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01 April 2017, Volume 33 Issue 2

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Chemical Research in Chinese Universities Vol.33 No.2 February 2017

2017, 33(2):  0-0. 

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Articles

Synthesis of a Heptapeptide and Its Application in the Detection of Mercury(II) Ion

FENG Huiyun, GAO Lei, YE Xinhui, WANG Lei, XUE Zechun, KONG Jinming, LI Lianzhi

2017, 33(2):  155-159.  doi:10.1007/s40242-017-6362-0

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A new heptapeptide, Cys-Pro-Gly-Cys-Pro-Gly-Cys-CONH₂(P7), was prepared via Fmoc solid-phase peptide synthesis, purified by high performance liquid chromatography(HPLC) and characterized by mass spectrometry(MS). The interactions of P7 with metal ions were also investigated by spectroscopy and the results show that P7 has highly selective binding affinity to Hg(II). Based on this specific character, a simple, rapid and sensitive detection method for Hg(II) was developed. When the mixture solution of P7 and Hg(II) was added to colloidal gold nanoparticles(GNP), the color of GNP remained unchanged. On the contrary, the color of GNP changed from red to blue when the mixture solutions of P7 and other metal ions were added.



Chemotransformation of Bacterial Cells Without Heat-shock

WANG Sainan, LI Zhenhua, CHEN Zhijun

2017, 33(2):  160-165.  doi:10.1007/s40242-017-6403-8

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Transformation of DNA into microbial cells via heat-shock approach has been well established in the field of molecular biology for decades. Herein we described an unexpected finding that heat-shock may not play an essential role in the transformation process. This observation was verified via UV-Vis and fluorescence spectroscopies, and confocal microscopy images for various DNAs and bacterial cells. The non-heat-shock approach proposed in this study can be a convenient and beneficial modification for DNA transformation, especially for those laboratories lacking ice machine and heat-shock equipment.



Fluorescence Spectroscopic Studies on the Interaction Between a New Bismuth(III) Schiff Base Complex and Bovine Serum Albumin

LI Xu, LI Chuanhua, JIANG Jianhong, GU Huiwen, WEI Deliang, YE Lijuan, HU Jilin, XIAO Shengxiong, ZHANG Hui, LI Xia, LI Qiangguo

2017, 33(2):  166-171.  doi:10.1007/s40242-017-6361-1

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In this work, the binding interaction between a new bismuth(III) Schiff base complex {[Bi(valen)]Cl·2H₂O}[H₂valen=N,N'-bis(2-hydroxy-3-methoxyphenylmethylidene)-2,6-pyridinediamine, C₂₁H₁₉N₃O₄] and bovine serum albumin(BSA) was studied via fluorescence quenching method. The static quenching constant K_LB and some thermodynamic parameters(e.g., △G^θ, △H^θ and △S^θ) of the interaction were estimated. In particular, the binding site between the complex and BSA was explored by molecular docking. On the basis of the mechanism of Förster energy transfer, the binding distance between the bismuth(III) Schiff base complex and BSA(Trp.213) as well as the transfer efficiency was obtained. Furthermore, the effect of the bismuth(III) Schiff base complex on the conformation of BSA was investigated using synchronous fluorescence spectroscopy.



Detection of Saponins and Oligosaccharides in Herbs Using Direct Analysis in Real-time Mass Spectrometry

HE Yangfang, LIU Wenlong, SU Rui, XIU Yang, PEI Jin

2017, 33(2):  172-178.  doi:10.1007/s40242-017-6297-5

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The use of direct analysis in real-time(DART) mass spectrometry(MS) for direct detection of saponins and oligosaccharides is difficult mainly because of the strong polarity of these molecules, which results in challenges regarding desorption and ionization of the compounds. Structure derivatization, such as methylation, is essential for improving the volatility and the proton affinity of saponin and oligosaccharides. In this study, solid-phase methylation of saponins and oligosaccharides was accomplished in a stainless steel methylation column, and the methylated products of astragaloside, salidroside, icariin, ginsenosides(Rb1, Rb2, Rb3, Rd, Re, Rf and Rg1), maltose, isomaltose, sucrose and maltotriose were analyzed using DART-MS. Fragmentations occurred during ionization and tandem mass spectrometry, and most fragments corresponded to the glycosidic bond, cross-ring cleavages, and the neutral loss of CH₃OH ions, but the aglycone cleavage fragment was not detected. Furthermore, the method was successfully used in the rapid and simultaneous analysis of saponins and oligosaccharides in a ginseng extract; quantitative analysis of ginsenoside Rb1 was also carried out, and consistent content results were obtained in DART-MS and high-performance liquid chromatography(HPLC).



