Science China-Chemistry
·
2023
·Vol. 67
·期 1
·374-382
·
IF 9.6
Luo Zhongfeng,Jiang Jingxing,Zou Lifang,Zhou Xiaoyu,Liu Junshan,Ke Zhuofeng,Chen Fengjuan,Jiang Huanfeng,Zeng Wei
We disclose the development of the Rh-catalyzed amine-directed remote 5,6-carboamination protocol of pyridines via dual Csp 2 –H functionalizations. A variety of readily available 2-aminopyridines and 1,2,3-triazoles are allowed for coupling cyclization to access polyfunctionalized azaindoles. Mechanistic studies including DFT calculations unveil that relay carbenoid-electrophilic addition to pyridines and the sequential pyridyl Csp 2 –H amination are involved in this transformation. The post-synthetic utility of this methodology is showcased by versatile and site-selective modification of azaindoles.
研究领域:
有机化学
·
催化化学
✓ 已验证
DOI
高影响因子
FARADAY DISCUSSIONS
·
2016
·Vol. 190
·219-230
·
IF 3.544
Yong-Qi Li,Huan Liu,Peng Wang,Da Yang,Xiao-Li Zhao,Ye Liu
A highly efficient and stable Rh–P catalytic system in the RTIL of [PEmim]BF4 was developed for the biphasic hydroformylation of 1-octene by using the diphosphine-functionalized ionic liquid (FIL) of 2. While 2-Rh(acac)(CO)2 was immobilized in [PEmim]BF4 (solvent), a typical biphasic catalysis was fulfilled with advantages of facile separation and recycling ability – 9 runs without any loss of activity. It was found that not only the acquired π-acceptor character of 2, but also the synergetic role of the piperidyl group in [PEmim]BF4 as an N-containing donor, cooperatively contributed to the efficient hydroformylation due to the facilitated formation and stability of the Rh-H active species (ν 2045 cm−1). This was supported by the in situ high-pressure FT-IR spectral analysis.
研究领域:
化学工程
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催化科学
✓ 已验证
DOI
PubMed
高影响因子
Science China-Chemistry
·
2019
·Vol. 62
·期 12
·1710-1719
·
IF 6.085
Wang Guishuo,Luo Ran,Yang Chengsheng,Song Jimin,Xiong Chuanye,Tian Hao,Zhao Zhi-Jian,Mu Rentao,Gong Jinlong
Metal oxide-promoted Rh-based catalysts have been widely used for CO 2 hydrogenation, especially for the ethanol synthesis. However, this reaction usually suffers low CO 2 conversion and alcohols selectivity due to the formation of byproducts methane and CO. This paper describes an efficient vanadium oxide promoted Rh-based catalysts confined in mesopore MCM-41. The Rh-0.3VO x /MCM-41 catalyst shows superior conversion (~12%) and ethanol selectivity (~24%) for CO 2 hydrogenation. The promoting effect can be attributed to the synergism of high Rh dispersion by the confinement effect of MCM-41 and the formation of VO x -Rh interface sites. Experimental and theoretical results indicate the formation of til-CO at VO x -Rh interface sites is easily dissociated into *CH x , and then *CH x can be inserted by CO to form CH 3 CO*, followed by CH 3 CO* hydrogenation to ethanol.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 45
·期 27
·12081-12090
·
IF 3.591
Meihuan Kang,Yichen Li,Jin Yan,Penghui Shi,Yulin Min,Jinchen Fan,Qunjie Xu
Titanium dioxide (TiO2) has been widely studied because of its stable chemical properties, low cost and non-toxicity. But some of its shortcomings also limit its development, such as a large band gap and weak catalytic ability under visible light. The photocatalytic performance of titanium dioxide has been improved by doping nonmetal boron (B) and noble metal rhodium (Rh) in the current study. In general, a metal's electron-deficient state can be regarded as the active sites in a hydrogen evolution reaction. The electron-deficient state of Rhδ+ contributes to its high ability to grab electrons. The light absorption range of Rh nanoparticles (NPs) can reach the visible light band. TiO2 with special morphology is synthesized by a one-step hydrothermal method, and B-doped titanium dioxide with an oxygen vacancy is obtained by adding a B source into the precursor solution. The influence of nonmetal ion doping on oxygen vacancy is studied. The Rh/B–TiO2-550 photocatalyst is synthesized by depositing Rh NPs onto B–TiO2, and the bifunctional photocatalyst with a visible light response is successfully prepared. The Rh/B–TiO2-550 catalyst shows good performance in the degradation of hydrogen and pollutants produced in the photocatalytic decomposition process. Under the irradiation of a 300 W xenon lamp, the hydrogen production reaches 108.67 μmol in 3 h, and the degradation effect of OPP reaches 99.48%.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
Molecular Catalysis
·
2024
·
IF 3.9
Yuhao Yang,Minghui Tan,Hailun Geng,Xiujuan Gao,Yisheng Tan,Qingde Zhang
