Nanoscale
·
2025
·
IF 5.1
Mohammadreza Rostami,Biao Yang,Xiaochuan Ma,Sifan You,Jin Zhou,Meng Zhang,Xuefeng Cui,Haiming Zhang,Francesco Allegretti,Bing Wang,Lifeng Chi,Johannes Barth
n-Armchair graphene nanoribbons (nAGNRs) are promising components for next-generation nanoelectronics due to their controllable band gap, which depends on their width and edge structure. Using non-metal surfaces for fabricating nAGNRs gives access to reliable information on their electronic properties. We investigated the influence of light and iron adatoms on the debromination of 4,4”-dibromo-p-terphenyl precursors affording poly(para-phenylene) (PPP as the narrowest GNR) wires through the Ullmann coupling reaction on a rutile TiO2(110) surface, which we studied by scanning tunneling microscopy and X-ray photoemission spectroscopy. The temperature threshold for bromine bond cleavage and desorption is reduced upon exposure to UV light (240-395 nm wavelength), but the reaction yield could not be improved. However, in the presence of codeposited iron adatoms, precursor debromination occurred even at 77 K, allowing for Ullmann coupling and PPP wire formation at 300-400 K, i.e., markedly lower temperatures compared to the conditions without iron adatoms. Furthermore, scanning tunneling spectroscopy data reveal that adsorbed PPP wires feature a band gap of ≈ 3.1 eV.
研究领域:
材料科学
·
表面化学
✓ 已验证
DOI
PubMed
高影响因子
Molecular Catalysis
·
2019
·
IF 2.938
Xin Ge,Meng Ge,Xinzhi Chen,Chao Qian,Xuemin Liu,Shaodong Zhou
The exploration of inexpensive and stable heterogeneous catalysts and application of green solvents for Ullmann C N coupling reaction remain challenging. We present a facile fabrication of copper nanoparticles on hydrochar as prepared from natural, inexpensive and renewable chitosan together with in-situ reduction of copper salt in a one-pot hydrothermal carbonization process. The copper nanoparticles were uniformly dispersed on hydrochar by choosing block copolymer F127 as surfactant. Moreover, maleic acid was introduced to improve the hydrophilicity of hydrochar. The most active copper nanocomposite catalyst, that is, Cu/HCS-MA-F127, exhibited excellent catalytic activity for Ullmann C N coupling reaction in water. The nature of the Cu/HCS-MA-F127 was characterized by FTIR spectroscopy, TG, XRD, SEM and XPS. Moderate to excellent yields of aimed products were gained by using this catalytic strategy. Moreover, the Cu/HCS-MA-F127 catalyst can be reused by simple centrifugal recovery with a stable performance.
研究领域:
化学
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材料科学
·
催化反应
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 47
·41108-41113
·
IF 3.289
Hongyan Zhao,Guijie Mao,Huatao Han,Jinyi Song,Yang Liu,Wenyi Chu,Zhizhong Sun
As an outstanding mesh catalyst support, reduced graphene oxide (RGO) has attracted enormous attention in recent years. Cu nanoparticles-RGO (Cu NPs@RGO) as a green catalyst was prepared through a green reduction method by ascorbic acid in N-methyl-2-pyrrolidone. The structure of prepared Cu NPs@RGO was characterized. The catalytic activity of Cu NPs@RGO was estimated. A green and efficient method for synthesizing symmetrical biaryl compounds was developed by Cu NPs@RGO-catalyzed Ullmann homocoupling of aryl halides or arylboronic acids in ionic liquids under microwave (MW) irradiation. The catalytic system could be recycled five times with slight loss of activity. Through this method, nine kinds of biaryls were prepared by homocoupling reaction of the corresponding aryl iodides, aryl bromides, aryl chlorides and aryl boronic acids in moderate to good yields.
