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01 June 2019, Volume 35 Issue 3

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Chemical Research in Chinese Universities Vol.35 No.3 June 2019

2019, 35(3):  0-0. 

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Articles

Formation of Lamellar Mesostructured Crystalline Silica by Self-assembly of CTAB

CUI Kai, FANG Yuxi, XU Dongdong, ZHANG Yunjuan, HAN Lu, CHE Shunai

2019, 35(3):  359-362.  doi:10.1007/s40242-019-8365-5

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Controlling organic-inorganic liquid crystal structures to form lamellar mesostructured crystalline silica nanosheets(LCS) was achieved by using the simple cationic surfactant cetyl trimethyl ammonium bromide(CTAB). The organic-inorganic interaction under the condtions of a high surfactant concentration and suitable synthesis temperature played an important role in the construction of mesostructured crystalline silica.



Synthesis and Characterization of Cu Decorated Zeolite A@Void@Et-PMO Nanocomposites for Removal of Methylene Blue by a Heterogeneous Fenton Reaction

LI Xiayu, ZENG Shangjing, QU Xuejian, DAI Jinyu, LIU Xiaofang, WANG Runwei, ZHANG Zongtao, QIU Shilun

2019, 35(3):  363-369.  doi:10.1007/s40242-019-8362-8

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Hydrothermal synthesized nano zeolite A has been encapsulated with ethyl bridged periodic mesoporous organosilica(Et-PMO) shell through a simple modified Stober method and an organosilane-directed growth-induced etching strategy, the obtained yolk-shell structured A@Et-PMO nanocomposite(YS-A@Et-PMO) was further functionalized by the impregnation of copper ions, realizing the composite material with hierarchical porous and catalytic properties. The morphology and metal content of the Cu/A and Cu/YS-A@Et-PMO were fully characterized. As compared to the parent material, the composite Cu/YS-A@Et-PMO has an efficient adsorption and catalytic degradation performance on methylene blue(MB), the removal efficiency reached as high as 95% of 60 mg/L MB within 10 min. These novel structured porous composites may have great potential application for the removal of organic dye including waste effluents.



Ru(II) Bipyridyl Complex and TiO₂ Nanocomposite Based Biomolecule-free Photoelectrochemical Sensor for Highly Selective Determination of Ultra-trace Hg²⁺ in Aqueous Systems

WU Shuo, YANG Xinlan, ZHAO Yanqiu

2019, 35(3):  370-376.  doi:10.1007/s40242-019-8392-z

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A biomolecule-free photoelectrochemical(PEC) probe(denoted as Ru-1) was designed, synthesized and coupled with TiO₂ nanoparticles(NPs) for the highly sensitive and selective PEC detection of Hg²⁺, a model analyte with hypertoxicity to both human health and ecosystem. The probe Ru-1 was designed with Ru(Ⅱ) bipyridyl complex as the chromophore, thiocyanate ligand as the recognition unit, and carboxylate group as the linkage site to connect Ru-1 to TiO₂ nanoparticles. Under irradiation, Ru-1 shows strong affinity to TiO₂ and good photophysical properties of strong visible light absorption, slow electron-hole(e-h⁺) recombination, and fast photoelectron injection to TiO₂ nanoparticles via the π-bridge of 4-(2,2'-bipyridin)-4-yl-thiophene moiety. However, the specific coordination of Hg²⁺ with Ru-1 via the thiol moiety in the thiocyanate enlarges the band gap of the complex and reduces the photocurrent significantly. The synergistic interaction between TiO₂ nanoparticles and the Ru-1 complex led to a selective PEC sensing strategy for Hg²⁺ detection. Detectable linear ranges from 10^-12 g/mL to 10^-7 g/mL and from 10^-7 g/mL to 10^-3 g/mL were obtained without the interference from possibly co-existed metal ions. The good analytical performances indicate the chemical probe based biomolecule-free PEC platform may offer a new route for the detection of biologically and environmentally important small molecules.



Profiling of Ubiquitination Modification Sites in Talin in Colorectal Carcinoma by Mass Spectrometry

WANG Ke, QIAO Lu, LI Xiaoou, LI Shimeng, WANG Yimin, XU Xuesong, HE Chengyan, FANG Ling

2019, 35(3):  377-381.  doi:10.1007/s40242-019-8377-1

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Talin protein was partially purified from human colorectal carcinoma tissues, which was subject to tryptic digestion. Immunoaffinity precipitation with specific antibodies that recognize diglycyl-lysine(Lys) remnants from tryptic digestion of ubiquitinated peptides was used to enrich ubiquitinated sites in talin. Mass spectrometry coupled with capillary reverse-phase high-performance liquid chromatography was used to analyze the enriched peptides. Specifically, four peptides containing diglycyl-Lys remnants from talin, namely, TAK(ub)VLVEDTK, QQQYK(ub) FLPSELRDEH, K(ub)STVLQQQYNR, and EGILK(ub)TAK can be determined using mass spectrometric data. This study provides an analytical method for further study in the relationship between ubiquitination modification of talin and its biological activity in colorectal cancer tissues with different pathological processes.



