A New Chemical Oscillator: Belousov-Zhabotinskii-Type Reaction Catalyzed by a Macrocyclic Nickel(II) Complex

Abstract

A new B-Z oscillator, the NaBrO₃-malic acid-H₂SO₄-[NiL](ClO₄)₂ system (L = 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene), is reported. The oscillating reactions are measured by monitoring the changes of the potentials of platinum and bromide selective electrode. The experimental results indicate that the concentration of bromide ion (Br^–) can act as an on-off switch in oscillating reaction while free radicals and HbrO₂ may be involved in the reaction process. The influences of the concentration of the component in the system and temperature on the oscillations are studied. It is found that oscillation period (T_p) is dependent on the initial concentrations of malic acid or H₂SO₄ but independent of the initial concentrations of NaBrO₃.