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Directional manipulation of submerged bubbles is fundamental for both theoretical research and industrial production. However, most current strategies are limited to the upward motion direction, complex surface topography, and additional apparatuses. Here, we report a meniscus-induced self-transport platform, namely, a slippery oil-infused pillar array with height-gradient (SOPAH) by combining femtosecond laser drilling and replica mold technology. Owing to the unbalanced capillary force and Laplace pressure difference, bubbles on SOPAH tend to spontaneously transport along the meniscus gradient toward a higher elevation. The self-transport performances of bubbles near the pillars depend on the complex meniscus shape. Significantly, to understand the underlying transport mechanism, the 3D meniscus profile is simulated by solving the Young-Laplace equation. It is found that the concave valleys formed between the adjacent pillars can change the gradient direction of the meniscus and lead to the varied transport performances. Finally, by taking advantage of a water electrolysis system, the assembled SOPAH serving as a bubble-collecting device is successfully deployed. This work should not only bring new insights into the meniscus-induced self-transport dynamics but also benefit potential applications in the field of intelligent bubble manipulation.

Silk fibroin is widely believed to be sustainable, biocompatible, and biodegradable, providing promising features such as carriers to deliver drugs and functional ingredients in food, personal care, and biomedical areas, which are consistent with emulsion characteristics; especially, green, all-natural biopolymer-based stabilizers are in great demand to stabilize Pickering emulsions and match the multifunctional needs for developing ideal materials. Herein, an unprecedented three-dimensional (3D) nanostructure, namely a brush-like silk nanobrush (SNB), is applied as the stabilizer to formulate and stabilize Pickering emulsions. The size and interfacial tension are compared among the SNB, a regenerated silk nanofiber, and a nanowhisker. Additionally, optimization processes are conducted to determine the ideal ultrasonication intensity and SNB concentration required to prepare Pickering emulsions by analyzing the morphology, creaming index, mean oil droplet size, and rheological behavior. The results indicate that an SNB with the characteristic structure and suitable size shows superior potential to form sophisticated and interconnected networks in oil-water interfaces, and is proved to be able to resist creaming at a wide range of concentrations and subsequently stabilize Pickering emulsions from liquid-like emulsions to gel-like emulsions. Additionally, SNB is proved to be biocompatible according to cell experiments, providing a promising alternative in designing all-natural, green, and biocompatible emulsions with the aim of efficiently delivering nutrients or drugs associated with health benefits.

Simultaneous imaging and especially visualizing the association of survivin mRNA and telomerase in living cells are of great value for the diagnosis and prognosis of cancer because their co-expression facilitates the development of cancer and identifies patients at high risk of tumor-related death. The challenge is to develop methods that enable visualizing the association of multiplex targets and avoid the distorted signals due to the different delivery efficiency of probes. Herein, we engineered a DNA triangular prism nanomachine (DTPN) for simultaneous multicolor imaging of survivin mRNA and telomerase and visualizing their association in living cells. Two recognizing probes targeted survivin mRNA and telomerase, and the reporter probe was assembled on the DTP in equal amounts, ensuring the same delivery efficiency of the probes to the living cells. The results showed that this DTPN could quantify intracellular survivin mRNA expression and telomerase activity. Moreover, it also enabled us to visualize the effect of the down-regulation of one target on the expression of another target under different drug stimulations. The results implied that our DTPN provided a promising platform for cancer diagnosis, prognosis, drug screening, and related biological research.

Miniaturized rotors based on Marangoni effect have attracted great attentions due to their promising applications in propulsion and power generation. Despite intensive studies, the development of Marangoni rotors with high rotation output and fuel economy remains challenging. To address this challenge, we introduce an asymmetric porosity strategy to fabricate Marangoni rotor composed of thermoresponsive hydrogel and low surface tension anesthetic metabolite. Combining enhanced Marangoni propulsion of asymmetric porosity with drag reduction of well-designed profile, our rotor precedes previous studies in rotation output (~15 times) and fuel economy (~34% higher). Utilizing thermoresponsive hydrogel, the rotor realizes rapid refueling within 33 s. Moreover, iron-powder dopant further imparts the rotors with individual-specific locomotion in group under magnetic stimuli. Significantly, diverse functionalities including kinetic energy transmission, mini-generator and environmental remediation are demonstrated, which open new perspectives for designing miniaturized rotating machineries and inspire researchers in robotics, energy, and environment.

