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01 October 2019, Volume 35 Issue 5

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Chemical Research in Chinese Universities Vol.35 No.5 October 2019

2019, 35(5):  0-0. 

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Non-Aufbau Principle to Achieve High Stability Organic Luminescence Radicals

TANG Benzhong

2019, 35(5):  743-744.  doi:10.1007/s40242-019-1001-6

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To solve the problem of stability of organic luminescence radicals, Li et al. proposed a new kind of organic luminescence radicals with non-Aufbau electronic structure by using donor-acceptor molecular structure. The stability of this kind of radicals was greatly improved and the high luminous efficiency was maintained. Using a non-Aufbau radical as the emission layer of an OLED, the maximum external efficiency of 5.3% has been achieved, which is among the highest efficiencies for pure organic near-infrared electroluminescence. This work has been published online in the Nature Materials on July 22, 2019.



Geminiarene: A New Macrocyclic Arene with Dual/Gemini Molecular Conformation and Guest Selectivity in the Solid State

XU Jialiang, BU Xian-He

2019, 35(5):  745-746.  doi:10.1007/s40242-019-1002-5

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Prof. YANG Yingwei and his coworker from Jilin University reported an entirely new kind of macrocyclic arene, namely geminiarene, featuring two different but interconvertible molecular configurations. Taking advantage of the dual/gemini conformational feature and the unique host-guest property of geminiarene, they developed unitary and dual guest selective adsorption/separation systems, in particular toward chlorobenzene and chlorocyclohexane.



Utilization of Azobenzene Units to Control Zinc-mediated Ring Opening Polymerization of Cyclic Esters

SUN Junqi

2019, 35(5):  747-748.  doi:10.1007/s40242-019-1003-4

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Salicylaldimine Zn(Ⅱ) complexes bearing azobenzene moieties were prepared to catalyze ring opening polymerization of various cyclic esters. The different reactivities of the trans and cis isomers of the zinc complexes provide a facile strategy to control polymerization processes as well as the compositions of the resultant polymers.



Articles

Two Zinc(Ⅱ) Complexes Based on Trans-(1R,2R)-cyclohexanediamine: Molecular Structure Analyses and Preparation of Composite Membrane

WANG Dawei, WANG Ying, ZHUANG Changfu, ZHAO Ping, YANG Jing, SHI Zhengjun

2019, 35(5):  749-754.  doi:10.1007/s40242-019-9142-1

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Two novel complexes Zn₂(chda)₂(TPA)Cl₂(1) and[Zn(chda)₂(H₂O)₂](TPA)(H₂O)₂(2)[chda is a chiral ligand of trans-(1R,2R)-cyclohexanediamine, H₂TPA is terephthalic acid] were synthesized at room temperature. The molecular structures of complexes 1 and 2 were identified by single-crystal X-ray diffraction measurement. The results showed that complex 1 had a binuclear structure, each Zn(Ⅱ) ion was four coordinated by two N atoms of chda, one O atom of TPA and one Cl atom, to construct a distorted tetrahedral geometry. For complex 2, the Zn(Ⅱ) ion was six coordinated by two chda molecules and two water molecules to form a ZnN₄O₂ octahedral geometry. Complexes 1 and 2 further extended into three-dimensional supramolecular frameworks by hydrogen-bonding interactions. Hirshfeld surface analysis and fingerprint plots were used to further analyze the contribution of different intermolecular interactions. Further, a composite membrane[Zn(chda)₂(H₂O)₂](TPA)(H₂O)₂/CA was prepared by adding 10%(mass fraction) of complex 2 into cellulose acetate using acetone/chloroform(V:V=1:1) as solvent.



Preparation and Gas Sensing Performance of Hierarchical Porous ZnO-based Materials with Sunflower Rods as a Biological Template

WANG Bowei, ZENG Qingrui, CHEN Shu, YUE Tongtong, HAN Bing, FENG Wei, YANG Defeng

2019, 35(5):  755-761.  doi:10.1007/s40242-019-9125-2

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A graded porous structure SnO₂/ZnO composite was prepared with sunflower rods as a biological template. The prepared samples were subjected to phase analysis by scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffractiometry(XRD) and X-ray photoelectron spectroscopy(XPS). ZnO sample was a pure phase of hexagonal wurtzite, and the template had been completely removed. The surface of the sample presented a honeycomb-like structure of a sunflower rod template, which was formed by interconnecting the porous channels, and had a smaller average size and exhibited n-n heterojunction at the n-type ZnO interface. Compared with that of pure ZnO, the response of the hierarchical porous structure SnO₂/ZnO composite to 100 mg/L n-butanol reached a maximum of 40.61 at 240℃, about 2.7 times higher than that of pure ZnO. Its response time and recovery time are 6 and 3 s, respectively, which are also better than those of pure ZnO. SnO₂/ZnO composite exhibits good gas selectivity, which is related to the improvement of the structure and the forming of n-n heterojunctions of the material.