Double Magnetic Separation-assisted Fluorescence Method for Sensitive Detection of Ochratoxin A

WANG Chengke, TAN Rong, LI Jiangyu, ZHANG Zexiang

2019, 35(3):  382-389.  doi:10.1007/s40242-019-8322-3

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A double magnetic separation-assisted fluorescence method was developed to rapidly detect ochratoxin A(OTA). The OTA aptamer functionalized magnetic nanomaterial(Fe₃O₄-Aptamer) and complementary DNA conjugated nitrogen-doped graphene quantum dots(NGQDs-cDNA) were used in this assay. Aptamer could hybridize with cDNA, which induced the NGQDs-cDNA to bind onto Fe₃O₄-Aptamer, and resulted in the fluorescence quenching of NGQDs. After the addition of OTA, the NGQDs-cDNA could release into the solution, and resulted in the recovery of fluorescence signal of NGQDs consequently. By utilizing the magnetic separation, the unbonded NGQDs-cDNA and residual Fe₃O₄-Aptamer were removed, which significantly increased the fluorescence signal intensity. OTA could be detected in the linear range of 10 nmol/L to 2000 nmol/L, with a limit of detection as 0.66 nmol/L. The advantages of this method include simple operation, good selectivity and high sensitivity, and this method can be used for the rapid detection of ochratoxin A in wheat and corn.



A New Strategy for Rapid Classification of Honeys by Simple Cluster Analysis Method Based on Combination of Various Physicochemical Parameters

ZHANG Xiaohua, ZHANG Suya, QING Xiangdong, LU Zuokun

2019, 35(3):  390-394.  doi:10.1007/s40242-019-8321-4

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An array of real honey samples from 3 different botanical origins and 4 provinces of China, as well as two honeys with common adulterants[white sugar and high fructose corn syrup(HFCS)], were analyzed with a new strategy of "simple cluster analysis" based on physicochemical parameters of honey. The results showed that the physicochemical parameters varied greatly for different honey samples. For example, the minimum conductivity of honey samples was less than 1/17 of the maximum value. Therefore, the physicochemical parameters could be used to distinguish different types of honey. The results are promising, as different kinds of testing honey were successfully discriminated into different groups, allowing us to verify the authenticity of honeys. Furthermore, this approach was followed to successfully analyze two honeys with common adulterants, which are difficult to be identified when they are mixed with true honeys. The results indicated the accuracy and reliability of the proposed strategy, and provided more references for the quality classification of honeys.



Synthesis of Chalcone Derivatives Containing Furan or/and Pyran Ring as Neuraminidase Inhibitors

CHEN Aiyu, LIANG Yongdong, YE Jiao, HU Aixi, LIAN Wenwen, LIU Ailin, DU Guanhua

2019, 35(3):  395-402.  doi:10.1007/s40242-019-8346-8

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Twenty-seven novel chalcone derivatives were designed and synthesized as neuraminidase(NA) inhibitors. A concise suitable synthetic strategy was employed in the target compounds' synthesis with relatively high yields. The synthesized compounds were evaluated for their inhibitory activities against the NA of influenza A virus in vitro. The results show that compound 9b possesses the most potent NA inhibitory activity. Structure-activity relationship studies indicate that the chalcone system and hydrogen bond donor substituent are significant for the NA inhibitory activity. And the chalcone derivatives containing pyran ring have better NA inhibitory activity than those without the pyran ring. In addition, molecular docking studies reveal that compounds 9b and 9u are in the good binding mode with Zanamivir binding sites. This study indicates that compound 9b could be selected as a potent compound for further structural optimization and development of novel NA inhibitors.



Synthesis and Thermal Properties of Three Energetic Ion Salts of 3,6-Bis[(1H-1,2,3,4-t etrazol-5-yl)-amino]-1,2,4,5-t etrazine

ZHOU Jie, WU Shaojie, ZHANG Wenhui, LIU Qing, YANG Bin, REN Yinghui, MA Haixia, ZHAO Fengqi, HU Rongzu