Ultrasonic-assisted Biodegradation of Endocrine Disrupting Compounds in Soil by Pseudomonas putida: the Importance of Rhamnolipid for Intermediate Product Degradation

CHEN Ying, ZHANG Chen, LI Yu

2017, 33(2):  179-186.  doi:10.1007/s40242-017-6281-0

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The present study aimed to completely remove estrogens, including oestrone(E1), oestradiol(E2), oestriol(E3), 17α-ethinylestradiol(EE2) and bisphenol-A(BPA), from soil using Pseudomonas putida(P. putida). A central composite design was developed to determine the optimal conditions of three variables(ultrasonication time, quantity of P. putida, and concentration of added rhamnolipid) for the removal of the estrogens, and the biodegradation rates of the estrogens were investigated under the optimum conditions. Moreover, a quantitative structure-biodegradation relationship(QSBR) was used to analyze the effect of the estrogenic physicochemical properties on the enhancement of the biological degradation. The optimal conditions were an ultrasonication time of 3 min, a P. putida quantity of 8 mL, and a rhamnolipid concentration of 100 mg/L. These conditions resulted in removal of 100%, 94.86%, 94.90%, 96.56% and 94.56% of E1, E2, EE2, BPA and E3, respectively after 7 d. The degradations were more rapid and complete than those reported in previous studies, indicating the suitability of the adaptation of P. putida to estrogen degradation under conditions of ultrasonic-assistance and adding rhamnolipid; improvement was particularly apparent from the complete degradation of E3. Based on a Pearson correlation analysis, the estrogen molecule polar surface area(PSA) and surface tension were significantly related to the biodegradation effect. An analysis of the QSBR model with the estrogen biodegradation rates as a dependent variable and the PSA and surface tension as independent variables indicated that larger PSA caused decreased estrogen biodegradation, while the biodegradation progress was dominated by the surface tension of the estrogens. The interaction of PSA and surface tension had an antagonistic effect on the biodegradation of estrogens. Therefore, rhamnolipid/ultrasonication can significantly improve the biodegradation rates of oestrogens in soil, while simultaneously adjusting other environmental conditions would influence and control the biodegradation processes of estrogens.



Synthesis and Biological Evaluation of Pyrano[2,3-f]chromene-4,8-dione Derivatives as Potential Anticancer Agents

LI Hongshuang, WU Xiaming, ZHANG Ruize, HAO Liqiang, DUAN Guiyun, XIAO Yuliang, XIA Chengcai, LI Furong, YOU Guirong, HAN Junfen

2017, 33(2):  187-193.  doi:10.1007/s40242-017-6472-8

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Based on the hit 5-hydroxy-2-methyl-10-propyl-2,3-dihydro-4H,8H-pyrano[2,3-f]chromene-4,8-dione(1), a series of pyrano[2,3-f]chromene-4,8-dione derivatives was designed and synthesized using phloroglucinol as starting material. Meanwhile, a regioselective synthetic route was developed for 5-methoxy-2,3-dihydro-4H,8H-pyrano-[2,3-f]chromene-4,8-dione products(11a-11f), and their structures were further confirmed by nuclear Overhauser effect(NOE). The evaluation of anticancer activities of these compounds against four human cancer cell lines, including human glioma cell line (SHG-44), human lung cancer cell line(H1299), breast cancer cell line(MCF7) and human colon carcinoma cell line(HCT-116) in vitro shows that 5-methoxy-2,2-dimethyl-9-chloro-10-trifluormethyl-2,3-dihydro-4H,8H-pyrano[2,3-f]chromene-4,8-dione(11e) possesses the best anticancer activities with IC₅₀ values of 6.68, 7.90, 5.16 and 4.82 μmol/L, respectively. Finally, the preliminary structure-activity relationships(SARs) were summarized, which could pave the way for generating more potent anticancer agents with drug-like properties.



