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  • Raising the capacity of lithium vanadium phosphate via anion and cation co-substitution
    Sci. China Chem. (IF 6.085) Pub Date : 2020-01-02
    Xian-Xiang Zeng, Hui Chen, Gang Guo, Sheng-Yi Li, Jin-Ying Liu, Qiang Ma, Guote Liu, Ya-Xia Yin, Xiong-Wei Wu, Yu-Guo Guo

    Abstract The pursuit for batteries with high specific energy provokes the research of high-voltage/capacity cathode materials with superior stability and safety as the alternative for lithium iron phosphate. Herein, using the sol-gel method, a lithium vanadium phosphate with higher average discharge voltage (3.8 V, vs. Li+/Li) was obtained from a single source for Mg2+ and Cl− co-substitution and uniform carbon coating, and a nearly theoretical capacity (130.1 mA h g−1) and outstanding rate performance (25 C) are acquired together with splendid capacity retention (80%) after 650 cycles. This work reveals that the well-sized anion and cation substitution and uniform carbon coating are of both importance to accelerate kinetic performance in the context of nearly undisturbed crystal structure for other analogue materials. It is anticipated that the electrochemistry comprehension will shed light on preparing cathode materials with high energy density in the future.

    更新日期:2020-01-04
  • Photocatalysis: an overview of recent developments and technological advancements
    Sci. China Chem. (IF 6.085) Pub Date : 2019-12-30
    Yuanxing Fang, Yun Zheng, Tao Fang, Yong Chen, Yaodong Zhu, Qing Liang, Hua Sheng, Zhaosheng Li, Chuncheng Chen, Xinchen Wang

    Abstract Photocatalysis, which is the catalyzation of redox reactions via the use of energy obtained from light sources, is a topic that has garnered a lot of attention in recent years as a means of addressing the environmental and economic issues plaguing society today. Of particular interest are photosynthesis can potentially mimic a variety of vital reactions, many of which hold the key to develop sustainable energy economy. In light of this, many of the technological and procedural advancements that have recently occurred in the field are discussed in this review, namely those linked to: (1) photocatalysts made from metal oxides, nitride, and sulfides; (2) photocatalysis via polymeric carbon nitride (PCN); and (3) general advances and mechanistic insights related to TiO2-based catalysts. The challenges and opportunities that have arisen over the past few years are discussed in detail. Basic concepts and experimental procedures which could be useful for eventually overcoming the problems associated with photo-catalysis are presented herein.

    更新日期:2020-01-04
  • A pH-regulated stimuli-responsive strategy for RNA-cleaving DNAzyme
    Sci. China Chem. (IF 6.085) Pub Date : 2019-12-18
    Shasha Lu, Shuang Wang, Jiahui Zhao, Jian Sun, Xiurong Yang

    RNA-cleaving DNAzymes possess important roles in DNAzymes and have been widely used in the biosensors, DNA nanomachines owing to their ion-specific dependence. However, there are still challenges in constructing universal but versatile stimuli-responsive strategies of RNA-cleaving DNAzymes. Herein, a stimuli-responsive strategy for RNA-cleaving DNAzyme is proposed by the artful design of hairpin nanostructure, in which the activities of DNAzyme (Pb2+-dependent DNAzyme as a model) in the hairpin’s loop are pH-regulated by using the triplex stem as the “lock”. Upon introducing the “key”, pH values, the DNAzyme will be activated and fragment the substrate of it in the presence of Pb2+, accompanied by the turn-on of the fluorescence quenched by fluorescence resonance energy transfer (FRET). The regulation ability of pH can be controlled by the length and sequence of the triplex stem, and the wide pH regulation range may be helpful for the application of DNAzymes in biological medicine delivery systems.

    更新日期:2019-12-20
  • Erratum on “Ozonated graphene oxides as high efficient sorbents for Sr(II) and U(VI) removal from aqueous solutions”
    Sci. China Chem. (IF 6.085) Pub Date : 2019-06-04
    Xia Liu, Xiangxue Wang, Jiaxing Li, Xiangke Wang

    We regret that our article “Ozonated graphene oxides as high efficient sorbents for Sr(II) and U(VI) removal from aqueous solutions ” (Sci China Chem, 2016, 59: 869–877) contained errors. The corrections in an erratum do not change or affect the result or conclusion of the paper. The Figure 2(a, b) in the original paper is in error, which results in the TEM and SEM images of GO have a big difference with the description.

    更新日期:2019-12-20
  • Erratum on “Complexation of radionuclide 152+154 Eu(III) with alumina-bound fulvic acid studied by batch and time-resolved laser fluorescence spectroscopy”
    Sci. China Chem. (IF 6.085) Pub Date : 2019-05-21
    Xiangxue Wang, Shujun Yu, Zhongshan Chen, Wencheng Song, Yuantao Chen, Tasawar Hayat, Ahmed Alsaedi, Wei Guo, Jun Hu, Xiangke Wang

    In the above referenced publication [1], the Figure 5 and data in Table 1 are correct, but we ignored to present the final pH values of the system, which is very important to understand the properties.

    更新日期:2019-12-20
  • Temperature-induced Sn(II) supramolecular isomeric frameworks as promising heterogeneous catalysts for cyanosilylation of aldehydes
    Sci. China Chem. (IF 6.085) Pub Date : 2019-12-11
    Kai Sheng, Li-Ming Fan, Xue-Fei Tian, Rakesh Kumar Gupta, Linna Gao, Chen-Ho Tung, Di Sun

    Two novel Sn(II) supramolecular isomeric frameworks, with the identical formula of {(NH2Me2)2[Sn(BDC)(SO4)]}n, Sn-CP-1-α (1) and Sn-CP-1-β (2) (H2BDC=terephthalic acid) were synthesized under solvothermal condition and fully characterized by single crystal X-ray diffraction (SCXRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), elemental analyses, and thermogravimetric analysis (TGA). Interestingly, the structures of 1 and 2 are governed by the temperature of the reaction, suggesting a temperature-induced supramolecular isomerism. The supramolecular isomers are primarily caused by the different bridging alignments of SO42−. Compounds 1 and 2 display 2D layer and 3D framework with different topologies, non-interpenetrated 44-sql and two-fold interpenetrated 4-connected dia topology, respectively. Due to Lewis acid properties of coordinatively unsaturated Sn(II) sites in CPs, they have been utilized as heterogeneous catalyst for the cyanosilylation of aldehydes with an excellent conversion yield over 99% under solvent-free conditions.

    更新日期:2019-12-17
  • Efficient and stable tin-based perovskite solar cells by introducing π -conjugated Lewis base
    Sci. China Chem. (IF 6.085) Pub Date : 2019-12-11
    Tianhao Wu, Xiao Liu, Xin He, Yanbo Wang, Xiangyue Meng, Takeshi Noda, Xudong Yang, Liyuan Han

    Tin-based perovskite solar cells (TPSCs) as the most promising candidate for lead-free PSCs have incurred extensive researches all over the world. However, the crystallization process of tin-based perovskite is too fast during the solution-deposited process, resulting in abundant pinholes and poor homogeneity that cause serious charge recombination in perovskite layer. Here, we employed the π-conjugated Lewis base molecules with high electron density to systematically control the crystallization rate of FASnI3 perovskite by forming stable intermediate phase with the Sn-I frameworks, leading to a compact and uniform perovskite film with large increase in the carrier lifetime. Meanwhile, the introduction of the π-conjugated systems also retards the permeation of moisture into perovskite crystal, which significantly suppresses the film degradation in air. These benefits contributed to a stabilizing power conversion efficiency (PCE) of 10.1% for the TPSCs and maintained over 90% of its initial PCE after 1000-h light soaking in air. Also, a steady-state efficiency of 9.2% was certified at the accredited test center.

