CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2020
·Vol. 36
·期 5
·934-939
·
IF 1.063
Li Ruyue,Wu Mingwei,Pan Biwei,Li Meng,Huang Jun
A 1,10-phenanthroline based polymer named PPPhen( i.e. , polymer from pyrene 1,10-phenanthrolin) was prepared by the Friedel-Crafts reaction of 1,10-phenanthroline and pyrene cross-linked with dimethoxymethane. The related Pd catalyst Pd@PPPhen was prepared by supporting Pd nanoparticles(NPs) on the PPPhen material. PPPhen and Pd@PPPhen were characterized by means of scanning electron microscopy(SEM), transmission electron microscopy, N 2 adsorption-desorption, Fourier-transform infrared and X-ray photoelectron spectroscopy analyses. The results showed that PPPhen polymer was highly porous and that the phenanthroline group can enhance the stability of the Pd nanoparticles. Pd@PPPhen also exhibited good catalytic activity in the aerobic oxidation of alcohols to aldehydes and ketones, and Pd@PPPhen was recyclable with durable activity and retentive structures.
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MOLECULES
·
2020
·Vol. 25
·期 11
·2475
·
IF 3.267
Yanliang Yang,Dexi Yang,Chi Zhang,Min Zheng,Ying Duan
The development of a simple and durable catalytic system for the production of chemicals from a high concentration of a substrate is important for biomass conversion. In this manuscript, 5-hydroxymethylfurfural (HMF) was converted to 1-hydroxy-2,5-hexanedione (HHD) using the combination of commercial Pd/C and acetic acid (AcOH) in water. The influence of temperature, H2pressure, reaction time, catalyst amount and the concentration of AcOH and HMF on this transformation was investigated. A 68% yield of HHD was able to be obtained from HMF at a 13.6 wt% aqueous solution with a 98% conversion of HMF. The resinification of intermediates on the catalyst was characterized to be the main reason for the deactivation of Pd/C. The reusability of the used Pd/C was studied to find that most of the activity could be recovered by being washed in hot tetrahydrofuran.Keywords:HMF;1-hydroxy-2,5-hexanedione;acetic acid;Pd/C;high concentration
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Biomolecules
·
2020
·Vol. 10
·期 2
·285
·
IF 4.082
Ehexige Ehexige,Mingming Bao,Purevbat Bazarjav,Xiang Yu,Hai Xiao,Shuqin Han,Huricha Baigude
Cutaneous melanoma is the most aggressive skin cancer with notorious drug resistance. Inhibition of immune checkpoint molecules is one of the most promising approaches for cancer therapy. Herein, we show that RNAi mediated silencing of STAT3 expression in the tumor tissue robustly inhibit tumor growth in B16F10 mouse model of melanoma. We designed a peptidomimetic-based lipid nanoparticles (LNPs) for the delivery of siRNA in mouse model of melanoma. When systemically administered, the novel formulation (denote DoCh) preferentially delivered siRNA to the tumor tissue. Remarkably, sequential intravenous injections of siRNA against STAT3 induced profound silencing of STAT3 expression in tumor tissue, which resulted in significant downregulation of PD-L1, leading to significant inhibition of tumor growth through inhibition of tumor immune checkpoint. Moreover, DoCh-mediated siRNA delivery did not show noticeable damage to the major organs. Collectively, our data demonstrated that DoCh LNP is a promising tumor-targeted siRNA delivery system.Keywords:peptidomimetic lipid nanoparticle;RNAi;STAT3;PD-L1;cancer immune checkpoints
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2020
·
IF 6.551
Jirui Yang,Xinhua Qi,Feng Shen,Mo Qiu,Richard Lee Smith
