GREEN CHEMISTRY
·
2011
·Vol. 13
·期 10
·2939-2947
·
IF 5.472
Guang Li,Hengquan Yang,Wei Li,Guoliang Zhang
An IPr-functionalized (IPr = N,N′-bis(2,6-diisopropylphenyl)imidazol-2-ylidene, a N-heterocyclic carbene ligand) mesoporous ethane-silica was synthesized through a co-condensation of IPr-bridged triethoxysilane and bis(triethoxysilyl)ethane. This functionalized mesoporous ethane-silica was characterized with N2 sorption, XRD, FT-IR, solid NMR and XPS. Owing to high surface area, large pore volume and organically functionalized surface, such a material can be used as a scaffold to design surface NHC-Pd [NHC = N-heterocyclic carbene] complexes. By variation of Pd precursors and/or ancillary ligands, a library of NHC-Pd complexes on the solid surface were tentatively created. It was found that the Pd precursor and ancillary ligands had significant impacts on the activities of the resultant heterogeneous catalysts in the Suzuki–Miyaura coupling of aryl chlorides. Surface NHC-Pd complexes with acetylacetonate (acac) and 3-chloropyridine as ancillary ligands are the most active. A wide range of aryl chlorides even with deactivated and sterically hindered groups were successfully coupled over this solid catalyst under the mild conditions at a relatively low loading of Pd (80 °C, 0.5 mol% Pd). This solid catalyst could be reused 10 times without a significant decrease in activity. This study not only provides the most efficient phosphine-free solid catalyst for the Suzuki–Miyaura couplings of less reactive substrates, but also demonstrates a noteworthy example that IPr-functionalized ethane-silica can be used as a versatile scaffold to create various active surface NHC-metal catalysts.
研究领域:
催化化学
·
有机合成
·
材料化学
·
绿色化学
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均相与多相催化
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2019
·Vol. 136
·期 44
·48169
·
IF 2.188
Lidan Wang,Ying Liu,Jianyou Wang
As a core component of anion exchange membrane (AEM) fuel cells, it has practical significance to improve the performance of AEMs. However, it is difficult to obtain AEM with both good stability and high conductivity. In this study, a series of AEMs were prepared by chloromethylation, quaternization, and crosslinking reactions. The quaternization reaction was carried out first to ensure that there are abundant quaternary ammonium groups on AEM and enhance the conductivity of membrane. N , N , N ′, N ′-tetramethylethylenediamine was used as a crosslinker to improve membrane stability and mechanical property. A simple, mild, and cost-effective AEM synthetic route was developed. This strategy achieves a certain balance of electrochemical and physical properties. The effect of the crosslinking reactions on the property of membrane was evaluated. Crosslinked membranes have better dimensional stability (water uptake: 20.2% and swelling ratio: 2.1%), mechanical properties (55.84 MPa), and alkaline stability because crosslinked structures result in large steric hindrance. The mutually independent quaternization and crosslinking reaction do not affect the electrochemical performance of membranes; in the crosslinking reaction stage, crosslinker also reacted as quaternization agent and increased the number of reactive groups in AEM. Thus, the resulting crosslinked AEM exhibits higher ion exchange capacity and ionic conductivities (46.4 mS cm −1 ). © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 48169.
