Polymer Chemistry
·
2019
·Vol. 10
·期 21
·2666-2673
·
IF 4.76
Xiaolong Zhang,Qi Hua,Ping Meng,Mingqi Wang,Yunfei Wang,Lu Sun,Liwei Ma,Baoyan Wang,Cuiyun Yu,Hua Wei
Incorporation of various dynamic stimuli-responsive bonds to nanocarriers has been repeatedly highlighted to provide an elegant solution to the tradeoff between extracellular stability and intracellular high therapeutic efficiency; however, most of the developed systems still suffer from drug leakage-associated side effects due to insufficient stability and unsatisfactory therapeutic efficiency attributed to low drug loading capacity. To further address these critical issues, herein we reported a coordination-driven formation of biocleavable crosslinked polyprodrug vesicles (CPV) based on the reversible coordination interactions between the electron acceptor-containing polyprodrug and electron donor-based crosslinker, 1,6-hexanediamine. The resulting CPV exhibited a high drug loading content of 34.8%, and simultaneously enhanced extracellular micelle stability and promoted intracellular redox-triggered decrosslinking and drug release. More importantly, a comparison study further revealed that the CPV outperformed the noncrosslinked analogues in terms of greater stability, faster redox-triggered decrosslinking and drug release, a more compact structure with a smaller size toward higher cellular uptake, and greater in vitro cytotoxicity. This work thus developed a robust reversible crosslinking strategy to address high stability vs. sufficient therapeutic efficiency dilemma of polyprodrug-based nanocarriers.
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Current Green Chemistry
·
2019
·Vol. 6
·期 2
·127-134
·
IF 0
Yu Zhaozhuo,Xu Fusheng,Li Yan,Konno Hiroyuki,Li Hu,Yang Song
Hydrogenation of furfural (FUR) to furfuryl alcohol (FFA) is a key step and one of the representative examples for comprehensive utilization of biomass, while relatively harsh conditions are typically required to achieve satisfactory results using molecular hydrogen, formic acid, or
alcohol as H-donor over expensive metal catalysts. In this work, a new and benign reaction system, composed of green and cheap tetraethylammonium fluoride and polymethylhydrosiloxane (PMHS), is developed to be efficient for transfer hydrogenation of bio-based FUR to high-value FFA under mild
conditions. After reacting at 35 132;ƒ for 0.5 h, 94.9% FUR conversion and 92.3% yield of FFA could be achieved. This protocol is also widely applicable to the selective reduction of various aromatic aldehydes, giving relevant alcohols in high yields of 81.0-99.9% at 35-60 °C within
30-120 min. Moreover, the mechanism of fluoride-activated hydrosilylation was demonstrated to be responsible for the efficient transfer hydrogenation process.
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NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 44
·期 5
·2102-2110
·
IF 3.288
Shuangyan Meng,Wei Zeng,Mingming Wang,Litong Niu,Shaoping Hu,Bitao Su,Yaoxia Yang,Zhiwang Yang,Qunji Xue
Polydopamine/MIL-53(Fe) (PDA/MIL-53(Fe)) nanocomposite photocatalysts were synthesized with PDA (PDA = polydopamine) and MIL-53(Fe) using a nature-mimicking method. The structures, morphologies, optical properties and thermal stabilities of all the synthesized materials were characterized using a series of methods. In particular, the separation efficiency of photogenerated charge significantly increased after the incorporation of PDA into MIL-53(Fe), which resulted in an elevated photocatalytic activity of PDA/MIL-53(Fe) compared with the control groups. The PDA/MIL-53(Fe) nanocomposite could accelerate the conversion of primary or secondary alcohols into the corresponding aldehydes or ketones with a high specificity by direct hole-involving oxidation under visible-light irradiation and room temperature. The catalysts could be cycled at least three times without a significant decrease in the catalytic activity and this result showed the excellent recyclability and stability of the catalysts.
