Table of Content

10 May 2020, Volume 41 Issue 5

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Contents

Cover and Content of Chemical Journal of Chinese Universities Vol.41 No.5(2020)

2020, 41(5):  0-0. 

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Review

Progress in Preparation and Gas-sensing Application of Hollow Multi-shell Structured Materials ^†

SUN Hui, LAI Xiaoyong

2020, 41(5):  855-871.  doi:10.7503/cjcu20190688

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Advanced gas sensing technology plays a very important role in the safe production and life of modern society, where the keypoint is the design and development of efficient sensing materials. Hollow multi-shell structured materials possess special physical and chemical properties due to their unique structures with both multiple shells and multi spaces and thus great potential in application for gas sensing. The conventional hard template and soft template methods as well as template-free method based on Osterwald ripening or Kirkendall effect have some limitations in the general preparation of hollow multi-shell structured materials and the precise control of the shell structure. The emergence of the sequential template approach greatly broke through the above-mentioned limitations and promoted the rapid development of the field. This paper briefly reviews the development of the preparative method of hollow multi-shell structured materials, introduces their applications in detecting formaldehyde, ethanol, acetone, toluene, nitrogen dioxide and other harmful gases, and analyzes their unique advantages in gas sensing, and finally summarizes and prospects the challenges and prospects.



Advances in Bacterial Detection Based on Raman Spectroscopy ^†

LI Wenshuai, WU Guorui, ZHANG Xijing, YUE Aiqin, DU Weijun, ZHAO Jinzhong, LIU Dingbin

2020, 41(5):  872-883.  doi:10.7503/cjcu20190684

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Bacteria is a kind of microorganism that is closely related to human activities, and its rapid and highly sensitive detection is very important for the prevention and control of major infectious diseases. In this paper, the basic principle of Raman spectroscopy for bacterial detection is introduced, and three main methods of Raman spectroscopy for bacterial detection, including bacterial composition detection, bacterial metabolites detection and Raman probe labeling based detection mode, are reviewed and compared. Finally, the development prospect of Raman spectroscopy in the field of bacterial detection was prospected, and five suggestions were put forward.



Recent Advances on Polyoxometalates as Metallodrug Agents for Alzheimer’s Disease ^†

MA Mengmeng, QU Xiaogang

2020, 41(5):  884-891.  doi:10.7503/cjcu20190714

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Alzheimer’s disease(AD) is a progressive neurodegenerative disorder characterized by cognitive dysfunction and memory loss. Although the exact pathogenesis of AD remains unclear, recent evidences have demonstrated that the accumulation and deposition of β-amyloid peptide(Aβ) is a key step in AD pathogenesis. Polyoxometalates(POMs) have the merits of adjustable structures, ease of preparation, and low cost, and thus have shown promising in AD treatment. Hence, recent advances on the POMs as a novel AD metallodrug agent are summarized.



Artificial Regulation of Receptor Clustering and Function on Cell Surface ^†

LI Jingying, CHEN Chen, LI Juan, YANG Huanghao

2020, 41(5):  892-900.  doi:10.7503/cjcu20190673

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In this review, various strategies for artificial regulation of receptor clustering on cell surface are introduced, which are realized either by physical-stimulations or biological macromolecules. The former one is induced by stimuli-responsive nanomaterials under physical stimulation, such as light, magnetic field, and heat. And the later one is achieved by utilizing the self-assembly of biomolecules including protein, peptide or nucleic acids, thus inducing artificial regulation of their targeting receptor. We aim to systematically introduce advances in this area and provide insights into the existing challenges and future perspectives.



Green Electronic Devices Based on Ionic Liquids ^†

GAO Naiwei, MA Qiang, HE Yonglin, WANG Yapei

2020, 41(5):  901-908.  doi:10.7503/cjcu20190634

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Our group has devoted to using ionic liquids as sensing materials to fabricate green electronic devices. This particular class of sensing liquids possesses intrinsic advantages of excellent recyclability, flexibility, self-healing property, remoldability and reconfigurability. There are still some challenges of synthesizing kinds of liquid electronic materials and fabricating complex integrated circuits. The breakthrough of these problems will broaden the application range of green electronic devices and provide an effective method to exploit multi-function green electronic devices. This review mainly pays attention to the development of electronic devices based on ionic liquids and perdict the enornous potential applications of this devices.



Recent Advances in Polymeric Nano-sized Carrier Systems ^†

ZHAO Yu, CAO Wanqing, LIU Yang

2020, 41(5):  909-923.  doi:10.7503/cjcu20190646

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In recent years, the nanotechnology has attracted a lot of attention in biomedicine owing to the great enhancement of therapeutic efficiency. A variety of polymeric nano-sized carrier systems have been deve-loped for targeted drug delivery and drug controlled release. In order to improve drug accumulation in the focal lesions and reduce the side effects, smart stimuli-responsive nano-sized carriers have emerged. Now, the polymeric nano-sized drug carriers have shown great potential for cancers, metabolic disorders and infectious diseases. This review focuses on the recent advances in polymeric nano-sized carriers and their applications in biomedicine.