2019, 35(3):  403-409.  doi:10.1007/s40242-019-8326-z

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Three energetic ion salts of 3,6-bis[(1H-1,2,3,4-tetrazol-5-yl)-amino]-1,2,4,5-tetrazine(BTATz), namely, methylamine salt(compound 1), ethylenediamine salt(compound 2), and diethylamine salt(compound 3), were synthesized and characterized by elemental analysis, Fourier transform infrared spectrometry, ¹H NMR spectroscopy, and ¹³C NMR spectroscopy. The crystal structure of compound 1 was determined by single-crystal X-ray crystallography, and structural analysis revealed that it belonged to the monoclinic system with P2₁/c space group. In addition, the thermal behavior of the three compounds was studied by differential scanning calorimetry and thermogravimetry techniques. The thermal decomposition peak temperatures of the compounds were 574.89, 545.60, and 606.72 K, indicating that the three ion salts exhibited good thermal stability. The kinetic mechanism equations of the main decomposition process and the entropy of activation(ΔS^≠), enthalpy of activation(ΔH^≠), and Gibbs free energy of activation(ΔG^≠) of the three compounds were also obtained. Moreover, the thermal safety of the compounds was evaluated by the values of the self-accelerated decomposition temperature(T_SADT), thermal ignition temperature(T_TIT), and critical temperature of thermal explosion(T_b). The results showed that all the compounds demonstrated good thermal safety, and the thermal safety of compound 3 was better than that of the others.



Design, Synthesis, Biological Activity and Molecular Docking Study of Coumarin Derivatives Bearing 2-Methyl b iphenyl Moiety

MA Junjie, HUANG Kun, NI Xin, CHEN Roufen, XU Boxuan, WANG Cuifang

2019, 35(3):  410-417.  doi:10.1007/s40242-019-8310-7

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A hybrid pharmacophore approach was used to design and synthesize a series of coumarin derivatives bearing 2-methylbiphenyl moiety, which were evaluated for their in vitro anticancer activities against four cancer cell lines(MCF-7, A549, H460 and HT29) and PD-1/PD-L1 inhibitory activities. Moreover, several compounds with excellent anticancer activities were selected to evaluate the cytotoxicities against one normal cell line(HEK-293). The most promising compound 11o showed the best anticancer activities against the four tested cancer cell lines with the IC₅₀ values of 6.45, 8.65, 6,57 and 8.13 μmol/L, respectively, and displayed weak cytotoxicity on the normal cell(HEK-293). Furthermore, screening of PD-1/PD-L1inhibitory activity revealed that compound 11o could effectively inhibit the binding of PD-1/PD-L1, and the binding interactions of compound 11o with PD-L1 protein were explored by molecular docking. All above evidences showed that compound 11o might be worthy of further study as a valuable leading compound for the treatment of cancer.



Ginsenoside Rb1 Upregulating AQP5 Protein Expression and Alleviating Salivary Secretion Impairment in Ovariectomized Sjögren's Syndrome Mice

HE Xi, YANG Liu, LIU Xintong, WEI Wei, SHI Ce, LI Baoquan, LI Jiang

2019, 35(3):  418-426.  doi:10.1007/s40242-019-9056-y

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Sjögren's syndrome(SS) is an autoimmune disease characterized as the impairment of salivary secretion mediated by abnormal aquaporin 5(AQP5). Here we used AQP5 promoter as the target to screen the effective components from natural drugs. Panax quinquefolius and its specific ingredient, Rb1, were identified to increase the AQP5 transcriptional activity and AQP5 expression. Then we investigated the possibility of Rb1 binding to sex hormone receptors and demonstrated that Rb1 bound specifically to estrogen receptor alpha(ERα), but not to androgen receptor. Next, we found that ERα overexpression magnified the effect of Rb1 induced AQP5 transcription, and the silence of ERα blocked this effect, demonstrating that Rb1 activated AQP5 transcription via ERα pathway. Importantly, we constructed SS mouse model and investigated the effects of Rb1 on salivary secretion in vivo. SS mice exhibited significant impairment in salivary secretion and decreased AQP5 expression in the submandibular gland. Intriguingly, SS mice administered with Rb1 exhibited dramatically increased salivary secretion, followed by decreased diary water consumption. In particular, Rb1 up-regulated AQP5 expression localized in the submandibular gland, almost similar to the SS mice administered with estrogen. Our data demonstrated that Rb1 bound with ERα to up-regulate AQP5 to increase saliva secretion, thus functioned as a potential natural phytoestrogen for the therapy of salivary secretion impairment in SS patients.



Improving Energy Metabolism of Deproteinized Extract of Calf Blood Through Regulation of Hmgcs2, Cpt1a, Angptl4, Cyp8b1, and Ehhadh Genes in Mice

ZHOU Tong, XU Guangyu, SUN Luyao, YU Zhenxiang, WANG Guixia

2019, 35(3):  427-433.  doi:10.1007/s40242-019-9021-9

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Herein, we described the physicochemical properties of deproteinized extract of calf blood(DECB) and established a hypoxia model treated with or without DECB to detect the sugar, lactic acid, protein, and ATP contents of mice and then identified and analyzed the differentially expressed genes between two groups using mRNA expression chip. According to the results of the airtight hypoxia experiment, mice in the model+DECB group had a significantly prolonged time of hypoxia tolerance compared with the model group. The biochemical test indicated that DECB could significantly increase the level of sugar, ATP and proteins and reduce the amount of lactic acid in mice. It also revealed that Hmgcs2, Cpt1a, Angptl4, Cyp8b1, and Ehhadh genes were involved in mice energy metabolism, and were closely associated with metabolic signaling pathway. These results suggest that DECB might be a potential drug to treat metabolic diseases. Among the genes with differential expression under hypoxia, Angptl4, Cyp8b1, and Ehhadh were critical factors for sugar metabolism. Hmgcs2 provided energy directly, and Cptla regulated cellular inflammatory responses, promoting energy metabolism.