    更新日期:2019-12-17
  • Side chain engineering of quinoxaline-based small molecular nonfullerene acceptors for high-performance poly(3-hexylthiophene)-based organic solar cells
    Sci. China Chem. (IF 6.085) Pub Date : 2019-12-11
    Bo Xiao, Qianqian Zhang, Gongqiang Li, Mengzhen Du, Yanfang Geng, Xiangnan Sun, Ailing Tang, Yingliang Liu, Qiang Guo, Erjun Zhou

    Poly(3-hexylthiophene) (P3HT) is one of the most used semiconducting polymers for organic photovoltaics because it has potential for commercialization due to its easy synthesis and stability. Although the rapid development of the small molecular non-fullerene acceptors (NFAs) have largely improved the power conversion efficiency (PCE) of organic solar cells (OSCs) based on other complicated p-type polymers, the PCE of P3HT-based OSCs is still low. In addition, the design principle and structure-properties correlation for the NFAs matching well with P3HT are still unclear and need to be investigated in depth. Here we designed a series of NFAs comprised of acceptor (A) and donor (D) units with an A2-A1-D-A1-A2 configuration. These NFAs are abbreviated as Qx3, Qx3b and Qx3c, where indaceno[1,2-b:5,6-b′]dithiophene (IDT), quinoxaline (Qx) and 2-(1,1-dicyanomethylene)rhodanine serve as the middle D, bridged A1 and the end group A2, respectively. By subtracting the phenyl side groups appended on both IDT and Qx skeletons, the absorption spectra, energy levels and crystallinity could be regularly modulated. When paired with P3HT, three NFAs show totally different photovoltaic performance with PCEs of 3.37% (Qx3), 6.37% (Qx3b) and 0.03% (Qx3c), respectively. From Qx3 to Qx3b, the removing of phenyl side chain in the middle IDT unit results in the increase of crystallinity and electron mobility. However, after subtracting all the grafted phenyl side groups on both IDT and Qx units, the final molecule Qx3c exhibits the lowest PCE of only 0.03%, which is mainly attributed to the serious phase-separation of the blend film. These results demonstrate that optimizing the substituted position of phenyl side groups for A2-A1-D-A1-A2 type NFAs is vital to regulate the optoelectronic property of molecule and morphological property of active layer for high performance P3HT-based OSCs.

    更新日期:2019-12-17
  • Cobalt-containing covalent organic frameworks for visible light-driven hydrogen evolution
    Sci. China Chem. (IF 6.085) Pub Date : 2019-12-12
    Jian Wang, Jian Zhang, Shing Bo Peh, Guoliang Liu, Tanay Kundu, Jinqiao Dong, Yunpan Ying, Yuhong Qian, Dan Zhao

    Covalent organic frameworks (COFs) have recently emerged as a new class of photocatalysts. However, integrated design is crucial to maximizing the performance of COF-incorporating photocatalytic systems. Herein, we compare two strategies of installing earth-abundant metal-based catalytic centers into the matrice of a 2D COF named NUS-55. Compared to NUS-55(Co) prepared from the post-synthetic metalation of coordination sites within the COF, the molecular co-catalyst impregnated NUS-55/[Co(bpy)3]Cl2 achieves a seven-fold improvement in visible light-driven H2 evolution rate to 2,480 µmol g−1 h−1, with an apparent quantum efficiency (AQE) of 1.55% at 450 nm. Our results show that the rational design of molecular anchoring sites in COFs for the introduction of catalytic metal sites can be a viable strategy for the development of highly efficient photocatalysts with enhanced stability and photocatalytic activities.

    更新日期:2019-12-13
  • Erratum on “Reductive immobilization of Re(VII) by graphene modified nanoscale zero-valent iron particles using a plasma technique”
    Sci. China Chem. (IF 6.085) Pub Date : 2019-11-27
    Jie Li, Changlun Chen, Rui Zhang, Xiangke Wang

    We regret that our article “Reductive immobilization of Re(VII) by graphene modified nanoscale zero-valent iron particles using a plasma technique” (Sci. China Chem., 2016, 59: 150–158) [1] contained errors. The corrections in an erratum do not change or affect the result or conclusion of the paper.

    更新日期:2019-11-30
  • A novel 58-nuclei silver nanowheel encapsulating a subvalent Ag 6 4+ kernel
    Sci. China Chem. (IF 6.085) Pub Date : 2019-11-27
    Zhi Wang, Qing-Ping Qu, Hai-Feng Su, Peng Huang, Rakesh Kumar Gupta, Qing-Yun Liu, Chen-Ho Tung, Di Sun, Lan-Sun Zheng

    The combination of CrO42− anion and N,N′-dimethylformamide (DMF)-containing solvent helps to stabilize an atom-precise ultrasmall Ag6 kernel into a 52-nuclei silver shell, giving a core-shell Ag6@Ag52 wheel-like structure (SD/Ag58b). The solution behavior and photocurrent response property were investigated in details.

    更新日期:2019-11-30
  • Para -selective borylation of monosubstituted benzenes using a transient mediator
    Sci. China Chem. (IF 6.085) Pub Date : 2019-11-27
    Jie Wu, Zengwei Wang, Xiao-Yue Chen, Yichen Wu, Daoming Wang, Qian Peng, Peng Wang

    Herein, we conceptualized a transient mediator approach that has the capability of para-selective C-H functionalization of monosubstituted aromatics. This approach is enabled by in situ generation of a versatile sulfonium salt via highly electrophilic phenoxathiine or thianthrene dication intermediate which can be readily generated from its sulfoxide with tri-fluoromethanesulfonic anhydride. Preliminary mechanistic study implied that the remarkable para selectivity might be related to the incredible electrophilicity of thianthrene dication intermediate. The versatility of this approach was demonstrated via para-borylation of various monosubstituted simple aromatics combining the sulfonium salt formation with further photocatalyzed transformation.

    更新日期:2019-11-30
  • Simultaneous bioimaging of MMP-2 and MMP-7 via Au-Se constructed fluorescence nanoprobe
    Sci. China Chem. (IF 6.085) Pub Date : 2019-11-27
    Xiaonan Gao, Wenfei Guo, Lulu Jiang, Bo Hu, Xiaojun Liu, Kehua Xu, Bo Tang

    Au-Se bond strategy has been applied to construct fluorescence nanoprobe that is being used to simultaneously dual-image the tumor markers matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-7 (MMP-7) in vitro. The two Se-terminating ligand peptide chains respectively labeled with fluorescein isothiocyanate (FITC) and 5-Carboxytetramethylrhodamine (5-TAMRA) dyes are attached to the surface of Au nanoparticles (NPs). The nanoprobe can be specifically cut off by MMP-2 and MMP-7 respectively to carry out significant enhanced fluorescence recovery for simultaneously imaging both markers. The nanoprobe not only displays high selectivity and sensitivity towards MMP-2 and MMP-7, but also has strong anti-interference stability against biothiols and enhanced fidelity for avoiding ‘false positive’ results. This approach offers new perspectives in designing tumor-related early diagnosis approaches and also provides strategies for clinical applications.

    更新日期:2019-11-30
  • Fluorescence detection of hydroxyl radical generated from oxygen reduction on Fe/N/C catalyst
    Sci. China Chem. (IF 6.085) Pub Date : 2019-11-27
    Li-Na Chen, Wen-Song Yu, Tao Wang, Xiao-Dong Yang, Hui-Juan Yang, Zhi-Xin Chen, Tan Wang, Na Tian, Zhi-You Zhou, Shi-Gang Sun

    Pyrolyzed Fe/N/C catalyst has been considered as the most promising candidate to replace Pt for oxygen reduction reaction (ORR) in fuel cells. However, poor stability of Fe/N/C catalyst, mainly attributed to the oxidation corrosion by aggressive •OH radical, severely hampers its applications. However, the exact mechanism for generation of •OH is unclear yet. Herein, we developed a fluorescent method to effectively detect •OH generated from ORR on Fe/N/C catalyst by using coumarin as a fluorescent probe. A great difference in potential dependence between •OH and H2O2 generated from the ORR was observed, which suggests that •OH is not generated from the decomposition of H2O2 as traditional viewpoint.

    更新日期:2019-11-30
  • Aromatic inorganic acid radical
    Sci. China Chem. (IF 6.085) Pub Date : 2019-11-26
    Jiawen Zhou, Weiya Zhu, Miao Zeng, Qingqing Yang, Ping Li, Linfeng Lan, Junbiao Peng, Yuan Li, Fei Huang, Yong Cao

    Stable radicals are challenging to prepare due to their intrinsic high reactivity. Herein, three trisphenolamine radicals were readily synthesized and exhibited unexpected thermal/electrochemical stability and semiconductor property. These three nitroxide radicals could be considered as a class of aromatized nitro groups or HNO3 derivatives. The closed-shell nitro-like and open-shell nitroxide resonance structure contribute to their outstanding stability. Furthermore, the tunable ground states, extremely low band gap and p-type charge transport properties were systematically investigated. More importantly, the work presents the concept of aromatic inorganic acid radical (AIAR) and aggregation-induced radical (AIR) mechanism to understand the intrinsic structure-property relationship of these radicals. In addition, we provide a novel strategy for the design of stable and low bandgap radicals for organic electronics, magnetics, spintronics, etc.

