CHEMISTRY-A EUROPEAN JOURNAL
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2016
·Vol. 22
·期 24
·8368-8375
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IF 5.771
Yan Leng,Dan Lu,Chenjun Zhang,Pingping Jiang,Weijie Zhang,Jun Wang
Graphical This cat has five lives : Novel ionic polymer microspheres bearing a Co III –salen moiety were demonstrated to be highly efficient catalysts (high activity, easy recovery, and reusable) for the cycloaddition reaction of CO 2 and epoxides (see figure). We report a unique strategy to obtain the bifunctional heterogeneous catalyst TBB-Bpy@Salen-Co (TBB=1,2,4,5-tetrakis(bromomethyl)benzene, Bpy=4,4’-bipyridine, Salen-Co= N , N ’-bis({4-dimethylamino}salicylidene)ethylenediamino cobalt(III) acetate) by combining a cross-linked ionic polymer with a Co III –salen Schiff base. The catalyst showed extra high activity for CO 2 fixation under mild, solvent-free reaction conditions with no requirement for a co-catalyst. The synthesized catalyst possessed distinctive spherical structural features, abundant halogen Br − anions with good leaving group ability, and accessible Lewis acidic Co metal centers. These unique features, together with the synergistic role of the Co and Br − functional sites, allowed TBB-Bpy@Salen-Co to exhibit enhanced catalytic conversion of CO 2 into cyclic carbonates relative to the corresponding monofunctional analogues. This catalyst can be easily recovered and recycled five times without significant leaching of Co or loss of activity. Moreover, based on our experimental results and previous work, a synergistic cycloaddition reaction mechanism was proposed.
研究领域:
化学工程
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催化化学
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材料科学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2020
·
IF 2.463
Dan Mo,Jingnan Shi,Dandan Zhao,Yuzhen Zhang,Yifu Guan,Yunjun Shen,Hedong Bian,Fuping Huang,Shengfu Wu
Three transition metal complexes (Fe III , Co III , and Cu II ) were synthesized by hydrothermal method from bis(2-hydroxy-1-naphthalene-formaldehyde) 3,4-diaminobenzoic acid (H 3 L). They were characterized by infrared spectroscopy, elemental analysis, mass spectrometry. Artificial enzymes were constructed by hybridizing bovine serum albumin (BSA) with the metal complexes and characterized by MALDI-TOF-MS. The interaction of the metal complexes with BSA was studied by Raman spectroscopy, fluorescence spectroscopy, and circular dichroism spectroscopy. All the three metal complexes can cause the intrinsic fluorescence quenching of BSA, which is mainly static quenching. The addition of metal complexes changed the conformation of BSA and decreased the content of α–helix structure. The activity of SOD was measured by xanthine oxidase-NBT method. All metal complexes exhibited certain SOD activity, which increased after the formation of hybrid proteins. Asymmetric oxidation of thioether catalyzed by artificial enzymes was studied. The optimum reaction conditions were obtained by optimizing the reaction conditions. Substrate universality experiments were carried out under the optimum reaction conditions, showing good activity and enantioselectivity, with enantioselectivity up to 81%.
研究领域:
生物化学
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金属有机化学
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酶学
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DOI
高影响因子
Small Science
·
2023
·Vol. 3
·期 4
·2200085
·
IF 12.7
Mingxiong Lin,Weishan Jiang,Tingshi Zhang,Bixia Yang,Zanyong Zhuang,Yan Yu
The design of advanced metal–organic framework (MOF) catalysts for solar-driven conversion of CO 2 into syngas (CO/H 2 mixture) is beneficial. Herein, the design of a joint MOF heterostructure consisting of orderly assembled Co II - and Co III -based Prussian blue analogs (PBAs) driven by their spontaneous lattice match in the growth process is reported. As-prepared H/Co III -PBA@Co II -PBA cage is a mesocrystal and exhibits superior photocatalytic syngas production activity ( V CO up to 50.56 mmol g −1 h −1 , CO/H 2 = 1:1), which is among the best state-of-the-art heterogeneous photocatalysts in the literature. Theoretical calculations and experimental results confirm that Co III -PBA exerts a stronger affinity for CO 2 molecules than Co II -PBA, thus serving as the active site. The built-in electric field in the Co III -PBA@Co II -PBA heterojunction can direct the fast transport of photogenerated electrons from Co II -PBA to the active Co III -PBA. In the present case, the engineering of electronics outweighs morphological engineering to enhance the catalytic properties of Co III -MOF@Co II -MOF for CO 2 -to-syngas conversion.
研究领域:
材料科学
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能源化学
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催化反应
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DOI
高影响因子
DALTON TRANSACTIONS
·
2021
·Vol. 50
·期 48
·18061-18068
·
IF 4.39
Jiahui Guo,Xueqing Feng,Songrui Wang,Qikang Wu,Shanshan Lv,Yan Zhou,Han Li,Zheng Chen,Yuzhong Zhang
Novel hexagonal α-cobalt hydroxide nanosheets are synthesized through a 2-methylimidazole-induced hydrolysis strategy with cetyltrimethylammonium bromide (CTAB) as a surfactant. The weak alkaline environment provides favorable conditions for the formation of metastable α-Co(OH)2, while the same raw material will produce β-Co(OH)2 when a strong alkali solution is used. CTAB plays a vital role not only in hexagonal oriented growth, but also in the formation of the hydrotalcite-like structure of α-Co(OH)2 with high crystallinity. The crystallinity of both α- and β-Co(OH)2 is very poor without CTAB as a surfactant. The Co in this Co(OH)2−x layer presents most of the CoII and a small part of the CoIII, and the interlayer nitrate anion balances the positive charge of the host layer. The redox function produced by the CoII and CoIII of α-Co(OH)2 together with the large layer spacing jointly promotes the electron and mass transfer. The use of hydrazine hydrate for transfer hydrogenation involves the transport of protons and electrons produced by decomposition, and the rapid transport is bound to be conducive to the reduction process. Nitro compounds with varieties of functional groups can be smoothly reduced to the corresponding amines with high selectivity, when α-Co(OH)2 was used as a catalyst under mild conditions.
研究领域:
材料科学
·
催化
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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