A new chemical oscillator: Belousov-Zhabotinskii-type reaction catalyzed by a macrocyclic nickel(II) complex

A new B-Z oscillator, the NaBTO3-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 oscill- ating 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.