Perspective on the Structure and Dynamics of Polymer Chains in Polymer Nanocomposites ^†

DAI Lijun, SUN Zhaoyan

2020, 41(5):  924-935.  doi:10.7503/cjcu20190640

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Polymer nanocomposites materials have attracted extensive attention due to their unique properties. Although significant progresses have been made in related fields, there still exist some microscopically major issues that have not been resolved yet, especially on the structures and dynamics of polymer chains. In this paper, recent progresses on the structure and dynamics of polymer including polymer diffusion as well as multiscale dynamics of polymer chains are systematically summarized from computer simulation and experimental aspects. We elaborate the influence of different factors on these properties in detail and describe the future perspectives of polymer dynamics.



Progress of Biomimetic Anisotropic Poly(N-isopropylacrylamide) Intelligent Response Actuators ^†

YAN Hao, TANG Ping, LI Shuhong, ZHAO Tianyi, LIU Mingjie

2020, 41(5):  936-946.  doi:10.7503/cjcu20190636

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A hydrogel is a three-dimensional network of hydrophilic polymers, which can hold a large amount of water while maintaining the structure. Due to its "soft" and "wet" characteristics, the resemblance to living tissue opens up many opportunities for applications in biomedical areas. However, compared with soft tissues, traditional hydrogels have rather weak mechanical properties due to the uneven cross-linking structures during polymerizations. Also, the mechanical properties of the hydrogels are isotropic, as oppose to most of the soft tissues, which are always anisotropic. Many soft tissues in nature are composed of multi-level anisotropic structures, which give animals the abilities to adapt changes in the harsh environment. Inspired by the anisotropic structure in nature, how to introduce highly ordered structures into hydrogel networks has become a hot research topic in recent years. Among the thermos-responsive polymers, poly (N-isopropylacrylamide) (PNIPAM) is the most important one because of transition across the lower critical solubility temperature(LCST). This unique property endows PNIPAM the ability to be used as smart actuators. In this review, several strategies of fabricating anisotropic PNIPAM-based smart actuators are summarized, and the impact of anisotropic structures on their actuating abilities are discussed in detail.



Article

Synthesis and Enzymatic Activity of Ni, Ru Co-doped CePO₄ Nanomaterials ^†

WANG Qishun, ZHANG Zeshu, WANG Huan, LIU Yu, SONG Shuyan, ZHANG Hongjie

2020, 41(5):  947-954.  doi:10.7503/cjcu20200119

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NiRu-CePO₄ nanoparticles with high specific surface area were synthesized by a simple hydrothermal method, which could avoid the separate nucleation process of the precious metal. The X-ray diffraction(XRD) pattern of NiRu-CePO₄ is consistent with hexagonal cerium phosphate. The transmission eletron microscopy(TEM) and energy dispersive X-ray(EDX) characterization indicated that the nanoparticles have a length of ca. 20 nm along the longitude and the doped metals Ni and Ru are uniformly dispersed. The BET area is determined as 178.4 m²/g, and the zeta potential as -18.2 mV. NiRu-CePO₄ exhibits good peroxidase-like and oxidase-like activities in wide pH range. 3,3',5,5'-tetramethylbenzidine(TMB) was used as the electron donor and the chromogenic reagent, and the activities were evaluated by monitoring the absorbance at 652 nm. The morphology, dispersion of the elements and valence state of Ce had no significant change when characterizing the used catalyst, confirming the good stability of NiRu-CePO₄.



Synthesis of 6β-Hydroxy-5,5,8aβ-trimethyloctahydronaphthalen-1(2H)-one Toward the Establishment of the Scaffold of Phenylspirodrimane Meroterpenoid Natural Products ^†

HU Zhiyuan, WAN Qiuxiang, ZHOU Hang, SONG Chuanjun, CHANG Junbiao

2020, 41(5):  955-959.  doi:10.7503/cjcu20190639

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Starting from ethyl(E)-5,9-dimethyldeca-4,8-dienoate, we developed a method for the synthesis of 6β-hydroxy-5,5,8aβ-trimethyloctahydronaphthalen-1-one(1), which was successfully applied to the establishment of the skeleton of phenylspirodrimane meroterpenoid natural products. Key steps such as regioselective epoxidation and Cp₂TiCl-promoted radical cascade cyclization have been optimized. The structures of the compounds synthesized have been characterized with nuclear magnetic resonance spectroscopy(NMR) and high resolution mass spectrometry(HRMS).



