First Evidence of ψ(3770) Hadronic Transition to J/ψπ+π—

Evidence of ψ(3770) decays to a non-DD final state is observed. A total of 6.8±3.0 ψ(3770)→J/ψ→π⁺π^— events are obtained from a data sample of 8.0±0.5 pb^-1 taken at center-of-mass energies around 3.773GeV using the BES-Ⅱ detector at the BEPC. The branching fraction is determined to be BF(ψ(3770)→J/ψ→π⁺π^—)=(0.59±0.26±0.16)%, corresponding to the partial width of Γ(ψ(3770)→J/ψπ⁺π^—)=(139±61±41)keV.     

水滑石层间阴离子为还原剂原位负载贵金属纳米颗粒

研究了以水滑石为载体原位负载贵金属纳米颗粒(Pd、Ag、Ru、Au)的方法,通过共沉淀合成甲酸根水滑石,以层间甲酸根为还原剂原位还原贵金属前驱体制得高分散水滑石(LDH)负载纳米颗粒。本方法无需载体预处理,操作方便、适用性强,阴离子前驱体(Au)和阳离子前驱体(Pd、Ag、Ru)均可顺利得到纳米颗粒。所得水滑石负载纳米颗粒系一种潜在的纳米催化剂,作为示例,Pd/LDH在Suzuki偶联反应中显示出较高催化活性。     

A penetrable interactive 3D display based on motion recognition (Invited Paper)

Based on light field reconstruction and motion recognition technique,a penetrable interactive floating 3D display system is proposed.The system consists of a high-frame-rate projector,a flat directional diffusing screen,a high-speed data transmission module,and a Kinect somatosensory device.The floating occlusioncorrect 3D image could rotate around some axis at different speeds according to user’s hand motion.Eight motion directions and speed are detected accurately,and the prototype system operates efficiently with a recognition accuracy of 90%on average.     

合成气制混合醇双功能催化研究进展

混合醇合成要求催化剂具备至少两类活性中心, 一类用于解离吸附CO以生成烷基链, 另一类用于非解离吸附CO以使烷基链含氧化生成醇. 两类中心通过协同作用共同构成混合醇合成所需的双活性中心. 简要综述了近年来合成气制混合醇过程中涉及的双功能催化研究进展, 并以几类典型的催化剂体系为例, 从双活性中心的构筑、典型的双活性中心结构、反应过程中双活中心结构的演变等方面进行了阐述. 混合醇催化剂的研发应从纳米尺度上对催化剂进行设计, 使催化剂表面具有足够多的双活性中心, 并设法稳定催化剂的双活性中心结构.     

A novel ferroceneylazobenzene self-assembled monolayer on an ITO electrode: photochemical and electrochemical behaviors

A novel ferroceneylazobenzene self-assembled monolayer (SAM) has been constructed on an indium-tin oxide (ITO) electrode via the covalent attachment of 4-(4'-11-ferrocenyl-undecanoxyphenylazo)benzoic acid ( FcAzCOOH) onto a silanized ITO substrate surface and verified by reflectance infrared spectroscopy and water contact angle. Atomic force microscopy (AFM) and cyclic voltammogram (CV) indicated that the FcAzCOOH formed a uniform and reproducible SAM on the ITO electrode with a surface coverage of ca. 1.9 x 10 (-10) mol/cm (2) (87 A (2)/molecule). The reversible photoisomerization behavior of the SAM was characterized by UV-vis spectra. The azo pi-pi* transition band intensity of the SAM gradually decreased with UV (365 nm) irradiation and was almost recovered again when subsequent exposure to ambient room light (400-800 nm). The increased tilt angle of the molecules on the ITO substrate after UV irradiation further confirmed the trans-to- cis isomerization of azobenzene moieties. The CV of the trans- FcAzCOOH modified ITO electrode showed a pair of waves due to redox of the ferrocene groups in the potential range of 0 to +800 mV (vs SCE), and the peak separation of the redox wave became larger after UV irradiation and almost returned to its original value after subsequent exposure to the visible light. Rate-dependent CV curves indicated that the charge transfer rate between the ferrocene species in the SAM and the ITO electrode was slowed down after UV irradiation due to the smaller porosity of the monolayer film and the more compact barrier layer between the redox species and the ITO electrode. It is the first time to directly observe the influence of photoisomerization of the azobenzene moiety on the redox behavior of redox species in the ferroceneylazobenzene-functionalized SAM. The present results provide profound insight into the role of redox microenvironment on electron transfer kinetics and also provide a simple and facile approach to the preparation of photocontrollable electrodes.     

