Complexes

A detailed understanding of the mismatched base-pairing interactions in DNA will help reveal genetic diseases and provide a theoretical basis for the development of targeted drugs. Here, we utilized mononucleotide fragment to simulate mismatch DNA interactions in a local hydrophobic microenvironment. The bipyridyl-type bridging ligands were employed as a mild stabilizer to stabilize the GG mismatch containing complexes, allowing mismatch to be visualized based on X-ray crystallography. Five single crystals of 2′-deoxyguanosine–5′–monophosphate (dGMP) metal complexes were designed and obtained via the process of self-assembly. Crystallographic studies clearly reveal the details of the supramolecular interaction between mononucleotides and guest intercalators. A novel guanine–guanine base mismatch pattern with unusual (high anti)–(high anti) type of arrangement around the glycosidic angle conformations was successfully constructed. The solution state ¹H–NMR, ESI–MS spectrum studies, and UV titration experiments emphasize the robustness of this g–motif in solution. Additionally, we combined the methods of single-crystal and solution-, solid-state CD spectrum together to discuss the chirality of the complexes. The complexes containing the g–motif structure, which reduces the energy of the system, following the solid-state CD signals, generally move in the long-wave direction. These results provided a new mismatched base pairing, that is g–motif. The interaction mode and full characterizations of g–motif will contribute to the study of the mismatched DNA interaction.

β-Cyanuryl Ribose, β-Barbituryl Ribose, and 6-Azauridine as Uridine Mimetics

Uridine (U) mimetics are sought after as tools for biochemical and pharmacological studies. Previously, we have identified recognition patterns of U by proteins. Here, we targeted the characterization of uridine mimetics-cyanuryl-ribose (CR), barbituryl-ribose (BR), and 6-azauridine (AU)-with a view to identify analogs with potentially more binding interactions than U with target biomolecules. We found that CR, BR, and AU retain selective U's natural H-bonds with adenosine vs guanosine. CR/AU and BR were 100- and 10,000-fold more acidic, respectively, than U. Under physiological pH, 54, 51, and 77% of CR, AU, and BR molecules, respectively, are ionized vs 13% for U. The electron-rich nature of CR and BR vs U was reflected by their ¹³C NMR chemical shifts and ε values. CR/AU and BR prefer N conformation (up to 73%) vs U (56%). Unlike U that prefers gg conformation around exocyclic methylol (48%), CR/AU and BR prefer both gt and gg rotamers. In conclusion, replacement of uridine's C6 by N or carbonyl, or C5-C6 by an amide, results in significant changes in U's ionization, electron density, conformation, base-stacking, etc., leading to potentially tighter binding than U with a target protein or nucleic acid and potential use for various biochemical and pharmacological applications.

Assembling Pentatopic Terpyridine Ligands with Three Types of Coordination Moieties into a Giant Supramolecular Hexagonal Prism: Synthesis, Self-Assembly, Characterization, and Antimicrobial Study

Three dimensional (3D) supramolecules with giant cavities are attractive due to their wide range of applications. Herein, we used pentatopic terpyridine ligands with three types of coordination moieties to assemble two giant supramolecular hexagonal prisms with a molecular weight up to 42 608 and 43 569 Da, respectively. Within the prisms, two double-rimmed Kandinsky Circles serve as the base surfaces as well as the templates for assisting the self-sorting during the self-assembly. Additionally, hierarchical self-assembly of these supramolecular prisms into tubular-like nanostructures was fully studied by scanning tunneling microscopy (STM) and small-angle X-ray scattering (SAXS). Finally, these supramolecular prisms show good antimicrobial activities against Gram-positive pathogen methicillin-resistant Staphylococcus aureus (MRSA) and Bacillus subtilis (B. subtilis).

Cofactor-Mediated Nucleophilic Substitution Catalyzed by a Self-Assembled Holoenzyme Mimic

A self-assembled Fe₄L₆ cage is capable of co-encapsulating multiple carboxylic acid containing guests in its cavity, and these acids can act as cofactors for cage-catalyzed nucleophilic substitutions. The kinetics of the substitution reaction depend on the size, shape, and binding affinity of each of the components, and small structural changes in guest size can have large effects on the reaction. The host is quite promiscuous and is capable of binding multiple guests with micromolar binding affinities while retaining the ability to effect turnover and catalysis. Substrate binding modes vary widely, from simple 1:1 complexes to 1:2 complexes that can show either negative or positive cooperativity, depending on the guest. The molecularity of the dissociative substitution reaction varies, depending on the electrophile leaving group, acid cofactor, and nucleophile size: small changes in the nature of substrate can have large effects on reaction kinetics, all controlled by selective molecular recognition in the cage interior.