Glucose Oxidation on Au-supported SBA-15 Molecular Sieve ^†

YE Xiaodong, QI Guodong, XU Jun, DENG Feng

2020, 41(5):  960-966.  doi:10.7503/cjcu20200070

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Conversion of glucose to high-valued chemicals is one of the important routes for biomass utilization. Gold and aluminum modified SBA-15 molecular sieve catalysts(Au-Al/SBA-15) were prepared for aerobic oxidation of glucose. The active site-catalytic performance relationship was investigated. The structures of Au-Al/SBA-15 catalysts with different Au and Al contents were characterized by means of solid-state nuclear magnetic resonance(NMR) in combination with other techniques. It was found that four-coordinated Al is generated on SAB-15 and Au mainly exists in form of metallic state. The supported Au can be stabilized by four-coordinated Al, resulting in smaller Au particles on SBA-15. The interaction between Au and Al species promotes glucose oxidation, while the extra-framework Al species causes the side reaction and lower selectivity to gluconic acid. The role of NaOH in the reaction was revealed by ¹³C solid-state NMR experiments, it benefits desorption of gluconic acid molecules from the catalyst surface, keeping the active sites uncovered and promoting the reaction.



Controlled Preparation and Optical Waveguide Property of 1,4-Dicarbazolidinylbenzene Microwires ^†

BAI Ruonan, LI Qing, QIAO Shanlin, ZHANG Chunhuan, ZHAO Yongsheng

2020, 41(5):  967-971.  doi:10.7503/cjcu20190704

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One-dimensional 1,4-dicarbazolylbenzene microwires(BeCzMW) with high crystallinity and uniform size were prepared with a liquid phase assembly method by changing the assembly conditions. The results of X-ray diffraction and selective area electron diffraction indicated BeCz molecules grew along the crystal [100] direction. Scanning near-field optical microscopy was used to find that the fluorescence from the BeCzMW excited with an ultraviolet laser was effectively confined in the nanowire structure and propagated along the one-dimensional direction. The optical loss coefficient of BeCzMW was 0.0628 dB/μm at 420 nm, indicating that BeCzMW has good optical waveguide performance.



Effects of Introducing Halogen Atoms to Biphenylmethyl Radical on Photostability, Photophysical and Electroluminescent Properties ^†

WU Chunxiao, AI Xin, CHEN Yingxin, CUI Zhiyuan, LI Feng

2020, 41(5):  972-980.  doi:10.7503/cjcu20190664

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Based on (N-carbazolyl)bis(2,4,6-trichlorophenyl) methyl(CzBTM), three new radicals, (3,6-difluoro-N-carbazoly)bis(2,4,6-trichlorophenyl) methyl (F₂CzBTM), (3,6-dichloro-N-carbazoly)bis(2,4,6-trichlorophenyl) methyl (Cl₂CzBTM) and (3,6-dibromo-N-carbazoly)bis(2,4,6-trichlorophenyl) methyl(Br₂CzBTM), were synthesized. By introducing the halogen atoms(F, Cl, Br) to the carbazole moiety, the electrochemical properties, theoretical calculation results, photophysical properties as well as photostability of the new radicals change obviously comparing with CzBTM. Cl₂CzBTM and Br₂CzBTM display higher photoluminescence quantum yield and F₂CzBTM exhibits the highest stability under a UV pulse laser irradiation. The organic light-emitting didoes(OLEDs) using Cl₂CzBTM and Br₂CzBTM as emitters were fabricated and the electroluminescence spectra of them are blue-shifted comparing with that of CzBTM. The maximum external quantum yield(EQE_max) of the devices based on Cl₂CzBTM and Br₂CzBTM are enhanced, which are 1.8 and 2.5 times that of CzBTM-based device, respectively.



Article: Inorganic Chemistry

Synthesis of NaA Zeolite Using Diatomite as Silicon Source and Its Proton Conduction Property ^†

SHI Huaizhong,MA Wenyan,ZHANG Jiani,LI Jiyang

2020, 41(5):  981-986.  doi:10.7503/cjcu20200015

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By utilizing diatomite as the silicon source, LTA-type silica-alumina zeolite NaA was rapid synthesized in the Na₂O-Al₂O₃-SiO₂(diatomite)-H₂O system under hydrothermal condition at low temperature. By adjusting the crystallization temperature and the activity of diatomite, the synthesis process of NaA zeolite has been further optimized, and pure phase of NaA zeolite was achieved at 70 ℃ for 3 h with stirring. The as-synthesized NaA zeolite exhibits good proton conduction property. Its proton conductivity is 1.72 10^-3 S/cm under the condition of 100%RH(Relative humidity) at room temperature. With the increase of temperature, the proton conductivity increases gradually, and the conductivity of NaA-4 reaches 5.96 10^-3 S/cm at 80 ℃ and 100%RH.



