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

We describe facile synthetic methods for accessing linear cationic tetrylene nickel(0) complexes [(SiiP)DippE center dot Ni(PPh3)(3)](+) (E = Ge (4) and Sn (5); (SiiP)Dipp = [(iPr(3)Si)(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 (SiiP)DippECl (E = Ge (1) and Sn (2)), Ni(cod)(2), PPh3, and Na[BAr4F]. 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.