The number of methods that exploit transition-metal-catalyzed C(sp³)−H activations for the assembly of cyclic systems is steadily growing. This Minireview covers the most relevant cyclization and cycloaddition approaches, discussed from a mechanistic perspective.

This review summarizes advances in the mechanistic study of newly developed piezocatalysis systems. The differences, relevance, evidence, and contradiction of the tentative mechanisms of energy band theory and screening charge effect are elaborated. The current challenges and perspectives for future mechanistic studies are provided.

An extensive overview of experimental elastic constant tensors for molecular crystals employs a rotation-invariant description of the Young's modulus to critically compare multiple observations and computational results. To encourage the wider use of experimental elastic constant tensors in studies of mechanical properties, outliers are clearly identified, resulting in a curated database of experimental results for molecular crystals.

A straightforward and simple method of electrochemical desaturative β-C(sp³)−H acylation of cyclic N-aryl amines has been developed to access the desired β-substituted enamines with excellent levels of chemo- and regioselectivity under mild conditions. This procedure proved to be a powerful route to the late-stage modification of natural products and derivatives.

A proof-of-concept is reported that the electrochemistry of redox liposome single impacts is a powerful and efficient analytical technique for sensing target toxins produced by pathogenic bacteria such as Rhamnolipid from Pseudomonas aeruginosa which interacts destructively with the lipid membrane of liposomes. A high sensitivity of sensing has been reached with a submicromolar concentration of Rhamnolipid detected in less than 30 minutes.

A cross-electrophile coupling between gem-difluoroalkenes and benzyl electrophiles proceeds through nickel-catalyzed chelation-assisted C−F bond activation and shows excellent stereoselectivity and enantioselectivity.

A highly luminescent organic antimony(III) hybrid (MePPh₃)₂SbCl₅ featured with STE emission is prepared with good reproducibility and high stability. High-efficiency OLEDs are demonstrated by this hybrid as an emitter with the luminance of 3500 cd m⁻², current efficiency of 6.8 cd A⁻¹ and EQE of 3.1 %, respectively.

A series of rat gut-microbiota-derived class III lanthipeptides with moderate antimicrobial activities were discovered by genome mining. The investigation of their biosynthesis revealed a subgroup of S8 family serine proteases for the removal of class III leader peptides.

The use of a chiral Au catalyst bearing an α-cationic phosphonite as an ancillary ligand and two successive alkyne hydroarylation events allows the assembly of dithia[5]helicenes with excellent enantioselectivity. Moreover, regioselective postsynthetic bromination of the dithia[5]helicene products generates starting materials for the efficient preparation of even more π-expanded systems, such as dithia[9]helicenes.

α-Trifluoromethyl cycloheptanones containing the C(sp³)−CF₃ bond on the chiral centers were accessed through a highly stereoselective Sc^III/chiral bisoxazoline-catalyzed homologation reaction of cyclic ketones with CF₃CHN₂ as the trifluoromethylation reagent. This reaction could be applied to construct silicon-stereogenic centers with moderate diastereoselectivities and high enantioselectivities.

A novel biocompatible selenopolypeptide was site-specifically conjugated to alpha-1-antitrypsin (A1AT). The conjugated A1AT fully retained its inhibitory activity on neutrophil elastase (NE), enhanced oxidation resistance, extended the serum half-life, and afforded long-lasting protective activity in a mouse model of acute lung injury.

A rapid, practical, efficient and broad-spectrum method for the synthesis of highly versatile and synthetically useful ortho-trifluoromethanesulfonylated anilines from N-arylhydroxylamines and trifluoromethanesulfinic chloride is described.

The first rare-earth metal-based deep-UV sulfate La(NH₄)(SO₄)₂, which exhibits a short-wavelength deep-UV absorption edge (below 190 nm) and the strongest SHG response among deep-UV NLO sulfates (2.4×KDP), has been successfully synthesized by a double-salt strategy involving introduction of complementary cations.