Preparation, Characterization and Water-based Lubricity of Modified Biodiesel Soot ^†

LI Chuan,WANG Xinyun,WU Fengyi,LIU Tianxia,HU Xianguo

2020, 41(5):  987-994.  doi:10.7503/cjcu20190668

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In order to realize the utilization of biodiesel soot(BDS) as lubricant additives in water, thermally oxidized biodiesel soot(TO-BDS) was prepared by thermal oxidation. The morphology, composition and dispersion of TO-BDS were analyzed by field-emission transmission electron microscopy, X-ray photoelectron spectroscopy and zeta potentiostat, and compared with that of BDS. The tribological properties and the lubricant mechanism of TO-BDS as an additive in water were investigated using a ball-on-disc reciprocating tribometer, 3D laser scanning microscopy, field-emission scanning electron microscopy, optical contact angle/interface tension meter and Raman spectrometer. Results indicate that the oxygen-containing functional groups and negative charges of TO-BDS are more than that of BDS, which leads to better dispersion of TO-BDS in water compared with BDS in water. The anti-friction and anti-wear properties are significantly improved after adding 0.2%(mass fraction) TO-BDS in water. The main reason is that TO-BDS can act as bearing during friction process and water containing TO-BDS is more facile than water to form lubricating film because the friction pairs are more wettable for water containing TO-BDS in comparison with water. Besides, it also can reduce friction and wear due to friction induced the exfoliating graphitic sheets of TO-BDS.



Syntheses, Structures and Catalytic Properties of Two Supramolecular Complexes Based on 2-Pyridylamine and Cluster ^†

LIU Yabing,LI Mingyang,TIAN Ge,ALATENG Shaga,PEI Tonghe,NIE Jingsi

2020, 41(5):  995-1003.  doi:10.7503/cjcu20190642

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Two new supramolecular complexes, [H₃PMo₁₂O₄₀]₂[C₅H₆N₂]₆(1) and [H₂PMo₁₂V₂O₄₂]·[C₅H₆N₂]₅·3H₂O(2)(C₅H₆N₂=2-pyridylamine), were synthesized and characterized by means of elemental analysis, infrared spectroscopy(FTIR), UV-Vis spectrum(UV-Vis), X-ray photoelectron spectroscopy(XPS), thermal gravimetric(TG) analysis, power X-ray diffraction(PXRD) and single-crystal X-ray diffraction analysis. Both of compounds 1 and 2 consisting of different clusters were assembled into 3D inorganic supramoleculae network with different packing modes. In addition, the catalytic properties of two complexes were investigated using the epoxidation of styrene.



Analytical Chemistry

Highly Sensitive Sensor for Lead Ion Based on Thioflavin T-induced G-quadruplex Formation ^†

XIA Jiaoyun,XU Tong,QING Jing,XIONG Yan,LIU Junjie,GONG Fuchun

2020, 41(5):  1004-1009.  doi:10.7503/cjcu20190689

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The simple and rapid Pb²⁺ detection method is constructed by using a fluorescent aptasensor that is based on G-quadruplex formation in Tris-HCl buffer solution. In the absence of Pb²⁺, the Thioflavin T (ThT) dye binds to the G-rich Pb²⁺ aptamer and forms a Pb²⁺ aptamer/ThT G-quadruplex complex, which results in high fluorescence intensity. Upon addition of Pb²⁺, the Pb²⁺ aptamer/ThT complex will be replaced by the formation of a Pb²⁺ aptamer/Pb²⁺ complex and the fluorescence intensity of the solution decreases dramatically.The experimental conditions such as the buffer solution, the concentration of ThT fluorescent molecules, the concentration of Pb²⁺ aptamer, and the reaction time were optimized. When the concentrations of ThT fluorescent molecules and Pb²⁺ aptamers were 10 μmol/L and 200 nmol/L, respectively, the fluorescence intensity decreased with the increase of Pb ²⁺ concentration in 10 mmol/L Tris-HCl(pH=8.3, containing 2 mmol/L MgCl₂) buffer solution. When the concentration of Pb²⁺ was in the range of 20—1000 nmol/L, there was a good linear relationship between the fluorescence intensity and the concentration of Pb²⁺(R²=0.9941), and this fluorescence aptasensor was highly sensitive and rapid, with a detection limit of 1 nmol/L and a total reaction time of only 10 min. Furthermore, this method is cost-effective and simple, removing the requirement for labeling the detection reagents with a fluorophore-quencher pair.