Guest recognition enhanced by lateral interactions

A hexacationic triangular covalent organic cage, AzaEx²Cage ⁶⁺, has been synthesized by means of a tetrabutylammonium iodide-catalyzed S_N2 reaction. The prismatic cage is composed of two triangular 2,4,6-triphenyl-1,3,5-triazine (TPT) platforms bridged face-to-face by three 4,4'-bipyridinium (BIPY ²⁺) spacers. The rigidity of these building blocks leads to a shape-persistent cage cavity with an inter-platform distance of approximately 11.0 Å. This distance allows the cage to accommodate two aromatic guests, each of which is able to undergo π-π interactions with one of the two TPT platform simultaneously, in an A-D-D-A manner. In the previously reported prism-shaped cage, the spacers (pillars) are often considered passive or non-interactive. In the current system, the three BIPY ²⁺ spacers are observed to play an important role in guest recognition. Firstly, the BIPY ²⁺ spacers are able to interact with the carbonyl group in a pyrene-1-carbaldehyde (PCA) guest, by introducing lateral dipole-cation or dipole-dipole interactions. As a consequence, the binding affinity of the cage towards the PCA guest is significantly larger than that of pyrene as the guest, even although the latter is often considered to be a better π-electron donor. Secondly, in the case of the guest 1,5-bis[2-(2-(2-(2-hydroxyethoxy)ethoxy)ethoxy)ethoxy]naphthalene (BH4EN), the pillars can provide higher binding forces compared to the TPT platform. Hence, peripheral complexation occurs when AzaEx²Cage ⁶⁺ accommodates BH4EN in MeCN. Thirdly, when both PCA and BH4EN are added into a solution of AzaEx²Cage ⁶⁺, inclusion and peripheral complexation occur simultaneously to PCA and BH4EN respectively, even though the accommodation of the former guest seems to attenuate the external binding of the latter. This discovery of the importance of lateral interactions highlights the relationship between the electrostatic properties of a highly charged host and its complexation behavior, and as such, provides insight into the design of more complex hosts that bind guests in multiple locations and modes.

A bio-relevant supramolecular Co(ii)-complex for selective fluorescence sensing of μM range inorganic As(iii) in aqueous medium and its intracellular tracking in bacterial systems

A bio-relevant fluorescent supramolecular Co(ii)-complex selectively detects μM range toxic inorganic As(iii) in water and in bacterial systems.

Association of Nucleobases in Hydrated Ionic Liquid from Biased Molecular Dynamics Simulations

We employed metadynamics-based classical molecular dynamics simulations to methylated adenine-thymine (mA-mT) and guanine-cytosine (mG-mC) base pairs to see favorable conformations in various concentrations of hydrated 1-ethyl, 3-methyl imidazolium acetate. We investigated various stacked and hydrogen-bonded conformations of association of base pairs through appropriately chosen collective variables. Stacked conformations more favored in water for both base pairs, whereas Watson-Crick (WC) hydrogen-bonding conformations are favored in pure and hydrated ionic liquids (ILs) except for 0.75 mol fraction IL. We observe that EMIm cations surround the base pairs in WC conformations creating a kind of hydrophobic cavity and protect the hydrogen bonds between base pairs. However, the five-membered heteroaromatic rings of cations stack with the nucleobases in the cation-base-cation (π-π-π) model, which resembles the base-base-base stacking in a DNA duplex. Interestingly, from additional simulations of 0.5 mol fraction hydrated choline dihydrogen phosphate IL, we observe that the stacked conformations become more favored than the WC conformation due to the absence of π-bonds in cations. The calculated values of relative solubility of base pairs in pure and hydrated ionic liquids compared to those in pure water correlate well with the free energy values of WC and stacked conformations.

