Breaking New Ground: MB ene Route toward Selective Vinyl Double Bond Hydrogenation in Nitroarenes

• Published in: Journal of the American Chemical Society 2023-12, Vol.145 (50), p.27459-27470
• Main Authors: Bhaskar, Gourab, Behera, Ranjan K, Gvozdetskyi, Volodymyr, Carnahan, Scott L, Ribeiro, Raquel A, Oftedahl, Paul, Ward, Charles, Canfield, Paul C, Rossini, Aaron J, Huang, Wenyu, Zaikina, Julia V
• Format: Article
• Language: English
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.3c08642

Doping, or incremental substitution of one element for another, is an effective way to tailor a compound's structure as well as its physical and chemical properties. Herein, we replaced up to 30% of Ni with Co in members of the family of layered LiNiB compounds, stabilizing the high-temperature polymorph of LiNiB while the room-temperature polymorph does not form. By studying this layered boride with in situ high-temperature powder diffraction, we obtained a distorted variant of LiNi Co B featuring a perfect interlayer placement of [Ni Co B] layers on top of each other─a structural motif not seen before in other borides. Because of the Co doping, LiNi Co B can undergo a nearly complete topochemical Li deintercalation under ambient conditions, resulting in a metastable boride with the formula Li Ni Co B. Heating of Li Ni Co B in anaerobic conditions led to yet another metastable boride, Li Ni Co B, with a CoB-type crystal structure that cannot be obtained by simple annealing of Ni, Co, and B. No significant alterations of magnetic properties were detected upon Co-doping in the temperature-independent paramagnet LiNi Co B or its Li-deintercalated counterparts. Finally, Li Ni Co B stands out as an exceptional catalyst for the selective hydrogenation of the vinyl C═C bond in 3-nitrostyrene, even in the presence of other competing functional groups. This research showcases an innovative approach to heterogeneous catalyst design by meticulously synthesizing metastable compounds.