A new Co(III) complex of Schiff base derivative for electrochemical recognition of nitrite anion

Abstract

The synthesis and characterization of a new Co(III) complex of a salphen-type Schiff base ligand, (E)-2-{[(2-aminopyridin-3-yl)imino]methyl}-4,6-di-tert-butylphenol (HL), are reported. The characterization has been carried out using X-ray single crystallographic, thermogravimetric, and spectroscopic techniques. The complex has been combined with polyvinyl chloride (PVC) membrane of various compositions and tested as an electrochemical electrode towards recognition of several anions. The electrode exhibits exceptional electrochemical recognition for the nitrite $$(\hbox {NO}_{2}^{-})$$ anion in aqueous media. The electrode exhibited a linear response to $$\hbox {NO}_{2}^{-}$$ with a detection limit of $$5.76\,{\upmu }\hbox {M}$$ and displayed a linear Nernstian slope over the nitrite concentration range of $$1.0 \times 10^{-5}$$ – $$1.0\times 10^{-1}\,\hbox {M}$$ in the pH range of 3–7 and a fast response time of less than 10 seconds. Theoretical calculations showed that the sensing could be via anion exchange in the Co(III) complex. SYNOPSIS An octahedral Co(III) complex of the salphen-type Schiff base, (E)-2-{[(2-aminopyridin-3-yl)imino]methyl}-4,6-di-tert-butylphenol, was synthesized, characterized and analyzed for its electrochemical anion recognition property through reversible anion exchange mechanism.