Making the invisible visible. Reactive glycosylation intermediates are identified using chemical exchange saturation transfer NMR spectroscopy.

Microwave-induced micro-hot spots were detected in liquid solutions through fluorescence thermometers attached on microwave-absorbing carbon particles. The fluorescent experiments confirmed the established microwave-irradiated energy-transfer model, whose results can guide precise control and optimization of conditions in microwave chemistry.

The synthesis of a rigid bidentate borane/phosphine ligand was explored within the background of statistical olefin copolymerization with group 10 metals. During this work, a mild oxidative dehydrochloroborylation reaction was found to convert different Ni⁰ σ-borane complexes into Ni^II boryl chloride complexes. This new ligand also allows the nickel catalyzed polymerization of ethylene, a first for a B-donor in group 10 olefin polymerization.

The introduction of phenyl side groups as rigid molecular spacers into polydimethylsiloxane (PDMS) imparted the methyl side groups with higher mobility and additional degrees of freedom for fast transport of aromatic compounds. Combined with the engineering design of the transport highway, the membrane achieved outstanding performance for aromatic removal.

The atomic bridging structure of nickel–nitrogen–carbon active sites confined in channel-rich porous carbon fibers enables the highly efficient electrocatalytic reduction of CO₂.

Low-symmetry, MOF-based patchy colloids are reported, which carry both shape and chemical information that enables precise directional colloidal assembly, producing hierarchical, multicomponent, and supra-framework architectures with unprecedented control over the position, rotation, and orientation of the constituent building blocks.

Solid supramolecules based on acrylamide–phenylpyridium copolymers with various substituent groups and cucurbit[7]uril not only exhibit tunable ultralong phosphorescence with lifetimes varying from 0.9 s to 2.2 s, but also co-assemble with organic dyes Eosin Y or SR101 to display high-performance phosphorescence energy transfer with multicolor delayed fluorescence properties.

Dianion and dication of a tetracyclopentatetraphenylene derivative were generated and investigated as the annulene-within-an-annulene models. Experiments based on X-ray crystallography and ¹H NMR, ¹³C NMR, and MCD spectroscopies indicate that the outer and inner conjugation circuits are significantly decoupled, strongly supporting the theoretically predicted structures.

Crystallographic and computational studies on a series of porphyrinic hydrogen-bonded organic frameworks (HOFs) reveal that metallization of porphyrin centers greatly alters the orbital overlap of the adjacent porphyrin, the geometry of the molecule/layer, and the strength of noncovalent interactions. Therefore, metalloporphyrin HOFs exhibit much higher stability, surface area, and catalytic activity than metal-free porphyrinic HOFs.

Pt−Co nanoalloys planted in the metal–nitrogen–graphene system achieved by a scalable molten salt pyrolysis method demonstrate improved activity and stability for oxygen reduction through a synergistic effect among multiple active sites and a strong metal–support interaction.

The crystallographic observation of reversible coordinative binding of SO₂ and NO₂ on open Ni^II sites in a robust metal–organic framework (NKU-100) incorporating unprecedented {Ni₁₂}-wheels has been achieved by in situ synchrotron single crystal X-ray diffraction.

Circular permutation of PQQ-glucose dehydrogenase creates an artificial allosteric enzyme controlled by ligand binding to N- and C-terminal domains. The developed biosensors demonstrated sub-nanomolar affinities for small molecules and proteins in colorimetric and electrochemical assays.

Long-lasting and broad-spectrum antimicrobial agents with the special structure of hexagonal column interpenetrated spheres (HCISs) are constructed through non-covalent assembly of plant gallic acid and quaternary ammonium surfactants. HCISs possess high substrate-adhesion on various substrates and high anti-water washing property, and can continuously provide antimicrobial ingredients in a multistage way, avoiding one-time burst release of antimicrobial units.