Delivery of Survivin siRNA Using Cationic Diphenylalanine Vesicles

GUAN Shuwen, YU Xiaoxuan, LI Junyang, XU Heng, HAN Wenzhao, SHI Guannan, XU Jia, WANG Liping

2019, 35(3):  434-439.  doi:10.1007/s40242-019-8184-8

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Small interfering RNA(siRNA) has been proved to be a powerful tool for silencing target gene in cells, raising the possibility that siRNA can be employed as a therapy for treating cancers and other genetic diseases. However, siRNA transfection has the limitation due to the difficulty in the delivery of siRNA to target cells and tissues. To explore an efficient biocompatible siRNA delivery system, cationic diphenylalanine vesicles(CDPVs) were constructed to transfer survivin siRNA to human ovarian cancer cells. The morphology of CDPVs was characterized by scanning electron microscopy(SEM) and the distribution of survivin siRNA was characterized by confocal laser scanning microscopy, which reveal that diphenylalanine and the survivin siRNA were successfully co-delivered. After co-incubation for 48 h, the CDPVs/siRNA exhibited enhanced tumor cell growth inhabitation and apoptosis inducted in human SK-OV-3 ovarian carcinoma cells. Overall, CDPVs is an efficient siRNA delivery system and has a pro- mising prospect for cancer therapy.



Enhanced Peroxymonosulfate Activation by Ni_xCo_1-xOOH for Efficient Catalytic Oxidation of Organic Pollutants

LYU Cong, LI Yicheng, FANG Chen, FENG Wei, SUN Wentian, ZHANG Qihui

2019, 35(3):  440-448.  doi:10.1007/s40242-019-9025-5

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Peroxymonosulfate(PMS) has received increasing attention as viable technology for recalcitrant organics removal from polluted waters. Although promising, alternative heterogeneous catalysts with stable structure, strong hydrophilicity, environmental friendliness and excellent catalytic performance are highly desirable to facilitate the wide industrialization of PMS. In this work, Ni doped CoOOH catalyst was employed as PMS activator. Ni dopant had a significant influence on the morphology, structure and catalytic performance of CoOOH. Ni_0.2Co_0.8OOH exhibited the best catalytic performance. Reaction rate of Ni_0.2Co_0.8OOH was 2, 4, and 4.4 times that of CoOOH, CoFe₂O₄ and Co₃O₄, respectively. Moreover, Ni_0.2Co_0.8OOH/PMS system had potential application to organic pollutants and displayed a great catalytic activity over a broader pH value(e.g., 4-10). More importantly, Ni doping accelerated the transformation of Co(Ⅲ) and Co(Ⅱ) and formed active species CoOH⁺ and NiOH⁺, which were responsible to the enhancement of PMS activation. ^·OH, SO₄^·-, O₂^·- and ¹O₂ were detected, indicating both non-radical and radical processes in the Ni_0.2Co_0.8OOH/PMS system. These findings provide a promising alternative to mixed-metal oxyhydroxides catalysts for PMS activation, demonstrating a great potential in environmental remediation and wastewater treatment.



Enhancement of Bio-based para-Xylene Selectivity in Catalytic Fast Pyrolysis of Cellulose Using a Surface-modified Mg/P/HZSM-5 Catalyst

WANG Yulan, FAN Minghui, ZHU Lijuan, WANG Shengfei, HE Yuting, LI Quanxin

2019, 35(3):  449-456.  doi:10.1007/s40242-019-9024-6

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With the growing consumption of oil, the production of p-xylene(PX) from renewable biomass has gained significant attention recently. This work demonstrated that cellulose, a main component in lignocellulosic biomass, was directly converted into PX over the Mg/P surface-modified zeolites. The catalysts modified by the incorporation of P₂O₅ and MgO into HZSM-5(HZ) promoted the isomerization of m-/o-xylenes to p-xylene. The PX selectivity was greatly enhanced using the modified zeolites due to the deactivation of external surface and the adjustment of pore entrance. In addition, the addition of methanol to cellulose was beneficial to increase the selectivity of xylenes due to the alkylation reactions and the Diels-Alder reactions between cellulose-derived furans and methanol-derived olefins. The highest PX yield of 10.7%(molar fraction) with a high PX selectivity in xylenes(97.1%) was obtained over the 10%Mg/5%P/HZ catalyst. The reaction pathway for the formation of p-xylene was addressed according to the study of the key reactions and the characterization of catalysts.