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Polymer Chemistry
·
2019
·Vol. 10
·期 43
·5905-5912
·
IF 4.76
Chuanzhi Wei,Xinhui Kou,Shaofeng Liu,Zhibo Li
Ring-opening polymerization (ROP) is a powerful method used for converting cyclic monomers to polymers, but ethylene carbonate (EC), which has a five-membered ring, is an exception owing to the unfavorable thermodynamics of its ring-opening reaction unless the release of CO2. This behavior stems from the faster cyclization to form a stable five-membered ring in comparison to the direct ring-opening reaction. Hence, many attempts have been made to copolymerize EC with other cyclic monomers such as cyclic esters to overcome the thermodynamic barrier. In this context, the copolymerization of EC with various cyclic esters, including ε-caprolactone (CL), δ-valerolactone (VL) and L-lactide (LLA), has been successfully achieved using an organocatalytic phosphazene superbase, such as a cyclic trimeric phosphazene base (CTPB). The random copolymerizations proceeded fast with a turnover frequency (TOF) of 19 800 h−1 under mild polymerization conditions and afforded the corresponding copolymers without formation of the ether unit. Under all kinds of experimental conditions, no homopolymerization of EC occurred. The molecular structures of the obtained P(EC-co-CL) copolymers were characterized using 1H NMR and 13C NMR, which demonstrated that ca. 38 mol% EC can be incorporated within the copolymer chain depending on the different ratios of the EC and CL monomers. With the same catalytic system and under similar conditions, the amounts of EC incorporated into EC/VL (up to 26 mol%) and EC/LLA (ca. 4.8 mol%) copolymerizations were lower than that for the EC/CL copolymerization. 2D NMR (1H–1H correlated spectroscopy (COSY), 1H–13C heteronuclear single quantum coherence (HSQC) and 1H–13C heteronuclear multiple bond correlation (HMBC)) were performed to confirm the assignments in the 1H NMR and 13C NMR spectra of the copolymers and to better understand the chain structures of the copolymers. Therefore, polycarbonate/polyester copolymers with greater incorporation of EC were realized using a fast, selective and metal-free process.
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ACS Catalysis
·
2019
·
IF 12.221
Nengchao Luo,Tingting Hou,Shiyang Liu,Bin Zeng,Jianmin Lu,Jian Zhang,Hongji Li,Feng Wang
Photocatalytic H2 evolution from organic feedstocks with simultaneous utilization of photogenerated holes achieves solar energy storage and coproduces value-added chemicals. Here we show visible-light H2 production from benzyl alcohol (BAL) with controllable generation of deoxybenzoin (DOB) or benzoin (BZ) through tandem redox reactions. Particularly, DOB synthesis circumvents the use of expensive feedstocks and environmentally unfriendly catalysts that are required previously. Under the irradiation of blue LEDs, the key of steering the major product to DOB rather than BZ is to decrease the conduction band bottom potentials of the ZnIn sulfide catalysts by increasing the Zn/In ratio, which results in the dehydration of intermediate hydrobenzoin (HB) to DOB proceeding in a redox-neutral mechanism and consuming an electron–hole pair. As a proof of concept, this method is used to synthesize DOB derivatives in gram scale.
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POLYMER DEGRADATION AND STABILITY
·
2018
·
IF 3.193
Shijie Hou,Yong Jian Zhang,Pingkai Jiang
Synergistic effects of synthetic phosphonium sulfonates (PhSs) bearing different groups with expandable graphite (EG) on flame retardancy properties in poly(ethylene-co-vinyl acetate) (EVA) rubber blends have been studied by limiting oxygen index (LOI), UL-94 test, cone calorimeter test (CCT), and thermogravimetric analysis (TGA). The EVA/EG/PhS composites revealed excellent flame retardancies. Upon adding 2.5 wt% of PhSs and 20 wt% of EG to EVA matrix, V-0 rating can be achieved. The heat release rate (HRR) and the total heat release (THR) of EVA/PhS-2(2.5 wt%)/EG(20 wt%) and EVA/PhS-4(2.5 wt%)/EG(20 wt%) blends decreased remarkably based on CCT. In addition, the thermal stabilities and mechanical properties of EVA/EG/PhS composites did not deteriorate comparing with those of EVA/EG composites.
