Journal of Physical Chemistry A, Vol.118, No.34, 6749-6756, 2014
Periodic Changes in the Distribution of Species Observed in the Ni2+-Histidine Equilibrium Coupled to the BrO3--SO32- pH Oscillator
The dynamical behavior of the system comprising of the pH-dependent complex formation between histidine and Ni(II) ions coupled to the BrO3--SO32- pH oscillator was studied. The pH oscillator was demonstrated to be capable of forcing the pH-sensitive nickel ion histidine equilibrium to alternate periodically between the unreacted and the fully complexed states. The periodic interconversions gave rise to an oscillatory distribution of the species that participate in the equilibrium and resulted in oscillations in the free [Ni2+], [NiHis(+)] and [Ni(His)(2)]. The preconditions of the successful coupling of metal ion amino acid complexes to a primary pH oscillator are briefly discussed. Model calculations were performed to simulate the dynamics observed in the BrO3--SO32- -Ni2+ -His CSTR system.