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149 results on '"Xu, Huanjun"'

11. Doping Ferrocene-Based Conjugated Microporous Polymers with 7,7,8,8-Tetracyanoquinodimethane for Efficient Photocatalytic CO 2 Reduction.

Author

Wang, Shenglin, Yan, Qianqian, Hu, Hui, Su, Xiaofang, Xu, Huanjun, Wang, Jianyi, and Gao, Yanan

Subjects
CARBON dioxide, POLYMERS, POROUS materials, PHOTOREDUCTION, CONJUGATED polymers, AMORPHOUS substances, FERROCENE
Abstract

The design and synthesis of organic photocatalysts remain a great challenge due to their strict structural constraints. However, this could be mitigated by achieving structural flexibility by constructing permanent porosity into the materials. Conjugated microporous polymers (CMPs) are an emerging class of porous materials with an amorphous, three-dimensional network structure, which makes it possible to integrate the elaborate functional groups to enhance photocatalytic performance. Here, we report the synthesis of a novel CMP, named TAPFc-TFPPy-CMP, constructed by 1,1′3,3′-tetra(4-aminophenyl)ferrocene (TAPFc) and 1,3,6,8-tetrakis(4-formylphenyl)pyrene (TFPPy) monomers. The integration of the p-type dopant 7,7,8,8-tetracyanoquinodimethane (TCNQ) into the TAPFc-TFPPy-CMP improved the light adsorption performance, leading to a decrease in the optical bandgap from 2.00 to 1.43 eV. The doped CMP (TCNQ@TAPFc-TFPPy-CMP) exhibited promising catalytic activity in photocatalytic CO2 reduction under visible light, yielding 546.8 μmol g−1 h−1 of CO with a selectivity of 96% and 5.2 μmol g−1 h−1 of CH4. This represented an 80% increase in the CO yield compared to the maternal TAPFc-TFPPy-CMP. The steady-state photoluminescence (PL) and fluorescence lifetime (FL) measurements reveal faster carrier separation and transport after the doping. This study provides guidance for the development of organic photocatalysts for the utilization of renewable energy. [ABSTRACT FROM AUTHOR]

Published
2024
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15. Metal Catalyst‐Free Oxidative Cleavage of Aryl C(OH)−C Bonds.

Author

Li, Chi, Gao, Yu, Li, Han, Li, Wenhao, Wang, Xinmei, Wang, Xuerong, Lin, Chunguang, Wang, Jinhui, Li, Yiying, and Xu, Huanjun

Subjects
SCISSION (Chemistry), METALS, BENZOIC acid, BENZOATES, KETONES, CARBON-carbon bonds, LIGNINS, LIGNIN structure
Abstract

A simple and efficient protocol for oxidative cleavage of aryl C(OH)−C bonds to acids was reported. In this protocol, KOtBu was found to be able to transform aryl alcohols and ketones to the desired benzoic acids without any other additives using 4 MPa O2 in mesitylene. Substrates with either electron‐donating or electron‐withdrawing groups could be transformed to the according benzoic acids in moderate to excellent yield. All these findings indicated that this oxidation of aryl secondary C(OH)−C bonds might proceed through a radical mechanism. And the represent lignin dimer model compound was successfully transformed to the benzoic acid, which indicated this protocol might has the potential to transform nature lignin. [ABSTRACT FROM AUTHOR]

Published
2023
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31. Immobilization of Ionic Liquid on a Covalent Organic Framework for Effectively Catalyzing Cycloaddition of CO 2 to Epoxides.

