Intermolecular Lithium η2-Alkene and κ2-Alkane Complexes: Synthesis, Bonding, and Facile Interconversion Mikhail A. Bogachev, Alexander N. Selikhov, Anton V. Cherkasov, Rinat R. Aysin, Sergey S. Bukalov, Alexander A. Trifonov Journal of the American Chemical Society, 2025 In this work, an approach enabling the synthesis of η2-alkene lithium complexes (Carb2,4,6-iPr)Li(η2-L) (L = 1-octene, cyclohexene) is elaborated. For 1,5-hexadiene, the same approach results in a binuclear μ-η2:η2-diene complex. The QTAIM parameters reveal the electrostatic nature of the Li-alkene interaction. When treated with cyclohexane, alkene ligands in (Carb2,4,6-iPr)Li(η2-L) are readily replaced to afford the Li-alkane complex (Carb2,4,6-iPr)Li(κ2-C6H12) featuring anagostic Li···H interactions. The reverse reaction readily proceeds in the presence of excess alkene. The QTAIM and LED analyses performed at the DLPNO–CCSD(T) level show a small difference between the complexes in the total dispersion contribution (16.0–18.5 kcal/mol) and interaction energy for Li–alkene (∼3.5 kcal/mol) or Li–C6H12 (∼4 kcal/mol). These values suggest the presence of an equilibrium between these entities, which can be readily shifted by the presence of an excess of alkene or alkane. (Carb2,4,6-iPr)Li(η2-L) and (Carb2,4,6-iPr)Li(κ2-C6H12) are transformed into η2-arene complexes upon treatment with benzene; however, a reverse reaction is not possible at room temperature.
Reversible hydrosilane addition to pyridines enabled by low-coordinate Ca(ii) and Yb(ii) hydrides Alexander N. Selikhov, Mikhail A. Bogachev, Yulia V. Nelyubina, Grigory Yu. Zhigulin, Sergey Yu. Ketkov, Alexander A. Trifonov Inorganic Chemistry Frontiers, 2024 Low-coordinate dimeric Ca(ii) and Yb(ii) hydrides {[tBu2CarbAr2]MH(THF)}2 and {[tBu2CarbAr2]MH(η6-C7H8)}2 efficiently catalyze PhSiH3 addition to pyridines at ambient T. At 90° C the same complex catalyzes the reverse reaction.