    更新日期:2019-11-28
  • Integrating photocatalytic reduction of CO 2 with selective oxidation of tetrahydroisoquinoline over InP–In 2 O 3 Z-scheme p-n junction
    Sci. China Chem. (IF 6.085) Pub Date : 2019-11-18
    Bohang Zhao, Yi Huang, Dali Liu, Yifu Yu, Bin Zhang

    The development of a facile strategy to construct stable hierarchal porous heterogeneous photocatalysts remains a great challenge for efficient CO2 reduction. Additionally, hole-trapping sacrificial agents (e.g., triethanolamine, triethylamine, and methanol) are mostly necessary, which produce useless chemicals, and thus cause costs/environmental concerns. Therefore, utilizing oxidation ability of holes to develop an alternative photooxidation reaction to produce value-added chemicals, especially coupled with CO2 photoreduction, is highly desirable. Here, an in situ partial phosphating method of In2O3 is reported for synthesizing InP–In2O3 p-n junction. A highly selective photooxidation of tetrahydroisoquinoline (THIQ) into value-added dihydroisoquinoline (DHIQ) is to replace the hole driven oxidation of typical sacrificial agents. Meanwhile, the photoelectrons of InP–In2O3 p-n junction can induce the efficient photoreduction of CO2 to CO with high selectivity and stability. The evolution rates of DHIQ and CO are 2 and 3.8 times higher than those of the corresponding In2O3 n-type precursor, respectively. In situ irradiated X-ray photoelectron spectroscopy and electron spin resonance are utilized to confirm that the direct Z-scheme mechanism of InP–In2O3 p-n junction accelerate the efficient separation of photocarriers.

    更新日期:2019-11-20
  • Near-infrared electrochromism of multilayer films of a cyclometalated diruthenium complex prepared by layer-by-layer deposition on metal oxide substrates
    Sci. China Chem. (IF 6.085) Pub Date : 2019-11-13
    Zhi-Juan Li, Chang-Jiang Yao, Yu-Wu Zhong

    A cyclometalated diruthenium complex 2 bridged by 1,2,4,5-tetra(pyrid-2-yl)benzene with six carboxylic acid groups at two ends was synthesized. Monolayer and multilayer films FTO/TiO2/(2)n(Zr) (n=1,2) and FTO/SnO2:Sb/(2)n(Zr) (n=1–4) have been prepared via interfacial layer-by-layer coordination assembly of 2 with zirconium(IV) ions. All films show two consecutive redox couples in the potential range between 0 and +1.0 V vs. Ag/AgCl. These films exhibit reversible near-infrared electrochromism upon switching of redox potential. The response time of the films on SnO2:Sb is around a few seconds, while that on TiO2 is around a few tens of seconds. The film deposition cycles were found to have a great impact on the electrochromic performance. Among six films examined, the two-layered film on SnO2:Sb displays the best balanced performance with a contrast ratio of 56% at 1,150 nm and good cyclic stability (9% loss of contrast ratio after 1,000 continuous double-potential-switching cycles), which is superior to that of the previously reported electropolymerized films of a related diruthenium complex with the same bridging ligand. In addition, the X-ray photoelectron spectroscopy, scanning electron microscopy, and electron transfer mechanism of these films have been investigated.

    更新日期:2019-11-18
  • The effect of alkyl chain branching positions on the electron mobility and photovoltaic performance of naphthodithiophene diimide (NDTI)-based polymers
    Sci. China Chem. (IF 6.085) Pub Date : 2019-11-13
    Jing Yang, Ning An, Su Sun, Xiangnan Sun, Masahiro Nakano, Kazuo Takimiya, Bo Xiao, Erjun Zhou

    Conjugated polymers are widely used in organic optoelectronic devices due to their solution processability, thermal stability and structural diversity. Generally, alkyl side chains must be utilized to increase the solubility of final polymers in the processing solvent. However, the effects of different type alkyl chains on the properties of n-type photovoltaic polymers have rarely been investigated. In this article, we synthesized three naphthodithiophene diimide (NDTI) based polymers containing bulky alkyl chains with different branching position, named as NDTI-1, NDTI-2 and NDTI-3, respectively. We systematically investigated the effect of different branching point on the molecular packing, charge transport and photovoltaic performance. When moving the branching point away from the backbone, the intermolecular interaction became stronger, which could be proved by 2D grazing incidence wide angle X-ray scattering (GIWAXS) measurement. Therefore, the electron mobilities in organic field-effect transistors gradually increased from 2.11×10−3 cm2 V−1 s−1 for NDTI-1 to 4.70×10−2 cm2 V−1 s−1 for NDTI-2 and 9.27×10−2 cm2 V−1 s−1 for NDTI-3, which are quite high values for polymers with face-on orientation. In addition, the NDTI-2 and NDTI-3 thin films exhibited red-shifted absorption spectra compared with NDTI-1. When blending with three classic donor polymers PBDB-T, PTB7-Th and PE61, NDTI-2 based devices always showed the higher power conversion efficiencies (PCEs) than the other two polymers (beside the comparable result of PTB7-Th:NDTI-3 combination) as a result of the high photocurrent response and high fill factor. Our results indicate that bulky alkyl chain with branching point at 2-position should be a good and safe choice for the design of naphthodithiophene diimide-based and even naphthalene diimide-based n-type photovoltaic polymers.

    更新日期:2019-11-18
  • Inactivity of YGL082W in vitro due to impairment of conformational change in the catalytic center loop
    Sci. China Chem. (IF 6.085) Pub Date : 2019-11-13
    Lining Lu, Yu Guo, Tian Wang, Lujun Liang, Suwen Zhao, Feng Wang, Lei Liu

    MINDY-1 is a recently discovered new family of deubiquitinating enzymes (DUB), but one of its yeast homologs, YGL082W, does not show any DUB activity in vitro. Sequence alignment shows that YGL082W possesses the correct catalytic triad, and yet did not catalyze either the hydrolysis of di-ubiquitin, crosslinking with C-terminally propargylated ubiquitin, or hydrolysis of ubiquitin-7-amino-4-methylcoumarin. After obtaining a crystal structure of the catalytic domain of YGL082W, we identified an interesting difference between the catalytic center loop of YGL082W and that of its human homolog MINDY-1. Because the conformation of the catalytic center loop was previously reported to be important for the deubiquitination activity of MINDY-1, we hypothesized that Glu27 (instead of the corresponding Pro136 in MINDY-1) of the catalytic center loop of YGL082W may impair the conformational change and account for the lack of activity. This hypothesis was supported by homology modeling and molecular dynamics simulations, which showed that the Pro-to-Glu mutation (P136E mutation for MINDY-1) creates a hydrogen bond that inhibits the conformation change of the catalytic center loop of MINDY-1. Further experiments through site-directed mutation validated this hypothesis, showing that the P27E mutation caused MIY1 (a homologous active DUB from yeast) to lose activity.

    更新日期:2019-11-18
  • Preparation of biomimetic gene hydrogel via polymerase chain reaction for cell-free protein expression
    Sci. China Chem. (IF 6.085) Pub Date : 2019-11-13
    Feng Li, Wenting Yu, Xue Zhang, Xiaocui Guo, Xihan Xu, Xiaolei Sun, Dayong Yang

    Deoxyribonucleic acid (DNA) hydrogels, a three-dimensional (3D) network made from DNA chains, have attracted great attention because of its molecular programmability, excellent biocompatibility and wide biomedical applications. Construction of hydrogel incorporating genetic function is still a challenge because of the limitations in available preparation methods. Herein, we develop a polymerase chain reaction (PCR) based strategy to construct gene integrated hydrogel to mimic the biofunction of nucleus zone. DNA primers were chemically modified by methacrylamide, which were used as modular primers in PCR to hybridize with template plasmid DNA, yielding methacrylamide functionalized gene (Acry-gene). Afterwards, Acry-gene was chemically cross-linked and compressed via free radical polymerization of terminal group methacrylamide to form a three-dimensional gene network, namely gene hydrogel. The gene hydrogel retained the genetic function and expressed protein successfully in a cell free protein expression system. This work provides a general approach for the construction of biofunctional gene hydrogel which mimics bioprocesses, showing great potential in biomedicine and biomimetic fields.

    更新日期:2019-11-18
  • Predictable site-selective radical fluorination of tertiary ethers
    Sci. China Chem. (IF 6.085) Pub Date : 2019-11-13
    Junyang Ma, Wentao Xu, Jin Xie

    In this communication, we disclose the first example of metal-free and site-selective radical fluorination of readily available tertiary alkyl ethers, enabled by synergistic photocatalysis and organocatalysis. This catalytic combination allows for exclusive fluorination of tertiary C-O bonds under mild conditions even in the presence of competing reaction sites. The excellent functional group tolerance affords valuable access to sterically hindered alkyl fluorides through late-stage modification of complex molecules. The successful use of tertiary alkyl ethers in radical fluorination enhances the structural diversity of aliphatic fluorides that can be derived from naturally abundant alcohols.