Author

Yan, Qianqian, Liang, Hao, Wang, Shenglin, Hu, Hui, Su, Xiaofang, Xiao, Songtao, Xu, Huanjun, Jing, Xuechao, Lu, Fei, and Gao, Yanan

Subjects
EPOXY compounds, CARBON dioxide, POROUS polymers, CATALYTIC activity, CHEMICAL reactions, RING formation (Chemistry), IONIC liquids
Abstract

Transforming CO2 into value-added chemicals has been an important subject in recent years. The development of a novel heterogeneous catalyst for highly effective CO2 conversion still remains a great challenge. As an emerging class of porous organic polymers, covalent organic frameworks (COFs) have exhibited superior potential as catalysts for various chemical reactions, due to their unique structure and properties. In this study, a layered two-dimensional (2D) COF, IM4F-Py-COF, was prepared through a three-component condensation reaction. Benzimidazole moiety, as an ionic liquid precursor, was integrated onto the skeleton of the COF using a benzimidazole-containing building unit. Ionization of the benzimidazole framework was then achieved through quaternization with 1-bromobutane to produce an ionic liquid-immobilized COF, i.e., BMIM4F-Py-COF. The resulting ionic COF shows excellent catalytic activity in promoting the chemical fixation of CO2 via reaction with epoxides under solvent-free and co-catalyst-free conditions. High porosity, the one-dimensional (1D) open-channel structure of the COF and the high catalytic activity of ionic liquid may contribute to the excellent catalytic performance. Moreover, the COF catalyst could be reused at least five times without significant loss of its catalytic activity. [ABSTRACT FROM AUTHOR]

Published
2022
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33. H2O2 -promoted C–C bond oxidative cleavage of β-O-4 lignin models to benzanilides using water as a solvent under metal-free conditions.

Author

Liu, Xinwei, Wang, Liguo, Zhai, Lianjing, Wu, Cailing, and Xu, Huanjun

Subjects
SCISSION (Chemistry), WATER use, AROMATIC compounds, METAL catalysts, OXIDIZING agents, LIGNINS, SOLVENTS
Abstract

The production of aromatic compounds from lignin is an essential issue in the transformation of biomass. Herein, a simple method has been presented for the synthesis of benzanilides and phenols from aniline involving the oxidative cleavage of β-O-4 lignin models using H2O2 as an oxidizing agent without any metal catalysts and under relatively mild conditions. [ABSTRACT FROM AUTHOR]

Published
2022
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35. Comparison of application value between conventional air insufflation and water infusion in colonoscopy

Author

Ma, Li’an, Yan, Jifu, Shen, Junquan, Sang, Jianzhong, and Xu, Huanjun

Subjects
Original Article
Abstract

Objective: To discuss the feasibility of water infusion colonoscopy and its difference with traditional air insufflation colonoscopy in application value. Methods: A prospective randomized controlled clinical study was designed to include 200 patients who underwent sedation-free diagnostic colonoscopy. Among them, 100 patients were treated with water infusion colonoscopy (observation group) and 100 patients were treated with air insufflation colonoscopy (control group). All operations were performed independently by the same experienced physician. The differences in colonoscopy related values, colon adenoma detection rate, and follow-up findings between the patients of two groups were compared. Results: There was no significant difference in the Boston bowel preparation scale (BBPS) score of the left hemicolon, transverse colon, right hemicolon, total BBPS scores, and bubble amount between the two groups (P>0.05). In the observation group, the scope-forward time, the time to reach the ileocecal junction, and the total operation time were significantly longer than that of the control group (P0.05). Compared with control group, the incidence of abdominal pain and VAS scores were significantly lower in the observation group (P

Published
2020

40. Cu2+Embedded Three-Dimensional Covalent Organic Framework for Multiple ROS-Based Cancer Immunotherapy

Author

Zhang, Xia, Wang, Shenglin, Tang, Kun, Pan, Wei, Xu, Huanjun, Li, Yanhua, Gao, Yanan, Li, Na, and Tang, Bo

