New oscillating Briggs-Rauscher reactions catalyzed by macrocyclic nickel complexes

A number of nickel complexes with various macrocyclic ligands were studied as catalysts of the Briggs-Rauscher reaction. Various types of nonlinear behavior were discovered, and the relationships between various parameters of oscillating reactions and the initial reactant concentrations were determined. A mechanism of catalysis and criteria for the choice of a catalyst were proposed. In particular, one may choose between one-electron pairs of transition metal complexes M ox /M red with a rather broad range of redox potentials (0.7-1.7 V relative to the standard hydrogen electrode) if labile coordination sites are available, which allow the interaction of a metal ion with a substrate inside the coordination sphere.