Chloride is the most abundant anion in cells and plays many critical roles in maintaining cellular homeostasis. However, current chloride indicators are rare with inherent sensitivity in their emission properties, such as vulnerability to pH changes or short emission lifetimes. These limitations restrict their application in aqueous media and imaging. In this work, we employed a transition-metal complex bearing pyridinium as a recognition unit for chloride and studied the phosphorescence emission properties. Iridium(III) complex 1 was synthesized as an alternative chloride-sensitive luminophore. The conjugable design also allows customization for the desired applications. Complex 1 exhibited high sensitivity and selectivity in chloride sensing across different physiological environments, regardless of pH fluctuation and ionic strength. Additionally, complex 1 featured a microsecond emission lifetime. The chloride sensing ability of complex 1 can be measured through both the luminescence intensity and long-lived phosphorescent lifetime, providing an alternative potential route for chloride imaging. The analogue 1b was successfully applied in the imaging of Cl- in cellular environments and showed dose-dependent responses in both live and fixed cells.

Harnessing mechanical force to modulate material properties and enhance biomechanical functions is essential for advancing smart materials and bioengineering. Polymer mechanochemistry provides an emerging toolkit to unlock unconventional chemical transformations and modulate molecular structures via mechanical force. One of the key challenges is developing innovative force-sensing mechanisms for precise, in situ force detection and quantification. This study addresses this challenge by introducing mDPAC, a mechanosensitive molecular gear with dynamic and sensitive mechanochromic properties. Its unique mechanoresponsive mechanism is based on the simultaneous configurational variation of its phenazine and phenyl moieties, facilitated by a worm-gear structure. We affirm mDPAC's sensitive mechanochemical response and elucidate its force transduction mechanism through our experimental emission data and comprehensive DFT and MD simulations. The compatibility of mDPAC with hydrogels is particularly notable, highlighting its potential for applications in aqueous biological environments as a dynamic molecular force sensor and mapping tool. Moreover, mDPAC's multicolored mechanochromism enables direct force sensing, visual detection, and real-time quantification, paving the way for integrating molecular gears into bulk materials for precise and instantaneous mechanical force sensing.

Harnessing mechanical force to modulate material properties and enhance biomechanical functions is essential for advancing smart materials and bioengineering. Polymer mechanochemistry provides an emerging toolkit for exploring unconventional chemical transformations and modulating molecular structures through mechanical force. One of the key challenges is developing innovative force-sensing mechanisms for precise and in situ force detection. This study introduces mDPAC, a dynamic and sensitive mechanophore, demonstrating its mechanochromic properties through synergetic conformational gearing. Its unique mechanoresponsive mechanism is based on the simultaneous conformational synergy between its phenazine and phenyl moieties, facilitated by a worm-gear-like structure. We confirm mDPAC's complex mechanochemical response and elucidate its mechanotransduction mechanism through our experimental data and comprehensive simulations. The compatibility of mDPAC with hydrogels is particularly notable, highlighting its potential for applications in aqueous biological environments as a dynamic force sensor. Moreover, mDPAC's multicolored mechanochromic responses facilitate direct force sensing and visual detection, paving the way for precise and real-time mechanical force sensing in bulk materials.

A method is developed for facile encapsulation of reactive organic bases with potential application for autonomous damage detection and self-healing polymers. Highly reactive chemicals such as bases and acids are challenging to encapsulate by traditional oil-water emulsion techniques due to unfavorable physical and chemical interactions. In this work, reactivity of the bases is temporarily masked with photo-removable protecting groups, and the resulting inactive payloads are encapsulated via an in situ emulsion-templated interfacial polymerization method. The encapsulated payloads are then activated to restore the organic bases via photo irradiation, either before or after being released from the core-shell carriers. The efficacy of the photo-activated capsules is demonstrated by a damage-triggered, pH-induced color change in polymeric coatings and by recovery of adhesive strength of a damaged interface. Given the wide range of potential photo-deprotection chemistries, this encapsulation scheme provides a simple but powerful method for storage and targeted delivery of a broad variety of reactive chemicals, promoting design of diverse autonomous functionalities in polymeric materials. Oil-water emulsion techniques can be used for encapsulation of chemicals and control of reactivity, but is challenging for highly reactive materials such as acids and bases. Here, the authors report the encapsulation of bases by masking of reactivity with photo-removable protecting groups.

