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A mechanical bond serves as a distinctive approach for harnessing the most beneficial features of both covalent and supramolecular chemistries, offering stability and structural adaptability owing to its unique dynamic nature. Molecules formed by mechanical bonding, known as mechanically interlocked molecules (MIMs) including catenanes, rotaxanes, and knots have opened new possibilities. Notably, the introduction of mechanically interlocked structures into polymers has led to the emergence of novel polymeric materials referred to as mechanically interlocked polymers (MIPs), such as polyrotaxanes and polycatenanes. The interlocked nature of these architectures can lead to particular conformational freedom and high mobility of their components, resulting in exceptional properties, such as ultra-stretchability, toughness, and immediate recoverability. These properties have found potential applications in diverse fields, including the development of tough hydrogels, scratch-resistant coatings, smart actuators, and batteries. Recent years have witnessed a surge in the synthesis and investigation of a diverse array of rotaxane-based MIPs, an essential class that has enabled researchers to begin grasping the impact of incorporating mechanical bonds within polymer structures, and of their mobility, on material properties. In this review, an overview of the dynamics of ring-containing polymers is presented. The review encompasses macromolecular rotaxanes, polyrotaxanes, and slide-ring networks, including the role of ring mobility in shaping the dynamics and properties of rotaxane polymers. [Display omitted] [ABSTRACT FROM AUTHOR]

• A novel (4Z,N'Z)-N'-(amino(pyridine-2-yl)methyl)isonicotionhydrazonic Pb(II) complex was synthesized and characterized using single crystal X-ray structural analysis, providing valuable insights into its molecular structure. • Hirshfeld surface analysis was carried out to validate the intermolecular interactions quantitatively. • Density functional theory computational studies were carried out to calculate the molecular geometry and global reactive parameters, allowed to gain a better understanding of the properties. • Non-covalent interactions and electron charge density distribution were explored using the QTAM and NCI models, providing further insights into the complex's behavior. The crystal structure of [Pb(apminh)Cl 2 ] has been analyzed, revealing its potential as a useful component in a storage device. The complex crystallizes in the P 1 ¯ space group and is composed of a central Pb ion coordinated with two chloride anions and a tridentate apminh organic ligand. The ligand forms two chelating rings with Pb using oxygen and nitrogen atoms, resulting in a trigonal bipyramidal geometry of the central metal ion. The crystal packing of the complex is characterized by distinct intra and intermolecular interactions, with hydrogen bond interactions playing a crucial role. The complex forms 2D polymeric chains with intermolecular π...π stacking, which are bridged by the lattice solvent (methanol) through hydrogen bonds, making the 2D chains more stable. Quantum chemical calculations suggest that the complex has high kinetic stability, low chemical reactivity, electron-donating ability, and high charge storage capacity, making it a promising component for storage devices. The electronic structure analysis demonstrates the insulating nature, stable electronic structure, and long-lasting properties of the complex, providing insights into the chemical properties of the bonding in the complex. Overall, our results highlight the potential of [Pb(apminh)Cl 2 ] as a storage device component, although further experimentation and testing are necessary to determine its suitability for this application. [ABSTRACT FROM AUTHOR]

Anion exchange membranes (AEMs) with high selective conductivity and low surface resistance are important for the development of electrodialysis desalination industry. In this work, we design and synthesize a rotaxane of β-cyclodextrin (CD)-alkyldiamine inclusion complex (CDIC) via a host-guest molecular recognition mechanism; the resulting CDIC rotaxane is employed for cross-linking chloromethylated, hydroxy quaternized polysulfone (HQPSf) to make AEMs. β-CD is inherently hydrophilic and its –OH on the outer surface can hydrogen-bond with HQPSf to promote ionic cluster aggregation, leading to enhanced microphase-separated morphology and improved conductivity; the rotaxane-cross-linked structure guarantees good ductility and ion selectivity of the membrane. Therefore, the optimized HQPSf-CDIC membrane gives the most excellent current efficiency discharge current efficiency (92.04 %), the lowest energy consumption (4.68 kWh kg−1), and the maximum Cl− mobility (75.38 mg m−2 s−1) in the electrodialysis tests, significantly better than the un-crosslinked HQPSf membrane (86.41 %, 5.17 kWh kg−1 and 71.29 mg m−2 s−1). Our work demonstrates that introducing CDIC rotaxane cross-linked structure can help to enhance microphase separation and improve the performance of AEMs for electrodialysis. The microphase separation mechanism of anion exchange membrane HQPSf-CDIC-x. [Display omitted] • Anion exchange membranes (AEMs) with high selective conductivity and low surface resistance are important for the development of electrodialysis desalination industry. In this work, we design and synthesize a rotaxane of β-cyclodextrin (CD) - alkyldiamine inclusion complex (CDIC) via a host-guest molecular recognition mechanism; the resulting CDIC rotaxane is employed for cross-linking chloromethylated, hydroxy quaternized polysulfone (HQPSf) to make AEMs. β-CD is inherently hydrophilic and its –OH on the outer surface can hydrogen-bond with HQPSf to promote ionic cluster aggregation, leading to enhanced microphase-separated morphology and improved conductivity; the rotaxane-cross-linked structure guarantees good ductility and ion selectivity of the membrane. Therefore, the optimized HQPSf-CDIC membrane gives the most excellent current efficiency discharge current efficiency (92.04 %), the lowest energy consumption (4.68 KWh kg 1), and the maximum Cl− mobility (75.38 mg m−2 s−1) in the electrodialysis tests, significantly better than the un-crosslinked HQPSf membrane (86.41 %, 5.17 kWh kg−1 and 71.29 mg m−2 s−1). Our work demonstrates that introducing CDIC rotaxane cross-linked structure can help to enhance microphase separation and improve the performance of AEMs for electrodialysis. [ABSTRACT FROM AUTHOR]

