Multiple chirality inversion of pyridine Schiff-base cholesterol-based metal-organic supramolecular polymers

An Encyclopedic Compendium on Chemosensing Supramolecular Metal-Organic Gels

Chemosensing, an interdisciplinary scientific domain, plays a pivotal role ranging from environmental monitoring to healthcare diagnostics and (inter)national security. Metal-organic gels (MOGs) are recognized for their stability, selectivity, and responsiveness, making them valuable for chemosensing applications. Researchers have explored the development of MOGs based on different metal ions and ligands, allowing for tailored properties and sensitivities, and have even demonstrated their applications as portable sensors such as paper-based test strips for practical use. Herein, several studies related to MOGs development and their applications in the chemosensing field via UV-visible or luminance along with electrochemical approach are presented. These papers explored MOGs as versatile materials with their use in sensing bio or environmental analytes. This review provides a foundational understanding of key concepts, methodologies, and recent advancements in this field, fostering the scientific community.

Multicolor circularly polarized luminescence inversion of metal-organic supramolecular polymers

Metal-organic supramolecular polymers (MOSPs) with multicolor circularly polarized luminescence (CPL) and handedness inversion were constructed from the coordination-driven assembly of pyridine-cyanostilbene-cholesterol and metal salts by modulating the treatment modes, solvents, and metal ions.

Co-assembly-mediated biosupramolecular catalysis: thermodynamic insights into nucleobase specific (oligo)nucleotide attachment and cleavage

Gaining control over the stability and cleavage of phosphoester and phosphodiester remains a matter of interest for their application in biotechnology to oligonucleotide-based therapeutics. Herein, we report an efficient unactivated phosphoester hydrolysis (stable mono/di/tri/cyclic nucleotide to nucleoside conversion) via a biosupramolecular system comprising of a non-covalent complex of enzyme, alkaline phosphatase (ALP), and Zn(II)-metallosurfactant. We also demonstrate the nucleobase selective activation or inhibition of ALP-mediated oligonucleotide digestion process using that complex. The higher binding affinity of Zn(II)-containing headgroup with phosphate-containing substrate enhanced the effective substrate concentration surrounding the enzyme, which, in turn, results in a drastic decrease in the Michaelis constant (KM), along with an increase in the turnover (kcat). The catalytic activation or inhibition of nucleobase-specific oligonucleotide digestion depends on the hydration, localization of the substrates, and viscosity of the resultant co-assembly upon substrate binding with the enzyme-metallosurfactant complex. Additionally, through isothermal titration calorimetry experiment, we demonstrate enthalpy-entropy change during both the supramolecular binding of (oligo)nucleotides and simultaneous activation/inhibition in catalytic cleavage. Overall, it showed the possible modularity of Zn(II)-mediated biosupramolecular interaction, describing intrinsic thermodynamic aspects in developing complex biocatalytic circuits with nucleobase-specific oligonucleotides inputs, which are relevant in designing nucleic acid-based cargo for drug delivery and bioimaging.

Metallophilic Interaction-Mediated Hierarchical Assembly and Temporal-Controlled Dynamic Chirality Inversion of Metal-Organic Supramolecular Polymers

The study of dynamic supramolecular chirality inversion (SMCI) not only helps to deepen the understanding of chiral transfer and amplification in both living organizations and artificially chemical self-assembly systems but also is useful for the development of smart chiral nanomaterials. However, it is still challenging to achieve the dynamic SMCI of the self-aggregation of metal-organic supramolecular polymers with great potential in asymmetric synthesis, chiroptical switches, and circular polarized luminescence. Here, we successfully developed a hierarchical coassembly system based on the mPAzPCC and various metal ions with effective chirality transfer and temporal-controlled SMCI. Due to the dynamic self-assembly and hierarchical chirality transfer of the Ag⁺/mPAzPCC complex driven by metallophilic interaction and coordination, morphological transition with nanoribbons, helical nanoribbons, and chiral nanotubules was successively obtained. Interestingly, the SMCI of chiral nanoaggregates was precisely regulated by solvents and metal ions in the Cu²⁺/mPAzPCC and Mn²⁺/mPAzPCC system. Besides, temporal-controlled dynamic SMCI switching from helix to bundled helix was clearly revealed in the aggregation of Cu²⁺/mPAzPCC, Mn²⁺/mPAzPCC, and Bi³⁺/mPAzPCC systems. This work provides a metallophilic interaction-mediated helical assembly pathway to dynamically modulate the chirality of metal-organic complex-based assemblies and deepen the understanding of the hierarchically dynamic self-assembly process, which would be of great potential in metal ion-mediated supramolecular asymmetric catalysis and bioinspired chiral sensing.

Iron(II) Mediated Supramolecular Architectures with Schiff Bases and Their Spin-Crossover Properties

Supramolecular architectures, which are formed through the combination of inorganic metal cations and organic ligands by self-assembly, are one of the techniques in modern chemical science. This kind of multi-nuclear system in various dimensionalities can be implemented in various applications such as sensing, storage/cargo, display and molecular switching. Iron(II) mediated spin-crossover (SCO) supramolecular architectures with Schiff bases have attracted the attention of many investigators due to their structural novelty as well as their potential application possibilities. In this paper, we review a number of supramolecular SCO architectures of iron(II) with Schiff base ligands exhibiting varying geometrical possibilities. The structural and SCO behavior of these complexes are also discussed in detail.

Polymeric Emissive Materials Based on Dynamic Covalent Bonds

Dynamic covalent polymers, composed of dynamic covalent bonds (DCBs), have received increasing attention in the last decade due to their adaptive and reversible nature compared with common covalent linked polymers. Incorporating the DCBs into the polymeric material endows it with advanced performance including self-healing, shape memory property, and so forth. However, the emissive ability of such dynamic covalent polymeric materials has been rarely reviewed. Herein, this review has summarized DCBs-based emissive polymeric materials which are classified according to the different types of DCBs, including imine bond, acylhydrazone bond, boronic ester bond, dynamic C-C bond, as well as the reversible bonds based on Diels–Alder reaction and transesterification. The mechanism of chemical reactions and various stimuli-responsive behaviors of DCBs are introduced, followed by typical emissive polymers resulting from these DCBs. By taking advantage of the reversible nature of DCBs under chemical/physical stimuli, the constructed emissive polymeric materials show controllable and switchable emission. Finally, challenges and future trends in this field are briefly discussed in this review.