    更新日期:2019-11-18
  • A C 2 -symmetric triple [5]helicene based on N -annulated triperylene hexaimide for chiroptical electronics
    Sci. China Chem. (IF 6.085) Pub Date : 2019-11-14
    Zetong Ma, Thorsten Winands, Ningning Liang, Dong Meng, Wei Jiang, Nikos L. Doltsinis, Zhaohui Wang

    Two diastereoisomers (NTPH-P and NTPH-T1) as a C2-symmetric triple [5]helicene based on N-annulated triperylene hexaimide were synthesized. Aided by nuclear magnetic resonance spectroscopy (NMR) and theoretical calculations, NTPH-P was assigned to three-blade propeller conformation while NTPH-T1 tended to exhibit twisted conformation with pyrrole ring fusing on a bowl-shaped PDI foil. Characterized by circular dichroism (CD) and circular polarized luminescence (CPL) measurements, the enantiomerically pure NTPH-P exhibited fairly good chiral activities both in the absorption and emission range with dissymmetry factors ∣gabs∣ of 4.1×10−3 and ∣glum∣ of 1.2×10−3. The diastereoisomers were further employed as acceptors for organic solar cells with distinct PCEs of 8.11% and 5.24% for NTPH-P and NTPH-T1 based devices, respectively, signifying the prospects in chiroptical electronics by designing molecularly defined aromatics.

    更新日期:2019-11-17
  • A first-principles microkinetic study on the hydrogenation of carbon dioxide over Cu(211) in the presence of water
    Sci. China Chem. (IF 6.085) Pub Date : 2019-11-14
    Xitong Sun, Peng Wang, Zhengjiang Shao, Xiaoming Cao, P. Hu

    The hydrogenation of carbon dioxide (CO2) is one of important processes to effectively convert and utilize CO2, which is also regarded as the key step at the industrial methanol synthesis. Water is likely to play an important role in this process, but it still remains elusive. To systematically understand its influence, here we computationally compare the reaction mechanisms of CO2 hydrogenation over the stepped Cu(211) surface between in the absence and presence of water based on microkinetic simulations upon density functional theory (DFT) calculations. The effects of water on each hydrogenation step and the whole activity and selectivity are checked and its physical origin is discussed. It is found that the water could kinetically accelerate the hydrogenation on CO2 to COOH, promoting the reverse water gas shift reaction to produce carbon monoxide (CO). It hardly influences the CO2 hydrogenation to methanol kinetically. In addition, the too high initial partial pressure of water will thermodynamically inhibit the CO2 conversion.

    更新日期:2019-11-17
  • Over 16.7% efficiency of ternary organic photovoltaics by employing extra PC 71 BM as morphology regulator
    Sci. China Chem. (IF 6.085) Pub Date : 2019-11-11
    Jinhua Gao, Jian Wang, Qiaoshi An, Xiaoling Ma, Zhenghao Hu, Chunyu Xu, Xiaoli Zhang, Fujun Zhang

    Ternary organic photovoltaics (OPVs) are fabricated with PBDB-T-2Cl:Y6 (1:1.2, wt/wt) as the host system and extra PC71BM as the third component. The PBDB-T-2Cl:Y6 based binary OPVs exhibit a power conversion efficiency (PCE) of 15.49% with a short circuit current (JSC) of 24.98 mA cm−2, an open circuit voltage (VOC) of 0.868 V and a fill factor (FF) of 71.42%. A 16.71% PCE is obtained in the optimized ternary OPVs with PBDB-T-2Cl:Y6:PC71BM (1:1.2:0.2, wt/wt) active layer, resulting from the synchronously improved JSC of 25.44 mA cm−2, FF of 75.66% and the constant VOC of 0.868 V. The incorporated PC71BM may prefer to mix with Y6 to finely adjust phase separation, domain size and molecular arrangement in ternary active layers, which can be confirmed from the characterization on morphology, 2D grazing incidence small and wide-angle X-ray scattering, as well as Raman mapping. In addition, PC71BM may prefer to mix with Y6 to form efficient electron transport channels, which should be conducive to charge transport and collection in the optimized ternary OPVs. This work provides more insight into the underlying reasons of the third component on performance improvement of ternary OPVs, indicating ternary strategy should be an efficient method to optimize active layers for synchronously improving photon harvesting, exciton dissociation and charge transport, while keeping the simple cell fabrication technology.

    更新日期:2019-11-13
  • A periodic metallo-supramolecular polymer from a flexible building block: self-assembly and photocatalysis for organic dye degradation
    Sci. China Chem. (IF 6.085) Pub Date : 2019-11-11
    Xiong-Fei Li, Xu-Bo Liu, Jin-Yu Chao, Ze-Kun Wang, Faiz-Ur Rahman, Hui Wang, Dan-Wei Zhang, Yi Liu, Zhan-Ting Li

    A water-soluble metallo-supramolecular polymer MSP-f-6Np, which possesses a regular pore aperture of 1.4 nm, has been assembled from a structurally flexible naphthalene-appended [Ru(bipy)3]2+ complex and cucurbit[8]uril. As the first periodic metallo-supramolecular polymer formed by a flexible building block, MSP-f-6Np exhibits a hydrodynamic diameter of 122 and 164 nm at 0.1 and 2.0 mM of the monomer concentrations. Synchrotron small angle X-ray scattering experiments confirm that MSP-f-6Np possesses porosity periodicity in both the solution and solid states. Compared with a control, the new highly ordered porous system displays enhanced photocatalytic activity for the degradation of organic dyes.

    更新日期:2019-11-13
  • Nickel-catalyzed reductive coupling of glucosyl halides with aryl/vinyl halides enabling β-selective preparation of C -aryl/vinyl glucosides
    Sci. China Chem. (IF 6.085) Pub Date : 2019-06-18
    Jiandong Liu, Chuanhu Lei, Hegui Gong

    This work describes stereoselective preparation of β-C-aryl/vinyl glucosides via mild Ni-catalyzed reductive arylation and vinylation of C1-glucosyl halides with aryl and vinyl halides. A broad range of aryl halides and vinyl halides were employed to yield C-aryl/vinyl glucosides in 42%–93% yields. Good to excellent β-selectivities were obtained for C-glucosides by using tridentate ligand.

    更新日期:2019-11-13
  • A neural network protocol for predicting molecular bond energy
    Sci. China Chem. (IF 6.085) Pub Date : 2019-11-06
    Chao Feng, Edward Sharman, Sheng Ye, Yi Luo, Jun Jiang

    Molecular bond energy is a key parameter for analyzing the properties of chemical activity, stability and flexibility. Calculating bond energy is a challenge due to the cost of first-principles simulations and unsatisfactory prediction using empirical formula. Here we show that a neural network (NN) machine-learning method can achieve quick prediction of bond energies of organic molecules. Using atomic species and charge information as descriptors, we trained a NN protocol and applied it to predict the bond energy in a certain chemical bond that agreed with density functional theory calculations. This protocol also provided a way to evaluate the effects of different methods of atomic charge analysis on NN training. Trained to accurately estimate bond energies, this NN protocol provides a cost-effective tool for optimizing chemical reactions, accelerating molecular design, and other important applications.

    更新日期:2019-11-11
  • Atomic-scale imaging of the defect dynamics in ceria nanowires under heating by in situ aberration-corrected TEM
    Sci. China Chem. (IF 6.085) Pub Date : 2019-11-06
    Xiaomin Li, Kaihui Liu, Wenlong Wang, Xuedong Bai

    The defects in the ceria usually work as the active reaction sites in their industrial applications. In this article, we studied the formation and atomic process of the defects of ceria nanowires under heating by using in situ aberration-corrected transmission electron microscopy (Cs-TEM) method. With the temperature elevating, ceria nanowires are reduced and defects begin to appear and grow up. When temperature reaches 1,023 K, the defect morphology exhibits the rhombus or hexagon patterns, which are surrounded by {111} and {200} planes with lower surface energy, and the heated ceria still maintain the same cubic fluorite structure as their parent. It is also indicated that the formation of defects originates from the release of lattice oxygen and the volatilization of surface Ce ions. This work provides an important insight into designing ceria-based catalysts and ionic conductors.

    更新日期:2019-11-11
  • Photocatalytic decarboxylative coupling between α-oxocarboxylicacids and alkenes
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-30
    Ziyue Chen, Fangling Lu, Feng Yuan, Juanjuan Sun, Linyu Du, Zhen Li, Meng Gao, Renyi Shi, Aiwen Lei

    Photocatalytic decarboxylative cross-coupling which achieves the derivatization of widespread organic acids has become a hot topic in organic synthesis. As special acids, α-oxocarboxylicacids show the great potential in running decarboxylation to construct ketone derivatives. In this article, we have developed a photocatalytic decarboxylative cross-coupling of α-oxocarboxylicacids and olefins to the synthesis of diverse aryl ketones. Various alkenes and α-oxocarboxylicacids were compatible, generating the desired products in up to 90% yield. Preliminary mechanism studies suggest that a free radical pathway is involved in this process.

