Metal-Promoted Reactivity of Cyanogen toward Compounds Containing Active Hydrogens on Carbon. 1. Reaction of Cyanogen with Bis (2,4-pentanedionato) nickel (II)

The reaction of cyanogen with bis (2,4-pentanedionato) nickel (II), [Ni(acac)2], in CH2C12 at room temperature leads to a complex of formula [Ni(acac)2(C2N2)2] which, upon recrystallization, gives a square-planar monomeric complex containing the anion derived from the deprotonation of 2-(l-iminoethyl)acetoacetyl cyanide. Spectroscopic data and structural parameters derived from single-crystal X-ray analysis are reported. The reaction product before recrystallization is proposed to be bis (3-(cyanoiminomethyl)-2,4-pentanedionato) nickel (II), resulting from cyanogen insertion into the C-H methino bonds of the coordinated acac-ligands. Finally to support the idea of the rearrangement from bis(3-(cyanoiminomethyl)-2,4-pentanedionato) nickel (II) to bis[2-(l-iminoethyl)-l-cyano-l,3-butanedionato] nickel (II), we have obtained the first of these two species in alkaline medium from NiCl2 and 3-(cyanoiminomethyl)-2,4-pentanedione. This ligand precursor has been characterized by us by IR, UV, and NMR techniques. © 1979, American Chemical Society. All rights reserved.