Synthesis and Biological Evaluation of Hydroxylcoumarin Derivatives as Antioxidant Agents

CHEN Chen, WANG Ping, ZOU Liwei, YANG Ling, FAN Yiming, HU Wenzhong, GE Guangbo

2017, 33(2):  194-199.  doi:10.1007/s40242-017-6411-8

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In this study, esculetin(1) was chosen as a lead compound and some structural modifications were designed to explore the antioxidant activities of esculetin derivatives. Meanwhile, a convenient method for selective methylation of catechol coumarins with different bases was developed. Furthermore, a few 5,7-dihydroxylcoumarins were synthesized and 7-hydroxylcoumarins were employed in order to explore the potential structure-antioxidant activity relationships. The antioxidant activities of these compounds were evaluated and compared with standard antioxidant Trolox by the 2,2'-diphenyl-1-picrylhydrazyl(DPPH) assay, 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonate) cation(ABTS⁺) assay and ferric reducing antioxidant power(FRAP) assay. The results show that the catechol group is the key pharmacophore. Meanwhile, introducing electronegative groups at the C4 position of esculetin(1) may enhance the antioxidative capacity, while introducing a group containing nitrogen as a hydrogen bond acceptor at the C8 position may slightly reduce the antioxidative capacity. Among them, the most powerful antioxidants are compounds 5 and 7, which exhibit higher antioxidant activity than esculetin(1) in all assays.



Potassium tert-Butanolate Promoted Reaction of Benzaldehydes and Indoles: a New Strategy for Synthesis of Bis(indolyl) arylmethanes

JIANG Chong, LI Jue, LÜ Guanghui, ZHENG Yang, YU Xinling, LÜ Songyang, HAI Li, WU Yong

2017, 33(2):  200-205.  doi:10.1007/s40242-017-6382-9

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t-BuOK-promoted synthesis of bis(indolyl) arylmethanes from aromatic aldehydes and indoles was achieved. Substrates bearing different functional groups, especially groups which are sensitive to acidic media, are well tolerated under the optimal condition, making this reaction particularly attractive for expanding the scope of the present protocols that provides bis(1H-indol-3-yl) arylmethanes.



Rapid Microwave Assisted Synthesis and Antiproliferative Evaluation of Novel Steroidal Thiazole Derivatives

HUANG Yanmin, ZHAO Dandan, LIU Chang, GAN Chunfang, ZHAN Junyan, LIN Qifu, SHI Haixin, CUI Jianguo

2017, 33(2):  206-212.  doi:10.1007/s40242-017-6372-y

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Three series of novel steroidal thiazole derivatives were synthesized by microwave assisted one-pot reaction from pregnenolone, testosterone and estrone, respectively. Their structures were characterized by IR, NMR and HRMS, and the antiproliferative activities of all the synthesized compounds against human cervical carcinoma (HeLa), human liver carcinoma(HepG2), human lung carcinoma(A549), nasopharyngeal carcinoma(CNE2) and normal kidney epithelial cells(HEK293T) were screened. Among the compounds, 1-estron-17'-ylidene-2-[4'-(p-bromophenyl)-2'-thiazol]hydrazone(12) displayed distinct antiproliferative activity against all the tested cancer cell lines and was almost inactive to normal kidney epithelial cells.



Unexpected Decarboxamidation of α-Arylsulfonyl Weinreb Amides by Grignard Reagents: Synthesis of α-Disubstituted Arylsulfones

LIU Wei, LI Houying, QIN Haijuan, ZHAO Wei, ZHOU Chen, JIANG Shengping, YANG Cheng

2017, 33(2):  213-220.  doi:10.1007/s40242-017-6371-z

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An unexpected decarboxamidation of α-arylsulfonyl Weinreb amides as a side reaction under the standard acylating conditions was found in Weinreb amides chemistry. The control experiments for mechanism study disclosed that α-sulfo group was necessary, and α-quaternary carbon was the key factor for the reaction. Meanwhile, an efficient method was established for the preparation of secondary alkyl arylsulfones by this unexpected C-C bond cleavage reaction using excess Grignard reagent.