Droplet manipulation is crucial for diverse applications ranging from bioassay to medical diagnosis. Current magnetic-field-driven manipulation strategies are mainly based on fixed or partially tunable structures, which limits their flexibility and versatility. Here, a reconfigurable magnetic liquid metal robot (MLMR) is proposed to address these challenges. Diverse droplet manipulation behaviors including steady transport, oscillatory transport, and release can be achieved by the MLMR, and their underlying physical mechanisms are revealed. Moreover, benefiting from the magnetic-field-induced active deformability and temperature-induced phase transition characteristics, its droplet-loading capacity and shape-locking/unlocking switching can be flexibly adjusted. Because of the fluidity-based adaptive deformability, MLMR can manipulate droplets in challenging confined environments. Significantly, MLMR can accomplish cooperative manipulation of multiple droplets efficiently through on-demand self-splitting and merging. The high-performance droplet manipulation using the reconfigurable and multifunctional MLMR unfolds new potential in microfluidics, biochemistry, and other interdisciplinary fields.

The anti-to-Cu 1,2-migration of alkynyl boronates is critical for the 1,1-E-selective difunctionalization of terminal alkynes with CO2 and organoboranes.

The detailed mechanism of Cu-catalyzed 1,2-hydrocarboxylation of 1,3-dienes and origin of Cu-boryl additions have been investigated.

Energy decomposition analysis reveals that the regioselectivities of Ni-catalyzed LLHT with aryl- and alkyl-substituted alkenes are controlled by charge transfer and Pauli repulsion, respectively.

The dominant factors for the CpX ligand effects (Cp* versus CpE) on the reactivity for alkyne insertion into cationic and neutral rhodacycles are identified based on energy decomposition analysis.

Stereoselective and one-pot synthesis of Lentinus giganteus glycans with antitumor activities has been accomplished, which features a newly developed merging reagent modulation and remote anchimeric assistance (RMRAA) α-galactosylation strategy.

Natural organisms can create various microstructures via a spontaneous growth mode. In contrast, artificial protruding microstructures are constructed by subtractive methods that waste materials and time or by additive methods that require additional materials. Here, we report a facile and straightforward strategy for a laser-induced self-growing mushroom-like microstructure on a flat surface. By simply controlling the localized femtosecond laser heating and ablation on the poly(ethylene terephthalate) tape/heat-shrinkable polystyrene bilayer surface, it is discovered that a mushroom-like architecture can spontaneously and rapidly grow out from the original surface within 0.36 s. The dimension of the re-entrant micropillar array (cap diameter, pillar spacing, and height) can be accurately controlled through the intentional control of laser scanning. Followed by a fluorination and spray coating, the obtained surface can realize the repellency and manipulation of oil droplets. This work provides new opportunities in the fields of microfabrication, microfluidics, microreactor engineering, and wearable antifouling electronics.

Microrobots have attracted considerable attention due to their extensive applications in microobject manipulation and targeted drug delivery. To realize more complex micro-/nanocargo manipulation (ie.g/i., encapsulation and release) in biological applications, it is highly desirable to endow microrobots with a shape-morphing adaptation to dynamic environments. Here, environmentally adaptive shape-morphing microrobots (SMMRs) have been developed by programmatically encoding different expansion rates in a pH-responsive hydrogel. Due to a combination with magnetic propulsion, a shape-morphing microcrab (SMMC) is able to perform targeted microparticle delivery, including gripping, transporting, and releasing by "opening-closing" of a claw. As a proof-of-concept demonstration, a shape-morphing microfish (SMMF) is designed to encapsulate a drug (doxorubicin (DOX)) by closing its mouth in phosphate-buffered saline (PBS, pH ∼ 7.4) and release the drug by opening its mouth in a slightly acidic solution (pHlt; 7). Furthermore, localized HeLa cell treatment in an artificial vascular network is realized by "opening-closing" of the SMMF mouth. With the continuous optimization of size, motion control, and imaging technology, these magnetic SMMRs will provide ideal platforms for complex microcargo operations and on-demand drug release.

The origins of ligand effects on PhCF3 reductive elimination from PdII complexes were computationally investigated by using energy decomposition analysis. The results indicate weak electrostatic interactions between ligands and Ph-Pd-CF3 lead to small barriers of PhCF3 reductive elimination. Two major factors affecting the electrostatic interactions are identified.

