Reactivity of bis(cyanomethanide) nickel and palladium complexes

The reactivity of the bis(cyanomethanide) nickel and palladium complexes is discussed. The synthetic scheme used to generate these complexes involves the use of a base to generate the anion of acetonitrile, followed by the reaction of this anion with the metal dihalide L2NiCl2 or L2PdCl2 to generate the desired complex L2Ni(CH2CN)2 or L2Pd(CH2CN)2. Regardless of the ligand L (PPh3, diphos, or bipy), it was found that the complex L2Ni(CH2CN)2 is much less stable than the analogous complex L2Ni(CH3)2. When the cyanomethanide nickel complex is oxidized to induce a reductive–elimination reaction, succinonitrile is generated. Though crystals of a nickel complex could not be obtained, the X-ray structure of the complex (diphos)Pd(CH2CN)2 is reported. Upon oxidation, the palladium complex does not undergo a reductive–elimination reaction.