Mechanical force has recently become a new tool for chemists to create colours, trigger reactions, and develop advanced fabrication techniques not possible using other methods. Force-induced multiple colouring has now been developed as a printing technique in soft lithography, enabling the colouring of polymeric materials without inks.

A near-infrared (NIR) mechanophore was developed and incorporated into a poly(methyl acrylate) chain to showcase the first force-induced NIR chromism in polymeric materials. This mechanophore, based on benzo[1,3]oxazine (OX) fused with a heptamethine cyanine moiety, exhibited NIR mechanochromism in solution, thin-film, and bulk states. The mechanochemical activity was validated using UV-vis-NIR absorption/fluorescence spectroscopies, gel permeation chromatography (GPC), NMR, and DFT simulations. Our work demonstrates that NIR mechanochromic polymers have considerable potential in mechanical force sensing, damage detection, bioimaging, and biomechanics.

Polymorphism makes it possible to clarify the relationship between emission property and crystal structure. However, based on the exact molecular conformation in tetraphenylethene polymorphisms, it is still challenging to evaluate the difference of intramolecular coplanarity without the support of calculation because of the complex combination of four different torsion angles between four peripheral benzenes and the central ethylene plane. Here, by using a di-formyl-functionalized tetraphenylethene derivative, two ideal polymorphisms with a consistent trend of the corresponding torsion angles have been obtained. For the first time, we explicitly demonstrated that intramolecular coplanarity is the underlying cause of the polymorphism-dependent emission of tetraphenylethene derivatives.

Detection and assessment of small-scale damage at early stages are essential for polymeric materials to extend lifetime, avoid catastrophic structural failure, and improve cost-efficiency. Previous self-reporting coatings provide visual indication of surface damage but have been limited to a single layer without information on the depth of crack penetration. Here, we present a novel strategy for autonomous indication of damage in multilayered polymeric materials using aggregation-induced emission luminogens (AIEgens). Three different AIEgens are encapsulated and layered into polymeric coatings. When scratches of varying depths penetrate the coating layers, different combinations of AIEgens are activated to visually detect the depth of damage based on the corresponding fluorescent colors. The AIEgen-based detection mechanism makes this system a powerful tool for damage indication in a variety of polymeric coatings.

Stimuli-responsive materials activated by a pair of molecular or ionic species are of interest in the design of chemical logic gates and signal amplification schemes. There are relatively few materials whose coactivated response has been well-characterized. Here, we demonstrate a specific ion coactivation (SICA) effect at the interfaces of transient polymer solids and liquid solutions. We found that depolymerization of the transient polymer, cyclic poly(phthalaldehyde) (cPPA), exhibited a SICA effect when the cPPA core-shell microcapsules were suspended in ion-containing acidic methanol solutions. Significant acceleration in cPPA depolymerization rate is triggered by the combination of acid and ion coactivators. Intriguingly, the SICA effect is related to the Hofmeister behavior. The SICA effect is primarily determined by anions, and cations exhibit a secondary effect that modulates the coactivation strength. Based on these observations, we developed cPPA programmable microcapsules whose payload release rates depend on the composition and concentration of the salt/acidic-methanol solutions.

Compartmentalized structures widely exist in cellular systems (organelles) and perform essential functions in smart composite materials (microcapsules, vasculatures, and micelles) to provide localized functionality and enhance materials' compatibility. An entirely water-free compartmentalization system is of significant value to the materials community as nonaqueous conditions are critical to packaging microcapsules with water-free hydrophilic payloads while avoiding energy-intensive drying steps. Few nonaqueous encapsulation techniques are known, especially when considering just the scalable processes that operate in batch mode. Herein, we report a robust oil-in-oil Pickering emulsion system that is compatible with nonaqueous interfacial reactions as required for encapsulation of hydrophilic payloads. A major conceptual advance of this work is the notion of the partitioning inhibitor-a chemical agent that greatly reduces the payload's distribution between the emulsion's two phases, thus providing appropriate conditions for emulsion-templated interfacial polymerization. As a specific example, an immiscible hydrocarbon-amine pair of liquids is emulsified by the incorporation of guanidinium chloride (GuHCl) as a partitioning inhibitor into the dispersed phase. Polyisobutylene (Pm) is added into the continuous phase as a viscosity modifier for suitable modification of interfacial polymerization kinetics. The combination of GuHCl and PIB is necessary to yield a robust emulsion with stable morphology for 3 weeks. Shell wall formation was accomplished by interfacial polymerization of isocyanates delivered through the continuous phase and polyamines from the droplet core. Diethylenetriamine (DETA)-loaded microcapsules were isolated in good yield, exhibiting high thermal and chemical stabilities with extended shelf-lives even when dispersed into a reactive epoxy resin. The polyamine phase is compatible with a variety of basic and hydrophilic actives, suggesting that this encapsulation technology is applicable to other hydrophilic payloads such as polyols, aromatic amines, and aromatic heterocyclic bases. Such payloads are important for the development of extended pot or shelf life systems and responsive coatings that report, protect, modify, and heal themselves without intervention.