Assembly of Two Isostructural Metal-organic Frameworks Based on Hetero-N,O Donor Ligand for Detecting Nitro Explosives

WANG Dongmei, LOU Shengjun, YING Yiting, GUO Zhiqi, WANG Lijun

2019, 35(5):  762-766.  doi:10.1007/s40242-019-9099-0

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Two isostructural metal-organic frameworks,[NO₃] [M₃(H₂O)₃O(TBA)₃]·2DMF·6H₂O(1 and 2)[M=In and Fe, H₂TBA=4-(1H-tetrazol-5-yl)-benzoic acid], have been successfully synthesized. Compounds 1 and 2 have three-dimensional structures bridged via the typical 6-connected tri-nuclear cluster units M₃O(COO)₆ and linear linker H₂TBA. The whole 3D framework possesses a 6-connected acs topology. Notably, by the fluorescence technique, compound 1 can detect nitro explosives through fluorescence quenching effect, especially for 2,4,6-trinitrophenol(TNP, K_sv=3.64×10⁴ L/mol). Furthermore, the fluorescence spectrum red shifts as the number of-NO₂ group increases. Based on the aforementioned consideration, compound 1 can be considered as a potential luminescent probe for the detection of TNP.



Dual-modal Colorimetric and Fluorometric Method for Glucose Detection Using MnO₂ Sheets and Carbon Quantum Dots

WANG Chengke, TAN Rong, LI Libo, LIU Dong

2019, 35(5):  767-774.  doi:10.1007/s40242-019-9130-5

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A novel dual-modal fluorometric and colorimetric method was developed for glucose detection using MnO₂ sheets and carbon quantum dots(CQDs). The glucose could be oxidized by glucose oxidase, in accompanied with the formation of H₂O₂ intermediate, which resulted in the decomposition of MnO₂ sheets, as well as the MnO₂ sheets(brown) changed to Mn²⁺ ions(colorless), which induced the absorption of MnO₂ sheet decreased and the fluorescence of CQDs increased, consequently. The linear detection ranges of glucose are 5-1000 μmol/L by fluorescent method and 5-60 μmol/L by colorimetric method. The limits of detection of these two measurements are 2.11 and 2.18 μmol/L, respectively. This method is easy to conduct, has reasonable sensitive and selectivity, and could be applied for the glucose detection in real human serum.



Chemiluminescence Determination of Cefixime Trihydrate Based on Acidic Diperiodatoargentate(Ⅲ)-Rhodamine 6-G System

MUHAMMAD Yousaf, MOHAMMED Yaqoob, MUHAMMAD Asghar, SAMAR Ali

2019, 35(5):  775-781.  doi:10.1007/s40242-019-9073-x

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A novel chemiluminescence(CL) method is proposed for cefixime trihydrate(CFX) determination based on its enhancement effect on diperiodatoargentate(Ⅲ)(DPA)-rhodamine 6-G(Rh6-G) reaction in conjunction with flow injection analysis(FIA). A linear calibration curve was achieved over the range from 0.01 mg/L to 2.5 mg/L CFX(R²=0.999, n=8) with relative standard deviation(RSD) of 1.4%-3.8%(n=4)), limit of detection(LOD) of 3.0×10^-3 mg/L(S/N=3), injection throughput of 180/h and regression equation of y=1113.2x-14.596[y=CL intensity (mV) and x=concentration of CFX(mg/L)]. The method was successfully applied to CFX determination in pharmaceutical formulations and the recoveries(%) for proposed FI-CL and a reported spectrophotometric method by applying the Student t-test[calculated t-test value:t=1.079215, and tabulated t-distributed(95%)=2.200985] were not significantly different. The CFX was efficiently extracted and no significant effect of commonly found excipients in the pharmaceutical formulations was observed. The mechanism of CL reaction is discussed briefly.



Chemical Fingerprint for Identification and Quality Control of Saccharides in Danhong Injection Based on HPLC-ELSD with Chemometrics

LI Hao, YANG Zhenzhong, WANG Jiaojiao, AN Yun, WANG Chenchen, GUO Xiaoguang, WANG Yi

2019, 35(5):  782-787.  doi:10.1007/s40242-019-9030-8

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Chemical fingerprinting has been widely used for the quality control of complex natural products inclu-ding traditional Chinese medicines and botanical drugs. However, there is still lack of appropriate method to monitor the batch-to-batch consistency of hydrophilic constituents, such as saccharides and oligosaccharides. In the present study, we developed a novel approach based on high performance liquid chromatography with evaporative light scattering detector(HPLC-ELSD) for establishing saccharide fingerprinting of Danhong Injection(DHI), which is a widely used botanical drug for treating cardiovascular diseases. Major saccharides in DHI were isolated and four compounds including fructose, glucose and two oligosaccharides were identified. The structures of two novel saccharides named glycerol-1-O-galactfpyranosyl-(1→4)-O-arabinofuranoside, and glycerol-1-O-galactpyranosyl-(1→4)[O-arabinfuranosyl-(1→3)]-O-arabinofuranoside were confirmed by NMR, HR-ESI-MS and GC-MS for the first time. The establishment approach was successfully applied to distinguishing 12 batches of DHI from other botanical drugs with the aid of principle component analysis as well as to evaluating batch-to-batch consistency with the help of calculating similarity of fingerprints. Our findings indicate that the chemical fingerprint of saccharides can be a useful tool for the quality control of complex natural products.