    更新日期:2019-11-04
  • Reversal of diastereoselectivity in palladium-arene interaction directed hydrogenative desymmetrization of 1,3-diketones
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-22
    Chang-Bin Yu, Heng-Ding Wang, Bo Song, Hong-Qiang Shen, Hong-Jun Fan, Yong-Gui Zhou

    For the metal-catalyzed asymmetric hydrogenation of α-substituted ketones, cis reductive products are generally obtained due to steric hindrance of substituents. Herein, an unprecedented trans reductive products were observed in palladium-catalyzed hydrogenative desymmetrization of cyclic and acyclic 1,3-diketones, providing the chiral trans β-hydroxy ketones with two adjacent stereocenters including one α-tertiary or quaternary stereocenter with high enantioselectivity and diastereoselectivity. Mechanistic studies and DFT calculations suggested that the rarely observed diastereoselectivity reversal is ascribed to the charge-charge interaction between the palladium and aromatic ring of the substrate, which could not only result in the reversal of the diastereoselectivity, but also improve the reactivity.

    更新日期:2019-10-25
  • Visible-light-promoted oxidative coupling of styrene with cyclic ethers
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-22
    Golam Kibriya, Debashis Ghosh, Alakananda Hajra

    A new visible-light-promoted oxidative coupling of vinylarenes with cyclic ethers has been developed using rose bengal as photocatalyst and tert-butyl hydrogenperoxide (TBHP) as oxidant under ambient air at room temperature. A library of α-oxyalkylated ketones with broad functionalities has been synthesized in moderate to good yields. A radical mechanism is suggested for the present protocol

    更新日期:2019-10-25
  • Endogenous nucleotide as drug carrier: base-paired guanosine-5′-monophosphate:pemetrexed vesicles with enhanced anticancer capability
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-22
    Lei Xu, Chunyang Yu, Dali Wang, Ji Pang, Leilei Shi, Yue Su, Lidong Gong, Deyue Yan, Xinyuan Zhu

    Endogenous substance such as nucleotide as a drug carrier has been proposed as a novel drug delivery system. The nucleotide guanosine-5′-monophosphate (GMP) is used to transport an anticancer drug pemetrexed disodium heptahydrate (PMX) via specific base pairing. The endogenous nature of GMP helps to avoid biocompatibility issues that are generally accompanied with nanocarriers including cytotoxicity, immunogenicity and blood compatibility. Furthermore, the low-molecular weight of the GMP nucleotide carrier significantly boosts the drug loading capacity compared to traditional liposomes and high-molecular weight carriers. Hydrogen-bonding interaction between the carrier and drug realizes the controlled release of loaded drug, and also facilitates large scale manufacture since no additional chemical synthesis is required. More importantly, in vivo experiments reveal that the base-paired GMP:PMX nanovesicles improve the target specificity and pharmacokinetic properties of PMX, and exhibit remarkably enhanced anticancer abilities compared to standalone PMX without any carriers. We envision that this strategy could be extended to other endogenous substances and drugs bearing functional groups capable of specific interaction, and promote the construction of drug delivery systems with inherent biocompatibility, enhanced drug delivery efficacy, and a simplified preparation method.

    更新日期:2019-10-25
  • Amides as surrogates of aldehydes for C-C bond formation: amide-based direct Knoevenagel-type condensation reaction and related reactions
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-22
    Wei Ou, Pei-Qiang Huang

    Aldehydes are perhaps the most versatile compounds that enable many C-C bond forming reactions, which are not amenable for other subclasses of carbonyl compounds. We report the first use of amides as surrogates of aldehydes for C-C bond formation, namely, the direct Knoevenagel-type condensation based on amides. The one-pot method consists of controlled reduction of an amide with LDBIPA [LiAlH(iBu)2(OiPr)], Lewis acid-mediated release of a reactive iminium ion intermediate, nucleophilic addition, and in situ elimination of amine. The reaction shows good functional group tolerance. We also demonstrated that the Schwartz reagent could be used as an alternative of LDBIPA. The employment of nitromethane and a silyl enol ether as the nucleophiles opens an avenue for the unprecedented amide-based nitro-aldol condensation reaction and aldol condensation reaction, respectively.

    更新日期:2019-10-25
  • A β-sheet-targeted theranostic agent for diagnosing and preventing aggregation of pathogenic peptides in Alzheimer’s disease
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-22
    Xiang Ma, Yanqing Wang, Jiai Hua, Congyu Xu, Tao Yang, Jian Yuan, Guiquan Chen, Zijian Guo, Xiaoyong Wang

    Amyloid-β peptide (Aβ) aggregates, particularly Aβ oligomers, are established biomarker and toxic species in Alzheimer’s disease (AD). Early detection and disaggregation of Aβ aggregates are of great importance for the treatment of AD due to the unavailability of therapy at the advanced stages of the disease. A multitalented agent, 2-{2-[(1H-benzoimidazol-2-yl)methoxy] phenyl}benzothiazole (BPB), is designed by merging two β-sheet targeting groups into one molecule to detect and inhibit the Aβ aggregation. BPB can quantitatively measure the β-sheet level of soluble Aβ oligomers and specifically distinguish the aggregates of Aβ40 and Aβ42 by unique luminescence spectrum. Animal tests demonstrate that BPB can efficiently penetrate the blood brain barrier and precisely stain Aβ plaques in the brain; more importantly, it can differentiate the blood of APP transgenic mice from that of normal ones. In addition to the diagnostic potential, BPB also suppresses the generation of ROS, protects the neurons from neurotoxicity, and disaggregates the Aβ aggregates in brain homogenates of APP transgenic mice induced by metal ions or self-assembly. In view of its detective ability toward Aβ oligomers and inhibition to Aβ-related neurotoxicity, BPB may be developed into a sensitive probe for screening blood samples in the early diagnosis of AD as well as an effective inhibitor for diminishing Aβ aggregates in the treatment of the disease.

    更新日期:2019-10-25
  • A selective and stepwise aggregation of a new fluorescent probe for dinitrate explosive differentiation by self-adaptive host-guest interaction
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-22
    Jinlan Jia, Wei Xu, Yaguo Yu, Yanyan Fu, Qingguo He, Huimin Cao, Jiangong Cheng

    Nitrate explosive is hard to detect due to lack of aromatic ring and weak interaction with fluorescence probe. More challenging is even to differentiate the dinitrates with multiple nitrate explosives based on photo induced electron transfer or aggregation caused fluorescence change mechanism. A highly selective dinitrate explosive probe was designed based on a new strategy—stepwise aggregation of multiple anchored fluorene dimer 8Py-2F. Compared with its monomer counterpart 2Py-F, 8Py-2F showed a selective and stepwise fluorescence quenching to dinitrate explosives—ethylene glycol (EGDN) and triethylene glycol dinitrate (TEGDN). The limits of detection (LODs) are 2.72 µM for TEGDN and 0.46 µM for EGDN, which is three orders of magnitude lower than those of 2Py-F. The stepwise quenching process is well matched with the stepwise aggregation process as evidence by scanning electron microscopy (SEM). Nuclear magnetic resonance (NMR) and quantum chemical calculation proved the interaction force between the dinitrate and 8Py-2F is hydron bonding interaction, and interaction distance is far less than that of the multiple nitrates coming from the flexibility of the chain and steric hinderance, which resulted in a self-adaptive interaction and higher selectivity. The new strategy is beneficial for the differentiation of the chemicals with similar energy level which is difficult to realize via other method, and the new method provides fluorometric probe for dinitrate explosive detection and makes it an ideal candidate for chemical detection and analysis in public safety and environmental monitoring.

    更新日期:2019-10-25
  • Transformations of N -arylpropiolamides to indoline-2,3-diones and acids via C≡C triple bond oxidative cleavage and C(sp 2 )–H functionalization
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-22
    Ming-Bo Zhou, Yang Li, Xuan-Hui Ouyang, Jin-Heng Li

    A new palladium-catalyzed oxidative conversion of N-arylpropiolamides and H2O to various indoline-2,3-diones and acids through the C≡C triple bond cleavage and C(sp2)–H functionalization is described, which is promoted by a cooperative action of catalytic CuBr2, 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) and O2. The method provides a practical tool for transformations of alkynes by means of a C–H functionalization strategy, which enables the formation of one C–C bond and multiple C–O bonds in a single reaction with high substrates compatibility and excellent functional group tolerance.