Transfer hydrogenation is highly effective for dechlorinating priority organic pollutants in wastewater. Lindane could be completely dechlorinated at room temperature and atmospheric pressure via transfer hydrogenation, in which Pd (3.1 wt%) supported on chitosan-derived porous carbon (3.1Pd@A600) and formic acid (FA) were used as catalyst and hydrogen source, respectively. Favorable catalytic activity of 3.1Pd@A600 is attributed to pyridinic N of the support that allowed Pd nanoparticles to be well-dispersed in the solid and to pyridinic N-Pd interactions that enhanced FA decomposition over that observed for commercial carbon supported Pd catalyst (5Pd@AC). In the reaction system containing 3.1Pd@A600 and FA, 99.7% lindane conversion and 100% dechlorination efficiency could be achieved at 25 °C and atmospheric pressure within 60 min. Benzene and cyclohexane were identified as end-products of lindane dechlorination . The transfer hydrogenation strategy developed in this study has wide application to chlorinated organic pollutants contained in actual waste streams.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2021
·Vol. 29
·期 2
·1824-1835
·
IF 4.223
Chen Yuan,Chen Yuancai
At present, there are many studies on microbial reduction of Pd (II), although few of these studies assess the bacterial toxicity of Pd (II) before and after reduction by microorganisms. In this study, the toxicity of Pd (II) to Bacillus wiedmannii MSM ( B. wiedmannii MSM) was assessed before and after reduction by live B. wiedmannii MSM cells (referred to as “Pd (0)-loaded cells”) and after biosorption by dead B. wiedmannii MSM cells (referred to as “Pd (II)-loaded cells”). B. wiedmannii MSM is a widely occurring, nonpathogenic aerobic bacterium. Compared with Pd (II), the EC 20 , EC 50 , and EC 80 of Pd (0)-loaded cells increased by 77.73-, 112.75-, and 163.91-fold, respectively, while the EC 20 , EC 50 , and EC 80 of Pd (II)-loaded cells increased by only 11.55-, 9.77-, and 8.29-fold, respectively. The sterilization contribution rates of the mechanisms of action of Pd (0)-loaded cells were ranked in the order of: remaining Pd (II) > oxidative stress > physical puncture. Pd (II) was found to increase cell membrane permeability, glutathione S-transferase (GST) enzyme activity, and reactive oxygen species levels in cells and decrease the cell membrane potential. XPS results indicated that Pd (II) increased the content of polysaccharides and peptides and decreased the content of hydrocarbons in cells. These findings reveal the bactericidal mechanism of toxicity of Pd (II) and Pd (0)-loaded cells on Bacillus wiedmannii MSM and provide an environmentally friendly and inexpensive method for Pd (II) detoxification.
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CHINESE JOURNAL OF ANALYTICAL CHEMISTRY
·
2021
·
IF 1.134
Yan-Xiong LIU,Long-Chun BIAN,Jie-Ren XIA,Qiu-E CAO
A novel Pd(II) ion-imprinted polymer (Pd(II)-AAP-IIP@VMWCNTs) was constructed by using 2-( N -allyl)aminopyridine (AAP), vinyl functionalized multi-walled carbon nanotubes (VMWCNTs), ethylene glycol dimethacrylate (EGDMA) and Na 2 PdCl 4 as functional monomer, carrier, cross-linker and template ions, respectively. The structure, morphology, adsorption property and applicability as adsorbent in solid phase extraction were characterized by Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), binding experiment and solid phase extraction (SPE) experiment, respectively. The equilibrium adsorption capacity and imprinting factor of Pd(II)-AAP-IIP@VMWCNTs for Pd(II) were found to be 9.053 mg/g and 3.46, respectively. The SPE column packed with Pd(II)-AAP-IIP@VMWCNTs displayed good adsorption selectivity to Pd(II). The adsorption rate and extraction rate of this column to Pd(II) were more than 90% and 74%, but below 40% and 15% to the other coexisting ions under the optimized SPE conditions. The obtained Pd(II)-AAP- IIP@VMWCNTs-based SPE method could be combined with inductively coupled plasma optical emission spectroscopy (ICP-OES) for determination of Pd(II) in environmental water. The recoveries were in the range of 87.2%–91.6% with the relative standard deviations of 2.5%–6.8%.