This work aimed to explore an alternative to the use of antibiotics for prevention and treatment of wounds infection caused by two common bacterial pathogens Staphylococcus aureus and Pseudomonas aeruginosa. For this purpose, three different essential oil components (EOCs), namely carvacrol, citronellol and cinnamic acid, were loaded into electrospun fibers of poly-ε-caprolactone (PCL) aided by alpha-cyclodextrin (αCD) and hydroxypropyl-β-cyclodextrin (HPβCD). Electrospun-fibers prepared with each EOC and their mixtures were screened for antimicrobial capability and characterized regarding morphological, mechanical, thermal, surface polarity, antibiofilm and antioxidant properties. αCD formed poly(pseudo)rotaxanes with PCL and weakly interacted with EOCs, while HPβCD facilitated EOC encapsulation and formation of homogeneous fibers (500–1000 nm diameter) without beads. PCL/HPβCD fibers with high concentration of EOCs (mainly carvacrol and cinnamic acid) showed strong antibiofilm (>3 log CFU reduction) and antioxidant activity (10–50% DPPH scavenging effects). Different performances were recorded for the EOCs and their mixtures; cinnamic acid migrated to fiber surface and was released faster. Fibers biocompatibility was verified using hemolysis tests and in ovo tissue integration and angiogenesis assays. Overall, HPβCD facilitates complete release of EOCs from the fibers to the aqueous medium, being an environment-friendly and cost-effective strategy for the treatment of infected wounds. • Structurally different EOCs can be electrospun in PCL fibers with the aid of cyclodextrins (CDs). • In absence of CDs, the EOCs melt the PCL fibers or migrate to their surface. • αCD forms poly(pseudo)rotaxanes with PCL but the stronger fibers failed to host EOCs. • HPβCD preferentially hosts EOCs, facilitates the electrospinning and regulates EOCs release. • PCL/HPβCD electrospun fibers with carvacrol or cinnamic acid and their binary mixtures efficiently inhibit bacteria biofilm. [ABSTRACT FROM AUTHOR]

Deciphering the molecular dynamics (MD) of rotaxanes is crucial for designing and refining their applications in molecular devices. This study employed fluorine-19 nuclear magnetic resonance (19F NMR) and magnetic resonance imaging (MRI) to unveil the interplay between mechanical bonds and steric hindrance in a series of fluorinated rotaxanes. 1H/19F NMR revealed stable "Z"-shaped wheel conformations minimizing steric clashes and favoring π-π interactions with the axle. Utilizing fluorines and axle protons as reporters, 1H/19F relaxation rates and solid-state 19F NMR studies demonstrated that mechanical bond primarily governs wheel motion, while steric hindrance dictates axle movement. Intriguingly, mechanical bond mainly affects local axle groups, leaving distant ones minimally impacted. MD simulations corroborated these findings. Temperature-dependent 19F NMR indicated that energy input enhances rotational motion and wheel conformational transitions. Furthermore, the drastic increase in 19F relaxation rates upon mechanical bond formation and steric hindrance enables sensitive and selective 19F MRI visualization of MD changes. This study, by elucidating the roles of internal and external factors on rotaxane molecular dynamics using 19F NMR/MRI, offers valuable insights that can advance the field of rotaxane-based molecular devices. Distinctive and complementary insights into the structural and dynamic characteristics of rotaxanes were obtained utilizing 19F NMR/MRI technologies through parameters such as 19F signal, relaxation rates, rotational correlation time, and imaging features, offering a new perspective for the understanding and rational design of molecular devices. [Display omitted] • Synthesized rotaxanes feature sensitive, selective, semi-quantitative 1H/19F NMR reporters for molecular dynamics analysis. • 19F NMR/MRI offers insights into rotaxanes' structure/dynamics using relaxation rates, rotational correlation time, and imaging features. • Reveals the interplay between mechanical bonds and steric hindrance in rotaxanes via comparative analysis. [ABSTRACT FROM AUTHOR]

