Self-Assembled Amphiphilic Janus Double Metallacycle

Recent Progress of Supramolecular Chemotherapy Based on Host-Guest Interactions

Chemotherapy is widely recognized as an effective approach for treating cancer due to its ability to eliminate cancer cells using chemotherapeutic drugs. However, traditional chemotherapy suffers from various drawbacks, including limited solubility and stability of drugs, severe side effects, low bioavailability, drug resistance, and challenges in tracking treatment efficacy. These limitations greatly hinder its widespread clinical application. In contrast, supramolecular chemotherapy, which relies on host-guest interactions, presents a promising alternative by offering highly efficient and minimally toxic anticancer drug delivery. In this review, an overview of recent advancements in supramolecular chemotherapy based on host-guest interactions is provided. The significant role it plays in guiding cancer therapy is emphasized. Drawing on a wealth of cutting-edge research, herein, a timely and valuable resource for individuals interested in the field of supramolecular chemotherapy or cancer therapy, is presented. Furthermore, this review contributes to the progression of the field of supramolecular chemotherapy toward clinical application.

A Janus carbaporphyrin pseudo-dimer

Carbaporphyrin dimers, investigated for their distinctive electronic structures and exceptional properties, have predominantly consisted of systems containing identical subunits. This study addresses the associated knowledge gap by focusing on asymmetric carbaporphyrin dimers with Janus-like characteristics. The synthesis of a Janus-type carbaporphyrin pseudo-dimer 5 is presented. It displays antiaromatic characteristics on the fused side and nonaromatic behavior on the unfused side. A newly synthesized tetraphenylene (TPE) linked bis-dibenzihomoporphyrin 8 and a previously reported dibenzo[g,p]chrysene (DBC) linked bis-dicarbacorrole 9 were prepared as controls. Comprehensive analyses, including 1H NMR spectral studies, single crystal X-ray diffraction analyses, and DFT calculations, validate the mixed character of 5. A further feature of the Janus pseudo-dimer 5 is that it may be transformed into a heterometallic complex, with one side coordinating a Cu(III) center and the other stabilizing a BODIPY complex. This disparate regiochemical reactivity underscores the potential of carbaporphyrin dimers as versatile frameworks, with electronic features and site-specific coordination chemistry controlled through asymmetry. These findings position carbaporphyrin dimers as promising candidates for advances in electronic structure studies, coordination chemistry, materials science, and beyond.

Potential of nonporous adaptive crystals for hydrocarbon separation

Hydrocarbon separation is an important process in the field of petrochemical industry, which provides a variety of raw materials for industrial production and a strong support for the development of national economy. However, traditional separation processes involve huge energy consumption. Adsorptive separation based on nonporous adaptive crystal (NAC) materials is considered as an attractive green alternative to traditional energy-intensive separation technologies due to its advantages of low energy consumption, high chemical and thermal stability, excellent selective adsorption and separation performance, and outstanding recyclability. Considering the exceptional potential of NAC materials for hydrocarbon separation, this review comprehensively summarizes recent advances in various supramolecular host-based NACs. Moreover, the current challenges and future directions are illustrated in detail. It is expected that this review will provide useful and timely references for researchers in this area. Based on a large number of state-of-the-art studies, the review will definitely advance the development of NAC materials for hydrocarbon separation and stimulate more interesting studies in related fields.

Shape Complementary Coordination Self-Assembly of a Redox-Active Heteroleptic Complex

We present here the coordination self-assembly of a new heteroleptic (bpyPd)₄L¹L₂² coordination complex (1) from one novel pyridinium-functionalized bis-2,4,6-tris(pyridin-3-yl)-1,3,5-triazine (bis-3-TPT, L¹) macrocyclic ligand, two separate 3-TPT (L²) ligands, and four cis-blocking bpyPd(NO₃)₂ (bpy = 2,2'-bipyridine). While homoleptic self-assemblies with either L¹ or L² gave dynamic mixtures of products, a single thermodynamic heteroleptic complex was obtained driven by the shape complementarity of building blocks. Moreover, the redox-active nature of the heteroleptic assembly facilitates the highly efficient catalytic aerobic photo-oxidation of aromatic secondary alcohols under mild conditions.

Self-sorting assembly of artificial building blocks

Self-assembly to build high-level structures, which is ubiquitous in living systems, has captured the imagination of scientists, striving to emulate the intricacy, homogeneity and versatility of the naturally occurring systems, and to pursue a similar level of organization in artificial building blocks. In particular, self-sorting assembly in multicomponent systems, based on the spontaneous recognition and consequent spatial aggregation of the same or interactive building units, is able to realize very complicated assembly behaviours, and usually results in multiple well-ordered products or hierarchical structures in a one-step manner. This highly efficient assembly strategy has attracted tremendous research attention in recent years, and numerous examples have been reported in artificial systems, particularly with supramolecular and polymeric building blocks. In the current review, we summarize the progress in recent years, and classify them into five main categories, based on their working mechanisms or principles. With the review of these strategies, we hope to provide not only some deep insights into this field, but also and more importantly, useful thoughts in the design and fabrication of self-sorting systems in the future.