    更新日期:2019-10-25
  • Association of altered serum acylcarnitine levels in early pregnancy and risk of gestational diabetes mellitus
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-22
    Hongzhi Zhao, Han Li, Yuanyuan Zheng, Lin Zhu, Jing Fang, Li Xiang, Shunqing Xu, Yanqiu Zhou, Hemi Luan, Wei Xia, Zongwei Cai

    Gestational diabetes mellitus (GDM) is a high-prevalence disease and diagnosed in middle pregnancy. Acylcarnitines are a series of fatty acid esters of carnitine and play important roles in fatty acid and carbohydrate metabolism. However, the role of acylcarnitine on the development of GDM remains unclear. This case-control study involving 214 study participants (107 GDM cases and 107 matched controls) was conducted in a cohort, in China, from 2013 to 2015. The levels of carnitine and 36 acylcarnitines in serum samples collected at the early stage of pregnancy were determined by using ultra-high performance liquid chromatography coupled with tandem mass spectrometry. The associations of the levels of the 37 targeted compounds with GDM risk were investigated by using binary conditional logistic regression models. Alterations in acylcarnitine levels were observed 9–17 weeks before GDM diagnosis. The increases in levels of propionyl-carnitine, malonyl-carnitine, isovaleryl-carnitine, palmitoyl-carnitine and linoleoyl-carnitine were associated with GDM risk with odds ratios (ORs) per standard deviation (SD) increment greater than 1 (p<0.05), after adjustment for potential confounding factors (pre-pregnancy body mass index and parity). On the contrary, the increases of decanoyl-carnitine, decenoyl-carnitine, tetradecenoyl-carnitine, tetradecandienoyl-carnitine levels were associated with the reduced risk for GDM (ORs per SD <1, p<0.05). To our knowledge, the present study is the largest case-control study to investigate the association between early-pregnancy acylcarnitine levels in serum and GDM risk. The findings add to the evidence for the association between acylcarnitine levels and GDM risk.

    更新日期:2019-10-25
  • Radical cascade reactions of unsaturated C-C bonds involving migration
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-22
    Ge Zhang, Yang Liu, Jinbo Zhao, Yan Li, Qian Zhang

    During the past few years, with the rapid development of mild methods for the generation of radical species, great progress in radical cascade reactions of unsaturated C-C bonds has been made. Many radical cascade reactions involve functional groups migration, which leads structurally much more diverse, complex and valuable compounds not easily obtained through other methods. In this review, the recent achievements in unsaturated C-C bonds radical cascade reactions involving migration are summarized.

    更新日期:2019-10-25
  • Enantioselective three-component Ugi reaction catalyzed by chiral phosphoric acid
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-22
    Jian Zhang, Yi-Yan Wang, He Sun, Shao-Yu Li, Shao-Hua Xiang, Bin Tan

    A catalytic enantioselective three-component Ugi reaction was developed. SPINOL-derived phosphoric acid with bulky 2,4,6-tricyclohexylphenyl groups at the 6,6′ positions was found to be the best catalyst to afford α-amino amide derivatives in good to excellent yields (62% to 99%) and enantiocontrol (81% to >99% enantiomeric excess). This asymmetric reaction was applicable well to an array of aliphatic aldehydes. The gram-scale synthesis, modification of dapsone, and enantioselective synthesis of (R)-Lacosamide underline the general utility of this methodology Influence of dihedral angles and substituents of the chiral phosphoric acids on the enantioselectivity was also discussed in this article.

    更新日期:2019-10-25
  • Trifluoromethyl radical triggered radical cyclization of N -benzoyl ynamides leading to isoindolinones
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-21
    Maud Cassé, Christian Nisole, Héloïse Dossmann, Yves Gimbert, Jean-Marie Fourquez, Laure Haberkorn, Cyril Ollivier, Louis Fensterbank

    Under photocatalytic reductive conditions, trifluoromethyl radical addition onto an ynamide followed by cyclization on a benzoyl moiety produces diverse isoindolinone platforms with good yields. The selectivity of the radical cyclization, N-benzoyl vs. N-benzyl as radical acceptor and the E/Z ratio of isomers have been rationalized by modeling.

    更新日期:2019-10-25
  • Recent advances in radical-mediated [2+2+ m ] annulation of 1, n -enynes
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-21
    Chong-Hui Xu, Yang Li, Jin-Heng Li, Jian-Nan Xiang, Wei Deng

    1,n-Enynes are a versatile class of unsaturated hydrocarbons that find broad applications in the synthetic community of natural products, biologically active structures and functional materials. Typical methods for the transformations of 1,n-enynes include the radical-mediated [2+2+m] annulation reaction as they are particularly efficient accesses to functionalized polycyclic compounds. We herein highlighted recent process in the radical-mediated [2+2+m] annulation of 1,n-enynes, including [2+2+1] and [2+2+2] modes, for the construction of five- to six-membered-ring-fused polycyclic scaffolds. Meanwhile, the mechanisms for these transformations were described.

    更新日期:2019-10-24
  • Mitochondria-targeting NIR fluorescent probe for rapid, highly sensitive and selective visualization of nitroxyl in live cells, tissues and mice
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-21
    Jianguo Wang, Wenping Zhu, Chunbin Li, Pengfei Zhang, Guoyu Jiang, Guangle Niu, Ben Zhong Tang

    Nitroxyl (HNO) has been reported to possess unique biological and pharmacological performances, and emerged as a novel therapy for congestive heart failure. Recent studies also suggest that HNO may be produced and involved in important metabolisms in mitochondria. However, due to its high reactivity and short life properties, fast, sensitive and selective observation and monitoring of HNO related dynamic changes in mitochondria still remains a great challenge. Herein, we synthesized a mitochondria-targeting near-infrared (NIR) fluorescent probe (DCMHNO) for rapid detection of HNO with remarkably high sensitivity, selectivity and photostability. DCMHNO shows fast response (about 4 min) towards HNO via 2-(diphenylphosphino)benzoyl group through the Staudinger reaction to boost the bright NIR emission (700 nm) with excellent sensitivity (detection limit of 13 nM), high pH stability and very low interference from other species. DCMHNO can selectively locate in mitochondria and visualize exogenous and endogenous HNO in live HeLa cells with high biocompatibility and photostability. The probe could also monitor the interaction between NO and H2S that gives rise to the generation of HNO in live HeLa cells. In addition, DCMHNO was further utilized in ex vivo NIR imaging of HNO in live mouse liver tissues at the depth of about 50 µm. In vivo imaging of HNO with high signal-to-noise ratio in live mice was also realized by using DCMHNO. These remarkable imaging performances could render NIR DCMNHNO as a useful tool to reveal HNO related dynamic changes in live samples.

    更新日期:2019-10-24
  • Single-atom electrocatalysis: a new approach to in vivo electrochemical biosensing
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-21
    Hanfeng Hou, Junjie Mao, Yunhu Han, Fei Wu, Meining Zhang, Dingsheng Wang, Lanqun Mao, Yadong Li

    Modulation of interfacial electron transfer has been proven to pave a new approach to in vivo electrochemical monitoring of brain chemistry; however, designing and establishing highly efficient electrocatalytic scheme towards neurochemicals remain a long-standing challenge. Here, we find that recently established single-atom catalyst (SAC) can be used for catalyzing the electro-chemical process of physiologically relevant chemicals and thus offers a new avenue to in vivo electrochemical biosensing. To prove this new concept, we used Co single-atom catalyst (Co-SAC), in which the atomic active sites are dispersed in ordered porous N-doping carbon matrix at atomic level, as an example of SACs for analyzing glucose as the physiologically relevant model chemicals. We found that Co-SAC catalyzes the electrochemical oxidation of hydrogen peroxide (H2O2) at a low potential of ca. +0.05 V (vs. Ag/AgCl). This property was further used for developing an oxidase-based glucose biosensor that was used subsequently as a selective detector of an online electrochemical system (OECS) for continuous monitoring of microdialysate glucose in rat brain. The OECS with Co-SAC-based glucose biosensor as the online detector was well responsive to glucose without interference from other electroactive species in brain microdialysate. This study essentially offers a new approach to in vivo electrochemical analysis with SACs as electrocatalysts to modulate interfacial electron transfer.

    更新日期:2019-10-23
  • Amphiphilic drug-drug conjugate for cancer therapy with combination of chemotherapeutic and antiangiogenesis drugs
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-21
    Mo Sun, Qiuhui Qian, Leilei Shi, Li Xu, Qunfang Liu, Linzhu Zhou, Xinyuan Zhu, Jian-Min Yue, Deyue Yan

    The progression and metastasis of solid tumors strongly rely on the process of forming nascent blood vessels. However, using angiogenesis inhibitors alone does not meet the cancer treatment needs. Herein, we used the amphiphilic drug-drug conjugate (ADDC) strategy to fabricate a new drug conjugate with the combination of chemotherapeutic drug and antiangiogenesis drug together. With one-step esterification of hydrophilic floxuridine (FUDR) and hydrophobic pseudolaric acid B (PAB), the conjugate was synthesized. The amphiphilic property of FUDR-PAB conjugate induced the self-assembly to form nanoparticles in water. From further in vitro and in vivo experiments, this FUDR-PAB conjugate does not only have a high antitumor effect, but also shows efficient antianiogenesis property. These results offer a promising ADDC strategy for designing drugs with combination of chemotherapeutic drug and antiangiogenesis drug together.