研究领域:
材料科学
·
化学工程
·
能源技术
✓ 已验证
DOI
高影响因子
Frontiers of Chemical Science and Engineering
·
2021
·Vol. 16
·期 4
·498-510
·
IF 4.204
Bo Jinxiao,Li Mei,Zhu Xinli,Ge Qingfeng,Han Jinyu,Wang Hua
The electrochemical conversion of CO 2 -H 2 O into CO-H 2 using renewable energy is a promising technique for clean syngas production. Low-cost electrocatalysts to produce tunable syngas with a potential-independent CO/H 2 ratio are highly desired. Herein, a series of N -doped carbon nanotubes encapsulating binary alloy nanoparticles (M x Ni-NCNT, M= Fe, Co) were successfully fabricated through the co-pyrolysis of mela-mine and metal precursors. The M x Ni-NCNT samples exhibited bamboo-like nanotubular structures with a large specific surface area and high degree of graphitization. Their electrocatalytic performance for syngas production can be tuned by changing the alloy compositions and modifying the electronic structure of the carbon nanotube through the encapsulated metal nanoparticles. Consequently, syngas with a wide range of CO/H 2 ratios, from 0.5:1 to 3.4:1, can be produced on M x Ni-NCNT. More importantly, stable CO/H 2 ratios of 2:1 and 1.5:1, corresponding to the ratio to produce biofuels by syngas fermentation, could be realized on Co 1 Ni-NCNT and Co 2 Ni-NCNT, respectively, over a potential window of −0.8 to −1.2 V versus the reversible hydrogen electrode. Our work provides an approach to develop low-cost and potential-independent electrocatalysts to effectively produce syngas with an adjustable CO/H 2 ratio from electrochemical CO 2 reduction.
研究领域:
材料科学
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电化学
·
可再生能源
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催化
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry B
·
2022
·Vol. 10
·期 19
·3723-3733
·
IF 7.571
Qing Hao,Jinghong Wang,Jie Shen,Rong Gu,Yu Rao,Jian Feng,Huanhuan Wang,John L. Brash,Hong Chen
In analogy with adsorbed protein films, we have fabricated a family of 2D nanofilms composed of poly(N-vinyl caprolactam-co-vinylimidazole) (PNVCL) nanogels. NVCL was copolymerized with 1-vinylimidazole (VIM), and then cross-linked with α,ω-dibromoalkanes with 2 to 8 carbons via quaternization to form the nanogels. The swelling ratio of the gels was precisely controlled by regulating the inter-chain spacing of the polymers at the level of the carbon atom chain length of the cross-linker. The short-chain alkanes used are relatively rigid and their dimensions provide an accurate estimate of the chain spacing in the nanogels. It was shown that small differences in the carbon atom number of the cross-linking agent led to significant differences in the mechanical properties of the nanogels, in particular in the softness, deformability, and contact area (in film form), all of which increased with increasing carbon number. Films of the softer gels not only showed good adhesion to a number of substrates, but were also mechanically robust. In addition, the films showed excellent light transmission and nontoxicity to L929 cells. Nanogels of intermediate softness were shown to inhibit the adhesion of bacteria and human umbilical vein smooth muscle cells (HUVSMCs), and to be resistant to the adsorption of the plasma protein fibrinogen, indicating strong anti-biofouling properties. Gels that were either too stiff or too soft showed somewhat weaker anti-fouling activity in terms both of HUVSMCs adhesion and protein adsorption.
研究领域:
材料科学
·
生物医学工程
·
纳米技术
·
生物材料
✓ 已验证
DOI
PubMed
高影响因子
CHEMOSPHERE
·
2020
·
IF 5.778
Jing Wang,Lidong Kou,Liang Zhao,Wenjie Duan
The use of waste sludge as a precursor of catalysts for environmental applications has been encouraged during the past few years. In this study, a series of magnetic Fe,N-codoped carbon catalysts (UBC- x ) were successfully prepared by a facile one-pot pyrolysis method using Fe-rich sludge and N-rich urea as the raw materials. By carefully controlling the mass ratio of urea/dry sludge ( x = 0–3), a significant amount of N (1–10 mass%) were incorporated, and the UBC- x catalysts, especially UBC-0.5 and UBC-0.75, could be imparted with high catalytic activity , convenient magnetic separation and high recycle stability. Phenolic contaminants like phenol and bisphenol A (BPA) could be nearly completely removed through peroxymonosulfate (PMS)-induced degradation by using UBC- x as the catalysts under a wide pH range (2–11) and with the co-existence of water constituents (chloride Cl − and sodium humate NaH, 0–50 mM). Among the several reactive oxidative species (ROS), singlet oxygen ( 1 O 2 ) was deemed as the main reactive species responsible for BPA degradation. Both Fe and N active sites contributed to the high catalytic activity of UBC- x , and their coordination made the catalysts rather stable with no significant Fe leaching under a wide pH range. Therefore, after an easy magnetic separation, the UBC- x could be recycled and reused efficiently in another BPA removal cycle. The as-synthesized magnetic Fe,N-codoped carbon catalysts provided a new route for sludge reutilization and showed potential applications in wastewater treatment .