Cyclodextrins (CDs) are essential in the pharmaceutical industry and have long been used as food and pharmaceutical additives. CD-based interlocked molecules, such as rotaxanes, polyrotaxanes, catenanes, and polycatenanes, have been synthesized and have attracted considerable attention in supramolecular chemistry. Among them, CD polyrotaxanes have been employed as slide-ring materials and biomaterials. CD polycatenanes are new materials; therefore, to date, no examples of applied research on CD polycatenanes have been reported. Consequently, we expect that applied research on CD polycatenanes will accelerate in the future. This review article summarizes the syntheses and structural analyses of CD polyrotaxanes and polycatenanes to facilitate their applications in the pharmaceutical industry. We believe that this review will promote further research on CD-based interlocked molecules. [Display omitted] [ABSTRACT FROM AUTHOR]

• Supramolecular binding strategy was developed to prepare novel COFs. • β-CD inclusion was used as building block for the preparation of COFs. • Por-CD-COF could greatly reduce the use of photoactive ingredients. • The threading of CD could significantly enhance the photoactivity of COFs. • Por-CD-COF exerted cyclodextrin enhanced PTT and PDT. As an emerging artificial porous material, covalent organic frameworks (COFs) with customizable structure and function, have always been the focus of polymer science. Controllable fabrication of COFs with brand-new structure is the top priority for its development. Here, the 'supramolecular binding' strategy is developed as a simple but efficient method to prepare COFs with novel structures and functions. By this means, polymeric rotaxanes threaded COFs, denoted as Por-CD-COF, was facilely prepared via the combination of dynamic covalent imine-bond formation with supramolecular self-assembly, in which the polyrotaxane formed via inclusion of aromatic linker with bactericidal active β-cyclodextrin macrocycle (CD) was condensed with the photosensitive porphyrin via the combination of mechanical grinding and solvothermal synthesis. The formation of polyrotaxane could change the distance between layers, avoiding the quench of photoactivity caused by the severe aggregation of layered structure. Under the same molar amount of reaction monomers, the weight of the Por-CD-COF is approaching five times of the CD-free COF, which could greatly reduce the use of photoactive ingredients. Further experiments demonstrated the introduction of CDs could also significantly improve the biocompatibility. Impressively, this special porphyrin-involved CD-COF, displays excellent photo activity, which could act as an efficient broad spectrum antibacterial agents realizing the combinational action of cyclodextrin enhanced photothermal and photodynamic antimicrobial at an extremely low quality of the effective photosensitizer (Porphyrin). Meanwhile, even at the same dose of fungicide, the bactericidal effect of Por-CD-COF is far exceeding the CD-free therapeutic agent. This novel synthetic strategy allows the incorporation of mechanically interlocked CDs (MIMs) into the porous polymeric materials, providing an easy access to low-cost preparation of COFs for the specific applications. [ABSTRACT FROM AUTHOR]

• A new Zn based polyrotaxane 3D metal-organic framework (MOF), {[Zn 3 (BTC) 2 (Bimb) 3.5 ][Zn(HCOO)(Bimb) 1.5 ]·CH 3 COO·2(CH 3) 2 NH·2DMF·9H 2 O} n (KA@MOF-S2) has been synthesized under solvothermal conditions. • KA@MOF-S2 possesses a new 3,3,3-c net 3-nodal interpenetrated network with (122.14)(8.122)(83) 2 topology. • Detection of various concentration of sucrose, 80 mg/dl and 100 mg/dl showed highest 85.6 % and 84.7 % quenching efficiency of KA@MOF-S2. • KA@MOF-S2 can be used as a highly sensitive fluorescence sensing material for the quantitative detection of Acetone, NB, NFT, UA and sucrose. • KA@MOF-S2 showed photocatalytic degradation of Rose Bengal (RB) and Congo Red (CR) dye under sun-light irradiation. A new Zn based polyrotaxane 3D metal-organic framework (MOF), {[Zn 3 (BTC) 2 (Bimb) 3.5 ][Zn(HCOO)(Bimb) 1.5 ]·CH 3 COO·2(CH 3) 2 NH·2DMF·9H 2 O} n (KA@MOF-S2)(Bimb = 1,4-bis[(1H-imidazol-1-yl)methyl]benzene, BTC3‒ = 1,3,5-benzenzetricarboxylate) has been synthesized under solvothermal conditions. Single-crystal X-ray diffraction analysis reveals that KA@MOF-S2 exhibits a novel 1D + 3D → 3D interpenetratedPolyrotaxane MOF architecture. KA@MOF-S2 possesses a new 3,3,3-c net 3-nodal interpenetrated network with (122.14)(8.122)(83) 2 topology. KA@MOF-S2 can be used as a selective fluorescence sensing material for the quantitative detection of VOCs (Acetone, NB), antibiotic (NFT) and biomolecules (UA, sucrose) and photocatalytic degradation of Rose Bengal (RB) and Congo Red (CR) dye under sun-light irradiation. Synthesised a new KA@MOF-S2 is highly fluorescence sensing material for the quantitative detection of Acetone, NB, NFT, UA and sucrose as well as degradation of RB and CR dye under irradiation. [Display omitted] [ABSTRACT FROM AUTHOR]