Abstract

Reactive oxygen species (ROS)-based cancer treatments have attracted much attention in recent years. However, most patients respond poorly to the monotypic ROS during these treatments. In this work, a multiple ROS-based cancer immunotherapy synergistic strategy has been developed to enhance the therapeutic effect of cancer. We prepare a three-dimensional covalent organic framework (3D COF-TATB), and embed copper ions (Cu2+) into the skeleton to obtain multifunctional nanomaterial, 3D Cu@COF-TATB. In this system, porphyrins in 3D COF-TATB serve not only as the photosensitizer for photodynamic process to produce singlet oxygen(1O2), but also as the binding sites to complex with Cu2+. Cu2+can be reduced by the GSH to generate Cu+to produce hydroxyl radical (•OH) through the Fenton-like reaction. Moreover, the generated multiple types of ROS induce the immunogenic cell death (ICD) of cancer cells to improve the immunogenicity and further activate an immune response for attacking the tumor. Combining with the immunoblocking inhibitor (aPD-1), 3D Cu@COF-TATB can effectively inhibit the tumor growth. This work will provide a guidance for multimodal cancer therapy in future clinical treatment settings.

Published
2022
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41. Task-specific ionic liquid and CO2-cocatalysed efficient hydration of propargylic alcohols to α-hydroxy ketones† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c5sc00040h Click here for additional data file

Author

Zhao, Yanfei, Yang, Zhenzhen, Yu, Bo, Zhang, Hongye, Xu, Huanjun, Hao, Leiduan, Han, Buxing, and Liu, Zhimin

Subjects
Chemistry
Abstract

Task-specific ionic liquid and CO2-cocatalysed efficient hydration of propargylic alcohols to α-hydroxy ketones., The hydration of propargylic alcohols is a green route to synthesize α-hydroxy ketones. Herein a CO2-reactive ionic liquid (IL), [Bu4P][Im], was found to display high performance for catalyzing the hydration of propargylic alcohols in the presence of atmospheric CO2, and a series of propargylic alcohols could be converted into the corresponding α-hydroxy ketones in good to excellent yields. In the IL/CO2 reaction system, CO2 served as a cocatalyst by forming α-alkylidene cyclic carbonates with propargylic alcohols, and was released via the rapid hydrolysis of the carbonates catalysed by the IL. This is the first example of the efficient hydration of propargylic alcohols under metal-free conditions.

Published
2015

42. Construction of the Copper‐Functionalized Covalent Organic Framework Used as a Heterogeneous Catalyst for Click Reaction.

Author

Gao, Tingjun, Su, Xiaofang, Xu, Huanjun, Hu, Hui, Zeng, Chaoyuan, and Gao, Yanan

Subjects
CHEMICAL reactions, CATALYTIC activity, CLICK chemistry, COPPER ions, WASTE recycling
Abstract

Functional modification of the covalent organic frameworks (COFs) has become an efficient strategy to expand its applications in various fields. In this investigation, an imine linked T−D COF has been synthesized via solvothermal method using 2,4,6‐tris(4‐aminophenyl)pyridine (TAPP) and 2,6‐dihydroxynaphthalene‐1,5‐dicarbaldehyde (DHNDA) as building blocks. While synthesizing T‐D COF, hydroxyl groups are strategically introduced to the adjacent sites of −C=N− bonds in the framework. Such a special structure enables a strong coordination between the loaded copper metal ion and the hydroxyl groups together with imine bounds in the COF layered structure. The obtained copper‐containing COF, (Cu@T−D COF) hybrid material was used as an efficient heterogeneous catalyst for the alkyne‐azide click chemistry reactions and showed excellent catalytic activity in methanol/water medium. Furthermore, this Cu@T−D COF is stable and easily recycled and reused without loss of its catalytic activity. [ABSTRACT FROM AUTHOR]

Published
2020
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46. 1, 6-di- O -caffeoyl- β - D -glucopyranoside, a natural compound from Callicarpa nudiflora Hook impairs P2Y 12 and thromboxane A 2 receptor-mediated amplification of platelet activation and aggregation

Author

Fu, Jianjiang, primary, Zhu, Xiaocui, additional, Wang, Wei, additional, Lu, Hong, additional, Zhang, Zhoumiao, additional, Liu, Ting, additional, Xu, Huanjun, additional, Fu, Huizheng, additional, Ma, Shuangcheng, additional, and Luo, Yuehua, additional

Published
2017
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