Cytosine-Cytosine Base-Pair Mismatch and Chirality in Nucleotide Supramolecular Coordination Complexes

The base-pair sequences are the foundation for the biological processes of DNA or RNA, and base-pair mismatch is very important to reveal genetic diseases and DNA rearrangements. However, the lack of well-defined structural information about base-pair mismatch is obstructing the investigation of this issue. The challenge is to crystallize the materials containing the base-pair mismatch. Engineering the small-molecule mimics or model is an effective strategy to solve this issue. Here, six cytidine-5'-monophosphate (CMP) and 2'-deoxycytidine-5'-monophosphate (dCMP) coordination polymers were reported containing cytosine-cytosine base-pair mismatch (i-motif), and their single-crystal structures and chiralities were studied. The precise control over the formation of the i-motif was demonstrated, in which the regulating of supramolecular interactions was achieved based on molecular design. In addition, the chiralities of these coordination polymers were investigated according to their crystal structures and solution- and solid-state circular dichroism spectroscopy.

Downstream Oligonucleotides Strongly Enhance the Affinity of GMP to RNA Primer-Template Complexes

Origins of life hypotheses often invoke a transitional phase of nonenzymatic template-directed RNA replication prior to the emergence of ribozyme-catalyzed copying of genetic information. Here, using NMR and ITC, we interrogate the binding affinity of guanosine 5'-monophosphate (GMP) for primer-template complexes when either another GMP, or a helper oligonucleotide, can bind downstream. Binding of GMP to a primer-template complex cannot be significantly enhanced by the possibility of downstream monomer binding, because the affinity of the downstream monomer is weaker than that of the first monomer. Strikingly, GMP binding affinity can be enhanced by ca. 2 orders of magnitude when a helper oligonucleotide is stably bound downstream of the monomer binding site. We compare these thermodynamic parameters to those previously reported for T7 RNA polymerase-mediated replication to help address questions of binding affinity in related nonenzymatic processes.

Design of a flexible organometallic tecton: host–guest chemistry with picric acid and self-assembly of platinum macrocycles

A new “flexible” and ditopic Pt(ii) organometallic compound is a tecton for the self-assembly of neutral metallacycles. It also exhibits significant binding affinity for picric acid.

Core cross-linked double hydrophilic block copolymer micelles based on multiple hydrogen-bonding interactions

Facile preparation and characterization of core cross-linked micelles via strong multiple hydrogen bonds using well-defined thermo-responsive double hydrophilic block copolymers.

Hydrogen Bonding between Metal-Ion Complexes and Noncoordinated Water: Electrostatic Potentials and Interaction Energies

The hydrogen bonding of noncoordinated water molecules to each other and to water molecules that are coordinated to metal-ion complexes has been investigated by means of a search of the Cambridge Structural Database (CSD) and through quantum chemical calculations. Tetrahedral and octahedral complexes that were both charged and neutral were studied. A general conclusion is that hydrogen bonds between noncoordinated water and coordinated water are much stronger than those between noncoordinated waters, whereas hydrogen bonds of water molecule in tetrahedral complexes are stronger than in octahedral complexes. We examined the possibility of correlating the computed interaction energies with the most positive electrostatic potentials on the interacting hydrogen atoms prior to interaction and obtained very good correlation. This study illustrates the fact that electrostatic potentials computed for ground-state molecules, prior to interaction, can provide considerable insight into the interactions.

The Halogen Bond

The halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. In this fairly extensive review, after a brief history of the interaction, we will provide the reader with a snapshot of where the research on the halogen bond is now, and, perhaps, where it is going. The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design.

Mutual induced fit in a synthetic host-guest system

Mutual induced fit is an important phenomenon in biological molecular recognition, but it is still rare in artificial systems. Here we report an artificial host-guest system in which a flexible calix[4]arene is enclathrated in a dynamic self-assembled host and both molecules mutually adopt specific three-dimensional structures. NMR data revealed the conformational changes, and crystallographic studies clearly established the precise structures at each stage.

Template-free multicomponent coordination-driven self-assembly of Pd(ii)/Pt(ii) molecular cages

This article summarizes the recent developments in the construction of multicomponent molecular hollowed-out cages through the metal–ligand coordination-driven self-assembly process, with a focus on the decreasing relevance of the use of templates.