77979-28-3Relevant articles and documents
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.
Suzuki-Miyaura cross-coupling of bulky anthracenyl carboxylates by using pincer nickel N-heterocyclic carbene complexes: An efficient protocol to access fluorescent anthracene derivatives
Xu, Mizhi,Li, Xingbao,Sun, Zheming,Tu, Tao
supporting information, p. 11539 - 11541 (2013/12/04)
A series of fluorescent (hetero)-aryl substituted anthracene derivatives were readily accessible from the corresponding bulky anthracen-9-yl carboxylates via Suzuki-Miyaura cross-coupling reactions by using pincer nickel N-heterocyclic carbene complex 1 even at the catalyst loading as low as 0.1 mol% in the presence of catalytic amounts of PCy3.
Reactivity of Polycyclic Aromatic Aryl Radicals
Chen, R. H.,Kafafi, S. A.,Stein, S. E.
, p. 1418 - 1423 (2007/10/02)
Results of experimental and theoretical studies of the properties and reactions of polycyclic aromatic aryl radicals are reported.Reactions of phenyl, 1- and 2-naphthalenyl, and 9-anthracenyl radicals with toluene and naphthalene were examined in the gas phase at 400 and 450 deg C.Arylation rates for each radical were measured relative to hydrogen abstraction from toluene (kar/kabs).For reactions with toluene of both phenyl and 2-naphthalenyl radicals, this ratio was 0.20-0.25.For the 1-naphthalenyl and 9-anthracenyl radicals, these ratios were significantlylower (0.05 and 0.01, respectively).Relative rates for arylating the different available positions in toluene and naphthalene, however, were not nearly as different.Differences in arylation/abstraction rates of the different radicals are explained in terms of differing degrees of reversibility for the initial addition step.Results are consistent with literature dissociation rate constants measured by Ladaki and Szwarc for aryl bromides.MNDO calculations on a range of arene-aryl radical pairs suggest that these differences originate primarily from differences in radical stabilities.Calculations also suggest that, on the basis of bond strenghts, aryl radicals can be roughly divided into three groups, which depend on the nature of the two neighboring aromatic carbon atoms and are independent of the size of the aromatic cluster.
