Prof. Andrey Khalimon gave a virtual talk at the ACS Fall 2024

Prof. Andrey Khalimon gave a virtual talk at the ACS Fall 2024 discussing his research group's recent project funded by the Ministry of Science and Higher Education of the Republic of Kazakhstan. Prof. Khalimon's research group explores the chemistry of easily accessible aminophosphine complexes of manganese, iron, and cobalt in applications to the catalytic transfer hydrogenation of nitriles with ammonia borane to obtain synthetically valuable primary amines.

Catalytic transfer hydrogenation (TH) has become a convenient reduction strategy in synthetic organic chemistry, offering several advantages in safety, selectivity, and investment costs of transformations compared to stoichiometric reductions with metal hydride reagents and hydrogenations with compressed hydrogen gas. Initially developed for precious metal catalysts (mostly Ru, but also Rh, Ir, etc.), transfer hydrogenation reactions have found widespread applications in the reduction of carbonyl compounds to alcohols, mainly due to the availability of various hydrogen sources, operational simplicity, and mild reaction conditions. During the past decades, numerous 3d metal (so-called base metals, such as Mn, Fe, Co, and Ni) catalysts have been extensively studied as more economical surrogates to precious metal systems for TH of carbonyl compounds. In contrast, the analogous base-metal-catalyzed TH of unsaturated N-containing molecules is developed to a lesser extent. Although easily accessible nitriles are considered convenient and economical precursors to amines, examples of efficient base metal catalysts for selective TH of nitriles to the corresponding primary amines are scarce and restricted to only a few reports on Co and Mn catalysts. In contrast, despite their widespread applications in the TH of carbonyl compounds, no Fe catalysts for the TH of nitriles to primary amines have been reported. With this in mind, we aimed to explore the chemistry of a series of structurally related base metal (Mn, Fe, and Co) complexes bearing easily accessible bidentate PNH ligands and investigate comparative catalytic activities of these complexes in the TH of nitriles using ammonia borane as a hydrogen source. This work has resulted in the development of the first example of a readily accessible Fe(II) catalytic system for selective TH of nitriles to primary amines.