10.1021/jo00343a001
The research focuses on the molten salt catalyzed transfer hydrogenation of polycyclic aromatic hydrocarbons, specifically the selective hydrogenation of anthracene and naphthacene by tetralin in the presence of molten antimony trichloride (SbCl3) as a catalyst at 80°C. The study aims to understand the redox-initiated ionic mechanism involving the arene radical cation and the 1-tetralyl cation as key intermediates in these transfer hydrogenation reactions. The conclusions drawn from the research indicate that anthracene and naphthacene are selectively hydrogenated to 9,10-dihydroanthracene and 5,12-dihydronaphthacene, respectively, without forming naphthalene, and instead, the dehydrogenated tetralin reacts with itself and unreacted arene to give alkylated products. The chemicals used in this process include anthracene, naphthacene, tetralin, and molten SbCl3, with additional compounds such as phenanthrene, pyrene, and perylene being tested under similar conditions to understand their reactivity patterns.
10.1021/jacs.9b03328
The research focuses on the regiocontrolled hydrogenation of polycyclic aromatic hydrocarbons (PAHs) using chromium and cobalt catalysis, which is a significant challenge due to the thermodynamic stability of PAHs arising from their aromaticity. The study employs a combination of experimental and theoretical approaches to achieve this hydrogenation at ambient temperature. The reactions are facilitated by the use of inexpensive chromium or cobalt salts, diimino/carbene ligands, and methylmagnesium bromide, leading to high regioselectivity and an expanded substrate scope, including rarely reduced PAHs like tetracene, tetraphene, pentacene, and perylene. The research provides a cost-effective and scalable catalytic protocol for hydrogenation, which can be further utilized in the synthesis of functionalized motifs such as tetrabromo and carboxyl-substituted derivatives. The experiments involve the optimization of reaction conditions, the use of various PAHs as substrates, and the analysis of products through techniques like NMR and GC. Theoretical mechanistic modeling using density functional theory (DFT) was also conducted to understand the active species involved in the hydrogenation process, suggesting that low-valent Cr and Co monohydride species, likely derived from zero-valent transition metals, mediate the hydrogenation of fused PAHs.