Reductive Amination of Carbonyl Compounds with Ammonia and Hydrogenation of Nitriles to Primary Amines with Heterogeneous Cobalt Catalysts

LIU Junmei, GUO Wanwan, SUN Hao, LI Ruyue, FENG Zhipeng, ZHOU Xuyang, HUANG Jun

2019, 35(3):  457-462.  doi:10.1007/s40242-019-8390-4

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Reductive amination of aldehydes/ketones with aqueous NH₃ and hydrogenation of nitriles to primary amines with Co catalysts were reported. Co@NC-700 exhibited remarkable activity and high selectivity for the reductive amination of aldehydes/ketones with aqueous NH₃ and the hydrogenation of nitriles to primary amines. Several primary amines can be obtained with good to excellent yields via the reductive amination of aldehydes/ketones and the hydrogenation of nitriles. The nitrogen-doped carbon(C)-supported Co@NC-700 metal catalyst was prepared via the pyrolysis of bioMOF Co/adenine in activated C. Co@NC-700 can be reused five times without evident loss of activity.



A Layered Chitosan/Graphene Oxide Sponge as Reusable Adsorbent for Removal of Heavy Metal Ions

ZHANG Di, LI Ning, CAO Shuai, LIU Xi, QIAO Mingwu, ZHANG Pingan, ZHAO Qiuyan, SONG Lianjun, HUANG Xianqing

2019, 35(3):  463-470.  doi:10.1007/s40242-019-8369-1

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Along with the growing severity of environment problem and energy crisis, it is inevitable to develop novel materials, which are contributed to the removal of hazardous pollutants from contaminated water. Herein, we reported a facile method for the preparation of free-standing chitosan/graphene oxide(CS/GO) composite sponges with low density, where CS/GO mixtures were first synthesized by the homogeneous reaction of chitosan and graphene oxide in aqueous acetic acid solution; then CS/GO sponges were obtained by lyophilizing the suspension, which were prefrozen at -20℃ and in liquid nitrogen successively. The obtained layered sponge showed good water-driven shape memory effect and was a good adsorbent of Co²⁺ and Ni²⁺ with a large adsorption capacity of 224.8 and 423.7 mg/g, respectively. Importantly, the successive adsorption-desorption studies employing CS/GO sponge indicated that the composite could be regenerated by HCl solution and reused in more than five cycles with regeneration efficiency beyond 80%. Also, the resultant sponge was explored as an exceptionally adsorbent for the removal of organic dye(e.g., methylene blue, MB).



Synthesis, Crystal Structure and Non-covalent Interactions Analysis of Novel N-Substituted Thiosemicarbazone

ZHANG Xing, HUANG Jie, ZHANG Yu, QI Fan, WANG Sifan, SONG Jirong

2019, 35(3):  471-477.  doi:10.1007/s40242-019-8354-8

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(E)-1-(4-Fluorobenzylidene)-4-(4-ethylphenyl)thiosemicarbazone was synthesized via the reaction of 4-(4-ethylphenyl)thiosemicarbazide and 4-fluorobenzaldehyde. The title compound was characterized by FTIR, ¹H and ¹³C NMR, mass spectrometry and elemental analysis techniques. Structural property of the title compound was displayed by the X-ray single crystal diffraction. The title compound crystallized in triclinic space group P1 with a=0.6494(4) nm, b=0.7971(5) nm, c=1.5492(10) nm, α=83.690(11)°, β=84.185(10)°, γ=84.348(11)°, molecular formula C₁₆H₁₆FN₃S, M_r=301.39, V=0.7868(9) nm³, Z=2, D_c=1.272 g/cm³, F(000)=316, μ=0.213 mm^-1, S=1.02, R=0.0513, and ωR[I>2σ(I)]=0.1662. The intermolecular interactions in the crystal structure were explained using the Hirshfeld surface and their associated two-dimensional fingerprint plots. The title compound showed C-H···S(1-x, -y, -z) and N-H···S(1-x, -y, -z) intermolecular interactions, and formed the supramolecular self-assemblies through R₂²(12) and R₂²(8) ring motifs. Shape index and curvedness were performed to further understand some unique weak interactions, for instance, the weak π…π stacking contacts in molecular structure with different characteristic regions. Besides, the reduced density gradient(RDG) function provided a real-space function for discussing non-covalent interactions within molecule, such as hydrogen bonds, weak van der Waals interactions and attractive or repulsive effects.