研究领域:
材料化学
·
绿色化学
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL SCIENCES
·
2017
·Vol. 129
·期 3
·289-294
·
IF 1.235
LIU YAOWEN,ZHAO FEN,ZHOU HAOHUA,XIE KAI,JIANG YUBO
CuI-catalyzed selective Ullmann C–O coupling of 1,4-disubstituted 1,2,3-triazole bromides with phenols were achieved through the coordination of N(2) atom. The ortho C–Br bond in N(1) aryl can be selectively coupled with phenols, while other C–Br bonds remain inert, generating ortho aryloxyl 1,4-diaryl 1,2,3-triazoles.
CuI-catalyzed selective Ullmann C–O couplings of 1,4-disubstituted 1,2,3-triazole bromides with phenols were achieved through the coordination of N(2) atom in triazole. The ortho C-Br bond in N(1) of aryl can be selectively coupled with phenols, while other C-Br bonds remain inert, generating ortho -aryloxyl 1,4-diaryl 1,2,3-triazoles.
研究领域:
有机化学
·
药物化学
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生物有机化学
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催化化学
·
合成方法学
✓ 已验证
DOI
高影响因子
Surfaces and Interfaces
·
2025
·
IF 6.3
Long Zhang,Yuran Cheng,Gengxin Xu,Yanran Wang,Ronger Zhou,Zuojun Wei
2,6-Dihydroxytoluene is a crucial chemical intermediate, but its preparation via direct Ullmann coupling hydroxylation of 2,6-dichlorotoluene presents challenges. The difficulties originate from the low water solubility and the low reactivity of 2,6-dichlorotoluene. To address these issues, this study systematically evaluated 10 surfactants and 14 ligands, including N-N, N-O, and oxamide N-N bidentate ligands, combined with three Cu(I) catalysts, to develop a biphasic system emulsified by surfactants. An impressive yield of 87.3 % 2,6-dihydroxytoluene was achieved over optimal system with 10 mmol/L cetyltrimethylammonium bromide, 10 mol % CuI, and 5 mol % 4,7-dihydroxy-1,10-phenanthroline, after 16 h of reaction at 180 °C. Analytical techniques, including microscopy, dynamic light scattering, and NMR spectroscopy studies on the microemulsion particle size distribution and the influence of cetyltrimethylammonium bromide on the proton microenvironment of 2,6-dichlorotoluene. The excellent performance of the catalytic reaction system could be attributed to the three key factors: (1) the effective catalytic action of CuI and 4,7-dihydroxy-1,10-phenanthroline; (2) the surfactant cetyltrimethylammonium bromide successfully emulsifying the oil-water biphasic system into micron- and nano-scale microemulsions, maximizing the reaction's surface area; (3) the cationic head of cetyltrimethylammonium bromide interacting with the aromatic ring of 2,6-dichlorotoluene, which enriched 2,6-dichlorotoluene and OH - at the interface, thereby enhancing the Ullmann coupling reaction.
研究领域:
有机化学
·
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Reaction Kinetics Mechanisms and Catalysis
·
2022
·Vol. 135
·期 5
·2565-2578
·
IF 1.843
Cai Zhaotian,Guo Xiaoxuan,Zhang Lixiang,Xiao Guomin
This work reports the synthesis of Zinc porphyrin-based porous (POP-ZnTPP) by a typical Yamamoto-Ullmann coupling reaction, which exhibited abundant tiny nanopores, excellent CO 2 adsorption capacity, and CO 2 /N 2 selectivity. The open pore environment of POP-ZnTPP facilitated the exposure of active sites, which intensified the catalytic activity in the cycloaddition reaction of epoxides (PO) with CO 2 under mild conditions. As expected, POP-ZnTPP catalyst completely converted PO to cyclic carbonates (COCs) at ambient temperature (25 °C, 1.5 MPa). It is also worth noting that POP-ZnTPP could convert PO into COCs under the simulated flue gas (15% CO 2 and 85% N 2 , v/v) atmosphere, which is very favorable for industrial applications of CO 2 . In addition, POP-ZnTPP catalyst as one of the most outstanding catalysts exhibited excellent broad substrate scope and remarkable reusability. This work has a certain guiding significance for developing an environmentally friendly COC production process.
研究领域:
材料科学
·
化学工程
·
环境科学
✓ 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）