Gold Nanoclusters Templated by Poly-cytosine DNA as Fluorescent Probes for Selective and Sensitive Detection of Thiocyanate

MO Lixin, ZHAO Hengxin, MA Zheng, YU Wenxiao

2019, 35(5):  788-791.  doi:10.1007/s40242-019-8361-9

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Gold nanoclusters(AuNCs) were prepared in the presence of the nucleobases of poly-cytosine DNAs in this paper. We have demonstrated that the fluorescence of the AuNCs is quenched by thiocyanate(SCN^-) through the interaction between SCN^- and gold atoms. AuNCs can receive energy from nucleobases to boost their emission intensity, while in the presence of SCN^-, they coordinate with Au atoms and influence the energy transfer between the nucleobases and AuNCs, leading to the fluorescence quenching. The decreased fluorescence intensity was in proportion to the concentration of SCN^- in the range of 8.0×10^-7-1.5×10^-5 mol/L with a limit of detection of 4.2×10^-7 mol/L(3σ). We further validated the practice of this probe through the detection of SCN^- in natural water samples.



Enantioselective Resolution of (±)-1-Phenylethyl Acetate by Using the Whole Cells of Deep-sea Bacterium Bacillus sp. DL-2

DONG Lu, XU Yongkai, ZHANG Yun, SUN Aijun, HU Yunfeng

2019, 35(5):  792-798.  doi:10.1007/s40242-019-9126-1

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Bacillus sp. DL-2 was isolated from the deep sea of the Western Pacific and further utilized as novel biocatalysts to efficiently asymmetrically hydrolyze (±)-1-phenylethyl acetate. After the optimization of hydrolytic reactions, chiral chemicals (R)-1-phenylethanol and (S)-1-phenylethyl acetate were obtained with high optical purities (96% and 99.8%, respectively). Our research is about the asymmeric hydrolysis of (±)-1-phenylethyl acetate using whole-cell biocatalysts. In addition, the optical purity of (S)-1-phenylethyl acetate generated through the kinetic resolution of (±)-1-phenylethyl acetate using the whole-cells of Bacillus sp. DL-2 was the highest report so far. Using the whole cells of deep sea bacterium Bacillus sp. DL-2 as the biocatalysts is an environmentally friendly method and will play critical roles in industrial asymmetric synthesis.



Design, Synthesis and Insecticidal Activities of Novel 5-Alkoxyfuran-2(5H)-one Derivatives

WANG Xianhao, LI Jianguo, WANG Guangjian, HAN Xianzheng, LI Dongmei, TIAN Zhongzhen

2019, 35(5):  799-805.  doi:10.1007/s40242-019-9122-5

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A series of novel 5-alkoxyfuran-2(5H)-one derivatives was synthesized, and characterized by ¹H NMR, ¹³C NMR and HRMS. Biological activities of all the title compounds were evaluated systematically. Preliminary bioassays indicated that most of the compounds exhibited moderate insecticidal activities against Aphis craccivora and Nilaparvata lugens at 100 mg/L. Compounds 4h and 4w exhibited 100% mortality rate against Aphis craccivora at 100 mg/L, and compound 4h exhibited good mortality rate against Aphis craccivora and Nilaparvata lugens (60% and 75%, respectively) even at 4 mg/L. The results demonstrated the impact of various chemical groups on insecticidal activities and provided a potential clue for further exploring novel high-effective broad-spectrum insecticides.



Hydrogen Bonding Assembled 3D Supramolecular Structures Formed by 5-Amino-2,4,6-triiodoisophthalic Acid and N-Heterocyclic Aromatic Ligands

YU Wenli, ZHANG Mingjuan, LIU Kang, YANG Yu, WANG Lei

2019, 35(5):  806-811.  doi:10.1007/s40242-019-9116-3

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Three salts constructed by 5-amino-2,4,6-triiodoisophthalic acid(ATIPA) with N-heterocycles aromatic coformers such as pyridine tetrazolium, tetramethylpyrazine and cyanuric acid were synthesized by slowing evaporation of solvent. X-Ray single crystal analysis shows that hydrogen protons of the carboxyl groups transfer to nitrogen atoms of the N-heterocyclic coformers to form N-H…O hydrogen bonds in all the three compounds. A huge amount of H-bonds play significant role in the construction of these compounds and all of them generate 3D structures through strong O-H…N, O-H…O, N-H…O and weak C-H…O hydrogen bonds. Moreover, solvent water molecules are indispensable in the formation of compounds 1 and 3, which constitutes different supramolecular synthons to bridge individual molecules and chains to form stable structures. In addition, these crystal structures were further characterized by thermogravimetric analysis and infrared spectroscopy.