Oriented designing the microenvironment of catalytic sites is essential for understanding catalytic processes. In this work, EDTA was first grafted in UiO-66 and then chelated Rh to obtain an efficient catalyst for 1-hexene hydroformylation reaction. EDTA not only served as a chelation site for Rh immobilization in UiO-66, but also markedly influenced the structure and properties of Rh/UiO-66. The incorporation of EDTA reduced the micropore content and suppressed the formation of heavy products. Moreover, the grafted EDTA regulated the electronic state of Rh effectively to improve the CO and propene adsorption, thus constructing an appropriate microenvironment for hydroformylation. Therefore, EDTA-modified Rh/U-E catalyst exhibited higher aldehydes yield, TOF and stability than Rh/U without EDTA. The dual role of EDTA in anchoring Rh sites and modulating the microenvironment for hydroformylation provides more prospects for designing customized MOFs-based catalysts.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Qi Yang,Pengfei Wang,Chen Li,Benlei Wang,Ying Zheng,Yi Feng,Zidi Miao,Maoshuai Li,Mei-Yan Wang,Shouying Huang,Xinbin Ma
Delineating the geometrical and electronic structure of supported metal is significant for developing heterogeneous hydroformylation catalysts. This study modulated the configuration and charge distribution of Rh to construct highly efficient Rh@SiO 2 catalysts for formaldehyde hydroformylation. The structure sensitivity of Rh species reveals that single-atom Rh can solely catalyze hydrogenation, while Rh aggregates are active for hydroformylation. Moderate Rh nanoclusters (0.98 nm) offered the highest TOF (183 h −1 ) and selectivity (90.8 %) of glycolaldehyde. Electronic effects demonstrate that synergy between Rh 0 and Rh + sites on the cluster is essential to enhancing the reaction. The Rh 0 species function as the adsorption/activation sites for H 2 and formaldehyde, and the Rh + sites act to coordinate PPh 3 and CO to form Rh δ+ (CO) x (PPh 3 ) y active species. This study provides new insights into the design of heterogeneous catalysts and guidance for understanding the structure sensitivity of active metal and hydroformylation mechanism.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ORGANIC CHEMISTRY
·
2022
·
IF 4.198
Shihai Lv,Ya-Nan Tian,Yanyan Yang,Chaoying Wen,Shiqing Li
An efficient one-pot synthesis of 1,1′-biisoquinolines by a three-component reaction of commercially available raw materials (benzils, NH4OAc, and alkynes) is disclosed. This complicated reaction involves in situ diimine formation via benzil-NH4OAc condensation, Rh(III)-catalyzed 2-fold imine-directed C–H activation, and annulation with alkynes. Both symmetric and unsymmetric 1,1′-biisoquinolines could be assembled in moderate to high yields. The reaction mechanism is supported through ESI-MS, in which Cp*ClRh+, Cp*(OAc)Rh+, Cp*(OPiv)Rh+, and two rhodacycle intermediates are successfully detected to explain the evolution of rhodium species.
研究领域:
有机化学
·
合成化学
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2018
·
IF 6.945
Juan Bai,Shi-Hui Xing,Ying-Ying Zhu,Jia-Xing Jiang,Jing-Hui Zeng,Yu Chen
Rationally tailoring the surface/interface structures of noble metal nanostructures emerges as a highly efficient method for improving their electrocatalytic activity , selectivity, and long-term stability. Recently, hydrogen evolution reaction is attracting more and more attention due to the energy crisis and environment pollution. Herein, we successfully synthesize polyallylamine-functionalized rhodium nanosheet nanoassemblies-carbon nanotube nanohybrids via a facile one-pot hydrothermal method . Three-dimensionally branched rhodium nanosheet nanoassemblies are consisted of two dimensionally atomically thick ultrathin rhodium nanosheets. The as-prepared polyallylamine-functionalized rhodium nanosheet nanoassemblies-carbon nanotube nanohybrids show the excellent electrocatalytic activity for the hydrogen evolution reaction in acidic media, with a low onset reduction potential of −1 mV, a small overpotential of 5 mV at 10 mA cm −2 , which is much superior to commercial platinum nanocrystals . Two dimensionally ultrathin morphology of rhodium nanosheet, particular rhodium-polyallylamine interface, and three-dimensionally networks induced by carbon nanotube are the key factors for the excellent hydrogen evolution reaction activity in acidic media.
研究领域:
材料科学
·
能源化学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Meng-Ting Chen,Ru-Lan Zhang,Jiu-Ju Feng,Li-Ping Mei,Yang Jiao,Lu Zhang,Ai-Jun Wang
The development of low-cost and high-efficiency electrocatalysts is very important for electrocatalytic hydrogen evolution reaction (HER) in water splitting system. Herein, ultrathin rhodium-iridium nanosheets were facilely in-situ grown on nickel foam (RhIr NSs/NF) by a one-pot aqueous strategy at room temperature. The sheet-like structures with the film thickness of 78 nm were identified by scanning electron microscopy and transmission electron microscopy. The catalyst showed greatly high HER features in both 1.0 M KOH and 0.5 M H 2 SO 4 with the overpotentials of 15 and 14 mV to achieve 10 mA cm −2 , respectively, surpassing most Pt-free catalysts. Also, the RhIr NSs/NF exhibited amazing catalytic stability during the long-term operation. This study offers a facile and rational pathway for design and synthesis of advanced HER electrocatalysts for energy conversion devices.