    更新日期:2019-10-23
  • Cascaded DNA circuits-programmed self-assembly of spherical nucleic acids for high signal amplification
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-21
    Xiang Li, Dongbao Yao, Junxiang Zhou, Xiang Zhou, Xianbao Sun, Bing Wei, Chengxu Li, Bin Zheng, Haojun Liang

    Signal amplification is an important issue in DNA nanotechnology and molecular diagnostics. In this work, we report a strategy for the catalytic self-assembly of spherical nucleic acids (SNAs) programmed by two-layer cascaded DNA circuits through integrating an entropy-driven catalytic network, a catalytic hairpin assembly circuit, and a facile SNA assembly-based reporter system. This integrated system could implement ~100,000-fold signal amplification in the presence of 1 pM of input target. Possessing powerful amplification ability of nucleic acid signal, our strategy should be of great potential in fabricating more robust dynamic networks to be applied for signal transduction, DNA computing, and nucleic acid-based diagnostics.

    更新日期:2019-10-23
  • Photocatalytic single electron transfer reactions on TiO 2 semiconductor
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-17
    Hideto Miyabe, Shigeru Kohtani

    The use of inorganic semiconductor particles such as titanium dioxide (TiO2) has received relatively less attention in organic chemistry, although semiconductor particles have been widely used as a single electron transfer photocatalyst in water-purification, air-cleaning, and self-cleaning. In recent years, the photocatalysis on semiconductor particles has become an active area of research even in organic chemistry, since the heterogeneous semiconductor photocatalysis leads to the unique redox organic reactions. In an early stage, the semiconductor photocatalysis was applied to the oxidation of organic molecules. Semiconductor particles have also the potential to induce the reductive chemical transformations in the absence of oxygen (O2), by using the suitable sacrificial hole scavenger. In this review, we summarize the representative examples of the reductive and oxidative organic reactions using semiconductor particles and the recent applications to the stereoselective reactions.

    更新日期:2019-10-21
  • The role of organic electron donors in the initiation of BHAS base-inducd coupling reactions between haloarenes and arenes
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-17
    Andrew J. Smith, Darren L. Poole, John A. Murphy

    Coupling reactions between haloarenes and arenes (including heteroarenes) that are conducted without added transition metals but in the presence of KOtBu or NaOtBu, have been a topic of great interest since their discovery in 2008. Diverse organic structures act as additives that assist these reactions. These additives are converted into organic electron donors by the butoxide base and this leads to initiation of the coupling reactions, which proceed by radical chain mechanisms. This review provides an overview of the initiation stages of these reactions.

    更新日期:2019-10-21
  • Iodine(III) reagent (ABX—N 3 )-induced intermolecular anti-Markovnikov hydroazidation of unactivated alkenes
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-16
    Xiaonan Li, Pinhong Chen, Guosheng Liu

    Anti-Markovnikov hydroazidation of unactivated alkenes using ABX2014;N3 as an initiator has been developed at room temperature, wherein hydrogen azide (HN3) acts as both hydrogen and azidating agent. Notably, the HN3 reagent was generated from azidotrimethylsilane (TMSN3) and acetic acid in situ. The reaction itself displays broad substrate scope, good yields and excellent regioselectivities.

    更新日期:2019-10-21
  • On the origin and regulation of ultrasound responsiveness of block copolymer nanoparticles
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-12
    Bo Yang, Jianzhong Du

    Noninvasive ultrasound is more convenient and easily accessible for controlled drug delivery of polymeric nanoparticles than many other stimuli. However, controlled ultrasound responsiveness is rather challenging as the mechanism is still unclear. In this article, we disclose the origin and the key regulating factors of ultrasound responsiveness of block copolymer nanoparticles such as simple vesicles, framboidal vesicles, lamellae, beads-like micelles and complex micelles that are self-assembled from a range of poly(ethylene oxide)-b-polymethacrylates based model copolymers. We discover that the intrinsic ultrasound responsiveness of block copolymer nanoparticles thermodynamically originates from their metastable states, and its expression kinetically relates to the mobility of the hydrophobic segments of block copolymers. Specifically, the self-assembly temperature (Ts) that has been usually considered as a less important factor in most of macromolecular self-assembly systems, and the solvents for the selfassembly are two dominant regulating factors of the ultrasound responsiveness because they determine the thermodynamic state (metastable or stable) of nanoparticles. For example, simple vesicles with good or excellent ultrasound responsiveness can be prepared in THF/water when the Ts is around or slightly below the glass transition temperature (Tg) of the hydrophobic segment of the block copolymer because the combination of this solvent with this Ts facilitates the formation of metastable vesicles. By contrast, thermodynamically stable solid nanoparticles such as spherical micelles and lamellae (mainly formed in DMF/water) are not sensitive to ultrasound at all, neither are the vesicles in THF/water at stable states when the Ts is highly above Tg. In addition, we unravel that the responsive rate is highly dependent on the sonication temperature (Tu), i.e., the higher the Tu, the faster the rate. Overall, the above important findings provide us with a fresh insight into how to design ultrasound-responsive nanoparticles and may open new avenues for synthesizing translational noninvasively responsive drug carriers.

    更新日期:2019-10-14
  • Active sites in CO 2 hydrogenation over confined VO x -Rh catalysts
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-10
    Guishuo Wang, Ran Luo, Chengsheng Yang, Jimin Song, Chuanye Xiong, Hao Tian, Zhi-Jian Zhao, Rentao Mu, Jinlong Gong

    Metal oxide-promoted Rh-based catalysts have been widely used for CO2 hydrogenation, especially for the ethanol synthesis. However, this reaction usually suffers low CO2 conversion and alcohols selectivity due to the formation of byproducts methane and CO. This paper describes an efficient vanadium oxide promoted Rh-based catalysts confined in mesopore MCM-41. The Rh-0.3VOx/MCM-41 catalyst shows superior conversion (~12%) and ethanol selectivity (~24%) for CO2 hydrogenation. The promoting effect can be attributed to the synergism of high Rh dispersion by the confinement effect of MCM-41 and the formation of VOx-Rh interface sites. Experimental and theoretical results indicate the formation of til-CO at VOx-Rh interface sites is easily dissociated into *CHx, and then *CHx can be inserted by CO to form CH3CO*, followed by CH3CO* hydrogenation to ethanol.

    更新日期:2019-10-14
  • Br-radical-mediated [3+2] annulation: synthesis of 2-bromomethyl-substituted alkenylcyclopentanes by the reaction of alkenylcyclopropanes with allyl bromides under photo irradiation
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-09
    Takahide Fukuyama, Takashi Kippo, Kanako Hamaoka, Ilhyong Ryu

    A radical chain addition of allyl bromides 2 to alkenylcyclopropanes 1 resulted in [3+2] annulation to give 2-bromomethyl-alkenylcyclopentanes 3 in good yields (16 examples). In this reaction, two kinetically fast radical reactions, cyclopropylcarbinyl radical-ring-opening and 5-exo-radical cyclization, preceded the β-fragmentation of a bromine radical to make the formal cycloaddition possible.

    更新日期:2019-10-14
  • Component reconstitution-driven photoelectrochemical sensor for sensitive detection of Cu 2+ based on advanced CuS/CdS p-n junction
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-09
    Jing Liu, Ying Liu, Wei Wang, Jing Li, Xinyuan Yu, Qinshu Zhu, Zhihui Dai

    The rational design of robust photoactive material and artful sensing strategy are vital for the construction of an ultrasensitive photoelectrochemical (PEC) sensor. Although great progress has been made in PEC sensing, the resultant detection performances and adoptable sensing strategies are still limited. Herein, through the design of a subtle component reconstitution strategy, an ultrasensitive PEC sensor is developed for the detection of Cu2+ based on advanced CuS/CdS nanohybrids (NHs). This proposed sensor shows superior sensing performances with a low detection limit of 0.1 nM and a wide detection range from 0.2 nM to 60 µM due to the formation of p-n junction between CuS and CdS and the component transformation of CdS to CuxS (x = 1,2). Moreover, such PEC sensor also displays goodish results for monitoring the Cu2+ released from apoptotic HeLa cells in vitro. This idea of component reconstitution provides a new paradigm for the design of advanced PEC sensors.

