4948-51-0Relevant articles and documents
Ligand-enabled and magnesium-activated hydrogenation with earth-abundant cobalt catalysts
Han, Bo,Jiao, Hongmei,Ma, Haojie,Wang, Jijiang,Zhang, Miaomiao,Zhang, Yuqi
, p. 39934 - 39939 (2021/12/31)
Replacing expensive noble metals like Pt, Pd, Ir, Ru, and Rh with inexpensive earth-abundant metals like cobalt (Co) is attracting wider research interest in catalysis. Cobalt catalysts are now undergoing a renaissance in hydrogenation reactions. Herein, we describe a hydrogenation method for polycyclic aromatic hydrocarbons (PAHs) and olefins with a magnesium-activated earth-abundant Co catalyst. When diketimine was used as a ligand, simple and inexpensive metal salts of CoBr2in combination with magnesium showed high catalytic activity in the site-selective hydrogenation of challenging PAHs under mild conditions. Co-catalyzed hydrogenation enabled the reduction of two side aromatics of PAHs. A wide range of PAHs can be hydrogenated in a site-selective manner, which provides a cost-effective, clean, and selective strategy to prepare partially reduced polycyclic hydrocarbon motifs that are otherwise difficult to prepare by common methods. The use of well-defined diketimine-ligated Co complexes as precatalysts for selective hydrogenation of PAHs and olefins is also demonstrated.
Chromium- and Cobalt-Catalyzed, Regiocontrolled Hydrogenation of Polycyclic Aromatic Hydrocarbons: A Combined Experimental and Theoretical Study
Han, Bo,Ma, Pengchen,Cong, Xuefeng,Chen, Hui,Zeng, Xiaoming
supporting information, p. 9018 - 9026 (2019/06/13)
Polycyclic aromatic hydrocarbons are difficult substrates for hydrogenation because of the thermodynamic stability caused by aromaticity. We report here the first chromium- and cobalt-catalyzed, regiocontrolled hydrogenation of polycyclic aromatic hydrocarbons at ambient temperature. These reactions were promoted by low-cost chromium or cobalt salts combined with diimino/carbene ligand and methylmagnesium bromide and are characterized by high regioselectivity and expanded substrate scope that includes tetracene, tetraphene, pentacene, and perylene, which have rarely been reduced. The approach provides a cost-effective catalytic protocol for hydrogenation, is scalable, and can be utilized in the synthesis of tetrabromo- and carboxyl-substituted motifs through functionalization of the hydrogenation product. The systematic theoretical mechanistic modelings suggest that low-valent Cr and Co monohydride species, most likely from zerovalent transition metals, are capable of mediating these hydrogenations of fused PAHs.
Method for selectively catalyzing and hydrogenating polycyclic aromatic hydrocarbon based on cobalt salt
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Paragraph 0037; 0038; 0039; 0040; 0041; 0042; 0043-0046, (2017/10/22)
The invention discloses a method for selectively catalyzing and hydrogenating polycyclic aromatic hydrocarbon based on cobalt salt. According to the method, cobalt salt and methyl magnesium bromide are taken as catalysts, N-heterocyclic carbine or 2,2'-dipyridyl is taken as a ligand, tetrahydrofuran is taken as a solvent, polycyclic aromatic hydrocarbon is stirred to react under mild conditions in an H2 atmosphere, so as to obtain a hydrogenated product. Based on regulation and control of N-heterocyclic carbine or 2,2'-dipyridyl and synergistic catalysis of cobalt salt and methyl magnesium bromide, the high-selectivity hydrogenation of polycyclic aromatic hydrocarbon is realized under mild conditions. The method has the advantages of low cost, mild reaction conditions, high selectivity, wide substrate application range and the like and can be used for hydrogenating different substituted anthracene derivative and other polycyclic aromatic hydrocarbon substrates.
Catalyzed hydrogenation of condensed three-ring arenes and their N-heteroaromatic analogues by a bis(dihydrogen) ruthenium complex
Borowski, Andrzej F.,Vendier, Laure,Sabo-Etienne, Sylviane,Rozycka-Sokolowska, Ewa,Gaudyn, Alicja V.
, p. 14117 - 14125 (2013/01/15)
A series of anthracene and acridine derivatives were hydrogenated under mild reaction conditions (80 °C, 3 bar of H2) using the bis(dihydrogen) complex [RuH2(η2-H2) 2{P(C6H11)3}2] (1) as a catalyst precursor. The influence of a methyl substituent on the substrate was studied. In all our systems, hydrogenation was only observed at the external rings leading to the corresponding 4H- or 8H-derivatives of anthracene and acridine. Three complexes resulting from the η4(C,C)-coordination of the substrate to the unsaturated fragment [RuH2{P(C 6H11)3}2] were characterized. In the case of 9-methyl acridine, the corresponding complex [RuH2(η 4-C14H11N){P(C6H11) 3}2] (4) turned out to be an active catalyst precursor leading to 1,2,3,4,5,6,7,8-octahydro-9-methylacridine as the sole product after 24 h. Regeneration of 1 from 4 supports the role of complex 4 in the catalytic cycle. Three hydrogenated products, 1,2,3,4-tetrahydroanthracene (4H-Anth), 1,2,3,4-tetrahydro-9-methylanthracene (4H-9-Me-Anth) and 1,2,3,4- tetrahydroacridine (4H-Acr), were characterized by X-ray diffraction. The Royal Society of Chemistry 2012.
Ruthenium-catalyzed regioselective 1,3-methylene transfer by cleavage of two adjacent σ-carbon-carbon bonds: An easy and selective synthesis of highly subsituted benzenes
Lian, Jian-Jou,Odedra, Arjan,Wu, Chang-Jung,Liu, Rai-Shung
, p. 4186 - 4187 (2007/10/03)
We report a new ruthenium-catalyzed 6-endo-dig cyclization of 6,6-cycloalkylidenyl-3,5-dien-1-ynes, which produces highly substituted benzenes with considerable structural reorganization. In this process, we observe a regioselective 1,3-methylene migratio