Synthesis of P-Stereogenic Diarylphosphinamides as Novel Inhibitors of Melanoma

TANG Xu, DU Zhijun, WU Guojie, HAN Fushe

2019, 35(5):  812-816.  doi:10.1007/s40242-019-9103-8

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In this paper, the evaluation on the biological activity of an array of P-stereogenic diaryphosphinamides as novel inhibitors of malignant melanoma was presented. Among 20 derivatives being screened, several of them displayed high inhibition rate up to 90% against the B16 melanoma cells at 100 μg/mL. Moreover, one of them displayed high inhibition activity with IC₅₀ value of 5.8 μg/mL. In contrast, a comparative assay showed that all the compounds were almost inactive or showed only very weak inhibition ability against an array of cell lines including HL7702, Bel7402, HT1080, A549 and McF7 cells. The results suggested that the P-stereogenic diarylphosphinamides may serve as a class of novel lead molecules for further development of new inhibitors for selective inhibition of melanoma.



Synthesis of A-B-C-ring Tricyclic Core of iso-Merrilactone A

TONG Jie, LIU Chang, WANG Bo

2019, 35(5):  817-822.  doi:10.1007/s40242-019-9064-y

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A desymmetrization approach for the synthesis of the A-B-C tricycle intermediate of iso-merrilactone A was described. The key steps of this synthesis to efficiently access the tetracyclic Illicium sesquiterpenes core included an intramolecular aldol cyclization and an oxidative lactonization reaction. A novel Au catalyzed hydrolytic cyclorearrangement cascade reaction was explored in the initial stage.



Inhibitory Activities on α-Glucosidase and Composition Analysis of Different Fractions of Ethanol Extracts from Actinidia chinensis Radix

NIE Changping, YANG Jun, WU Dan, WAN Luping, LIANG Guangping

2019, 35(5):  823-829.  doi:10.1007/s40242-019-9037-1

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The inhibitory actions of ethyl acetate, n-butanol and water fractions from Actinidia chinensis Radix (A. chinensis Radix) ethanol extracts on α-glucosidase were investigated. We found that the inhibitory activity of different ethanol extract fractions on α-glucosidase is concentration-dependent. At the same concentration, the ethyl acetate and n-butanol fractions showed higher inhibitory activities on α-glucosidase in comparison with acarbose. We then determined the chemical constituents of the ethyl acetate and n-butanol fractions through ultra performance liquid chromatography-triple-time of flight/mass spectrometry(UPLC-Triple-TOF/MS). Based on the mass spectrometry analysis and the databases Scifinder and Reaxys, 21 compounds(A1-A21) were identified from the ethyl acetate fraction. In addition, 11 of those compounds(A2, A3, A5, A6, A8, A10, A11, A13, A15, A19, A20) were identified for the first time from A. chinensis Radix. We also identified 14 compounds(A22-A32 and A4-A6) from the n-butanol fraction and compound A29 is a new natural product. From the n-butanol fraction, 7 additional compounds (A22, A25, A27, A28, A30-A32) were identified from A. chinensis Radix for the first time.



Utilization of One Novel Microbial Esterase WDEst9 in the Kinetic Resolution of (S)-Methyl 2-chloropropionate and (S)-Ethyl 2-chloropropionate

WANG Yilong, XU Yongkai, ZHANG Yun, SUN Aijun, HU Yunfeng

2019, 35(5):  830-836.  doi:10.1007/s40242-019-9104-7

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One novel microbial esterase WDEst9 from Dactylosporangium aurantiacum subsp. Hamdenensis NRRL 18085 was functionally characterized and the results demonstrated that the enantio-preference of WDEst9 was opposite to that of three other microbial esterases(BSE01701, PHE14 and Bae02030) in the kinetic resolution of racemic methyl lactate. We further investigated the potential of esterase WDEst9 in the kinetic resolution of both (±)-methyl 2-chloropropionate and (±)-ethyl 2-chloropropionate. The enantio-preference of WDEst9 was also interestingly opposite to that of esterases EST12-7 and EstC10, and generated (S)-methyl 2-chloropropionate and (S)-ethyl 2-chloropropionate with high enantiomeric excess(both e.e. >98%) and high yield after many iterations of process optimization. Through genome mining, microbial esterase WDEst9 was characterized to be a novel esterase which may provide valuable complementary enantio-selectivity and possesses very good potential in the kinetic resolution of high value-added chiral chemicals.



Nanopore-based DNA Supersandwich Structure for Detection of Streptavidin

QIAO Yujuan, QIAN Yue, LIU Mengfei, LIU Nannan, TANG Xingxing

2019, 35(5):  837-841.  doi:10.1007/s40242-019-8378-0

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Natural and synthetic nanopores are increasingly popular tools in biosensors. In this work, the DNA supersandwich structure, which was made from two specially designed probes has been used to be fabricated in solid nanopores. Integrating the idea of affinity between streptavidin and biotin, the DNA supersandwich structure with biotins was successfully constructed for streptavidin detection, and the limitation of detection was found to be 10 fmol/L. This nanodevice allows specific, sensitive and versatile detection of diverse analytes with easy operations, thus we believe that it could be developed to detect some disease-related molecular targets and play a considerable role in biotechnology.