Combined QSAR/QSPR, Molecular Docking, and Molecular Dynamics Study of Environmentally Friendly PBDEs with Improved Insulating Properties

LIU Sicheng, SUN Shijun

2019, 35(3):  478-484.  doi:10.1007/s40242-019-8353-9

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To improve the insulating properties of polybrominated diphenyl ethers(PBDEs), we studied the molecular structures and energy gap(E_g) values of 209 PBDEs using a three-dimensional quantitative structure-activity relationship(3D-QSAR) model, molecular docking, and molecular dynamics. We also analyzed the interaction mechanisms of PBDEs using a 2D-QSAR model, molecular substitution characteristics, and molecular docking. The 3D-QSAR model showed that the 2-, 4-, 5-, and 6-positions significantly influenced the PBDE insulating properties. Using BDE-34 as a template molecule, we designed six derivatives with 0.47%-28.44% higher insulation than BDE-34. Compared with BDE-34, the stability and flame retardancy of the above six derivatives were not adversely affected. These derivatives, except for 2,6-cyanomethyl-BDE, 2-cyanomethyl-BDE, and 2-aminomethyl-BDE, were more toxic and biodegradable than BDE-34, but showed weaker bioaccumulation and migration abilities than BDE-34. Mechanism analysis showed that the highest occupied orbital energy, the most negative charge, and the dipole moment were the main quantitative parameters that affected the PBDE insulating properties. PBDE insulation gradually decreased as the number of Br atoms increased. The level of similarity between the substitution patterns on the two benzene rings was significantly correlated with PBDE insulation, with hydrophobic groups having a more significant effect on PBDE insulation.



Decomposition Mechanism of 5,5'-Bis(tetrazole)-1,1'-diolate(TKX-50) Anion Initiated by Intramolecular Oxygen Transfer

ZHAO Shengxiang, ZHAO Ying, XING Xiaoling, JU Xuehai

2019, 35(3):  485-489.  doi:10.1007/s40242-019-8332-1

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Density functional theory calculations at the B3LYP/6-31+G^** and B3LYP/6-311++G^** levels were performed on thermal decomposition of 5,5'-bis(tetrazole)-1,1'-diolate(TKX-50) anion with an intramolecular oxygen transfer being an initial step. The results show that the intramolecular oxygen transfers are the rate-limiting steps for the decomposition of title anion with activation energies being in the range of 287-328 kJ/mol. Judged by the nu- cleus-independent chemical shift values, the formation of antiaromatic ring in transition state or the decrease of aromaticity of the tetrazole ring of the reactant makes somewhat contribution to the high potential energies of the rate-limiting transition states. However, the activation energies of the following N₂ elimination through various pathways are in a low range of 136-166 kJ/mol. The tetrazole ring acts as an electron donor or acceptor in different pathways to assist the bond rupture or group elimination. The rate constants in a temperature range of 500-2000 K for all the intramolecular oxygen transferring reactions were obtained. The corresponding linear relationships between lnk and 1/T were established.



Zirconium Doped Hydrotalcite-based NiAl Mixed Oxides-Enhanced Performance for Adsorption of SO₂ and NO

ZHAO Ling, ZHANG Yu, LI Lexin, XING Yating, WANG Shuai, Christopher J. MARTYNIUK

2019, 35(3):  490-497.  doi:10.1007/s40242-019-8324-1

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In the present study, the adsorptive behavior of zirconium doped hydrotalcite-based NiAl mixed oxides for reducing NO and SO₂ was compared. According to the experimental results, the Zr⁴⁺ cations were partially dissolved in crystalline NiO phase. With the addition of Zr, new centers for oxygen release and storage were formed, Lewis acid strength increased, and weakly and strongly alkaline sites were expanded. Moreover, in situ FTIR(Fourier transform infrared spectroscopy) investigation demonstrated that the amounts of surface bisulfite, sulfite, nitrite and nitrate species of ZrNiAlO were much more than those of NiAlO. On the whole, this study concluded that the addition of Zr⁴⁺ to NiAlO works to improve this compound as major absorbent for SO₂ and NO.



Furfural Reduction via Hydrogen Transfer from Supercritical Methanol

MA Fei, LI Hengli, JIANG Jiuxing

2019, 35(3):  498-503.  doi:10.1007/s40242-019-8319-y

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Furfural derived from biomass hemicelluloses is an important intermediate for biofuels and chemicals. In order to further upgrade, furfural is usually reduced into 2-methyl furan that is more stable and useful. In this work, furfural was reduced by CuZnAl, CuMgAl, Cu₂Cr₂O₅, CuNiAl as catalysts in a supercritical methanol without external H₂ source. The best yield of 2-methyl furan was achieved among the H₂ free furfural process reported as high as 74%. And the catalytic behaviors were discussed under different catalysts and temperatures conditions.