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JOURNAL OF MOLECULAR LIQUIDS
·
2019
·
IF 4.561
Xiaoqing Yuan,Zhiyong Li,Ying Feng,Yuanchao Pei,Huiyong Wang,Diandian Liu,Dayu Wang,Jianji Wang
At present, it is still a challenge for reversible regulation of phase behavior and microstructure of microemulsions with less energy input and no composition change of the system. Photo-responsive microemulsions provide a potential way to solve these problems. In this work, 10 kinds of photo-responsive ionic liquids (ILs) with azobenzene group were used as photo-responsive surfactants to form microemulsions with water and some alcohols. Factors affecting the phase behavior and sub-regions of microemulsions, such as chemical structure of the ILs, temperature, alcohols properties and UV irradiation , were studied by conductivity, small-angle X-ray scattering, dynamic light scattering and cryo-TEM techniques. It was found that azobenzene-based ILs with a more hydrophilic head group and a shorter alkyl spacer length were favor of the formation of the microemulsions. The phase behavior of the microemulsions only slightly changed after UV irradiation, however, the area of O/W and bi-continuous sub-regions of the microemulsion could be regulated by UV irradiation. At the same time, droplets size increased after UV light irradiation , and could be restored close to the initial value by alternative vis-light irradiation.
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ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA
·
2018
·Vol. 166
·期 6
·483-490
·
IF 1.454
Guofeng Mao,Jiaxin Tian,Ting Li,Hatem Fouad,Hassan Ga'al,Jianchu Mo
The attraction of parasitoids to their hosts is a key issue in efforts to enhance biological control efficiency. This study was conducted to identify which rice plant volatiles are attractive to females of the rice planthopper egg parasitoid Anagrus nilaparvatae Pang et Wang (Hymenoptera: Mymaridae) by using Y-tube olfactometer behavior assays. Our results demonstrated that 10 of 17 selected volatiles – that is, 3-carene, linalool oxide, linalool, benzyl alcohol, benzaldehyde, methyl salicylate, ( E )-2-hexenal, ( E )-2-hexen-1-ol, ( E )-3-hexen-1-ol, and hexanal – from three major groups of rice plant volatiles – terpenoids, aromatic compounds, fatty acid derivatives – attracted female A. nilaparvatae at various doses. Two full-component mixtures of 10 behaviorally active compounds at different ratios were more attractive to wasps compared with individual volatiles. Blends composed of the 10 behaviorally active compounds in their optimally attractive doses (i.e., each in the dose that elicited the strongest response in the wasps) or at equal mass ratio may be considered as attractants for A. nilaparvatae and thus help to control rice planthoppers.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2018
·
IF 11.698
Xiangju Ye,Yinghao Chen,Yahui Wu,Xuemei Zhang,Xuchun Wang,Shifu Chen
In a reaction system, the simultaneously efficient utilization of photogenerated electrons and holes to realize the photocatalytic selective redox reactions of organics has been a hot topic. In this paper, the Zn 3 In 2 S 6 samples were synthesized via a simple solvothermal method with different solvents, which could make full use of photogenerated electrons and holes to achieve the photocatalytic selective transformation of aromatic alcohols to aromatic aldehydes and hydrogen evolution under mild conditions. The results show that the Zn 3 In 2 S 6 synthesized with water (Zn 3 In 2 S 6 -W) exhibits the highest photocatalytic performance among the selected samples, with which the yields of benzaldehyde and hydrogen reach up to 732 and 708.8 μmol under light irradiation (λ ≥ 380 nm) for 4 h, respectively. The molar ratios between aldehydes and hydrogen are close to 1: 1. The apparent quantum efficiency is about 6.48% for wavelength λ = 380 ± 10 nm over Zn 3 In 2 S 6 -W sample. A possible reaction mechanism for the photocatalytic selective transformation of benzyl alcohol to benzaldehyde and hydrogen evolution under light irradiation is proposed. This work highlights that a reaction system is developed to effectively make use of the photogenerated electrons and holes for selective transformation of aromatic alcohols to aromatic aldehydes and hydrogen evolution over Zn 3 In 2 S 6 photocatalysts under mild conditions.