    更新日期:2019-10-14
  • Hydrogen production via catalytic decomposition of NH 3 using promoted MgO-supported ruthenium catalysts
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-09
    Xiu-Cui Hu, Wei-Wei Wang, Rui Si, Chao Ma, Chun-Jiang Jia

    Catalytic decomposition of NH3 to high purity hydrogen offers a promising strategy for fuel cells, but presents challenges for high hydrogen yields at comparatively low temperatures due to the lack of efficient catalysts. Here, we report the facile preparation of ultra-fine ruthenium (Ru) species dispersed on MgO, which show excellent activity and high temperature stability for NH3 decomposition reaction. The hydrogen yield of the prepared Ru/MgO catalysts reaches ca. 2,092 mmol H2 gRu−1 min−1 at 450 °C, far exceeding that of the previously reported most reactive Ru-based catalysts and the same chemical composition samples prepared by other approaches. Various characterization techniques containing X-ray absorption fine structure (XAFS), in-situ diffuse reflectance infrared Fourier transform spectroscopy (in-situ DRTFTS) and temperature-programmed reduction/desorption (TPR/TPD) were carried out to explore the structure-function relation of the prepared Ru/MgO catalysts. We found that the Ru species interact strongly with the MgO support, which can efficiently protect the Ru species and MgO support from agglomerating during NH3 decomposition test, maintaining the stability of the catalysts.

    更新日期:2019-10-14
  • Visible-light-mediated external-reductant-free reductive cross coupling of benzylammonium salts with (hetero)aryl nitriles
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-08
    Meng Miao, Li-Li Liao, Guang-Mei Cao, Wen-Jun Zhou, Da-Gang Yu

    Herein we report a novel visible-light-mediated external reductant-free reductive cross coupling for the construction of C sp2–C sp3 bonds. A variety of benzylammonium salts underwent selective coupling with (hetero)aryl nitriles to deliver important diarylmethanes under mild reaction conditions. Importantly, photocatalysts can be omitted for many cases, which might involve the electron donor acceptor (EDA) complex. Mechanistic studies indicated benzylic radicals might be involved as the key intermediates. Moreover, the in situ generated NMe3 via cleavage of C–N bond in ammonium salts acts as the electron donor, thus avoiding the use of external-reductant.

    更新日期:2019-10-14
  • Photo-driven water splitting photoelectrochemical cells by tandem organic dye sensitized solar cells with I − /I 3 − as redox mediator
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-08
    Shicong Zhang, Haonan Ye, Haoran Ding, Fengtao Yu, Jianli Hua

    Dye-sensitized photoelectrochemical tandem cells have shown the promise for light driven hydrogen production from water owing to the low cost, wide absorption spectra in the visible region and ease to process of their constitutive photoelectrode materials. However, most photo-driven water splitting photoelectrochemical cells driven by organic dye sensitized solar cells exhibit unsatisfactory hydrogen evolution rate, primarily attributed to their poor light capturing ability and low photocurrent performance. Here we present the construction of a tandem system consisting of an organic blue-colored S5 sensitizer-based dye-sensitized photoelectrochemical cell (DSPEC) wired in series with three spectral-complemental dyes BTA-2, APP-3 and APP-1 sensitizers-based dye-sensitized solar cell (DSC), respectively. The two spectral-complemental chromophores were used in DSC and DSPEC to ensure that the full solar spectrum could be absorbed as much as possible. The results showed that the photocurrent of tandem device was closely related to the open-circuit voltage (Voc) of sensitized DSC, in which the tandem configuration consisting of S5 based DSPEC and BTA-2 based DSC gave the best photocurrent. On this basis, tandem device with the only light energy and no external applied electrical bias was further constructed of BTA-2 based 2-junction DSC and S5 based DSPEC and obtained a photocurrent of 500 µA cm−2 for hydrogen generation. Furthermore, I−/I3− was used as a redox couple between dye regeneration and O2 production on the surface of Pt-IrO2/WO3. The strategy opens up the application of pure organic dyes in DSC/DSPEC tandem device.

    更新日期:2019-10-14
  • Metal-organic framework nanosheets: a class of glamorous low-dimensional materials with distinct structural and chemical natures
    Sci. China Chem. (IF 6.085) Pub Date : 2019-10-08
    Yuan Peng, Weishen Yang

    Metal-organic framework nanosheets have gained great attention because of the diversified structures, tunable chemical functionalities, large surface area and ultrathin thickness. In this review, we introduce the recent progress in the favorable applications for catalysis, sensing, energy storage and gas separation, which has significantly addressed the advantages of the nanosheets. A summary of nanosheet fabrication approaches is put forward to establish a comprehension on the origin of the MOF nanosheets. And at last but not the least, we present the concerns on the challenges and opportunities of these materials from our perspectives.

    更新日期:2019-10-14
  • 3D-printed optical-electronic integrated devices
    Sci. China Chem. (IF 6.085) Pub Date : 2019-06-27
    Yingying Liu, Xianqing Lin, Cong Wei, Chuang Zhang, Jiannian Yao, Yong Sheng Zhao

    The monolithic incorporation of electrical and optical components is critically important for achieving high-speed on-chip signal processing, but yet hard to satisfy the explosive growth in the demands on bandwidth and information density. Three-dimensional (3D) circuits, which are desirable for their improved performance in data handling, are ideal candidates to simultaneously promise high-capacity computing with improved speed and energy efficiency. In such highly integrated circuits, however, the selective electrical modulation of light signals is still difficult to achieve owing to the lack of controllable integration of microscale optical functional devices and modulation units. In this work, we demonstrate an electrically modulated microlaser module on a 3D-integrated microsystem composed of a dye-doped polymeric microcavity and an underneath microscale electrical heating circuit. The lasing mode was modulated based on electrical heating-assisted thermo-optic response of the polymeric matrices, which were further fabricated into coupled microdisks, yielding wavelength-tunable single-mode microlasers with selective electrical modulation. On this basis, a prototype of electrically controlled microlaser module with reduced signal crosstalk was achieved. The results will provide a useful enlightenment for the rational design of novel tunable optical devices with more complicated functionalities under far-field regulation, paving the way for the on-chip optoelectronic integration.

    更新日期:2019-10-03
  • Size effect of lead-free halide double perovskite on luminescence property
    Sci. China Chem. (IF 6.085) Pub Date : 2019-07-19
    Peigeng Han, Xue Zhang, Xin Mao, Bin Yang, Songqiu Yang, Zhaochi Feng, Donghui Wei, Weiqiao Deng, Tõnu Pullerits, Keli Han

    Lead-free halide double perovskites have gathered wide scientific interest since they are environmentally friendly and stable. However, compared to the lead perovskites, their optoelectronic properties are compromised. Herein we report a series of bulk lead-free mixed Bi-In halide double perovskites: Cs2AgBi1−xInxCl6 (0

    更新日期:2019-10-03
  • Graphdiyne oxide enhances the stability of solid contact-based ionselective electrodes for excellent in vivo analysis
    Sci. China Chem. (IF 6.085) Pub Date : 2019-08-29
    Lijun Zhao, Ying Jiang, Jie Hao, Huan Wei, Wei Zheng, Lanqun Mao

    Quantitively and stably tracking ion dynamics in the living brain of animals is essential to understanding many physiological and pathological processes. Solid-state ion-selective electrodes (ISEs) are powerful tools for monitoring the dynamic change of ions at physiological concentration range; however, the unintentional accumulation of an aqueous layer at the ion selective membrane/ solid contact interface compromises the electrode potential stability, limiting its in vivo application. Here, using manganese dioxide (MnO2) and potassium ISE (K+-ISE) as model solid contact and ISEs, we demonstrate for the first time that graphdiyne oxide (GDYO) can enhance the potential stability of solid contact-based ISEs. Our results suggest that the intrinsic structural and hydrophobic features of GDYO, plays a key role in impeding and stabilizing the formation of water layer. With GDYO-MnO2 acting as the solid contact, the K+-ISE displays an excellent short-term potential stability and maintains great selectivity, achieving reliable K+ sensing at the animal level. The GDYO-based strategy is generalizable to different ISEs and does not require complicated processing steps, paving an exciting opportunity for in vivo ion recognition and sensing.

    更新日期:2019-10-03
  • Radical-mediated hydroalkylation of 2-vinylpyrrolidine derivatives: a versatile entry into indolizidine alkaloids
    Sci. China Chem. (IF 6.085) Pub Date : 2019-09-26
    Sankar Rao Suravarapu, Bettina Peter, Philippe Renaud

    A concise route for the preparation of two simple optically pure indolizidin-5-ones has been developed. The key chain elongation process was achieved using a triethylborane/catechol mediated hydroalkylation of Boc-protected 2-vinylpyrrolidines. By using complementary strategies, these two bicyclic lactams can be alkylated with complete control of the stereochemistry at C(5) and their conversion to a variety of indolizidine alkaloids such as coniceine, indolizidine 209D and 167B, 5-epi-indolizidine 249A and monomorine has been reported in the literature.

    更新日期:2019-09-30
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