Structure and Positioning of Three Transmembrane Segments from Slc11a1 in SDS Micelles

QI Haiyan, TANG Wanxia, BAI Liming, GAO Lidi

2017, 33(2):  221-226.  doi:10.1007/s40242-017-6288-6

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Slc11a1 is an integral membrane protein with 12 predicted transmembrane domains(TM). In the present work, the secondary structures and positioning of the peptides associated with Slc11a1-TM2, TM3 and TM4(wild-type peptides and functional mutants) in sodium dodecyl sulfate(SDS) were analyzed using circular dichroism(CD) and fluorescence techniques. The results indicate that TM3 is significantly different in secondary structure and topology from TM2 and TM4 in SDS. The peptide TM3 is less structured and is embedded in the SDS less deeply than TM2 and TM4 at pH=4, 5.5 and 7. In addition, the position of TM3 is remarkably shifted towards the direction of the SDS surface with increasing pH, whereas the locations of TM2 and TM4 in SDS are less affected by pH. The E139A substitution in TM3 significantly impairs the pH dependence of the buried depth of TM3 and causes a decrease in helicity in SDS at the three pH values. The G169D mutation has little effect on the topological arrangement of TM4 in SDS. In contrast, TM2 and TM4 are topologically similar.



Highly Efficient White Organic Light-emitting Devices with Optimized Electron Transporting Layers

ZHANG Tianyu, ZHENG Yu, WANG Chengming, ZHANG Yixin, LIU Shihao, MA Jian, ZHANG Letian, XIE Wenfa, CHEN Ping, LIN Jun, LIU Yujuan

2017, 33(2):  227-230.  doi:10.1007/s40242-017-6421-6

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We fabricated three phosphorescent blue organic light-emitting devices based on blue phosphor of iridium(III) bis[(4,6-difluorophenyl)-pyridinato-N,C2'](Firpic) with different electron transporting layer(ETL) materials. By analyzing efficiency curves and spectral characteristics, the significant effect of ETL on many aspects of device performance was demonstrated. With optimized ETL, the characteristics of devices, such as voltage and efficiency were significantly improved. Combined with a yellow phosphor of iridium(III) bis(4-phenylthieno[3,2-c]pyridinatoN,C2') acetylacetonate(PO-01), phosphorescent white organic light-emitting devices(PhWOLEDs) were obtained. Then, with an aim to promote the performance of the PhWOLEDs, a thin layer of 4,4',4″-tri(N-carbazolyl)-triphenylamine(TCTA) was introduced between two light emission layers, and the diffusion of excitons was confined. The outperformance device fabricated with 4,7-diphenyl-1,10-phenanthroline(Bphen) as the electron transporting layer exhibited a peak current efficiency of 36.6 cd/A, a peak power efficiency of 19.2 lm/W, and the International Commission on Illumination coordinates(0.37, 0.46).



Synthesis, Post-modification and Catalytic Properties of Metal-organic Framework NH₂-MIL-53(Al)

LIU Lili, TAI Xishi, ZHOU Xiaojing, LIU Lijuan

2017, 33(2):  231-238.  doi:10.1007/s40242-017-6420-7

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A postsynthetic modification method was used to prepare salicylaldehyde functionalized metal-organic frameworks through the nucleophilic addition of salicylaldehyde with the amine group present in the frameworks of NH₂-MIL-53(Al). Hydroxyl groups were successfully grafted onto NH₂-MIL-53(Al), and imine groups were formed. Importantly, these hydroxyl and imine groups of the resulting NH₂-MIL-53(Al)-SA can be used as the anchoring group to stabilise Au³⁺ ions and Au⁰ nanoparticles(NPs). By doing this, Au³⁺ ions and Au⁰ NPs were successfully encapsulated in the cages of NH₂-MIL-53(Al) by a simple impregnation method. The resulting gold functionalized NH₂-MIL-53(Al) showed good catalytic activities in the one-pot synthesis of structurally divergent propargylamines by three-component coupling reactions of aldehydes, amines and alkynes. Various aromatic/aliphatic aldehydes, aromatic alkynes, and piperidine were able to undergo three-component coupling on NH₂-MIL-53(Al)-Au. In addition, the catalyst NH₂-MIL-53(Al)-Au was recovered easily by centrifugation and reused up to four times. Thus, it can be used for the environmentally friendly synthesis of propargylamines.



Studies on Hydrolysis Mechanism of Anticancer Ruthenium Drug ImH[trans-Ru(Im)₂Cl₄] via ABEEMσπ Polarizable Force Field Combined with QM and MD-FEP

LI Hui, ZOU Huiyuan, LIU Linlin, ZHAO Dongxia, YANG Zhongzhi

2017, 33(2):  239-247.  doi:10.1007/s40242-017-6401-x

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We used ABEEMσπ(atom-bond electronegativity equalization method) polarizable force field(ABEEMσπ PFF) method combined with QM and molecular dynamics-free energy perturbation(MD-FEP) methods to investigate the function of water molecules in hydrolysis process of ImH[trans-Ru(Im)₂Cl₄](ICR). The activation free energies obtained via MD-FEP calculation are in fair agreement with the experimental data. In addition, QM/MM(ABEEM) rationally describes the charge distributions and the electrostatic interaction between molecules. ABEEMσπ fluctuating charge model has the following good characteristics:(1) not only atomic charge regions but also σ, π bond and lone pair charge regions are explicitly represented for a molecule; (2) the region charges are geometry dependent and calculated from time to time in the dynamic simulation without any iterative procedure so that its performance is time-saving compared with the Drude model and induced dipole model.