研究领域:
环境科学
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催化
·
废水处理
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材料科学
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2019
·Vol. 48
·期 15
·5072-5082
·
IF 4.052
Shuang Huang,Xi Hong,He-Zhen Cui,Quan Zhou,Yue-Jian Lin,Xiu-Feng Hou
Seven new chelated cyclometalated Ir complexes of ABON,P, ABON,O, and ABON,C(carbene) based on a rigid and tunable 2-arylbenzo[d]oxazole backbone have been prepared for the N-methylation of amines. Among these three coordinated modes, ABON,C(carbene)-chelated iridium-based catalysts exhibited good performance in the monomethylation of aromatic amines with methanol (MeOH) as the green methylation reagent. The steric-modified synthesis of ABON,C(carbene) complexes was described. The most active ABON,C(carbene) complex with marginal steric hindrance as a catalyst was obtained from the benzoxazole ring without a substituent and methyl group of the benzimidazole ring on the N-heterocyclic carbene (NHC) ligand. A variety of amines including para- and meta-substituted aromatic amines, as well as heterocyclic amines, were formulated as suitable substrates. Importantly, this catalyst considerably promoted the yield of the N-methylation of ortho-substituted aromatic amines. Controlled kinetic experiments and deuterium-labeling reactions of these ortho-substituted amines were conducted under optimized conditions. On the basis of the experimental results, a plausible mechanism was proposed.
研究领域:
有机化学
·
催化
·
合成化学
✓ 已验证
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2016
·
IF 4.219
Jinyu Li,Dandan Liu,Guoxin Tan,Zhinan Zhao,Xinggang Yang,Weisan Pan
To develop a potential nanocarrier for the topical ocular administration of curcumin (CUR), a novel thiolated chitosan was synthesized by the covalent binding between N -acetyl- l -cysteine (NAC) and chitosan (CS) to surface modify the nanostructured lipid carrier loaded CUR (CUR-NLC). And the superiorities of the CS-NAC co polymer coated CUR-NLC over chitosan oligosaccharides (COS) or carboxymethyl chitosan (CMCS) modification were also verified in detail. As expected, the increment in particle size and the reversal of zeta potential occurred after surface decorating, and the most prominent electropositivity was obtained for the CS-NAC-CUR-NLC group. Additionally, the utilization of the CS-NAC coating demonstrated an effectively controlled release over 72 h and attained a 6.4 and 18.8 fold increase in apparent permeability coefficients (P app ) compared with the CUR-NLC and the self-made eye drops, respectively. Meanwhile, the clearance rate of the NLC labeled with Rhodamine B was significantly delayed in the presence of CS-NAC. By contrast, CS-NAC-CUR-NLC was superior to the COS and CMCS coated ones in view of in vitro release, drug permeability and corneal retention. Moreover, the results of the in-vivo and in-vitro characteristics demonstrated that the promoting effect of CMCS coating was relatively weaker than COS coated ones. Ocular irritation test was executed on the CS-NAC-CUR-NLC, neither a sign of toxicity nor irritation to the external ocular tissues was observed. In conclusion, CS-NAC-CUR-NLC possesses a greater potential as an ocular drug-delivery system comparing with the COS-CUR-NLC and CMCS-CUR-NLC.