Millirobots that can be actuated and accurately steered by external magnetic fields, are highly desirable for bioengineering and wearable devices. However, existing designs of millirobots are limited by their specific material composition, hindering their wider application due to a lack of scalability. Here, we present a method for the generation of heterogeneous magnetic millirobots based on magnetic coatings. The coatings, composed of hard-magnetic CrO

The spin-orbit interaction of light is a fundamental manifestation of controlling its angular momenta with numerous applications in photonic spin Hall effects and chiral quantum optics. However, observation of an optical spin Hall effect, which is normally very weak with subwavelength displacements, needs quantum weak measurements or sophisticated metasurfaces. Here, we theoretically and experimentally demonstrate the spin-orbit interaction of light in the form of strong chiroptical responses by breaking the in-plane inversion symmetry of a dielectric substrate. The chiroptical signal is observed at the boundary of a microdisk illuminated by circularly polarized vortex beams at normal incidence. The generated chiroptical spectra are tunable for different photonic orbital angular momenta and microdisk diameters. Our findings, correlating photonic spin-orbit interaction with chiroptical responses, may provide a route for exploiting optical information processing, enantioselective sensing, and chiral metrology.

Natural silk nanofibers (SNFs) can not only be used as good building blocks for two- or three-dimensional biomaterials but also provide a clue for understanding the theory of structure-function relationships. Nevertheless, it is still difficult to directly extract SNFs from natural silk fibers due to their high crystallinity and recalcitrant complex structures. In the present study, a dilute alkali-assisted separation of high-yield SNFs is proposed. The degummed silk was first treated with a tiny amount of alkali at a mild temperature, followed by high-pressure homogenization. Under the optimized conditions (2% sodium hydroxide, 0 °C, 48 h), SNFs with diameters of 8-42 nm and lengths of 0.9 ± 0.3 μm were prepared with yields higher than 75%, which retained the natural structures at the nanoscale and some inherent properties of silk fibers. Interestingly, SNFs can be used as a stabilizing matrix to assist carbon nanotubes (CNTs) to disperse, aiming to form a uniform and stable CNT/SNF dispersion. Thereafter, a strong and flexible conductive composite film was fabricated with good mechanical properties. The composite film showed good piezoelectric properties and electric thermal response, which has promising application prospects for SNFs, such as in optical devices, nanoelectronics, and biosensors.

Inspired by origami/kirigami, three-dimensional (3D) mesostructures assembled via a mechanics-guided approach, with reversible and maneuverable shape-morphing capabilities, have attracted great interest with regard to a broad range of applications. Despite intensive studies, the development of morphable 3D mesostructures with high-order (multi-degree-of-freedom) deformation and untethered high-frequency actuation remains challenging. This work introduces a scheme for a magnetically encoded transferable 3D mesostructure, with polyethylene terephthalate (PET) film as the skeleton and discrete magnetic domains as actuation units, to address this challenge. The high-order deformation, including hierarchical, multidirectional and blending shape morphing, is realized by encoding 3D discrete magnetization profiles on the architecture through ultraviolet curing. Reconfigurable 3D mesostructures with a modest structural modulus (∼3 GPa) enable both high-frequency (∼55 Hz) and large-deformation (∼66.8%) actuation under an alternating magnetic field. Additionally, combined with the shape-retention and adhesion property of PET, these 3D mesostructures can be readily transferred and attached to many solid substrates. On this basis, diverse functional devices, including a switchable colour letter display, liquid mixer, sequential flashlight and biomimetic sliding robot, are demonstrated to offer new perspectives for robotics and microelectronics.

Gating systems have been extensively researched in energy harvesting, lab-on-chip applications, and so forth. However, the controlled drug delivery system with artificial hydrogel-based porous gating systems (HPGSs) is rarely reported. Herein, a biomimetic HPGS with a pH-responsive hydrogel as the valve and polydimethylsiloxane as the frame is fabricated by in situ femtosecond laser microdrilling and subsequent ultraviolet exposure. The proposed HPGS loaded with doxorubicin hydrochloride (DOX) is stable under physiological conditions, has a low drug leakage rate, and can achieve sustained drug release in a low pH environment. The experimental results show that the drug release is mainly controlled by non-Fickian diffusion, which renders the dynamic speed control of molecular transport possible. Moreover, the HPGS can also be prepared into an antitumor microcapsule. The results of in vitro cell experiments demonstrate that DOX@HPGS can release drugs and achieve terrific therapeutic efficacy in the elimination of HeLa cells in the acidic environments around tumor cells. This functional HPGS is envisioned to be an ideal pH-response carrier for sustained drug release treatment of digestive diseases such as inflammatory bowel disease and gastrointestinal cancer.

