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Aggregation-induced deactivation has long been a challenge in the field of photocatalysis based on molecular porphyrin derivative-based photocatalysts. The development of polyhedral porphyrin cage-based heterogeneous catalysts has shown promise in addressing this issue by preventing intermolecular face-to-face packing. However, this shift towards heterogeneous catalysis comes at the cost of catalytic activity. Herein, we report the design and synthesis of an ionic porphyrin cage, TPPCage·8I, characterized with a high charge density within the skeleton. This strategy effectively circumvents spontaneous aggregation by harnessing the electrostatic repulsion that naturally occurs between adjacent cage hosts. Furthermore, the strategic incorporation of hydrophilic iodine counteranions surrounding the cage not only modulates their solubility, making them uniformly dispersed in the solvent, but also imparts an additional heavy-atom effect. These modifications lead to substantial enhancement in photophysical properties, resulting in extraordinary catalytic activity in the photocatalytic oxidation coupling reaction of benzylamines, with a remarkable conversion rate exceeding 99% and a record turnover frequency (TOF) of 1980.0 h−1, coupled with excellent stability. In addition, the current homogeneous photocatalyst offers ease of recycling through a straightforward exchange process with a robust hydrophobic anion (sodium dodecyl sulfate, SDS).

Discovering and constructing molecular functionality platforms for materials chemistry innovation has been a persistent target in the fields of chemistry, materials, and engineering. Around this task, basic scientific questions can be asked, novel functional materials can be synthesized, and efficient system functionality can be established. Poly(ionic liquid)s (PILs) have attracted growing interest far beyond polymer science and are now considered an interdisciplinary crossing point between multiple research areas due to their designable chemical structure, intriguing physicochemical properties, and broad and diverse applications. Recently, we discovered that 1,2,4-triazolium-type PILs show enhanced performance profiles, which are due to stronger and more abundant supramolecular interactions ranging from hydrogen bonding to metal coordination, when compared with structurally similar imidazolium counterparts. This phenomenon in our view can be related to the smart hydrogen atoms (SHAs), that is, any proton that binds to the carbon in the N-heterocyclic cations of 1,2,4-triazolium-type PILs. The replacement of one carbon by an electron-withdrawing nitrogen atom in the broadly studied heterocyclic imidazolium ring will further polarize the C–H bond (especially for C5–H) of the resultant 1,2,4-triazolium cation and establish new chemical tools for materials design. For instance, the H-bond-donating strength of the SHA, as well as its Bro̷nsted acidity, is increased. Furthermore, polycarbene complexes can be readily formed even in the presence of weak or medium bases, which is by contrast rather challenging for imidazolium-type PILs. The combination of SHAs with the intrinsic features of heterocyclic cation-functionalized PILs (e.g., N-coordination capability and polymeric multibinding effects) enables new phenomena and therefore innovative materials applications.

The ability to grow properly sized and good quality crystals is one of the cornerstones of single-crystal diffraction, is advantageous in many industrial-scale chemical processes1–3, and is important for obtaining institutional approvals of new drugs for which high-quality crystallographic data are required4–7. Typically, single crystals suitable for such processes and analyses are grown for hours to days during which any mechanical disturbances—believed to be detrimental to the process—are carefully avoided. In particular, stirring and shear flows are known to cause secondary nucleation, which decreases the final size of the crystals (though shear can also increase their quantity8–14). Here we demonstrate that in the presence of polymers (preferably, polyionic liquids), crystals of various types grow in common solvents, at constant temperature, much bigger and much faster when stirred, rather than kept still. This conclusion is based on the study of approximately 20 diverse organic molecules, inorganic salts, metal–organic complexes, and even some proteins. On typical timescales of a few to tens of minutes, these molecules grow into regularly faceted crystals that are always larger (with longest linear dimension about 16 times larger) than those obtained in control experiments of the same duration but without stirring or without polymers. We attribute this enhancement to two synergistic effects. First, under shear, the polymers and their aggregates disentangle, compete for solvent molecules and thus effectively ‘salt out’ (that is, induce precipitation by decreasing solubility of) the crystallizing species. Second, the local shear rate is dependent on particle size, ultimately promoting the growth of larger crystals (but not via surface-energy effects as in classical Ostwald ripening). This closed-system, constant-temperature crystallization driven by shear could be a valuable addition to the repertoire of crystal growth techniques, enabling accelerated growth of crystals required by the materials and pharmaceutical industries.

MOF-based heterogeneous catalysts with enhanced dispersibility in solution are highly promising for liquid-phase catalysis, yet their preparation remains a great challenge. Herein, viaintroducing responsive polymer-functionalized hollow pollen as pivots, a general strategy toward preparing MOF@Pollen composites with adjustable dispersibility, environment-responsive activity and significantly enhanced liquid-phase photocatalytic performance is presented.