Organic Chemistry

Transformation of Ginsenoside Rb₃ and C-Mx by Recombinant β-Xylosidase ^†

ZHU Ling,WANG Yuchen,ZHAO Jiangyuan,WEN Mengliang,LI Minggang,HAN Xiulin

2020, 41(5):  1010-1017.  doi:10.7503/cjcu20190626

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The β-xylosidase gene anxyl which was amplified from Aspergillus niger NG1306 was cloned into pPICZαA to construct the recombinant expression vector(pPICZαA-anxyl). The recombinant protein(Anxyl) was further expressed in Pichia pastoris KM71H for ginsenoside Rb₃, C-Mx biotransformation and catalytic kinetic study. The results showed that anxyl could convert ginsenosides Rb₃ and C-Mx to Rd and C-K, respectively. The results of corresponding enzymatic properties showed that the optimum pH of Anxyl was 2.5, and the optimum reaction temperature was 35 ℃. It has good stability at pH of 2.0—5.0 and 20—30 ℃. Mg ²⁺ could improve the catalytic activity of Anxyl and had good tolerance for glucose and ethanol. The K_mvalues of p-nitrophenyl-β-D-xylopyranoside(pNPX), ginsenoside Rb₃ and C-Mx were 3.1, 1.55 and 1.04 mmol/L, the V_maxvalues of pNPX, Rb₃ and C-Mx were 1.9 10 ², 0.8 10³ and 8 10³ mmol/min, and the K_cat values of pNPX, Rb₃ and C-Mx were 5.55, 0.17 and 1.85 s ^-1, respectively. The results indicated that the recombinant Anxyl had a higher affinity for the natural substrates Rb₃ and C-Mx.



Improving Catalytic Efficiency of Bacillus Cereus Amine Dehydrogenase for Acetophenone Reduction by Iterative Saturation Mutagenesis ^†

WU Tao,MU Xiaoqing,NIE Yao,XU Yan

2020, 41(5):  1018-1025.  doi:10.7503/cjcu20190621

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Based on the 3D structure of Bacillus cereus amine dehydrogenase established by homology modeling, 8 amino acid residues(L42, G43, M67, A115, E116, T136, V293 and V296) around the substrate binding pocket were selected to site-directed saturation mutagenesis. Positive mutants were screened on 3 sites(116, 136, 293) by color-rendering method. The best triple-sites mutant(V293A/E116V/T136S) was obtained by iterative saturation mutation strategy and its catalytic efficiency for acetophenone reached 2.54 L·min ^-1·mmol^-1, which was 719% higher than BcAmDH. Compared with BcAmDH, the substrate concentrations and conversions of asymmetric reduction reaction of acetophenone were increased from 100 mmol/L to 300 mmol/L and from 42.1% to 80.2% at the optimal reaction conditions, respectively. It was suggested that the decrease of steric hindrance in the substrate binding pocket of the mutant and the expansion of the substrate entrance channel were the main reasons for improving catalytic efficiency by molecular docking results.



Design, Synthesis and Insecticidal Activity of 1-(4-Chlorophenyl)-2-cyclopropylpropan-1-one Oxime Ether ^†

LI Kangming,CHEN Jia,YI Yangjie,YAN Zhongzhong,YE Jiao,LONG Chuyun,LIU Aiping,HU Aixi,LI Jianming

2020, 41(5):  1026-1034.  doi:10.7503/cjcu20190582

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Based on the intermediate derivatization method, the active fragment of oxime ether was introduced into 1-(4-chlorophenyl)-2-cyclopropylpropan-1-one as a basic skeleton, and 32 novel compounds were designed and synthesized with the fragment of 1-(4-chlorophenyl)-2-cyclopropylpropan-1-one. Their chemical structures were confirmed by nuclear magnetic resonance spectroscopy and mass spectrometry. Single crystal X-ray diffraction of compound 2n was carried out. The result showed that compound 2n belonged to the monoclinic system and space group of 2n was P2₁/c. The initial screening activity showed that the mortality rate of compound 1i and 1g against aphids and red spiders were 78.57% and 69.95% at the concentration of 200 mg/L, respectiviely, while the mortality rate of compound 1i were 100% and 85% against aphids at the concentration of 200 and 12.5 mg/L, respectiviely. The results showed that compound 1i had the value of further development.



Physical Chemistry

Two-Electron Storage Viologen for Aqueous Organic Redox Flow Batteries

HAN Juntian,CUI Yaoxing,SU Zhijun,WU Yi,CHEN Liuping,XU Junhui

2020, 41(5):  1035-1041.  doi:10.7503/cjcu20190722

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A two-electron storage, 1,1'-bis(2,3-dihydroxypropyl)-(4,4'-bipyridine)-1,1'-diium chloride(DHPV²⁺Cl^2-), was synthesized by simply one-step reaction of 3-chloro-1,2-propanediol with 4,4'-bipyridine. The theoretical specific capacity of the viologen anolyte is up to 142.56 mA·h/g in NaCl solution(1.5 mol/L) and the reduction potential is as low as -0.807 V(vs. Ag/AgCl). In full battery testing, with the two-electron storage viologen as anolyte, 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl(4-OH-TEMPO) as catholyte in NaCl supporting electrolyte, the full battery voltage is up to 1.562 V. At the same time, the charge and discharge curves exhibit two-electron storage characteristics of DHPV²⁺Cl^2-. Furthermore, the full battery performance showed that the battery could operate stably at the current density from 10 mA/cm² to 100 mA/cm². The effective utilization rate of the active material is 70.90% at the current density of 25 mA/cm². After 100 cycles, the capacity retention rate of the battery and the capacity average retention rate per cycle are 98.09% and 99.93%, respectively. The DHPV²⁺Cl^2-/4-OH-TEMPO AORFB showed attractive cycle performance. These AORFB materials are built from earth-abundant elements and are environmentally friendly, thus representing a promising choice for safe and sustainable energy storage.