Structure of Solution of Colloid and Hydrogen Bonding Fluid Near a Semipermeable Membrane

ZHAO Meng, CHEN Hanfei, GU Fang, WANG Haijun

2017, 33(2):  248-254.  doi:10.1007/s40242-017-6398-1

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The local fluid structure of a solution consisting of colloid particles and hydrogen bonding(HB) fluid separated from pure solvent by a semipermeable membrane was investigated, where the colloid particles and HB fluid serve as solute and solvent, respectively. In this paper, the semipermeable membrane allows the passage of solvent molecules but not solute particles, and therefore, it provides a nano-confinement for colloid particles. The density profiles of the two species near the semipermeable membrane were determined via density functional theory(DFT) for classical fluids. Based on the predicted density profiles under various conditions, the effects of HB strength, functionality, total bulk density, density fraction and the size ratio of two species on the fluid structure were discussed. As an application, the osmotic pressures of the system were also presented. It is shown that the local structure and osmotic pressure can be efficiently regulated by these factors due to the competition between the excluded volume interactions and the HB interaction. The present results are expected to be helpful to study the osmotic phenomena and relevant problems on the nanoscale.



Density Functional Theory Study of CO₂ and H₂O Adsorption on a Monoclinic WO₃(001) Surface

LIU Li, LIN Maohai, LIU Zhongbo, SUN Honggang, ZHAO Xian

2017, 33(2):  255-260.  doi:10.1007/s40242-017-6378-5

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Understanding the interaction of WO₃ with CO₂ and H₂O is vital for clarifying its role in the photocatalytic reduction of CO₂. In this study, we employed density functional theory to investigate the interaction of CO₂ and H₂O with both perfect and defective monoclinic WO₃(001) surfaces. The interactions of co-adsorbed CO₂ and H₂O were also studied. The major finding is that the presence of oxygen vacancies and co-adsorbed CO₂ or H₂O can significantly increase the stability of CO₂ and H₂O on the WO₃(001) surface. A defective WO₃(001) surface is more capable of adsorbing a single CO₂ or H₂O molecule than a perfect WO₃(001) surface, and H₂O adsorbed onto a defective WO₃(001) surface spontaneously dissociates into a hydrogen atom and a hydroxy group. The presence of co-adsorbed H₂O can increase the stability of CO₂ on the WO₃(001) surface, while the presence of the co-adsorbed CO₂ can increase the stability of H₂O on WO₃(001) surface. The analysis of the bonding mechanisms shows that the charge redistribution between the adsorbate and the WO₃(001) surface containing oxygen vacancies and co-adsorbed CO₂ or H₂O is stronger than that between the adsorbate and the perfect WO₃(001) surface; thus, adsorption energy is higher in the former case. The results will be useful for designing WO₃ photocatalysts, as well as for an atomistic-level understanding of the photocatalytic reduction of CO₂.



Molecular Dynamics Simulation of Antipolyelectrolyte Effect and Solubility of Polyzwitterions

YANG Shengchun, ZHU Youliang, QIAN Hujun, LÜ Zhongyuan

2017, 33(2):  261-267.  doi:10.1007/s40242-017-6354-0

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In this work, by using coarse-grained molecular dynamics simulations, we found that poly(2-methacryloyloxyethyl phosphorylcholine)(PMPC) showed a strong solubility and a so-called antipolyelectrolyte effect(APE) in water. In contrast, obvious aggregations but no APE were found in n-butyl-substituted choline phosphate polymers(PMBP) solutions. The underlying mechanisms for different solution behaviors of PMPC and PMBP were investigated in detail. Our results indicate that the presence of butyl groups in PMBP enhances both the electrostatic interactions and the hydrophobicity of PMBP molecules in the system. Both factors were found to contribute to the formations of aggregates in the PMBP system. Further researches revealed that hydrophobicity arising from the butyl group plays a more important role than electrostatic interactions in inducing the PMBP aggregation. In addition, the strong hydrophobicity in PMBP was found to be responsible for the absence of APE. These results are expected to contribute to a better understanding and a better design of the solution properties of polyzwitterions.