Direct Pyrolysis of Molybdophosphate-based Ionic Salt for One-step Synthesis of N,P Co-doped Carbon/MoO_3-x Hybrids with Superior Lithium Storage Performance

ZHANG Lifeng, SHEN Kechao, JIANG Yongtao, GUO Yu, LIU Yi, GUO Shouwu

2019, 35(5):  842-847.  doi:10.1007/s40242-019-9149-7

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N, P co-doped carbon/MoO_3-x hybrids(NPC/MoO_3-x) were synthesized via one-step pyrolysis of molybdophosphate-based ionic salt precursor. Doped carbon and oxygen vacancies(OVs) were synchronously introduced into the NPC/MoO_3-x hybrids without any other redundant procedure. As anodes for lithium-ion batteries, the NPC/MoO_3-x hybrids delivered a high initial Coulombic efficiency(ICE) of 81% as well as high charge capacity of 516 mA·h/g after 100 cycles at 1 A/g, indicating the excellent reversibility and rate capability. The enhanced lithium storage performance was attributed to the rational combination of surface engineering and OVs, which is beneficial to the more active sites and fast ionic/electronic transport.



Studies on 3-Amino-4-(1H-tetrazol-5-yl)-furazan: Crystal Structure, Thermal Behavior and Energetic Performance

MA Xiao, WANG Xiaohong, SHANG Fan, DING Zimei, HANG Xiaojing, HUANG Jie

2019, 35(5):  848-853.  doi:10.1007/s40242-019-9138-x

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The structure of 4-amino-3-(5-tetrazolate)-furazan(HAFT) was characterized by single crystal X-ray diffraction. The thermal decomposition process of HAFT was investigated by MS-FTIR-DSC-TG coupling technique. The result shows that the exothermic process occurs from 278.7-350℃, with a peak temperature of 324.7℃. The thermal decomposition gaseous products of HAFT are NO₂, CO₂, HCN, CO, NH₃ and H₂O. The detonation velocity and detonation pressure of HAFT were calculated by the nitrogen equivalent equation. The detonation velocity of HAFT is 7727.46 m/s, which is higher than that of TNT(7178 m/s). The detonation pressure of HAFT(25.27 GPa) is satisfactory. The sensitivity tests reveal HAFT possesses excellent insensitivities to impact and friction.



In situ Deposition of ‘Naked’ Gold Nanoparticles Supported on Silica Spheres as Recyclable Catalysts in Styrene Epoxidation

SHEN Qihui, ZHOU Xinyu, LYU Yang, LI Miao, LIU Yan

2019, 35(5):  854-859.  doi:10.1007/s40242-019-9127-0

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The rational designs of particle size, morphology and surface states of the Au nanoparticles(AuNPs) are crucial for Au nanocatalyst. We herein report a method to synthesize the silica microspheres supported AuNPs(ca. 1 nm) and their application in controlling the reaction conversion and selectivity in styrene epoxidation. Surfactant-free AuNPs deposited on silica microspheres were in situ fabricated with aid of the Ag nanoparticles (AgNPs) as sacrificial template by galvanic replacement reaction, leading to AuNPs/SiO₂ catalyst directly without any post-treatment to expose crystal facets. A high conversion of 46.7% and selectivity of 91.7% to styrene oxide was achieved with H₂O₂ as oxidant in ethanol. The solid catalyst could be reused at least 10 reaction cycles without significant decrease in activity and selectivity. This study not only supplies an active, recoverable catalyst for styrene oxidation with green oxidant and solvent, but also demonstrates that the silica microspheres functionalized with thiol groups have a superior ability in stabilizing noble metal nanoparticles even without any surfactant.



Synthesis of Cu^Ⅱ/ZIF-8 Metal-organic Framework Catalyst and Its Application in the Aerobic Oxidation of Alcohols

HOU Junying, HAO Jianjun, WANG Yaya, LIU Jingchun

2019, 35(5):  860-865.  doi:10.1007/s40242-019-9133-2

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The three-dimensional copper-doped zeolitic imidazolate framework ZIF-8(Cu^Ⅱ/ZIF-8) was prepared by a metal ion exchange process, using reaction of three different copper salts, zinc nitrate hexahydrate[Zn(NO)₃·6H₂O] and 2-methylimidazole(2-MeIM) under nitrogen atmosphere at the room temperature. The TEM and PXRD results indicated that the morphology of Cu^Ⅱ/ZIF-8 was rhombic dodecahedron and the structure was intact after copper was doped into the porous ZIF-8. The synthesized Cu(NO₃)₂/ZIF-8 heterogeneous catalyst showed an excellent activity for the aerobic oxidation of primary alcohols employing molecular oxygen as oxidant. Moreover, the Cu(NO₃)₂/ZIF-8 heterogeneous catalyst can cycled 15 times without leaching of copper.