Regulation of Phase State of Dipolar Janus Particles and Its Application ^†

LI Honghong,GENG Keying,TIAN Fuyue,GU Fang,WANG Haijun

2020, 41(5):  1042-1047.  doi:10.7503/cjcu20190709

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The aggregation and phase states of dipolar Janus particles were presented based on the thermodynamic perturbation theory. An attempt was made to find how the association, dipole-dipole interaction and external electric field regulate the cluster structures and properties of the system. It was shown that there existed a competition between chainlike and branched structures in a cluster, which resulted in an entirely different phase behavior from the common fluids. As an application, the dielectric constants for the gas-like and liquid-like phases were carried out, which demonstrated a significant dependence on the association, dipole-dipole interaction and external electric field. Interestingly, the reproducibility of dielectric constant with changeable temperature for the liquid-like phase was found, which could be useful for designing the relevant materials.



Preparation and Electrochemical Performance of Porous Carbons Prepared from Binary Ionic Liquids ^†

CHENG Shifu,HU Hao,CHEN Bihua,WU Haihong,GAO Guohua,HE Mingyuan

2020, 41(5):  1048-1057.  doi:10.7503/cjcu20190703

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Nitrogen, phosphorus and sulfur co-doped porous carbons(PCs) were prepared with a protic ionic liquid 1-hydrogen-3-butylimidazolium hydrogen sulfate(HVImHSO₄) as precursor and 1-butyl-3-methylimi-dazolium hexafurophosphate(BMImPF₆) as assistant through one-step carbonization process at 1000 ℃ in nitrogen atmosphere. The PCs were characterized by nitrogen adsorption-desorption, scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction(XRD), Raman spectroscopy, thermo-gravimetric analysis(TGA) and X-ray photoelectron spectroscopy(XPS). The results showed that the PCs mainly had micro pores and the specific surface area could be up to 1111 m²/g under m(BMImPF₆)/m(HVImHSO₄)=0.4. The amorphous and disordered graphitic layers were dominant in PCs. Nitrogen bonding state was mainly N-Q(N substituted groups of aromatic graphite structure), phosphorus was mainly in O—P type groups, and sulfur was attributed to C—S—C of thiophene-type sulfur. Meanwhile, the capacitance of PC-BMImPF₆-0.5 was 138 F/g at 0.5 A/g and 100 F/g at 10 A/g, the retention ratio was 95.8% after being cycled for 10000 times at 2 A/g in the electrolyte of 6 mol/L KOH. A simple and easy method for preparation of N, P and S co-doped PCs from ionic liquids has been provided, and the PCs have a certain extent application prospect in supercapacitor electrode materials.



Electrochemical Spectroscopy Analysis for Kinetics of the CO₂ Electroreduction Reaction on Ni Single Atom Catalysts ^†

MAO Qing,ZHAO Jian,LIU Song,GUO Chang,LI Bingyu,XU Keyi,CAO Ziqiang,HUANG Yanqiang

2020, 41(5):  1058-1067.  doi:10.7503/cjcu20190699

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Single site mechanism and bi-function mechanism were both put forward for CO₂ electro-reduction reaction(CO₂RR) on the carbon-nitride anchoring Ni single atoms catalysts. The former is specific to the CO₂RR only on the active site Ni and the latter considers both reductions on the Ni site and water spitting on the anchoring carbon nitride site. Kinetic analysis of the CO₂RR as well as sensitivity analysis for the model parameters were both performed by means of static CO₂RR models and experimental polarizations. Electrochemical impedance spectroscopy(EIS) and total harmonic distortion(THD) spectroscopy were also simulated using dynamic CO₂RR models to explore its linear and nonlinear frequency response behaviors, respectively. It is suggested that CO₂ concentration is the most sensitive parameters to CO₂RR performance. The elemental step to form COOH_ads is the rate determines step as the CO₂RR follows the single site mechanism. As for the bi-function mechanism, both CO_2,ads electro-reduction on the Ni site and water splitting on the carbon nitride site are rate-determining steps of the CO₂RR. Transient simulation of CO₂RR reveals that the EIS is able to tell the difference of the single site mechanism from the bi-function mechanism theoretically over the THD spectroscopy.