A general approach to produce a variety of free-standing asymmetric MOF hybrid membranes and superstructure arrays on “inert” substrates with tailored crystal sizes and shapes was developed. The obtained MOF hybrid membrane exhibits fast actuation in response to external gas stimulus.

Incorporating metal nanoparticles (MNPs) into porous composites with controlled size and spatial distributions is beneficial for a broad range of applications, but it remains a synthetic challenge. Here, we present a method to immobilize a series of highly dispersed MNPs (Pd, Ir, Pt, Rh, and Ru) with controlled size (<2 nm) on hierarchically micro- and mesoporous organic cage supports. Specifically, the metal–ionic surfactant complexes serve as both metal precursors and mesopore-forming agents during self-assembly with a microporous imine cage CC3, resulting in a uniform distribution of metal precursors across the resultant supports. The functional heads on the ionic surfactants as binding sites, together with the nanoconfinement of pores, guide the nucleation and growth of MNPs and prevent their agglomeration after chemical reduction. Moreover, the as-synthesized Pd NPs exhibit remarkable activity and selectivity in the tandem reaction due to the advantages of ultrasmall particle size and improved mass diffusion facilitated by the hierarchical pores.

A series of metal–organic frameworks based on a flexible, highly charged Bpybc ligand, namely 1⋅Mn⊃OH−, 2⋅Mn⊃SO42−, 3⋅Mn⊃bdc2−, 4⋅Eu⊃SO42−(H2BpybcCl2=1,1′‐bis(4‐carboxybenzyl)‐4,4′‐bipyridinium dichloride, H2bdc=1,4‐benzenedicarboxylic acid) have been obtained by a self‐assembly process. Single‐crystal X‐ray‐diffraction analysis revealed that all of these compounds contained the same n‐fold 2D→3D Borromean‐entangled topology with irregular butterfly‐like pore channels that were parallel to the Borromean sheets. These structures were highly tolerant towards various metal ions (from divalent transition metals to trivalent lanthanide ions) and anion species (from small inorganic anions to bulky organic anions), which demonstrated the superstability of these Borromean linkages. This non‐interpenetrated entanglement represents a new way of increasing the stability of the porous frameworks. The introduction of bipyridinium molecules into the porous frameworks led to the formation of cationic surface, which showed high affinities to methanol and water vapor. The distinct adsorption and desorption isotherms of methanol vapor in four complexes revealed that the accommodated anion species (of different size, shape, and location) provided a unique platform to tune the environment of the pore space. Measurements of the adsorption of various organic vapors onto framework 1⋅Mn⊃OH−further revealed that these pores have a high adsorption selectivity towards molecules with different sizes, polarities, or π‐conjugated structures.

An organic molecular system with proton-tunable photoluminescence properties based on a mono-substituted bipyridinium derivative 1-(3-carboxybenzyl)-4,4′-bipyridinium chloride, which possesses both pyridine and carboxylic acid groups as proton-responsive units, has been developed. Through controlling the pH value of the self-assembled systems, three compounds with different degrees of protonation have been obtained. These compounds display distinctly different luminescence behaviors and undergo solid-state structural conversion in response to changes in pH values. In particular, luminescence switching triggered by acid–base vapor can be realized.

A flexible viologencarboxylic acid derivative forms single‐ and triple‐stranded helices by hydrogen‐bonding interactions, and undergoes pH‐triggered helical transformation by a water‐mediated solid‐state conversion (see picture). This transformation is accompanied by a fluorescence signal change that can be directly observed by the naked eye under a UV lamp.

In Augenschein genommen: Ein flexibles Viologenderivat mit Carboxygruppen bildet über H‐Brücken ein‐ und dreisträngige Helices und vollzieht eine pH‐induzierte Helixtransformation über eine wasservermittelte Festphasenumwandlung (siehe Bild). Mit dieser Transformation geht eine Veränderung der Fluoreszenz einher, die direkt mit bloßem Auge unter einer UV‐Lampe beobachtet werden kann.

Ti-alloy is widely used in engineering because it possesses excellent specific strength and corrosion resistance. The effect of welding process on J-integral value and fatigue crack growth (FCG) rate in a Ti-alloy is experimentally investigated in this paper. A series of test is performed with SENB specimens for J-integral test and CT specimens for the FCG rate test respectively. Base metal, welded joint and HAZ materials were used to make different test specimens. Results show that the J-integral values of welded joint and HAZ are obviously smaller than those of the base metal. And that the FCG rate value of welded joint is much higher than those of base metal and HAZ material. It means that welding process may lead to a great reduction in fracture toughness and the fatigue property for titanium alloy. Therefore, the inhomogeneity of the welded joint must be considered when assess welded structures.