Synthesis of Pt-SnO_x/TS-1@SBA-16 Composites and Their High Catalytic Performance for Propane Dehydrogenation

LI Hongda, ZHAO Zhen, LI Jiacheng, LI Jianmei, ZHAO Linlin, SUN Jiachen, FAN Xiaoqiang

2019, 35(5):  866-873.  doi:10.1007/s40242-019-9120-7

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A novel composite material of TS-1@SBA-16 was synthesized by enwrapping TS-1 zeolite crystals with mesoporous SBA-16 silica. This composite was used as catalyst support for loading Pt-SnO_x in the propane dehydrogenation(PDH) reaction. Catalysts were characterized by means of N₂ adsorption-desorption, XRD, SEM, TEM, XPS, UV-Vis, and Raman spectroscopy. The effect of different contents of TS-1 on PDH was investigated, and the optimal amount of TS-1 was determined to be 10%. The catalyst with TS-1 content of 10% showed the highest PDH activity and the initial conversion of propane over it can achieve 54.5%, higher than those over TS-1 or SBA-16-supported ones. The superior catalytic performance of Pt-SnO_x/TS-1@SBA-16 is related to the synergistic effect of the excellent mass transfer performance through the hierarchical porous structure, suitable acid acidity and electronic effect of Ti species.



Benzohydrazide Derivatives: Gelation and Application in Oil Spill Recovery

ZHANG Tianren, ZHANG Chunxue, CHE Xiangyang, BAI Binglian, LI Min, WANG Haitao

2019, 35(5):  874-878.  doi:10.1007/s40242-019-9089-2

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The synthesis and gelation properties of a series of organogelators containing a benzohydrazide unit and two alkoxy chains(oBn) were reported herein. oBn(n=8, 10, 12) could form stable gels in commercial fuels(e.g., diesel), which were characterized by low critical gelation concentrations(CGCs) and good mechanical properties (G'>10⁵ Pa). The gelation process was further studied by field-emission scanning electron microscopy(FE-SEM), Fourier transform infrared spectroscopy(FTIR) and X-ray diffraction(XRD), etc. It was demonstrated that in these organogels, molecules self-assembled into fibrils 3D-network, where hydrogen bonding, van der Waals force and π-π interaction were confirmed as the driving forces. As compounds oBn(n=8, 10, 12) show very good gelation properties in diesel, their applications in oil spill treatment have also been tested. It was found that oBn could achieve rapid (<30 s) and effective oil removal at room temperature, being good candidates for oil spill treatment in the future. Also, the removal efficiency could be as high as 95%.



Simultaneous Photoreduction and Nitrogen Doping of Graphene Oxide for Supercapacitors by Direct Laser Writing

FU Xiuyan, XU Shuai, LUO Yang, LI Aiwu, YANG Han

2019, 35(5):  879-883.  doi:10.1007/s40242-019-9060-2

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Graphene-based supercapacitors have attracted tremendous attention owing to their outstanding electrochemical performance. In terms of material, nitrogen(N)-doped graphene(NDG) displays enhanced specific capaci-tance and rate performance compared with bare graphene used as a supercapacitor electrode. However, it still remains a challenge to develop a facile and simple method of NDG in cost-effective manner. Here, we used a simple direct laser writing technique to accomplish the simultaneous photoreduction and N-doping of graphene oxide(GO) using urea as a N source. The N content of the resultant reduced N-doped graphene oxide(NGO) reached a maximum value of 6.37%. All reduced NGO(NRGO)-based supercapacitors exhibited a higher specific capacitance than those based on pure reduced GO(RGO). Interestingly, the electrochemical performance of NRGO-based supercapacitors varied with different contents of N species. Therefore, we can control the properties of the obtained NRGOs by adjusting the doping ratios, an important step in developing effective graphene-based energy storage devices.



Theoretical Investigation on Mechanism, Thermochemistry, and Kinetics of the Gas-phase Reaction of 2-Propargyl Radical with Formaldehyde

Tien V. PHAM

2019, 35(5):  884-891.  doi:10.1007/s40242-019-9054-0

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Gas-phase mechanism and kinetics of the reactions of the 2-propargyl radical(H₂CCCH), an important intermediate in combustion processes, with formaldehyde were investigated using ab initio molecular orbital theory at the coupled-cluster CCSD(T)//B3LYP/6-311++G(3df,2p) method in conjunction with transition state theory(TST), variational transition state theory(VTST) and Rice-Ramsperger-Kassel-Marcus(RRKM) calculations for rate constants. The potential energy surface(PES) constructed shows that the H₂CCCH+HCHO reaction has six main entrances, including two H-abstraction and four additional channels, in which the former is energetically more favorable. The H-abstraction channels slide down to two quite weak pre-complexes COM-01(-9.3 kJ/mol) and COM-02(-8.1 kJ/mol) before going via energy barriers of 71.3(T0/P1) and 63.9 kJ/mol(T0/P2), respectively. Two post-complexes, COM-1(-17.8 kJ/mol) and COM-2(-23.4 kJ/mol) created just after coming out from T0/P1 and T0/P2, respectively, can easily be decomposed via barrier-less processes yielding H₂CCCH₂+CHO(P1, -12.4 kJ/mol) and HCCCH₃+CHO(P2, -16.5 kJ/mol), respectively. The additional channels occur initially by formation of four intermediate states, H₂CCCHCH₂O(I1, 1.1 kJ/mol), HCCCH₂CH₂O(I3, 4.5 kJ/mol), H₂CCCHOCH₂(I4, 10.2 kJ/mol), and HCCCH₂OCH₂(I6, 19.1 kJ/mol) via energy barriers of 66.3, 59.2, 112.2, and 98.6 kJ/mol at T0/1, T0/3, T0/4, and T0/6, respectively. Of which two channels producing I4 and I6 can be ignored due to coming over the high barriers T0/4 and T0/6, respectively. The rate constants and product branching ratios for the low-energy channels calculated show that the H₂CCCH+HCHO reaction is almost pressure-independent. Although the H₂CCCH+HCHO→I1 and H₂CCCH+HCHO→I3 channels become dominant at low temperature, however, they are less competitive channels at high temperature.