The origins of regioselectivity in Ni-catalyzed alkene hydrofunctionalizations were computationally investigated by using energy decomposition analysis. The results indicate the Markovnikov selectivity with aryl-substituted alkenes is favored due to the stabilizing charge transfer effect, and the anti-Markovnikov selectivity with alkyl-substituted alkenes is favored because of the destabilizing Pauli repulsion effect.

Micromachines with high environmental adaptability have the potential to deliver targeted drugs in complex biological networks, such as digestive, neural, and vascular networks. However, the low processing efficiency and single processing material of current 4D printing methods often limit the development and application of shape-morphing micromachines (SMMs). Here, two 4D printing strategies are proposed to fabricate SMMs with pH-responsive hydrogels for complex micro-networks traversing. On the one hand, the 3D vortex light single exposure technique can rapidly fabricate a tubular SMM with controllable size and geometry within 0.1 s. On the other hand, the asymmetric multimaterial direct laser writing (DLW) method is used to fabricate SMMs with designable 3D structures composed of hydrogel and platinum nanoparticles (Pt NPs). Based on the presence of ferroferric oxide (Fe

Airy beams, which propagate along a curved trajectory, have been widely utilized in optical tweezers, biomedical analysis, and material processing. However, the dynamic regulation of nonlinear Airy beams is still challenging. Here, we demonstrate directionally switchable nonlinear Airy beams via three-dimensional (3D) nonlinear photonic crystals (NPCs) fabricated by the femtosecond laser erasing technique. The 3D NPCs contain several sequential arrays of spatially modulated nonlinearities with different spatial frequencies and cubic coefficients. By tuning the wavelength of the fundamental beam, the quasi-phase-matching condition can be switched to modulate the acceleration direction and wavelength of the generated nonlinear Airy beam. This offers a versatile platform for dynamic nonlinear Airy beam generation, paving the way for applications in optical trapping, optical communication, and biomedical imaging.

Structural color (SC) has enormous potential for improving the visualization and identification of functional micro/nano structures for information encryption and intelligent sensing. Nevertheless, achieving the direct writing of SCs at the micro/nano scale and the change of color in response to external stimuli simultaneously is rather challenging. To this end, we directly printed woodpile structures (WSs) utilizing femtosecond laser two-photon polymerization (fs-TPP), which demonstrated obvious SCs under an optical microscope. After that, we achieved the change of SCs by transferring WSs between different mediums. Furthermore, the influence of laser power, structural parameters, and mediums on the SCs was systematically investigated, and the mechanism of SCs using the finite-difference time-domain (FDTD) method was further explored. Finally, we realized the reversible encryption and decryption of certain information. This finding holds broad application prospects in smart sensing, anti-counterfeiting tags, and advanced photonic devices.

Featuring extraordinarily curved propagation trajectories, self-accelerating Airy beams have stimulated considerable interests from academic research to practical applications. However, generation of high-quality Airy beams using compact optical devices is still highly desirable. Here we present a design of integrated Airy phase plates (IAPPs) with a miniature size ( $60\,\,\mu \text{m}\,\,\times 60\,\,\mu \text{m}\,\,\times 1.1\,\,\mu \text{m}$ ). In addition, a phase-type Fresnel zone plate (FZP) is incorporated in the phase element to further reduce the system dimension, endowing the IAPPs the ability of directly generating Airy beams without introducing a bulky Fourier transform (FT) lens. The fabrication of IAPPs is facilitated by femtosecond direct laser writing (FsDLW), and the experimentally generated Airy beams are in good agreement with the numerical simulations. Furthermore, the flexible fabrication of IAPPs with different focal lengths is demonstrated, which results in the generation of Airy beams at different Fourier planes as desired. Our design strategy and fabrication methodology of the microscale three-dimensional (3D) phase plates can unfold new capacities of Airy beams for miniaturization applications in fiber optics and in on-chip photonics.