Artificial Esterase Based on Self-assembly Gel Microspheres Constructed from Chitosan and Amino Acids

CAO Jing, WANG Miao, CHEN Weihua, SHE Yongxin, WANG Jing, WANG Fengzhong, LAO Shuibing

2019, 35(3):  504-508.  doi:10.1007/s40242-019-8283-6

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A novel artificial esterase based on chitosan and amino acids was synthesized in the present study. The Fmoc-His and Glu were linked to chitosan by active ester method(AEM). The hydroxide radical in chitosan, imidazole group of Fmoc-His and carboxyl from Glu formed a catalytic center of natural esterase. Gel microspheres were coated with a protective layer and a supporting layer by self-assembly construction function in carboxymethylcellulose sodium(CMCS) solution. As for catalytic activity, chitosan-His-Glu was found to be more efficient than chitosan-His and chitosan-Glu in mimicking the core catalytic sites of natural esterase, and the best ratio(mass ratio) of chitosan-His-Glu:CMCS was 1:3. Furthermore, metal ions, such as Ca²⁺, Mg²⁺, Fe²⁺, etc., were able to improve the catalytic efficiency of artificial esterase. And the Lineweaver-Burk plot indicated that the catalytic kinetics of artificial esterase conformed to Michaelis-Menten equation.



S-1805/Ag/Au Hybrid Transparent Electrodes for ITO-f ree Flexible Organic Photovoltaics

WEN Xuemei, YI Fangshun, JI Jinhai, BI Yangang, ZHANG Wenyi, WANG Wenquan

2019, 35(3):  509-513.  doi:10.1007/s40242-019-8269-4

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We fabricated an S-1805/Ag/Au hybrid transparent electrode based on 4.4 nm ultrathin Au film, which exhibited a high transparency(T=78% at 550 nm), a low sheet resistance(R_s=70 Ω/sq), and an extremely smooth surface(roughness=0.37 nm). The three-dimensional(3D) island growth mode of 4.4 nm Au film was resisted by the chemical bonding effect of the nonconductive S-1805 film and the wetting behavior of 0.6 nm Ag layer. The S-1805/Ag/Au hybrid transparent electrodes were used as the replacement of ITO anodes in flexible organic photovoltaics(OPVs), and the S-1805/Ag/Au-based OPVs resulted in the similar power conversion efficiency compared to ITO-based devices. High flexibility and mechanical robustness were demonstrated in the ITO-free OPVs without obvious degeneration in device performance after over 2000 repeated bending cycles.



DOPA-IGF-1 Coated HA/PLGA Microspheres Promoting Proliferation and Osteoclastic Differentiation of Rabbit Bone Mesenchymal Stem Cells

LIU Guomin, LI Yalong, YANG Shuting, ZHAO Yi'an, LU Tiancheng, JIA Wenyuan, JI Xuan, LUO Yungang

2019, 35(3):  514-520.  doi:10.1007/s40242-019-9007-7

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To explore the ability of dihydroxyphenylalanine-insulin-like growth factor-1(DOPA-IGF-1) coated hydroxyapatite/poly(lactic-co-glycolic acid)(HA/PLGA) microspheres to promote the proliferation and osteoclastic differentiation of rabbit bone mesenchymal stem cells(rBMSCs), HA/PLGA microspheres with different HA content (10%, 30%, 50%, mass fraction) were prepared by electrospinning method and HA/PLGA microspheres with 50% HA were coated with IGF-1 and DOPA-IGF-1, respectively. They were co-cultured with rBMSCs, respctively. Cell counting kit-8(CCK-8) detection, confocal laser scanning microscopy(CLSM), alkaline phosphatase(ALP) detection and osteogenesis related genes COL1A1, Runx2 and bone morphogenetic protein-2(BMP-2) detection were conducted to detect the proliferation activity, cell morphology, differentiation ability and the expression level of osteogenesis-related genes of cells cultured on all microspheres groups. The results showed that rBMSCs proliferation increased in an HA content dependent manner, and cells proliferated more in the IGF-1 coated and DOPA-IGF-1 coated groups, in particular in DOPA-IGF-1 coated group, and the differences were more remarkable over time (P<0.05). HA/PLGA microspheres promoted the proliferation and osteogenic differentiation of rBMSCs, and DOPA-IGF-1 coating enhanced the proliferation and osteogenic differentiation of rBMSCs.



In-situ Synthesis and Characterization of Poly(vinyl alcohol)/Hydroxyapatite Composite Hydrogel by Freezing-thawing Method

MENG Deyue, ZHOU Xiuqing, ZHENG Keyan, MIAO Chong, SHENG Ye, ZOU Haifeng

2019, 35(3):  521-529.  doi:10.1007/s40242-019-8341-0

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Poly(vinyl alcohol)/hydroxyapatite(PVA/HA) composite hydrogel was successfully in-situ synthesized via three cycles of freezing-thawing. The composition and structure of products were investigated by X-ray diffraction(XRD), Fourier transformed infrared spectroscopy(FTIR) and scanning electron microscopy(SEM). The influence of different preparation methods and contents of material on the mechanical properties of PVA/HA composite hydrogel was discussed through tensile and compressive tests. The template of PVA could avoid the agglomeration of HA particles, which improves the mechanical properties of the composite hydrogel effectively. The tensile strength, modulus and compressive performances of the PVA/HA composite hydrogel prepared by the in-situ synthesis method were better than those of hydrogel obtained by the simple blend method. In addition, the effect of the content of PVA, HA, and the pH value on the properties of the PVA/HA composite hydrogel has been discussed in detail.