Preparation of Novel Ultrathin Co doped MoS₂ Nanosheets Piezocatalyst for Fast Simultaneous Decomposition of Cr(VI) and MB in Dark

WIN Thi Yein, WANG Qun, JIAN Jiahuang, LI Yang, WU Xiaohong

2019, 35(5):  892-900.  doi:10.1007/s40242-019-9006-8

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Ultrathin Co doped MoS₂ nanosheets(NSs) with thickness of 3.2 nm was used to simultaneously decompose Cr(VI) and MB in dark through ultrasonic vibration-assisted piezocatalytic effect. The significantly enhanced piezocatalytic performance of Co doped MoS₂ NSs was found in comparison to the pristine MoS₂ NSs. The high piezocatalytic activity of Co doped MoS₂ NSs may originate from the large amount of charge carriers due to Co doping. The efficient separation of electron-hole pairs under spontaneous polarization were also investigated in detail, which is responsible for reduction of Cr(VI) and oxidation of methylene blue(MB). The active species trapping experiments demonstrate that e and ^·O₂^- are main active substances for Cr(VI) reduction, while h⁺, ^·OH, and ^·O₂^- participate in MB degradation.



Influences of Synthesis Conditions on the Formation of Methotrexate Intercalated Layered Double Hydroxides by Exfoliation-reassembly Route

LIU Zhenlei, JIA Qingyang, ZHAO Xiufen, LI Shuping, SHEN Jian, LI Xiaodong

2019, 35(5):  901-907.  doi:10.1007/s40242-019-8371-7

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The intercalation of methotrexate(MTX) into layered double hydroxides(LDHs) via an exfoliation-reassembly process was performed and the resulting hybrids were then characterized by X-ray diffractiometry(XRD), Fourier transform infrared(FTIR) spectroscopy, thermogravimetry(TG) and differential scanning calorimetry(DSC), etc. In the synthesis procedure, LDHs particles were firstly delaminated, and the reassembly process was performed to get MTX intercalated LDH(MTX/LDHs) hybrids. The reassembly conditions, such as reassembly time and different reassembly solvent, were studied emphatically. It was found that 20 min is the optimum time and formamide is the most suitable solvent in the reassembly process. At last, the controlled release property and the drug-loading capacity were examined emphatically to reveal that MTX/LDHs hybrids reassembled in formamide exhibit the highest drug-loading capacity. The cytotoxicity of the hybrids was estimated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide,thiazolyl blue tetrazolium bromide(MTT) assays on the human lung cancer cells(A549), with the results showing that MTX/LDHs hybrids have effective suppress role on the proliferation of cancer cells, and the hybrids obtained from the formamide solution present much better anticancer effect than the other samples.



A Polysaccharide-based Hydrogel and PLGA Microspheres for Sustained P24 Peptide Delivery: An In vitro and In vivo Study Based on Osteogenic Capability

CAI Qing, QIAO Chunyan, NING Jun, DING Xinxin, WANG Haoyang, ZHOU Yanmin

2019, 35(5):  908-915.  doi:10.1007/s40242-019-9177-3

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A bone morphogenetic protein-2(BMP-2) derived synthetic oligopeptide, S[PO₄]KIPKASSVPTELSAI-STLYLDDD(P24), has shown great potential for facilitating bone regeneration. However, P24 cannot be directly used onto bone defects, while a continuous sustained delivery of P24 may lead to a better formation of bone tissue. Based on this issue, we have developed a sustained delivery system incorporating P24-loaded poly(lactide-co-glycolide) (PLGA) microspheres and nano-hydroxyapatite(n-HA) into the composite hydrogel. The P24-contained compound material was characterized with NMR, FTIR and SEM to demonstrate the formation of compound structure contai-ning P24, PLGA and n-HA. A continuous drug release of P24 was observed for over 60 d that evidently enhanced the efficiency in promoting the proliferation of MC3T3-E1 cells and the secrete of alkaline phosphatase(ALP) in vitro. Moreover, the osteoinduction effect of the hydrogel system with P24 peptide microspheres was demonstrated in vivo and manifested by the result of immunohistochemistry. This novel injectable composite hydrogel is expected to be applied to improving the bone defect treatment in bone tissue engineering.