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NEOPLASIA
·
2021
·
IF 5.715
Yihui Ma,Peiyi Xia,Zhengyang Wang,Jingjing Xu,Lan Zhang,Yanan Jiang
Protein Disulfide Isomerase Family A Member 6 (PDIA6) is an endoplasmic reticulum protein that is capable of catalyzing protein folding and disulfide bond formation. Abnormally elevated expression of PDIA6 has been reported to predict poor outcomes in various cancers. Herein, gain-of- and loss-of-function experiments were performed to investigate how PDIA6 participated in the carcinogenesis of pancreatic cancer (PC). By analyzing the protein expression of PDIA6 in 28 paired PC and para carcinoma specimens, we first found that PDIA6 expression was higher in PC samples. Both the overall survival and disease-free survival rates of PC patients with higher PDIA6 expression were poorer than those with lower PDIA6 ( n = 178). Furthermore, knockdown of PDIA6 impaired the malignancies of PC cells — suppressed cell proliferation, invasion, migration, cisplatin resistance, and xenografted tumor growth. PDIA6-silenced PC cells were more sensitive to cytotoxic natural killer (NK) cells. Overexpression of PDIA6 had opposite effects on PC cells. Interestingly, COP9 signalosome subunit 5 (CSN5), a regulator of E3 ubiquitin ligases known to promote deubiquitination of its downstream targets, was demonstrated to interact with PDIA6, and its expression was increased in PC cells overexpressing PDIA6. Additionally, PDIA6 overexpression promoted deubiquitination of β-catenin and PD-L1 and subsequently upregulated their expression in PC cells. These alterations were partly reversed by CSN5 shRNA. Collectively, the above results demonstrate that PDIA6 contributes to PC progression, which may be associated with CSN5-regulated deubiquitination of β-catenin and PD-L1. Our findings suggest PDIA6 as a potential target for the treatment of PC.
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高影响因子
Catalysts
·
2021
·Vol. 11
·期 8
·888
·
IF 4.146
Jingzhen Wang,Kaijie Mu,Xuedong Zhao,Dianliang Luo,Xiaodi Yu,Wenpeng Li,Jie Chu,Jing Yang,Qinzheng Yang
Metal, as a high-performance electrode catalyst, is a research hotspot in the construction of a high-performance microbial fuel cell (MFC). However, metal catalyst nanoparticles and their dispersed carriers are prone to aggregation, producing catalytic electrodes with inferior qualities. In this study, Pd is uniformly dispersed on the graphene framework supported by carbon black to form nanocomposite catalysts (Pd/GO-C catalysts). The effect of the palladium loading amount in the catalyst on the catalytic performance of the air cathode was further studied. The optimized metal loading afforded a reduced resistance and improved accessibility of Pd particles for the ORR. The maximum current output of the 0.250 Pd (mg/cm2) MFC was 1645 mA/m2, which is 4.2-fold higher than that of the carbon paper cathode. Overall, our findings provide a novel protocol for the preparation of high-efficient ORR catalyst for MFCs.Keywords:oxygen reduction reaction;microbial fuel cell;air cathode
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CARBON
·
2019
·
IF 7.466
Chun Pu,Jie Zhang,Ganggang Chang,Yueyang Xiao,Xiaochen Ma,Jian Wu,Tingting Luo,Kexin Huang,Shanchao Ke,Jiaxin Li,Xiaoyu Yang
Nitrogen-doped carbon-supported metal catalysts are of considerable significance in a diverse range of applications. However, the controllable synthesis of morphology and composition of carbon support materials, in turn, the particle size of supported metal nanoparticles (NPs) is still a great challenge. Herein, nitrogen precursors-mediated synthesis of N-doped hierarchically porous carbon (HPC) with controlled morphology and composition by using MOF as sacrificial template has been demonstrated for the first time. By simply varying the category of nitrogen precursors that with different chemical environment, the morphology, nitrogen configurations and hydrophilicity of the resulted HPC can be effectively tuned. Particularly, the delicate honeycomb-like morphology, the largest amount of nitrogen dopants and excellent wettability of HPC-DCD (dicyandiamide) can effectively stabilize, isolate and disperse the Pd NPs to yield highly dispersed Pd NPs. More importantly, the resulted Pd@HPC-DCD showed excellent catalytic activity and stability toward the hydrodeoxygenation of vanillin in aqueous solution with >99% yield, as well as good universality toward a series of unsaturated hydrocarbons catalyzed by using H 2 or formic acid as hydrogen source in aqueous reaction. Such excellent catalytic performance of Pd@HPC-DCD in aqueous solution can be attributed to the hierarchical structure, well-dispersed Pd sites, as well as the favorable hydrophilicity.