A two-dimensional oxonium-embedded COF with vinylene linkages was synthesized by condensation of a trimethyl-substituted pyrylium with a tritopic aromatic aldehyde derivative, which was readily converted to a neutral pyridine-cored COF by in situ replacing oxonium with nitrogen atoms under the treatment of ammonia.

Inspired by the unique natural reaction of azaphilones with amines, an efficient, highly chemoselective and activation-free primary amine bioconjugation protocol has been developed and demonstrated in a variety of applications.

A light-up fluorescent probe (UBER) that reacts rapidly with apurinic/apyrimidinic (AP) sites visualizes base excision repair (BER) of mitochondrial DNA (mtDNA) in cells. Monitoring of the mtDNA BER process in cells over time illuminated the time lag between the initiation of oxidative stress and the initial step of DNA repair, along with the effect of DNA defensive enzymes, MTH1 and OGG1.

A concept for the transformation of the excellent tetrazine-ligation dependent fluorogenicity of blue-excitable cores to biologically preferable emission ranges is presented herein. Such relay mechanism resulted in improved yellow/red fluorogenicities together with increased photostabilities and large apparent Stokes-shifts. The presented fluorogenic dyads were utilized in multicolor single excitation imaging schemes and STED imaging as well.

Cholesterol-modified programmable DNA probes are developed to image transient interactions and membrane order in live cell membranes. The membrane order during the activation of T-cell receptor signaling has also been measured.

By means of radiation chemistry, different stages of CeO₂ mesocrystal formation are revealed. The nucleation and growth of the primary particles, followed by their self-assembly into mesocrystals, occur inside a hydrated Ce^IV hydroxide phase. The hydroxide forms as the initial phase and serves as an intermediate in the liquid-to-solid transformation. Mesocrystals can be used as buildings blocks for designing complex hierarchical structures.

Interface pH change seriously influences dendrite formation, while its importance has not been revealed. We constructed a N-modification graphdiyne interface to stabilize pH by accelerating hydrated zinc ions desolvation, enabling the direct electron transfer from anode to Zn²⁺ (rather than the coordinated H₂O). Operando pH detection reveals the pH stabilization. Zn-V₆O₁₃ battery works well at 20.65 mA cm⁻² and 1.07 mAh cm⁻². This work highlights interface pH and provides a new approach to address Zn dendrite issue.

Reported herein is a triple-functional H₂S delivery system, which is triggered by the bioorthogonal click-and-release reaction between a newly designed diphenylamino-substituted 1,3-dithiolium-4-olate (DTO) and a strained alkyne. This COS-based H₂S release platform can realize in-mitochondria H₂S release in a controllable manner, and provide a concomitant fluorescence for spatiotemporal feedback of the exogenous H₂S in cells.

Co dual-atom catalysts were used for CO₂ reduction with superior CH₄ selectivity. The charge at the inserted Co₂ active sites in tri-3s-triazine was enriched as compared to that at Co single sites, thus promoting a lower activation energy barrier by stabilizing the rate-limiting COOH* and CHO* intermediates.

We report smart nanofluidic devices based on oriented two-dimensional covalent organic framework membranes that offer vertically aligned nanofluidic channel arrays, leading to an ultrahigh ion flux and pH-gating nanofluidic transport.

An unambiguous structural elucidation using microcrystal electron diffraction provides insight into unique properties of a layered conductive metal-organic framework (MOF) Cu₃(C₆O₆)₂. The presence of strong interlayer electronic coupling exerts a profound effect on the electrical and magnetic properties of the MOF.

A DNA nanocomplex containing cascade DNAzymes and promoter-like Zn-Mn-Ferrite was synthesized. The promoter-like ZMF decomposed in response to intratumoral glutathione to release a sufficient quantity of metal ions, thus promoting cascade DNA/RNA cleavage and free radical generation, and achieving combined gene/chemo-dynamic therapy.