研究领域:
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 16
·7695-7703
·
IF 3.925
Qi Wu,Changfeng Zhao,Qinzhong Wang,Jing Liu
This study proposes the efficient separation of Au(III)/Pd(II)/Pt(IV)/Rh(III) through the 2-mercaptobenzothiazole-functionalised ionic liquid ([C6mim][2MBT]) using a cloud point extraction system. Direct cloud point extraction of Au(III) (about 99.9%) was realised without involving any functionalised ionic liquids. A significant enhancement of the Pd(II) extraction performance was found by adding rationally constructed [C6mim][2MBT]. Consequently, a fairly high extraction percentage of about 99.4% was obtained. However, further advancement of the proposed cloud point extraction showed that it could not be applied for the preconcentration of Pt(IV) and Rh(III) without adding stannous chloride, which plays a critical role in the segregation and could be adjusted by changing the hydrochloric acid concentration. Under the optimised conditions, the Rh(III) extraction process shows a high yield percentage (ca. 83.0%), where the majority of Pt(IV) was enriched in the aqueous phase. In addition, the underlying possible extraction mechanism was investigated using UV-vis, FT-IR and TEM measurements, which indicated that TX-114 acted as a solvent for the extracted metals. The developed procedure reveals efficient direct Au(III)/Pd(II)/Pt(IV)/Rh(III) separation using [C6mim][2MBT] via cloud point extraction.
研究领域:
分析化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2015
·
IF 1.098
Yu Niu,Fuying Li,Kai Yang,Ting Qiu,Renzhang Wang,Cheng Lin
A unique Rh/TiO 2 solid acid catalyst modified with H 2 SO 4 was synthesized and evaluated in the esterification reaction of propylene glycol methyl ether and decomposition of methyl orange (MO) in aqueous phase under halogen lamp irradiation. For this purpose, rhodium (Rh) nanoparticles were loaded on SO 4 2 − /TiO 2 via the photo-deposition method. It was found that SO 4 2 − /Rh–TiO 2 exhibited stronger catalytic activity than SO 4 2 − /TiO 2 . The new catalysts were characterized by X-ray powder diffraction (XRD), Brunauer–Emmett–Teller (BET), Transmission electron microscopy (TEM) and high-resolution (HRTEM), X-ray photoelectron spectroscopy (XPS) and Fourier Transform infrared spectroscopy (FTIR). Results from XRD and BET show that SO 4 2 − /Rh–TiO 2 has higher specific surface area and smaller pore size than SO 4 2 − /TiO 2 . The distribution of loaded Rh was found to be uniform with a particle size of 2–4 nm. Data from XPS reveal that Rh primarily exists as Rh 0 and Rh 3 + in Rh–TiO 2 and SO 4 2 − /Rh–TiO 2 . These valence forms of Rh likely contribute to the enhanced catalytic activity. Furthermore, FT-IR spectra of the catalysts show an abundance of surface hydroxyl groups, which help the formation of hydroxyl radicals and the enhancement of surface acid density. The results show that more acid sites are formed on the sulfated Rh–TiO 2 , and these acidic sites are largely responsible for improving the catalytic performance. This superior SO 4 2 − /Rh–TiO 2 catalyst has potential applications in reactions requiring efficient acid catalysts, including esterification reactions and waste water treatment.
研究领域:
材料科学
·
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
HETEROCYCLIC COMMUNICATIONS
·
2023
·Vol. 29
·期 1
·
IF 2.3
Mingyu Zhang,Yuqi Tang,Rui Xu,Dong Yan,Shuangping Xu,Yanqing Qu,Jingyu Xu,Hongge Jia
Due to the chemical properties of Group VIII transition metals and their importance in catalytic processes, the reactions of rhodium and its neighboring organic complexes have received much attention as model systems. In the present experiments, we successfully prepared two new rhodium complexes named [Rh(cod)(TTP)Cl] and [Rh(cod)(CDP)Cl] using tri( o -tolyl)phosphine and clohexyldiphenylphosphine as ligands, respectively, and the proofs of their structures were completed using 1 H NMR and 13 C NMR. Subsequently, it was applied to the polymerization reaction of phenylacetylene (PA), and the effects of different solvents, time, and temperature on the yield and molecular weight of the polymerization reaction products were discussed. The experimental results show that both complexes can play a catalytic role in the polymerization of PA. From the point of view of polymer molecular weight, the best reaction conditions for both catalysts were 3 h at 20°C in THF solvent (molecular weight up to 2.40 × 10 5 ). From the point of view of yield, the best reaction conditions for both catalysts were 4 h at 35°C in THF solvent (yield up to 89.2%).
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）