Accessing cationic tetrylene-nickel(0) systems featuring donor–acceptor E–Ni triple bonds (E = Ge, Sn)

Abstract

We describe facile synthetic methods for accessing linear cationic tetrylene nickel(0) complexes [^SiiPDippE·Ni(PPh₃)₃]⁺ (E = Ge (4) and Sn (5); ^SiiPDipp = [(iPr₃Si)(Dipp)N]⁻), which feature donor–acceptor E–Ni triple bonds. These species are readily accessed in a one-pot protocol, combining the bulky halo-tetrylenes ^SiiPDippECl (E = Ge (1) and Sn (2)), Ni(cod)₂, PPh₃, and Na[BAr^F₄]. Given the diamagnetic nature of 4 and 5, they each contain a formal zero-valent Ni centre, making the E–M triple bonds in these complexes unique compared to previously reported metal tetrylidyne complexes, which typically feature covalent/ionic bonding. In-depth computational analyses of these species further support triple bond character in their E–Ni interactions.