Spontaneous wrinkling of films with a thickness gradient offers a new opportunity for constructing various 3D hierarchical surface morphologies. Unfortunately, accurately and facilely controlling the gradient film thickness to yield multiscale and 3D hierarchical micro-/nanostructures is still difficult. Here, a rapid, facile, and highly controllable fabricating strategy for realizing 3D multiscale hierarchical micro-/nanofolds on a shape memory polymer (SMP) surface is reported. First, the nanoparticle film with gradient thickness is rapidly (100 ms to 4 s) and facilely obtained by laser intermittent ablation on the SMP, termed as laser ablation-induced gradient thickness film. Following one-time constrained heating, the 3D micropillars grow out of the substrate based on the "self-growing effect," and the nanoparticle gradient film on its top shrinks into multiscale micro-/nanofolds simultaneously. Significantly, the evolution process and the underlying mechanism of the 3D micro-/nanofolds are systematically investigated. Fundamental basis enables us to accurately regulate the gradient thickness of nanoparticle films and feature size of folds by varying laser scanning times and scanning path. Finally, desirable patterns on micro-/nanofolds can be readily realized by programmable laser cleaning technology, and the tunable adhesion of the water droplet on the multiscale structured surface is demonstrated, which is promising for microdroplet manipulation.

Functional microdevices based on responsive hydrogel show great promise in targeted delivery and biomedical analysis. Among state-of-the-art techniques for manufacturing hydrogel-based microarchitectures, femtosecond laser two-photon polymerization distinguishes itself by high designability and precision, but the point-by-point writing scheme requires mechanical apparatuses to support focus scanning. In this work, by predesigning holograms combined with lens phase modulation, multiple femtosecond laser spots are holographically generated and shifted for prototyping of three-dimensional shape-morphing structures without any moving equipment in the construction process. The microcage array is rapidly fabricated for high-performance target capturing enabled by switching environmental pH. Moreover, the built scaffolds can serve as arrayed analytical platforms for observing cell behaviors in normal or changeable living spaces or revealing the anticancer effects of loaded drugs. The proposed approach opens a new path for facile and flexible manufacturing of hydrogel-based functional microstructures with great versatility in micro-object manipulation.

The origins of the reactivity of strain-increase allylborations were computationally investigated. The low reactivity of vinylcyclopropyl boronates is due to weak electronic interactions between benzaldehyde and allylboronates. By increasing the acidity of the boron center, the reactivity is significantly improved because the stronger stabilizing O→B interaction effectively compensates for destabilizing steric effects.

White-light non-diffraction beams such as Airy beam and Bessel beam have potential applications in multispectral imaging and micromanipulation. Generation of white-light Airy beam and Bessel beam with high quality and high efficiency still remains challenging for conventional diffractive or refractive optics which suffers from significant chromatic dispersion. In this paper, both high-quality white-light Airy beam and Bessel beam are generated using a deformable mirror by modulating the incident LED beam with tunable cubic and conical wavefronts. The main lobe of the generated white-light non-diffraction beams does not suffer from chromatic dispersion along the propagation. The results also show that the generation of the white-light Bessel beam has higher requirements for spatial coherence than white-light Airy beams. Our work expands the understanding of the white-light non-diffraction beams and paves the way for the applications.

The accessibility to long, branched and complex glycans containing many 1,2

Bionanomaterial based hydrogels originated from natural biopolymer have drawn much attention for advanced applications. However, nanosilk-based hydrogels derived from top-down approaches remain in their infancy. First, nanosilks based on existing methods fail to prepare hydrogels; second, both nanosilk extraction and surface modification remain a challenge due to high crystallinity and sophisticated hierarchical structures. To produce nanosilk-based hydrogels, pretreatment and oxidation are necessary. In this work, pretreatments were conducted first to loosen the sophisticated structures of natural silk fibers, NaClO oxidation was utilized in succession to introduce carboxyl groups onto silk fibroin. Combined with moderate mechanical disintegration, silk nanocrystals with additional carboxyl groups were prepared facilely. Finally, silk nanocrystal-based hydrogels were prepared successfully through gas phase coagulation. An optimization of pretreatment approaches and oxidation conditions was carried out. The morphologies, chemical and crystalline structures of original, pretreated and oxidized silk fibroin as well as nanofibrillated silk were investigated. In addition, the silk nanocrystal-based hydrogel exhibited outstanding mechanical properties compared to those of dissolved and regenerated silk fibroin-based hydrogels. Moreover, silk nanocrystal-based aerogels present highly porous, interconnected, and crisscrossed network nanostructures, which are ideal candidates for tissue regeneration and provide new prospects as porous scaffolds for bioengineering applications.