研究领域:
药剂学
·
生物材料
·
眼科
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Chenjie Ding,Shifei Kang,Wenxin Li,Weikang Gao,Zhihao Zhang,Lulu Zheng,Lifeng Cui
Heterogeneous photo-Fenton catalysts prepared by doping metal ions in g-C 3 N 4 are promising alternatives to traditional homogeneous Fenton catalysts, but are restricted by poor mesoporous structure and agglomerate of metal species. Recently, the highly uniformly dispersed metal-N active sites in various photocatalysts have been proved to be the critical reason for their enhanced catalytic activity. In this study based on reasonable control of mesoporous structure and metal-N active sites, mesoporous Fe-g-C 3 N 4 was synthesized using a simple one-step thermal shrinkage polymerization method using ferrous oxalate as iron source and pore-forming agent. The Fe and N elements in the triazine ring skeleton of Fe-g-C 3 N 4 form a σ-π bond, thus the photogenerated electrons can be quickly transferred to Fe 3+ to form Fe 2+ under the interaction of chemical bonds, accelerating the Fenton reaction rate. Density functional theory calculations results demonstrate that the energy band structure and electron cloud density distribution of Fe-Nx active structure are better than that of routine FeOx crystal structure with metal species agglomeration. In addition, the excellent mesoporous structure of Fe-g-C 3 N 4 creates conditions for the high exposure of Fe-Nx active sites in the photo-Fenton reaction under visible light. The as-developed Fe-g-C 3 N 4 system shows high recyclability and excellent photo-Fenton performance for removal of typical intractable pollutants (The degradation rate of dye and tetracycline reaches 98.2% and 98.7% at 60 and 120 min, respectively). This work provides a facile and sustainable route to develop mesoporous highly-active heterogeneous Fenton-like catalysts and even further general the design of general catalyst with ideal metal-N active sites, thereby promoting a feasible and efficient wastewater remediation solution.
研究领域:
环境科学
·
材料科学
·
催化
·
光化学
✓ 已验证
DOI
PubMed
高影响因子
ACS Omega
·
2021
·
IF 3.512
Lin-Xi Wan,Yong-Qi Zhen,Zhen-Xiang He,Yang Zhang,Lan Zhang,Xiaohuan Li,Feng Gao,Xian-Li Zhou
A new series of N-aryltacrine derivatives were designed and synthesized as cholinesterase inhibitors by the late-stage modification of tacrine, using the palladium-catalyzed Buchwald–Hartwig cross-coupling reaction. In vitro inhibition assay against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) demonstrated that most of the synthesized compounds had potent AChE inhibitory activity with negative inhibition of BuChE. Among them, N-(4-(trifluoromethyl)phenyl)-tacrine (3g) and N-(4-methoxypyridin-2-yl)-tacrine (3o) showed the most potent activity against AChE (IC50 values of 1.77 and 1.48 μM, respectively). The anti-AChE activity of 3g and 3o was 3.5 times more than that of tacrine (IC50 value of 5.16 μM). Compound 3o also displayed anti-BuChE activity with an IC50 value of 19.00 μM. Cell-based assays against HepG2 and SH-SY5Y cell lines revealed that 3o had significantly lower hepatotoxicity compared to tacrine, with additional neuroprotective activity against H2O2-induced damage in SH-SY5Y cells. The advantages including synthetic accessibility, high potency, low toxicity, and adjunctive neuroprotective activity make compound 3o a new promising multifunctional candidate for the treatment of Alzheimer’s disease.