Selective Adsorption Performance of H₆P₂Mo₁₅W₃O₆₂-based Cu₃(BTC)₂ Composite in Treatment of Simulated Cationic Dye Wastewater

LIU Xiaoxia, LUO Jing, CHEN Xiuyun, YANG Yun, YANG Shuijin

2017, 33(2):  268-273.  doi:10.1007/s40242-017-6350-4

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Removal of methylene blue(MB) from aqueous solution by a new polyoxometalate-based metal-organic framework composite(POM@MOF) was systematically explored in batch tests. The chemical structure and surface properties of the composite were characterized by means of FTIR, XRD, EDS, N₂ adsorption-desorption isotherms and zeta potential measurements. The results showed that MB adsorption onto H₆P₂Mo₁₅W₃O₆₂@Cu₃(BTC)₂ highly depended on initial solution pH, which was mainly related to the electrostatic attraction between negatively charged composite surface and positively charged MB molecules. Thus, the improved adsorption performance of H₆P₂Mo₁₅W₃O₆₂@Cu₃(BTC)₂ can be attributed to the modification of H₆P₂Mo₁₅W₃O₆₂ resulting in its higher electronegative charge than Cu₃(BTC)₂. The thermodynamic parameters indicated that the adsorption was spontaneous and exothermic process. The isotherm obtained fitted the Langmuir model and the maximum adsorption capacity of the composite at 30℃ was 77.22 mg/g. All the results illustrated that H₆P₂Mo₁₅W₃O₆₂@Cu₃(BTC)₂ composite can effectively and selectively remove cationic organic pollutants, represented by MB, implying the promising application of designing a novel adsorbent polyoxometalate-based metal-organic frameworks in treatment of dye wastewater.



A Simplified Chemical Reaction Mechanism for Surrogate Fuel of Aviation Kerosene

LIU Yunpeng, YAN Yingwen, DAI Chao, LI Jinghua

2017, 33(2):  274-281.  doi:10.1007/s40242-017-6280-1

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n-Decane was chosen as a one-component surrogate fuel to investigate the combustion performance of Rocket Propellant-3(RP-3) aviation kerosene. Sensitivity analysis and the reaction-path analysis method were used to simplify the detailed reaction mechanism of n-decane, and a simplified mechanism including 36 species and 62 elementary reaction steps was obtained. Moreover, 38-step elementary reaction investigated in the reference was simulated in the paper. Numerical simulation method was conducted for both the 62-step and the 38-step reaction mechanisms using pre-evaporation combustion models. Simultaneously Bunsen burner for the combustion of premixed, pre-evaporated RP-3 aviation kerosene was designed to verify the simplified mechanism, and the temperature and gas component concentrations in the axial and radial directions at different heights were measured. The experimental results revealed that the reaction temperature and the CO₂ concentration increased first and then decreased across the axial positions, but on the contrary for the O₂ concentration. The temperature and the O₂ concentration distributions of experimental results are in good agreement with that of numerical simulation results for the 62-step simplified reactions, and the CO₂ concentration distribution is in general agreement with the numerical data. But the 38-step simplified reactions can only predict the change trend for the important parameters which are mentioned above. Through the contrastive analysis for these two kinds of simplified reactions, the 62-step reactions can more accurately simulate the combustion characteristics of RP-3 kerosene. And n-decane can be used as a one-component surrogate fuel for RP-3 aviation kerosene.



Kinetics of Desilification Pretreatment from High-aluminium Coal Fly Ash in Alkaline Medium Under Pressure

LU Min, CHANG Yanwei, CHEN Long

2017, 33(2):  282-286.  doi:10.1007/s40242-017-6230-y

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In this paper, desilification for high-aluminium coal fly ash in alkaline media under pressure was reported to improve the efficiency of sodium leaching. Factors such as the alkaline quantity, reaction temperature, time and liquid-to-solid ratio on desilification were studied in detail. At the same time, the kinetics of desilification were analysed to further reveal the leaching mechanism. The results showed that the alkaline quantity, reaction temperature and liquid-to-solid ratio had significant effects on the desilification efficiency with increasing reaction time. The maximum SiO₂ leaching rate was 65.78% under the optimal experimental conditions. According to the shrinking core model, the process of leaching is controlled by surface chemical reactions in the earlier stage and diffusion of the solid layer in the later stage.