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JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2018
·Vol. 57
·期 2
·90-100
·
IF 2.588
Fanfan Du,Ying Zheng,Wenhua Yuan,Guorong Shan,Yongzhong Bao,Suyun Jie,Pengju Pan
Development of effective organocatalysts for the living ring-opening polymerization (ROP) of lactones is highly desired for the preparation of biocompatible and biodegradable polyesters with controlled microstructures and physical properties. Herein, a new class of hydrogen-bond donating bisurea catalysts is reported for the ROP of lactones under solvent-free conditions. ROP of lactones mediated by the bisurea/7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD) catalyst exhibits a living/controlled manner, affording the polymers and copolymers with the well-defined structure, predictable molecular weight, narrow molecular weight distribution, and high selectivity for monomer at low catalyst loadings at ambient temperature. The possible mechanism of bisurea/MTBD-catalyzed ROP of lactones is proposed, in which the bisurea activates the carbonyl group of lactones while MTBD facilitates the nucleophilic attack of the initiating/propagating alcohol by hydrogen bonding. Moreover, the poly(ε-caprolactone- co -δ-valerolactone) [P(CL- co -VL)] random copolymers with various compositions were synthesized using the bisurea/MTBD catalyst. The measurements of thermal properties and crystalline structure demonstrate that the CL and VL units are cocrystallized in the crystalline phase of P(CL- co -VL) copolymers. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57 , 90–100
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Polymers
·
2018
·Vol. 10
·期 10
·1089
·
IF 2.935
Lili Liu,Xiaojing Zhou,Yongmei Yan,Jie Zhou,Wenping Zhang,Xishi Tai
The metal-organic zeolite imidazolate framework-8 (ZIF-8) supported gold-silver bimetallic catalysts with a core-shell structure (Au@Ag/ZIF-8 and Ag@Au/ZIF-8) and cluster structure (AuAg/ZIF-8) were successfully prepared by the deposition-redispersion method. Energy dispersive X-ray spectroscopy (EDS) elemental mapping images displayed that in the Au@Ag/ZIF-8 catalyst, Ag atoms were deposited on an exposed Au surface, and core-shell structured Au@Ag particles with highly dispersed Ag as the shell were formed. Additionally, the XPS investigation at gold 4f levels and silver 3d levels indicated that the Au and Ag particles of Au@Ag/ZIF-8, Ag@Au/ZIF-8, and AuAg/ZIF-8 were in a zero valence state. Among the resultant catalysts obtained in this study, Ag@Au/ZIF-8 catalysts showed the highest catalytic activity for the selective oxidation of benzyl alcohol, followed by AuAg/ZIF-8 and Au@Ag/ZIF-8. The turnover frequency (TOF) values were in the order of Ag@Au/ZIF-8 (28.2 h−1) > AuAg/ZIF-8 (25.0 h−1) > Au@Ag/ZIF-8 (20.0 h−1) at 130 °C within 1 h under 8 bar O2when using THF as solvent. The catalysts of Au@Ag/ZIF-8 and Ag@Au/ZIF-8 with core–shell structures have higher benzaldehyde selectivities (53.0% and 53.3%) than the AuAg/ZIF-8 catalyst (35.2%) in the selective oxidation of benzyl alcohol into benzaldehyde. The effect of the solvent, reaction temperature, reaction time, and reaction pressure on benzyl alcohol conversion and benzaldehyde selectivity in benzyl alcohol selective oxidation over Au@Ag/ZIF-8, Ag@Au/ZIF-8, and AuAg/ZIF-8 were also investigated. All of the catalysts showed excellent performance at 130 °C under 8 bar O2within 1 h when using THF as the solvent in the selective oxidation of benzyl alcohol to benzaldehyde. Moreover, the catalysts can be easily recycled and used repetitively at least four times.Keywords:metal-organic frameworks;core-shell;bimetallic catalyst;aerobic oxidation;benzyl alcohol
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PubMed
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2018
·
IF 4.513
Wei Jiang,Lei Dong,Huan Li,Hao Jia,Linhua Zhu,Wenshuai Zhu,Huaming Li
Magnetic core-shell structure microspheres with tunable pore volumes were synthesized and used to immobilize a polyoxometalate-based ionic liquid for oxidative desulfurization of diesel fuel. The as-prepared catalysts were characterized by transmission electron microscopy , Fourier transform infrared spectroscopy , Raman spectroscopy , and nitrogen adsorption–desorption. The results showed that the small catalyst had a large pore volume and the large catalyst had a small pore volume, while their BET surface areas and pore sizes were almost the same. Compared with the large catalyst, the small catalyst showed better catalytic activity, probably due to the promotion of its large pore volume. Under the optimal reaction conditions, the removal of 4,6-dimethyldibenzothiophene could reach 95.4% with a residual sulfur content of 9.2 mg kg −1 . After the reaction, the catalyst could be separated by a magnetic field and recycled at least 7 times with little decrease in desulfurization efficiency.
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