研究领域:
药物化学
·
药理学
·
神经科学
✓ 已验证
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Chenghong Sun,Enze Zhu,Chaoyang Shi,Juan Yu,Shubiao Yin,Chunxia Liu,Xiaoying Cui,Weiping Liu,Mingli Xu
The vigorous development of efficient cathode-side oxygen reduction reaction (ORR) catalysts is one of the keys to the practical application of fuel cells and Zn-air batteries (ZABs). Herein, a facile and green photochemical method is developed to synthesize pure-phase Mn 3 O 4 nanoparticles , which are uniformly anchored on nitrogen-doped reduced graphene oxide (N-rGO), followed by simple one-step annealing to highly catalytical active and stable MnO/N-rGO. The resultant MnO/N-rGO exhibits exciting ORR performance in alkaline media. Particularly, both GDE (gas diffusion electrode) half-cell and ZABs assembled from MnO/N-rGO have excellent overall performance and outstanding long-term durability, obviously better than Pt/C-based GDE half-cell and Pt/C + RuO 2 -based ZABs, respectively. It is mainly attributed to the synergistic effect between MnO nanoparticles and N-rGO support, which significantly increases the active sites and facilitates 4-electron transfer. This research paves a way for the green photochemical synthesis of transition metal oxide ORR catalysts at room temperature.
研究领域:
材料科学
·
电化学
·
能源存储
·
催化
✓ 已验证
DOI
高影响因子
ANALYTICA CHIMICA ACTA
·
2022
·
IF 6.911
Jing Zhu,Liutao Chen
Fluorescent dye DITO-1 has almost no fluorescence in the absence of nucleic acid . G bases in single strand DNA can induce maximum fluorescent enhancement followed by the A bases when it binds the DITO-1. However, the incorporation efficiency of the dATP was higher than dGTP in terminal transferase (TdT) polymerization. As a consequence, ploy (A) n , rather than ploy (G) n via TdT polymerization had the superior photoluminance when it binded DITO-1 fluorescent dye. Here, we developed a high selective and sensitive sensing strategy for assaying TdT and T4 polynucleotide kinase activity (T4 PNK) based on the ploy (A) n -DITO-1 fluorescent probe. An increasing amounts of TdT enzyme could promote the distinct incorporation of dATP on the DNA primer and form poly (A) n ssDNA with a difference in length. A good linear relationship between the ΔF and the concentrations of TdT in a range of 0.2–50 U/mL was obtained and the detection limit was 0.05 U/mL. Based on the experimental results for TdT, we further expanded the application of this method for detection of a series of concentrations of T4 PNK. The ΔF and the logarithm concentrations of T4 PNK in the range of 0.1–10 U/mL showed a good linear response and the detection limit of 0.02 U/mL was obtained. In addition, the detection of T4 PNK in Hela cell lysate was achieved, demonstrating that the proposed method had the potential application in complex system. The ploy (A) n -DITO-1 fluorescent probe had the excellent properties of one-step readout, robustness for target detection in complex system, and easiness operation, and showed the great potential in clinical diagnostics, inhibitor screening, and drug discovery.
研究领域:
分子生物学
·
生物化学
·
分析化学
·
生物医学工程
✓ 已验证
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2020
·
IF 4.939
Wenyu He,Jinhui Wei,Ting Huang,Enren Zhang
For practical applications of microbial fuel cells (MFCs), 5H-dibenz [b,f] azepine-5-carboxamide (Carbamazepine, CBZ) was used as the organic precursor for the synthesis of catalysts composed of Fe–N–C complexes (named as Fe-CBZ-Cats) through a sacrificial support method. Characterizations by SEM, XPS and TEM-EDS elemental mapping show that the synthesized Fe-CBZ-Cats have porous structure and uniformly dispersed Fe/N/C complex centers which could play key roles in effective ORR . Linear scanning voltammetry (LSV) measurements show that the synthesized Fe-CBZ-Cats exhibits ORR activity comparable to commercial Pt/C catalysts under the same catalyst loading (2 mg cm −2 ). The maximum power density produced by cathode-limiting MFCs with Fe-CBZ-Cats air cathodes was 431 ± 23 μW cm −2 , higher than those in the control MFCs with Pt/C air cathodes (403 ± 13 μW cm −2 ) and activated carbon air cathodes (296 ± 24 μW cm −2 ). In addition, the toxicity tolerance of the synthesized Fe-CBZ-Cats is much higher than Pt/C.
研究领域:
环境科学
·
电化学
·
生物工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）