Synthesis and Properties of Polymeric Host Materials Constructed by Silane-carbazole Backbone and Electron-affinitive Cyanohexyl Substituent for Blue Phosphorescence Dopant

HU Dehua, LIU He, LI Xiaoxiao, SUN Xiaoyi, LU Fang, BAI Qing, LU Ping

2017, 33(2):  287-293.  doi:10.1007/s40242-017-6477-3

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A series of blue phosphor hosts, using 3,6-linked carbazole with δ-π tetraphenylsilane segment as the main chain and modified by peripheral cyanohexyl group with different ratios, was designed and synthesized. These polymers show good solubility in common organic solvents. They all possess wide bandgap of 3.40 eV, high thermal stabilities and good film forming abilities. The peripheral cyanohexyl substituents have no effect on the polymer backbones but enhance the electron transporting properties of the polymers in devices. Among them, doped devices using poly[(tetraphenylsilicon/9-hexyl-9H-3,6-carbazole)₅₀-co-(tetraphenylsilicon/9-hexanenitrile-9H-3,6-carbazole)]₅₀ (PCNCzSi50) as the host and bis[(4,6-difluorophenyl)pyridinato-N,C²]-(picolinato)iridium(III)(FIrpic) as the guest show the best performance with the maximum current efficiency and power efficiency of 2.00 cd/A and 1.40 lm/W, respectively.



Functionalization of Magnetic Titanium Dioxide for Targeted Drug Delivery and UV-induced Release

CAI Linjun, LI Junbo, WANG Shipeng, ZHAO Mengzhe, ZHAO Bing, JIANG Chunlai, KONG Wei

2017, 33(2):  294-297.  doi:10.1007/s40242-017-6406-5

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Magnetic titanium dioxide core-shell nanoparticles(Fe₃O₄@TiO₂ NPs) were synthesized as particles with appropriate size for intravenous injection. They subsequently were functionalized with p-aminothiophenol(PATP) to facilitate the covalent attachment of target drugs through azo coupling reaction, which can be universally observed in a variety of drugs containing phenols, anilines, and imidazoles. The proposed drug nanocarrier was designed to possess the ability to release drugs upon UV irradiation because of the photocatalytic property of the TiO₂ shells. All the results indicate the potential application of the Fe₃O₄@TiO₂ NPs in targeted drug delivery with greater chemical stability and universality.



Three-dimensional Flower-like Rutile TiO₂ Microsphere Composed of Nanorods: a Potential Material as Light Scattering Layer for DSSCs

SHI Yan, YANG Yulin, DONG Guohua, JIANG Yanxia, WEI Liguo, SU Ting, FAN Ruiqing

2017, 33(2):  298-304.  doi:10.1007/s40242-017-6363-z

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The low spectrum utilization and the recombination of photo-generated electrons are the main challenges for improving the performance of dye sensitized solar cells(DSSCs). In this article, a three-dimensional flower-like rutile titanium dioxide(TDF-TiO₂) was successfully synthesized via a simple sol-thermal process. X-Ray diffraction patterns(XRD) and scan electron microscopy(SEM) images exhibit that the TDF-TiO₂ are the rutile TiO₂ microsphere composed of lots of regular cuboid nanorods. Applying this TDF-TiO₂ as light scattering layer on the photoanode of DSSCs, the devices present an excellent photovoltage performance, yielding a power conversion efficiency(PCE) of 7.69%, which can be mainly attributed to the enhanced light utilization and the reduced recombination of photo-generated electrons upon a combined analysis of electrochemical impedance spectroscopy(EIS), open-circuit voltage decay(OCVD), and intensity-modulated photocurrent spectroscopy and intensity-modulated photovoltage spectroscopy(IMPS/IMVS), etc. As a conclusion, TDF-TiO₂ is a potential material as light scattering layer and optical transition medium to improve the performance of DSSCs, and this work further demonstrated that regulating the morphology and particle size of TiO₂ is an efficient approach for enhancing the performance of DSSCs by optimizing the utilization of light and the transporting behaviors of photo-generated electrons.