A series of isorecticular and heterobimetallic two-dimensional metal–organic frameworks achieves chemiresistive sensing of ppm concentrations of carbon monoxide at low power. Spectroscopic techniques and computational methods, along with comparative experiments, suggest the contribution of Cu nodes to CO binding and the essential role of metallophthalocyanine units in tuning and amplifying the sensing response.

Synthetic silica nano-organelles designed to regulate kinetics and pathway selection in enzymatic cascade reactions are reported. Like cell organelles, synthetic nano-organelles can be combined to create integrated systems. Multicompartmentalized synthetic cells were built using synthetic nano-organelles and giant polymeric vesicles.

How far can the dynamic chirality of Möbius hexaphyrins be controlled lies firstly on the capacity of an attached source of chirality to explore the Möbius ring environment, which depends on several convoluted dynamic processes; secondly on the responsiveness of the system, making this exploration tunable and multi-reversible; and thirdly on the unwavering optimism of the experimenter.

This work reports the novel example of linear non-conjugated polyester exhibiting yellow-green clusteroluminescence and a high quantum yield of 38 %. The formation of ester-unit cluster is responsible for the emission and is decided by balancing flexible and rigid structures of chains.

Titanocene catalysis delivers D to the more substituted C-atom of epoxides with high efficiency, deuterium incorporation, and stereoselectivity. A novel method of catalyst activation that prevents isotope scrambling warrants the excellent performance of the reaction.

A supramolecular polymer that consists of an antiaromatic π-system as the monomer has been created. An amide-functionalized Ni^II norcorrole derivative forms a one-dimensional supramolecular polymer through π-π stacking and hydrogen-bonding interactions. The formation of a long-range π-π-stacking array ensures the persistency of the conducting pathway against thermal perturbation and achieves high charge-carrier mobility along the tightly-bound linear aggregates.

Cubic arsenic nitride was synthesized from arsenic and nitrogen under high-pressure and high-temperature conditions using a laser heated diamond anvil cell. The crystalline structure of AsN (P2₁3), in which every As atom is single-bonded to three N atoms and vice versa, was determined by synchrotron X-ray diffraction. The discovery of AsN is relevant to the fundamental chemistry of pnictogens and to synthesis of new advanced materials.

A polymeric hole-transport material (HTM) based on the phenanthrocarbazole derivative PC6 features a two-dimensionally conjugated phenanthrocarbazole and S-O noncovalent conformational locking. Perovskite solar cells employing PC6 as a dopant-free HTM afforded an excellent power conversion efficiency (PCE) of 22.2 % and long-term stability.

SnF₂ is an efficient catalyst for the polymerization of DOL and also an effective additive for improving the interfacial wettability with Li-metal, of benefit in reaching the dendrite free and dense Li-deposition in all-solid-state cells. However, P-DOL-SPE tends to be thermally decomposed at 110 °C with the formation of formaldehyde gas and other epoxides, restricting the operating temperature window of P-DOL based electrolytes.

Anion-coordination-driven assembly (ACDA) between organic tris-carboxylates and tris-bis(urea) ligands afforded an Archimedean solid (truncated tetrahedron) and a double-walled tetrahedron featuring a ravel topology. The results demonstrate the promising ability of tris-carboxylates as new anion coordination centers in constructing novel topologies on account of the modifiable size and function of these organic anions.

A new class of polythiourethane soft actuators based on liquid crystal and thiourethane segments has been developed by a one-pot approach. The formation of well-defined thiourethane segments affords supramolecular cross-links through hydrogen-bonding interactions yielding materials that can be reprocessed and reprogrammed into arbitrary 3D shapes. A detailed understanding and characterization of the developed material are presented.

A glycosylation method for non-specialists: Commercially available pyrylium salts catalyze stereoselective glycosylation reactions with trichloroacetimidate electrophiles. A wide range of phenolic nucleophiles are compatible with the procedure. The standard conditions involve mixing three components at ambient conditions and proceed with minimal formation of undesired by-products.