Multiple Hydrogen Bonding Enables the Self-Healing of Sensors for Human–Machine Interactions

Despite its widespread use in signal collection, flexible sensors have been rarely used in human–machine interactions owing to its indistinguishable signal, poor reliability, and poor stability when inflicted with unavoidable scratches and/or mechanical cuts. A highly sensitive and self-healing sensor enabled by multiple hydrogen bonding network and nanostructured conductive network is demonstrated. The nanostructured supramolecular sensor displays extremely fast (ca. 15 s) and repeatable self-healing ability with high healing efficiency (93 % after the third healing process). It can precisely detect tiny human motions, demonstrating highly distinguishable and reliable signals even after cutting–healing and bending over 20 000 cycles. Furthermore, a human–machine interaction system is integrated to develop a facial expression control system and an electronic larynx, aiming to control the robot to assist the patient's daily life and help the mute to realize real-time speaking.     

Excited‐State Deactivation of Branched Phthalocyanine Compounds

The excited‐state relaxation dynamics and chromophore interactions in two phthalocyanine compounds (bis‐ and trisphthalocyanines) are studied by using steady‐state and femtosecond transient absorption spectral measurements, where the excited‐state energy‐transfer mechanism is explored. By exciting phthalocyanine compounds to their second electronically excited states and probing the subsequent relaxation dynamics, a multitude of deactivation pathways are identified. The transient absorption spectra show the relaxation pathway from the exciton state to excimer state and then back to the ground state in bisphthalocyanine (bis‐Pc). In trisphthalocyanine (tris‐Pc), the monomeric and dimeric subunits are excited and the excitation energy transfers from the monomeric vibrationally hot S1 state to the exciton state of a pre‐associated dimer, with subsequent relaxation to the ground state through the excimer state. The theoretical calculations and steady‐state spectra also show a face‐to‐face conformation in bis‐Pc, whereas in tris‐Pc, two of the three phthalocyanine branches form a pre‐associated face‐to‐face dimeric conformation with the third one acting as a monomeric unit; this is consistent with the results of the transient absorption experiments from the perspective of molecular structure. The detailed structure–property relationships in phthalocyanine compounds is useful for exploring the function of molecular aggregates in energy migration of natural photosynthesis systems.     

Reply to the Comment on “Realization of Lewis Basic Sodium Anion in the NaBH3− Cluster”

We reply to the comment by S. Pan and G. Frenking who challenged our interpretation of the Na⁻:→BH₃ dative bond in the recently synthesized NaBH₃⁻ cluster. Our conclusion remains the same as that in our original paper ( https://doi.org/10.1002/anie.201907089 and https://doi.org/10.1002/ange.201907089 ). This conclusion is additionally supported by the energetic pathways and NBO charges calculated at UCCSD and CASMP2(4,4) levels of theory. We also discussed the suitability of the Laplacian of electron density (QTAIM) and Adaptive Natural Density Partitioning (AdNDP) method for bond type assignment. It seems that AdNDP yields more sensible results. This discussion reveals that the complex realm of bonding is full of semantic inconsistencies, and we invite experimentalists and theoreticians to elaborate this topic and find solutions incorporating different views on the dative bond.     

A Mitochondrion-Localized Two-Photon Photosensitizer Generating Carbon Radicals Against Hypoxic Tumors

The efficacy of photodynamic therapy is typically reliant on the local concentration and diffusion of oxygen. Due to the hypoxic microenvironment found in solid tumors, oxygen-independent photosensitizers are in great demand for cancer therapy. We herein report an iridium(III) anthraquinone complex as a mitochondrion-localized carbon-radical initiator. Its emission is turned on under hypoxic conditions after reduction by reductase. Furthermore, its two-photon excitation properties (λ_ex=730 nm) are highly desirable for imaging. Upon irradiation, the reduced form of the complex generates carbon radicals, leading to a loss of mitochondrial membrane potential and cell death (IC₅₀^light=2.1 μm , IC₅₀^dark=58.2 μm , PI=27.7). The efficacy of the complex as a PDT agent was also demonstrated under hypoxic conditions in vivo. To the best of our knowledge, it is the first metal-complex-based theranostic agent which can generate carbon radicals for oxygen-independent two-photon photodynamic therapy.