Manipulating underwater bubbles (UGBs) is realized on morphology-tailored or stimuli-responsive slippery lubricant-impregnated porous surface (SLIPS). Unfortunately, the volatile lubricants (e. g., silicone oil, ferrofluid) greatly decrease their using longevity. Designed is light-responsive paraffin-infused Fe3O4-doped slippery surface (LR-PISS) by incorporation of hybrid lubricants and superhydrophobic micropillar-arrayed elastometric membranes resulted from one-step femtosecond laser vertically scanning. Upon LR-PISS, the dynamic motion control bwteen pinning and sliding along free routes over UGB could be realized by alternately loading/discharging NIR-trigger. The underlying principle is that when the NIR was applied, UGB would be actuated to slide along the NIR trace because the irradiated domain melts for a slippery surface within 1.0 s. Once the NIR is removed, the liquefied paraffin would be reconfigured to solid phase for pinning a moving UGB within 0.5 s. Newly explored hydrokinetics imparts us with capability of steering UGBs to arrange any desirable patterns and switch light-path behaving as the light-control-light optical shutter. In comparison with previously reported SLIPS, current LR-PISS unfolds unparalleled ultrarobust antidisturbance ability even in flowing liquid ambient. More significantly, even subjected to physical damage, underwater LR-PISS is capable of in situ self-healing within 13 s under the assistance of remote NIR. The results here could inspire the design of robust bubble manipulator and further boost their applications in optofluidics and all-optical modulators.

Optical activity, demonstrating the chiral light-matter interaction, has attracted tremendous attention in both fundamental theoretical research and advanced applications of high-efficiency enantioselective sensing and next-generation chiroptical spectroscopic techniques. However, conventional chiroptical responses are normally limited in large assemblies of chiral materials by circularly polarized light, exhibiting extremely weak chiroptical signals in a single chiral nanostructure. Here, we demonstrate that an alternative chiral freedom of light-orbital angular momentum-can be utilized for generating strong helical dichroism in single chiral nanostructures. The helical dichroism by monochromatic vortex beams can unambiguously distinguish the intrinsic chirality of nanostructures, in an excellent agreement with theoretical predictions. The single planar-chiral nanostructure can exhibit giant helical dichroism of ∼20% at the visible wavelength. The vortex-dependent helical dichroism, expanding to single nanostructures and two-dimensional space, has implications for high-efficiency chiroptical detection of planar-chiral nanostructures in chiral optics and nanophotonic systems.

The current understanding of Lewis acid effects on transition metal catalysis is generally based on the enhanced charge transfer from metal to substrate due to the formation of Lewis acid–base adducts. The critical factors of how Lewis acids manipulate complex catalyst–substrate interactions to facilitate reactions are seldom clarified. Herein, using the energy decomposition approach, we quantify the contributions of multiple factors which account for the Lewis acid acceleration in Ni-catalyzed C–X (X = H, C, O) bond cleavage via oxidative addition. The results reveal that the dominant factors for Lewis acid promotion highly depend on the features of transition states with Lewis acids. In the transition states having only heteroatom–Lewis acid interactions (e.g., C–H, C–CN and C(acyl)–O oxidative additions), the reactivity is improved majorly by enhancing charge transfer from the metal to the Lewis acid-activated substrates, which is consistent with the conventional viewpoint. However, for the transition states with heteroatom–Lewis acid and heteroatom–transition metal interactions (e.g., C(benzyl)–O and C(aryl)–O oxidative additions), the decisive factor for the improved reactivity is ascribed to the reduced Pauli repulsion between occupied orbitals. Further, in the transition states having heteroatom–Lewis acid and Lewis acid–transition metal interactions (e.g., C(benzyl)–O oxidative addition), the reaction is facilitated by strengthening electrostatics and polarization due to greater charge separation and electron delocalization effects. These three types of dominant factors are generally employed by a series of different Lewis acids in promoting Ni-catalyzed bond cleavage.

A novel activity-based Cu2+ fluorescent probe featuring multidentate binding sites was synthesized. It functions through chelation with Cu2+, which in turn specifically triggers hydrolysis of the probe to release a near-infrared emission with AIE + ESIPT properties. The probe was found to be capable of ratiometric imaging of Cu2+ in living HeLa cells.

The mechanism and origin of stereoselectivity of silver-catalyzed hydroalkylation of alkynes were computationally investigated at the B3LYP-D3BJ/6-311+G(d,p)-SDD//B3LYP/6-31G(d)-LANL2DZ level. The complex of alkynyl trialkylboronate with cationic silver is a key intermediate, which triggers the rate- and stereoselectivity-determining 1,2-migration step. Energy decomposition analysis indicates that the difference of Pauli repulsion dominates the stereoselectivity.