Effects of Anchoring Group on the Catalytic Activity of HKUST-1/TEMPO Co-catalysts ^†

XUE Yun,YAN Mi,SHEN Yanming,MAO Huiling,WANG Chen,CHENG Hu,ZHUANG Jinliang

2020, 41(5):  1068-1075.  doi:10.7503/cjcu20190683

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By using isonicotinic acid(Iso-NTA) as a bridging molecule, a pyridyl functionalized 2,2,6,6-tetramethylpiperidinyl-1-oxy(TEMPO) radical(Iso-NTA-TEMPO) was synthesized by the condensation of 4-amino-2,2,6,6-tetramethylpiperidino-1-oxy(4-NH₂-TEMPO) and isonicotinic acid. Compared with TEMPO, Iso-NTA-TEMPO exhibited higher oxidation potential, which facilitates the oxidation reaction of benzyl alcohol, without the use of Cu(Ⅱ). In the case of Iso-NTA-TEMPO/HKUST-1 hybrid catalytic system, the Iso-NTA-TEMPO can be(partially) coordinated to Cu(Ⅱ) sites of HKUST-1 by pyridyl group during catalysis. As consequence, the Iso-NTA-TEMPO/HKUST-1 catalytic system shows much higher catalytic activity than that of TEMPO/HKUST-1 system, toward the oxidation of aromatic alcohols. Moreover, HKUST-1 synthesized by template assisted solvent-induced crystallization consists a significant amount of defects, which facilitates the diffusion of Iso-NTA-TEMPO into the pores of HKUST-1, thus, improving the catalytic activity of Iso-NTA-TEMPO/HKUST-1. The Iso-NTA-TEMPO/HKUST-1 system enables the oxidation of a broad range of primary aromatic alcohols with various substituted groups and heteroatoms, as well as secondary aliphatic alcohols with high efficiency and selectivity.



Enhancement of CO₂ Foam Stability with Modified Silica Nanoparticles in High Salinity Brine ^†

ZHANG Xuan,ZHANG Tianci,JIANG Ping,GE Jijiang,ZHANG Guicai

2020, 41(5):  1076-1082.  doi:10.7503/cjcu20190670

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The liquid phase stability and CO₂ foam stability were studied with mixing cationic surfactant and modified nanoparticles(NPs) solutions. It was concluded that inorganic ions screened the electrostatic attraction force between the NPs and cationic surfactant. Moreover, the ratio of surfactant and NPs determined the solution stability in constant salinity brine. From the interfacial tension(IFT) measurement, when the surfactant concentration was higher than its critical micelle concentration, the IFT was similar before and after adding NPs and the lowest IFT was 6 mN/m, whereas it was not as the surfactant concentration was lower than CMC. The bulk foam stability results shown that the NPs enhanced the foam half-life with more than twice time. However, it depended on the concentration ratio. Furthermore, the apparent viscosity of foam stabilized with mixture was increased from 20 mPa·s to 55 mPa·s, nearly triple higher than that with only surfactant in sand-pack with total injection velocity 2 mL/min and foam quality 70%. In summary, adding NPs to surfactant solution, the foam flooding would be more efficient at specified conditions.



Tuning Microstructures of Iron-Nickel Alloy Catalysts for Efficient Oxygen Evolution Reaction ^†

LIU Lu,WU Hanyue,LI Jing,SHE Lan

2020, 41(5):  1083-1090.  doi:10.7503/cjcu20190660

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N-doped carbon(NC) coated iron-nickel alloy catalysts loaded on the carbon fiber papers(CFP) were prepared by firstly hydrothermal depositing iron-nickel based hydroxide/carbonates, then coating dopamine on their surface, and finally annealing the materials. Particularly, the active alloy species can be tuned to be Fe_0.64Ni_0.36 and FeNi₃ and the microscopic structures of the catalysts show to be nanotubes, nanoflowers and nanosheets upon different atomic ratio of Fe²⁺ to Ni²⁺. In an alkaline media, the FeNi₃@NC(1∶3) catalyst exhibits superior oxygen evolution reaction catalytic activities, which only requires an overpotential of 277 mV to reach a current density of 20 mA/cm². At the same time, FeNi₃@NC(1∶3) displays no obvious activity loss after continuous running for 30 h at 20 mA/cm², indicating a good durability. The excellent performances of the alloy catalysts in alkaline solution can be ascribed to their microstructural features: (1) The composites made by NC shell and alloy cores create copious active sites; (2) The NC coating layer prevents the erosion of alloy nanoparticles which thus improves the durability; (3) The three-dimensional structures well promote mass transfer and effectively suppress the gas peeling effect.



