Organic phase cyclopentadienylnickelthiolate sensor system for
electrochemical determination of sulfur dioxide
Morrin, AoifeORCID: 0000-0002-3031-4794, Moutloali, Richard M., Killard, Anthony J.ORCID: 0000-0001-6953-3655, Smyth, Malcolm R., Darkwa, James and Iwuoha, Emmanuel I.
(2004)
Organic phase cyclopentadienylnickelthiolate sensor system for
electrochemical determination of sulfur dioxide.
Electronanalysis, 16
(23).
pp. 1944-1948.
ISSN 1040-0397
A series of cyclopentadienylnickelthiolate complexes, [Ni(PBu3)(h
5
-C5H5)(SC6H4X-4)] (X
¼
F, Cl, Br, NH2), were
shown to express stable reversible electrochemical properties even after formation of SO2 adducts in organic phase
consisting of argon purged CH2Cl2/0.1 M [n-Bu4N][BF4]. The formal potentials (E8’) values of the compounds ranged
from 265 to 431 mV/Ag-AgCl depending on the para substituent of the benzene thiolate ligand. Electrochemical, UVvis
and
1
H NMR spectroscopic analyses show that the formation of SO2 adducts causes the perturbation of the
electronic density of the nickel metal center, indicated by shifts in the E8’ values of the Ni
II/III
redox couple that is
dependent on SO2 concentration. The detection limits of the resulting organic phase electrochemical gas sensor
system was as low as 0.56 ppm SO2 for the fluoro complex, while the linear range was as high as 700 – 2000 ppm SO2
for the amino complex.