Complexes with macrocyclic ligands, VII: Demetallation of Ni2+ macrocyclic complexes by cyanide ions

Abstract

The reaction of cyanide with Ni²⁺ macrocyclic complexes proceeds in two separated steps. In a first reaction one can observe the rapid formation of cyanide adducts with 1 :1 and in some instances 1: 2 stoichiometry, the spectra and stabilities of which are here reported. In the second step the cyanide adducts react with more CN^- to give Ni(CN)₄^2- and the free ligand. Our results indicate striking differences in rates as well as in mechanisms for the demetallation of the 12-, 13- and 14-membred macrocyclic Ni²⁺ complexes by cyanide ions.