Copper Salt Anchored on a Covalent Organic Framework as Heterogeneous Catalyst for Chan-Lam Coupling Reaction ^†

LIU Hengshuo,YU Zhiquan,SUN Zhichao,WANG Yao,LIU Yingya,WANG Anjie

2020, 41(5):  1091-1100.  doi:10.7503/cjcu20190630

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A bipyridine containing covalent organic framework(COF), namely TpBpy, modified with copper ions was prepared. The obtained Cu@TpBpy was used as a heterogeneous catalyst for C—N cross-coupling reaction of arylboronic acid with imidazole. To optimize the reaction conditions, we have screened various parameters such as the catalyst, solvent, base and reaction time. The experimental result showed that using the polar solvent MeOH gives the best yield with the promotion of base TEA, while Cu(OAc)₂@TpBpy is the optimal catalyst. The reaction achieves maximum yield of 66% after 4 h reaction catalyzed by Cu(OAc)₂@TpBpy with TEA in MeOH at 70 ℃. In the optimal reaction conditions, arylboronic acid with different substituents were examined in the coupling reaction with imidazole, among them, 4-chlorophenylboric acid showed the best yield of 62%.



Baeyer-Villiger Oxidation of Cyclic Ketones Catalyzed by Amino Alcohol Heteropoly Acid Ionic Liquid ^†

GAO Chong,YU Fengli,XIE Congxia,YU Shitao

2020, 41(5):  1101-1107.  doi:10.7503/cjcu20190618

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A series of amino alcohol heteropolyacid ionic liquids was synthesized and used to catalyze the Baeyer-Villiger oxidation of cycloketones. 2-Heptylcyclopentanone was used as a template substrate and H₂O₂ was used as an oxidant. The catalytic activity of such amino alcohol heteropoly acid ionic liquids was investigated. The catalyst with the highest catalytic activity was [Pro-ps]H₂PW₁₂O₄₀. The obtained optimum reaction conditions were n(2-heptylcyclopentanone)∶ n(catalyst)∶ n(H₂O₂)=1∶ 0.03 ∶ 4 at 40 ℃ for 8 h by solvent free. Under the optimum conditions, the conversion rate of 2-heptylcyclopentanone was 98.19%, and the selectivity of δ-dodelactone was up to 82.84%. After simple treatment, the ionic liquid [Pro-ps]H₂PW₁₂O₄₀ could be reused, and the catalytic activity did not decrease significantly after five cycles. [Pro-ps]H₂PW₁₂O₄₀ could also be used to catalyze the Baeyer-Villiger oxidation of various cyclic ketones. The results showed that the catalyst had good reusability and substrate adaptability.



Polymer Chemistry

Thixotropic Behavior of Hydrophobically Modified Ethoxylated Urethane-thickened Waterborne Latex ^†

LU Man,SONG Chunmei,WAN Bo

2020, 41(5):  1108-1119.  doi:10.7503/cjcu20190606

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Hydrophobically modified ethoxylated urethanes(HEURs) were synthesized by preparing the prepolymers from the reaction between polyethylene glycol(PEG, M_n=4000, 6000, 8000) and isophorone diisocyanate(IPDI), and then end-capping the polymers with liner alkanols(C12, C14, C16, C18). The structure, molecular weight and polymer dispersity index(PDI) of HEUR were characterized by proton nuclear magnetic resonance( ¹H NMR), Fourier transform infrared spectroscopy(FTIR) and gel permeation chromatography(GPC) respectively, and the rheology behaviors of the HEUR-thickened latex were also studied. It was found that the rheological curve of the HEUR-thickened latex(Latex/HEUR) showed thixotropic loops when HEUR were substituted by C14, C16 and C18 and the mass fraction was more than 1.0%, indicating that these Latex/HEUR were thixotropic fluids. The location of thixotropic loops moved to low shear rate and the viscosity of Latex/HEUR dropped sharply with an increase of the ratio between the molecular weight of hydrophilic segment and that of the hydrophobic end. As the amount of HEUR increased, the thixotropic loop area(S_loop) showed the upward trend. These rheological behavior were attributed to the association, hydrogen bonding and chain entanglement of HEUR in latex. Scanning electron microscope(SEM) and atomic force microscope(AFM) were used to characterize the aggregation state and surface morphology of Latex/HEUR. The results showed that the size of Latex/HEUR particles increased and the surface became rough with the increase of the HEUR end group length.



Material Chemistry

Multi-color Circularly Polarized Luminescence Properties of Cellulose Nanocrystal ^†

ZHAO Ziyi,ZHENG Hongzhi,XU Yan

2020, 41(5):  1120-1126.  doi:10.7503/cjcu20190635

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Multi-color circularly polarized luminescence with high luminescence dissymmetry(g_lum) factors is key in photonic technologies. Leveraging on the intrinsic circular polarization ability of cellulose nanocrystals(CNC), we demonstrate that mixing of CNC suspensions, which are supersonically treated for a different period of time, provides an effective approach to produce freestanding CNC films with a broad photonic bandgap that can effectively transform spontaneous emissions to multicolor right-handed CPL signals with high g_lum. We also show that lamination of multiple CNC-CdSe/ZnS films affords an easy approach to broaden photonic bangdap and ability to produce multicolor circularly polarized luminescence with high g_lum.