The nature of transition-metal–olefin bonding has been explained by the Dewar–Chatt–Duncanson model within a continuum of two extremes, namely, a π-complex and a metallacyclopropane. The textbook rule suggests that a low-spin late-transition-metal–ethylene complex more likely forms a π-complex rather than a metallacyclopropane. Herein, we report a low-spin late-transition-metal–bis-ethylene complex forming an unprecedented planar metalla-bis-cyclopropane structure with magnesium-based metalloligands. Treatment of LMgEt (L = [(DippNCMe)2CH]−, Dipp = 2,6- i Pr2C6H3) with Ni­(cod)2 (cod = 1,5-cyclooctadiene) formed the heterotrimetallic complex (LMg)2Ni­(C2H4)2, which features a linear Mg–Ni–Mg linkage and a planar coordination geometry at the nickel center. Both structural features and computational studies strongly supported the Ni­(C2H4)2 moiety as a nickelaspiropentane. The exposure of (LMg)2Ni­(C2H4)2 to 1 bar H2 at room temperature produced a four-hydride-bridged complex (LMg)2Ni­(μ-H)4. The profile of H2 activation was elucidated by density functional theory calculations, which indicated a novel Mg/Ni cooperative activation mechanism with no oxidation occurring at the metal center, differing from the prevailing mono-metal-based redox mechanism. Moreover, the heterotrimetallic complex (LMg)2Ni­(C2H4)2 catalyzed the hydrogenation of a wide range of unsaturated substrates under mild conditions.

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An efficient para-alkylation of primary and secondary anilines with a variety of sterically encumbered alkenes using a simple β-diketiminato scandium catalyst is reported. This protocol features 100% atom economy, excellent chemo-and regioselectivity, broad substrate scope, and good functional group tolerance. Mechanistic studies disclosed that the reaction probably proceeded via a tandem hydroamination/Hofmann−Martius rearrangement.

Heteronuclear metal complexes comprised of main group metals and transition metals have attracted widespread attention from researchers due to their applications in stoichiometric and catalytic activation of small molecules with...

In this study, a novel method for obtaining high-quality krill oil from wet Antarctic krill by using subcritical dimethyl ether (SDE) was proposed.

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