A single-crystal X-ray study was carried out on the product of the reaction between Ni(t-BuNC)4 and diazodicyanomethane, N2 C(CN)2. The product is shown to be the ketenimine complex Ni(t-BuN═C═C(CN)2)(t-BuNC)2. Evidence is presented which shows that the reaction proceeds via an intermediate diazodicyanomethane complex, Ni(N2 C(CN)2)(t-BuNC)3. The remarkably facile thermal decomposition of this complex is proposed to involve a metal-assisted carbene addition to a coordinated isocyanide. The ketenimine complex thus formed crystallizes in space group D2h15-Pbca of the orthorhombic system, with eight molecules in a unit cell of dimensions a = 10.199 (3), b = 34.283 (9), and c = 12.662 (3) Å. The structure has been refined by least-squares techniques to a final R index of 4.1 % based on 1905 reflections above background. The coordination about the Ni atom is approximately trigonal, if the ketenimine is regarded as a monodentate ligand. The ketenimine is coordinated to the metal via the carbon-heteroatom unsaturation. The cumulene system N═C═C is severely distorted from linearity upon coordination, the bond angle around the central carbon atom being 144.2 (4)°. A comparison is made between the structural parameters of the coordinated ketenimine and those of uncomplexed ketenimines.
ASJC Scopus subject areas
- Colloid and Surface Chemistry