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NEW JOURNAL OF CHEMISTRY
·
2019
·Vol. 43
·期 47
·18601-18610
·
IF 3.069
Siwen Xia,Yu Yang,Changli Lü
Functionalized two-dimensional graphene oxide sheets and their inorganic–organic nanohybrids have aroused great interest because of their excellent synergetic effect on metal-based nanocatalyst PdNPs supported on highly hydrophilic quaternized polyhedral oligomeric silsesquioxane (QPOSS) functionalized reduced graphene oxide (rGO) and were successfully constructed as a nanohybrid catalyst for efficient heterogeneous catalytic reactions. Octaammonium POSS (OAPOSS) was first covalently grafted to carboxylated GO nanosheets through an amidation reaction, and then the OAPOSS decorated on rGO nanosheets was quaternized with glycidyltrimethylammonium chloride (GDTMAC) via an epoxide ring-opening reaction to obtain a highly functional hydrophilic QPOSS@rGO hybrid. Finally, the PdNPs were loaded onto QPOSS@rGO nanosheets through an in situ reduction route. The quaternary ammonium groups on QPOSS@rGO can strongly coordinate with PdNPs, making it particularly advantageous for stabilizing PdNPs and preventing the leaching of Pd metals. Compared to the PdNPs@rGO catalyst without modification with hydrophilic QPOSS, the low-dose PdNPs@QPOSS@rGO nanocatalysts exhibited outstanding catalytic efficiency in the reduction of methylene blue and nitrophenols. In addition, the as-designed nanocatalysts also showed high catalytic activity for the Suzuki coupling reaction when utilizing pure water as a green solvent. It was proved that QPOSS and rGO can synergistically catalyze and promote the diffusion of reactants. In particular, the PdNPs@QPOSS@rGO nanohybrid catalyst showed no significant loss of catalytic activity after reusing it five times. Our results demonstrated that highly hydrophilic QPOSS endows the resulting PdNPs@QPOSS@rGO nanohybrid with good dispersibility and stability in water, which remarkably further improves the catalytic activity of the nanocatalyst.
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CHEMOSPHERE
·
2019
·
IF 5.108
Yating Jia,Fan Hu,Yuancai Lv,Yuancai Chen,Yongyou Hu
Polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants and challenges for water treatment due to their persistence and toxicity. In this study, the reduction of 2′2′4′4′-tetrabromodiphenyl ether (BDE-47) was investigated in a nano-bio-integrated system. Results showed that the introducing of P. putida could markedly accelerate the demineralization of BDE-47 in nZVI/Pd- P.p system; the continuous generation of acidic metaboliates by P. putida could decrease pH, which could alleviate the surface passivation to some extent, resulting in the releasing of Fe 2+ and high generation of H 2 O 2 , the shift in reactive oxygen species from Fe(IV) to •OH. The BDE-47 was firstly debrominated to the DE by the highly reductive [Pd·2H] generated by nZVI/Pd, then oxidized to bromophenol and phenol, catechol as well as hydroquinone via the P. putida strain and the Fenton-like system. The toxicity assays confirmed the combined system could avert generation of nocuous intermediates, and could be an alternative strategy for complete remediation of recalcitrant POPs.
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ChemCatChem
·
2019
·Vol. 11
·期 11
·2676-2682
·
IF 4.495
Qinglin Yuan,Wanbing Gong,Yixing Ye,Jun Liu,Yue Lin,Chun Chen,Haimin Zhang,Pengfei Li,Weiren Cheng,Xiangjun Wei,Changhao Liang
Graphical Coupling reaction : A novel Pd/BiOCl catalyst is designed to catalyze benzaldehyde for high-selectively synthesizing benzoin ethyl ether utilizing the nucleophilic action of Cl − ions. DFT calculations and experimental evidences demonstrated the key role of dissociated Cl − ions with Pd NPs by suppressing the dissociation of Cl − ions and changing the reaction pathway. Exploring novel catalyst supports with unique performance creates more opportunity for transforming organic chemicals in heterogeneous catalysis. In this paper, BiOCl is first presented as an effective support for Pd nanoparticles (NPs) toward application in the coupling reaction of benzaldehyde. The Cl − ion dissociates from BiOCl, which forms nucleophile with Pd nanoparticles; this is key for the one-step synthesis of benzoin ethyl ether, the conversion and selectivity of which can reach to 100 % and 97.9 % at 100 °C, respectively. DFT calculations reveal that Cl − ions can be stabilized by stronger Bi−Cl bonds through doping of Fe ions in substituting Bi sites in BiOCl. The parallel catalytic evaluation using Pd/Fe-doped BiOCl catalyst shows the suppression of coupling reaction, conversely, demonstrating the crucial role of nucleophile. This work provides new insights into support tailoring for the synthesis of vital organic chemicals in heterogeneous catalysis by changing chemical reaction pathway.
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