Highly Soluble Phenylethynyl-terminated Imide Oligomers and Thermosetting Polyimides Based on 2,2',3,3'-Biphenyltetracarboxylic Dianhydride

MENG Xiangsheng, LU Gewu, LIU Xiuju, MENG Qingjie, SHI Junwei, YUAN Hang, KE Hongjun, WANG Xianwei, FAN Weifeng, LIU Jingfeng, YAN Jingling, WANG Zhen

2019, 35(3):  530-536.  doi:10.1007/s40242-019-8334-z

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The properties of a series of imide oligomers were characterized according to their molecular weights, solubility, and thermal and rheological properties. This series of imide oligomers was synthesized via a two-step method using 2,2',3,3'-biphenyltetracarboxylic dianhydride(3,3'-BPDA) and aromatic diamines as the monomers, and 4-phenylethynyl phthalic anhydride(PEPA) as the end-capping agent. The imide oligomers based on 3,3'-BPDA showed excellent solubility in low boiling point solvents and low melt viscosity, which were attributed to their unique bent architectures. High-performance thermosetting polyimides were produced from these oligomers via thermal crosslinking of the phenylethynyl groups. The mechanical and thermal properties of the thermosets were studied using tensile testing, dynamic mechanical thermal analysis(DMTA), and thermogravimetric analysis(TGA). The 3,3'-BPDA-based thermosets exhibited excellent thermal properties, with glass transition temperatures of up to 455℃, and 5% mass loss temperatures of up to 569℃ in air. The thermosets based on 3,3'-BPDA showed superior thermal properties compared to those derived from TriA-X series oligomers.



One-pot Synthesis of PEGylated Gd-based Nanoparticles as High-performance and Biocompatibility Contrast Agents for T ₁-Weighted Magnetic Resonance Imaging In vivo

HUANG Sa, HAN Qinghe, WANG Lei, GONG Tingting, YUAN Qinghai

2019, 35(3):  537-541.  doi:10.1007/s40242-019-8327-y

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Polyethylene glycol modified(PEGylated) NaGdF₄(PEG-NaGdF₄) nanoparticles as a novel T₁-weighted magnetic resonance imaging(MRI) contrast agent was successfully constructed by a one-pot hydrothermal synthesis method. Because of the functionalization of PEG, the nanoprobes had excellent dispersity, excellent stability and high biocompatibility. More importantly, the as-prepared PEG-NaGdF₄ nanoprobes revealed the high longitudinal relaxivity value and prominent T₁-weighted MRI contrast performance, which was superior to the commercial MRI contrast agents. With the facile synthesis, excellent dispersity, outstanding stability, remarkable contrast performance and high biocompatibility, the PEGylated NaGdF₄ nanoparticles brought more opportunities to the new generation of nanoparticulate-based T₁-weighted MRI contrast agents in clinic.



Research on Ice Crystal Growth Inside the Vitrified Vs55 with Magnetic Nanoparticles During Devitrification by Cryomicroscopy

LIU Ke, XU Yi, YU Hongmei

2019, 35(3):  542-548.  doi:10.1007/s40242-019-8230-6

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The effect of magnetic nanoparticles(mNPs) on the devitrification crystallization of typical vitrification solution Vs55 was systematically explored by differential scanning calorimetry(DSC) and cryomicroscope system. The results show that, (i) the mNPs coated by both carboxylic acid(CA) and polyethylene glycol(PEG) had little effect on the glass transition temperature(T_g) of Vs55, but had significant effect on the devitrification transition temperature(T_d) and devitrification enthalpy(H_Td), (ii) in the range of the devitrification area(-85- -60℃), the MNPs coated by CA can significantly accelerate the devitrification of Vs55 as the isothermal temperatures and the cooling rates increased, and the ice growth rate was 0.37 μm/s at the isothermal temperature of -85℃, and was about 2.19 μm/s at -75℃. Also, the ice growth rates rose from 1.72 μm/s to 3.54 μm/s when the cooling rates were increased from 2℃/min to 100℃/min(at the isothermal temperature of -75℃), (iii) magnetic nanoparticles coated by both PEG and CA could promote the devitrification of Vs55, for instance, without any crystal growth inside Vs55 at the isothermal temperature of -80℃, but 1.04 and 2.31 μm/s for adding magnetic nanoparticles coated by CA and PEG, respectively. Compared with the samples coated by CA, PEG promoted the devitrification of Vs55 in a much more positive way, and the ice growth rates were 0.62 and 6.25 μm/s at the isothermal temperatures of -85 and -75℃, respectively. These results indicate that the surface coating of MNPs could significantly affect the recrystallization of Vs55, and further work should be conducted in the future research.