Increasing structural and functional complexity in self-assembled coordination cages

Progress in metallo-supramolecular chemistry creates potential to synthesize functional nano systems and intelligent materials of increasing complexity. In the past four decades, metal-mediated self-assembly has produced a wide range of structural motifs such as helicates, grids, links, knots, spheres and cages, with particularly the latter ones catching growing attention, owing to their nano-scale cavities. Assemblies serving as hosts allow application as selective receptors, confined reaction environments and more. Recently, the field has made big steps forward by implementing dedicated functionality, e.g. catalytic centres or photoswitches to allow stimuli control. Besides incorporation in homoleptic systems, composed of one type of ligand, desire arose to include more than one function within the same assembly. Inspiration comes from natural enzymes that congregate, for example, a substrate recognition site, an allosteric regulator element and a reaction centre. Combining several functionalities without creating statistical mixtures, however, requires a toolbox of sophisticated assembly strategies. This review showcases the implementation of function into self-assembled cages and devises strategies to selectively form heteroleptic structures. We discuss first examples resulting from a combination of both principles, namely multicomponent multifunctional host-guest complexes, and their potential in application in areas such as sensing, catalysis, and photo-redox systems.

Supramolecular cancer nanotheranostics

Among the many challenges in medicine, the treatment and cure of cancer remains an outstanding goal given the complexity and diversity of the disease. Nanotheranostics, the integration of therapy and diagnosis in nanoformulations, is the next generation of personalized medicine to meet the challenges in precise cancer diagnosis, rational management and effective therapy, aiming to significantly increase the survival rate and improve the life quality of cancer patients. Different from most conventional platforms with unsatisfactory theranostic capabilities, supramolecular cancer nanotheranostics have unparalleled advantages in early-stage diagnosis and personal therapy, showing promising potential in clinical translations and applications. In this review, we summarize the progress of supramolecular cancer nanotheranostics and provide guidance for designing new targeted supramolecular theranostic agents. Based on extensive state-of-the-art research, our review will provide the existing and new researchers a foundation from which to advance supramolecular cancer nanotheranostics and promote translationally clinical applications.

Self-Assembly of Metallo-Supramolecules with Dissymmetrical Ligands and Characterization by Scanning Tunneling Microscopy

Asymmetrical and dissymmetrical structures are widespread and play a critical role in nature and life systems. In the field of metallo-supramolecular assemblies, it is still in its infancy for constructing artificial architectures using dissymmetrical building blocks. Herein, we report the self-assembly of supramolecular systems based on two dissymmetrical double-layered ligands. With the aid of ultra-high-vacuum, low-temperature scanning tunneling microscopy (UHV-LT-STM), we were able to investigate four isomeric structures corresponding to four types of binding modes of ligand LA with two major conformations complexes A. The distribution of isomers measured by STM and total binding energy of each isomer obtained by density functional theory (DFT) calculations suggested that the most abundant isomer could be the most stable one with highest total binding energy. Finally, through shortening the linker between inner and outer layers and the length of arms, the arrangement of dissymmetrical ligand LB could be controlled within one binding mode corresponding to the single conformation for complexes B.

Oxidation triggers guest dissociation during reorganization of an FeII 4L6 twisted parallelogram

A three-dimensional FeII 4L6 parallelogram was prepared from ferrocene-containing ditopic ligands. The steric preference of the bulky ferrocene cores towards meridional vertex coordination brought about this new structure type, in which the ferrocene units adopt three distinct conformations. The structure possesses two distinct, bowl-like cavities that host anionic guests. Oxidation of the ferrocene FeII to ferrocenium FeIII causes rotation of the ferrocene hinges, converting the structure to an FeII 1L1 + species with release of anionic guests, even though the average charge per iron increases in a way that would ordinarily increase guest binding strength. The degrees of freedom exhibited by these new structures - derived from the different configurations of the three ligands surrounding a meridional FeII center and the rotation of ferrocene cores - thus underpin their ability to reconfigure and eject guests upon oxidation.

Recent developments in the construction and applications of platinum-based metallacycles and metallacages via coordination

Coordination-driven suprastructures have attracted much interest due to their unique properties. Among these structures, platinum-based architectures have been broadly studied due to their facile preparation. The resultant two- or three-dimensional (2D or 3D) systems have many advantages over their precursors, such as improved emission tuning, sensitivity as sensors, and capture and release of guests, and they have been applied in biomedical diagnosis as well as in catalysis. Herein, we review the recent results related to platinum-based coordination-driven self-assembly (CDSA), and the text is organized to emphasizes both the synthesis of new metallacycles and metallacages and their various applications.

From Dimeric to Octameric Metallo-Supramolecular Macrocycles Based on Sterically Congested Ligand-assisted Self-Assembly with Zn(II), Cd(II), and Fe(II)

Two sterically congested 2,2':6',2″-terpyridine-based ligands LA and LB, composed of asymmetrically contiguous terpyridine units, are designed and synthesized for metallo-supramolecular architectures. The significant advantage of this design is that the terpyridines in these ligands have different chemical environments and show a selective coordination ability with each other. For ditopic ligand LA, the self-assembly with Zn(II), Cd(II), and Fe(II) gave the rhombic dimers, which have the same sets of terpyridine signals as ligand LA. The self-assembly behavior of tritopic ligand LB with Cd(II) and Zn(II) are observed for discrete tetramers under thermodynamic control, whereas ligand LB and Fe(II) are assembled to generate a mixture of tetramer, hexamer, and octamer, which are successfully isolated using regular chromatographic separation. Moreover, the sterically congested ligands and metal ions formed stable intermediates to drive the formation of discrete structures, which is also proved by mixing LB and Cd(II) with a precise stoichiometric ratio of 1:1. These supramolecular complexes are thoroughly characterized by NMR spectroscopy, electrospray ionization-mass spectrometry, and 2D traveling-wave ion mobility-mass spectrometry. This conceptually new design of sterically congested ligands provides a novel strategy for precisely controlled supramolecular complexes with diverse architectures.

Coordination-driven self-assembly of discrete supramolecular double-metallacycles

This review comprehensively summarizes the recent advances in the coordination-driven self-assembly of discrete supramolecular double-metallacycles.