Synthesis of giant unimolecular dendrimers is challenging due, in part, to difficulties encountered at higher generations, in both convergent and divergent protocols because of the multistep construction/purification process. Herein, we report a hybrid synthetic procedure in which the core is constructed last. This quantitative assembly generated a metallodendrimer that is supercharged (120+), large (11.3 nm diameter), and its core was previously established. The series of complexes has been unequivocally characterized by NMR, ESI-IM-MS, and TEM techniques.

A series of coordination-driven, heteroleptic self-assembled, bowtie-shaped bis-macrocycles were designed and constructed by combining tetrakis(terpyridinyl)thianthrene and bis-terpyridine, 60°-directed, Ru2+ dimers. The resulting complexes were characterized by NMR spectroscopy and ESI-MS coupled with travelling wave ion mobility spectrometry (ESI-TWIM-MS) experiments. The desired bis-macrocycles were obtained in quantitative yields through the use of long alkyl-chain substituents, in contrast to the lower yields obtained for smaller alkyl moieties.

Perylene-based, terpyridine-Ru(II) complexes are synthesized and their electrochemical and photoelectrochemical properties are studied; their fabrication into dye-sensitized solar cells are described (DSSCs) and their resultant photovoltaic properties are evaluated.

Archimedische supramolekulare Käfige werden ausgehend von einem gebogenen, X-förmigen Terpyridinliganden und Zn2+- oder Cd2+-Ionen erhalten, wie G. R. Newkome, C. Wesdemiotis et al. in der Zuschrift auf S. 9356 ff. beschreiben. Durch Änderungen der Konzentration oder Austausch der Gegenionen konnte ein Verschmelzungs-Spaltungs-Prozess zwischen einem Kuboktaeder und zwei Oktaedern ausgelöst werden, der an biologische Prozesse bei der Zellteilung erinnert.

Archimedean-based supramolecular cages are stoichiometrically synthesized from a bent, X-type, terpyridine-based ligand and Zn2+ or Cd2+ ions as described by G. R. Newkome, C. Wesdemiotis et al. in their Communication on page 9224 ff. Triggered by changing the concentration or the counterions, these unique materials undergo a fission–fusion process between a cuboctahedron and two octahedra that is reminiscent of the well-known biological processes observed in cell replication. Archimedean-based supramolecular cages are stoichiometrically synthesized from a bent, X-type, terpyridine-based ligand and Zn2+ or Cd2+ ions as described by G. R. Newkome, C. Wesdemiotis et al. in their Communication on page 9224 ff. Triggered by changing the concentration or the counterions, these unique materials undergo a fission–fusion process between a cuboctahedron and two octahedra that is reminiscent of the well-known biological processes observed in cell replication. Intermetallic Phases M. G. Kanatzidis and co-workers describe in their Communication on page 9186 ff. an intermetallic semiconductor that adopts a non-centrosymmetric structure. The band gap in EuIr4In2Ge4 is a direct result of strong IrIr bonding.1 Mercury Pollutants A method for the detoxification of organomercurials using N-methylimidazole-based thiones/selones under physiologically and environmentally relevant conditions is described by G. Roy and co-workers in their Communication on page 9323 ff.1 High Oxidation States In their Communication on page 9280 ff., M.-S. Miao et al. show by first-principles calculations that Hg can form stable compounds of HgF4, a molecular crystal, and HgF3, a metallic, ferromagnetic extended solid, under high pressure.1