Proton Conductivity Improvement Effect of Cellulose on SPEEKK Based PEM

ZHAO Qi, LIANG Xiaoxiao, YOU Yingxue, WANG Yuliang, DU Xinwei, LIU Baijun, HU Wei

2019, 35(5):  916-923.  doi:10.1007/s40242-019-9065-x

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The proton exchange membranes(PEMs) were prepared through the solution mixing method of sulfonated poly(ether ether ketone ketone)(sPEEKK) and cellulose. Cellulose was dissolved by 1-allyl-3-methylimidazolium chloride(AMIMCl) and then mixed with sPEEKK solution. sPEEKK/cellulose(SC) composite membranes were prepared by solution casting. The membranes have high flexibility and transparency, which meant the compounding in molecular level. Meanwhile, the composite membranes showed excellent mechanical properties and high proton conductivity. The mechanical property reached 29 MPa, and the proton conductivity was as high as 0.32 S/cm. Thus, as a kind of biomaterials, cellulose could be an excellent reinforcing material for poly(aryl ether ketone)(PAEK) based PEMs.



Facile Synthesis of ZnO-Au Nanopetals and Their Application for Biomolecule Determinations

XIANG Siyuan, MENG Qingnan, ZHANG Kai, GU Yue, LIU Wendong, YANG Bai

2019, 35(5):  924-928.  doi:10.1007/s40242-019-9063-z

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Using dextran as both reductant and stabilizing agent, nanopetals(ZnO-Au NPs) were easily synthesized and possessed a petal-like morphology. The feature structure and size of such ZnO-Au NPs were adjustable by regulating the amount of chloroauric acid(HAuCl₄). Moreover, the electrochemical property of the obtained NPs was evaluated by being immobilized on the glassy carbon electrode(GCE), which performed both high sensitivity and stability in dopamine(DA) determinations. Furthermore, the as-prepared ZnO-Au NPs could also detect DA and uric acid(UA) simultaneously in the mixture without interference, indicating good selectivity and showing promising potential in biosensing.



Synthesis of PEGylated Salicylaldehyde Azine via Metal-free Click Chemistry for Cellular Imaging Application

CHEN Xin, XIAO Chunsheng, CHEN Xuesi

2019, 35(5):  929-936.  doi:10.1007/s40242-019-9077-6

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In this work, two kinds of PEGylated salicylaldehyde azine(SA) polymers were prepared and investigated for cellular imaging applications. First, a diazido derivative of SA was synthesized and subsequently PEGylated with polyethylene glycol monomethyl ether(mPEG) by metal-free azide-alkyne 1,3-dipolar cycloaddition reaction. The formed triazole group in mPEG-SA was then converted into cationic triazolium group by N-alkylation reaction. Both the synthesized polymers, mPEG-SA and N-alkylated mPEG-SA, showed good dispersibility in water, but differences in self-assembly of nanostructures. The mPEG-SA with triazole groups self-assembled into micelles, while the N-alkylated mPEG-SA with triazolium groups self-assembled into vesicles. Furthermore, mPEG-SA and N-alkylated mPEG-SA nanoparticles showed bright fluorescence due to the aggregation of AIE-active SA molecules in the nanoparticles and could be successfully used as fluorescent nanoprobes for bioimaging applications in HeLa cancer cells. Finally, both the synthesized polymers showed minimal cytotoxicity and low hemolytic activity. Therefore, these PEGylated SA polymers proved to be promising bioimaging nanoprobes or traceable drug delivery vehicles.



Preparation and Properties of Hybrid Silane-crosslinked Sulfonated Poly(aryl ether ketone)s as Proton Exchange Membranes

LIU Zhenchao, WANG Peng, HU Wei, LIU Baijun

2019, 35(5):  937-944.  doi:10.1007/s40242-019-9066-9

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A series of novel organic-inorganic hybrid proton-conducting electrolyte membranes with silane-crosslinked sulfonated poly(aryl ether ketone)(SC-SPAEK) networks was prepared via a simple procedure that includes solution casting and acid treatment. The organosilicon pendants of the silane-grafted SPAEK, which were expected to serve as coupling and crosslinking agents, were found to play a key role in the homogenous dispersion of inorganic particles and improved the performance of hybrid membranes. The hybrid membranes exhibited enhanced proton conductivity, and SC-SPAEK/TiO₂-4 showed an extremely high proton conductivity of 0.1472 S/cm at 100℃. The crosslinked hybrid membranes also demonstrated good chemical resistance, oxidative stability, and mechanical properties. The crosslinked hybrid membranes with excellent comprehensive performance may be a promising material for proton exchange membrane fuel cells.



Inspired by Grape Seed and Wine: Tannic Acid as a Modified Coating for Fabricating Highly Flexible, Transparent and Conductive Film

ZHAO Jie

2019, 35(5):  945-950.  doi:10.1007/s40242-019-8315-2

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The application of transparent conductive films in flexible electronics has shown promising prospects recently. Tannic acid(TA) was successfully applied to modifying the surface of polydimethylsiloxane(PDMS) to fabricate highly flexible, transparent and conductive Ag nanowires(NWs) based films. TA modification transformed the PDMS surface from hydrophobicity into hydrophilicity without decreasing the transparence. A sheet resistance(R_s) of 80 Ω/cm² with an optical transmittance of 94% was achieved, which was superior to that of indium tin oxide(ITO) films. More importantly, the TA layer enhanced the interaction between Ag NWs and the PDMS substrate. The Ag NWs films on TA modified PDMS substrate exhibited excellent stability in R_s when subjected to a bending test.