Alternating Terpolymers Based on Tunable Bi-donors with Manipulating Energy Levels and Molecular Geometry

CHEN Zhenzhu, YANG Jia, WU Feiyan, CHEN Lie, CHEN Yiwang

2017, 33(2):  305-311.  doi:10.1007/s40242-017-6322-8

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Three novel regular acceptor-donor1-acceptor-donor2(A-D1-A-D2) terpolymers were prepared via embedding a second donor(D2) unit into the traditional D-A backbone to manipulate the energy levels and molecular geometry with no complex synthesis or solubility loss. In these A-D1-A-D2 terpolymers, benzodithiophene(BDT, D1) and diketopyrrolopyrrole(DPP, A) were selected as the basic skeleton, and the dithienopyrrole(DTPy), carbazole(CZ) and fluorine(FL) units with different electron donating ability were chosen as the second donor unit(D2). The HOMO energy levels can be effectively modulated by only varying D2 unit because of the push-pull interaction between donor and acceptor units. Versus the D-A bipolymer PDPP-BDT, incorporation of the D2 unit into the copolymers can distinctly lower the highest occupied molecular orbital(HOMO) levels to -5.47 eV for PDDPP-BDT-DTPy, -5.38 eV for PDDPP-BDT-CZ and -5.23 eV for PDDPP-BDT-FL, which shows the strong dependence on electron-donating ability. Density functional theory(DFT) simulation and X-ray diffraction(XRD) measurements also reveal the effect of the D2 units on the molecular geometry of the terpolymers and their molecular packing. Notably, a PDDPP-BDT-DTPy combined with a thiophene ring and forked tail pendant away from the backbone had less backbone torsion and more compact packing than the other two counterparts. These results demonstrate that embedding a second donor(D2) unit into the backbone to construct an A-D1-A-D2 structure can be an effective and direct strategy to manipulate the energy levels and molecular geometry and develop organic semiconducting materials.



Influence of Thermal Temperature on the Structure and Sealed Micropores of Stabilized Polyacrylonitrile Fibers

ZHAO Ruixue, ZHAO Xudong, GAO Zhongmin, LIU Xiaoyang, CHE Xiaolei

2017, 33(2):  312-317.  doi:10.1007/s40242-017-6262-3

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Thermal stabilization is an important process in carbon fibers' production, during which the polyacrylonitrile fibers are heated from 180℃ to 280℃ in air. In this study, the samples were characterized by X-ray diffraction, Fourier infrared spectroscopy, differential scanning calorimetry, small angle X-ray Scattering(SAXS) and mechanical tensile tests. A new rule was suggested by the results of structural characterization for the cyclization, dehydrogen ation and oxidation reactions that were observed to be drastic from 200℃ to 220℃, from 220℃ to 250℃, and in the later period of the thermal stabilization reactions, respectively. The sizes, shapes and distributions of the sealed micropores were obtained from the SAXS data. The breaking elongation was significantly affected by the drastic cyclization and dehydrogenation reactions. The breaking force was affected considerably by the bigger micropores, especially from 220℃ to 250℃, owing to the drastic dehydrogenation reactions.



Removal of Ni and Cd Ions from Aqueous Solution Using Iron Dust-zeolite Composite: Analysis by Thermodynamic, Kinetic and Isotherm Studies

Zahra AHALI ABADEH, Mehdi IRANNAJAD

2017, 33(2):  318-326.  doi:10.1007/s40242-017-6150-x

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To examine the effectiveness of iron dust-zeolite composite as an adsorbent for the removal of heavy metal ions from aqueous solutions, the adsorption isotherms, the kinetic, thermodynamic and optimum conditions, such as initial concentration, pH, contact time, adsorbent dosage and competitive adsorption conditions of heavy metals were investigated. The characterization of the composite was characterized via FTIR, SEM, XRF and XRD methods. Kinetic results on the removal of heavy metal ions from aqueous solutions have been well described by the pseudo-second-order model. The adsorption data for Cd and Ni ions were fitted well with the Langmuir and Freundlich isotherm models, respectively. The maximum adsorption capacities of iron dust-zeolite for Cd and Ni ions were equal to 78.125 and 76.33 mg/g, respectively. The thermodynamic parameters such as enthalpy, entropy and free energy of adsorption of metal ions were determined. It was found that the process is endothermic, favorable and spontaneous. The competitive adsorption ability of heavy metal ions in the binary system on the composite showed that Cd ions had a synergistic effect on the adsorption of Ni and Ni ions had the negative effect on Cd adsorption.