TY - JOUR
T1 - Significance of Hammett and Taft substituent constants on bonding potential of organic corrosion inhibitors
T2 - Tailoring of reactivity and performance
AU - Verma, Chandrabhan
AU - Alfantazi, Akram
AU - Quraishi, M. A.
AU - Rhee, Kyong Yop
N1 - Publisher Copyright:
© 2023 Elsevier B.V.
PY - 2023/11/15
Y1 - 2023/11/15
N2 - By changing the electron density at donor sites (also called adsorption or coordination sites), the substituents significantly impact the coordination proficiency of organic inhibitors. The effects of the substituents can be inductive or resonance depending on where they are located in the aromatic ring. The substituents at the p-position can produce either inductive (I–) or resonance (R–) or a combined effect of both, and the substituents at the m-position can manifest the inductive effect only. The substituents effect on the inhibition potential of aromatic and aliphatic compounds can be described with the help of Hammett (σ) and Taft (σ*) constants, respectively. The polar substituents such as –OH, –OCH3, –NH2, –NMe2, –CN, –NO2, –COOH etc. at p-position develop resonance effect. Because of the potential chelation and substituent effects of polar substituents at the o-position, the corrosion inhibition efficiency (%IE) may occasionally be improved by e-withdrawing polar substituents at the o-position. In general, e-withdrawing substituents like –NO2, –CN, –COOH, etc. have a negative effect on the %IE because of their –R-effect, but in macromolecules (polymers), they may improve %IE by making the inhibitor more soluble. The present article describes the substituents effect on organic inhibitors' coordination ability and binding potential based on the information available in the literature. In addition to the inductive and resonance effects, other factors have been explored, including steric hindrance, the molecular size effect, solubility, and chelation. This paper discusses the significance of the Hammett (σ) and Taft (σ*) constants on the %IE of organic compounds, but it is also possible to link them to their various other applications, including tribological, pollutant decontamination, medicinal, and catalytic.
AB - By changing the electron density at donor sites (also called adsorption or coordination sites), the substituents significantly impact the coordination proficiency of organic inhibitors. The effects of the substituents can be inductive or resonance depending on where they are located in the aromatic ring. The substituents at the p-position can produce either inductive (I–) or resonance (R–) or a combined effect of both, and the substituents at the m-position can manifest the inductive effect only. The substituents effect on the inhibition potential of aromatic and aliphatic compounds can be described with the help of Hammett (σ) and Taft (σ*) constants, respectively. The polar substituents such as –OH, –OCH3, –NH2, –NMe2, –CN, –NO2, –COOH etc. at p-position develop resonance effect. Because of the potential chelation and substituent effects of polar substituents at the o-position, the corrosion inhibition efficiency (%IE) may occasionally be improved by e-withdrawing polar substituents at the o-position. In general, e-withdrawing substituents like –NO2, –CN, –COOH, etc. have a negative effect on the %IE because of their –R-effect, but in macromolecules (polymers), they may improve %IE by making the inhibitor more soluble. The present article describes the substituents effect on organic inhibitors' coordination ability and binding potential based on the information available in the literature. In addition to the inductive and resonance effects, other factors have been explored, including steric hindrance, the molecular size effect, solubility, and chelation. This paper discusses the significance of the Hammett (σ) and Taft (σ*) constants on the %IE of organic compounds, but it is also possible to link them to their various other applications, including tribological, pollutant decontamination, medicinal, and catalytic.
KW - Chelation
KW - Coordination bonding
KW - Corrosion inhibition
KW - Hammett constant
KW - Inductive/Resonance effect
KW - Taft constant
UR - http://www.scopus.com/inward/record.url?scp=85168456160&partnerID=8YFLogxK
U2 - 10.1016/j.ccr.2023.215385
DO - 10.1016/j.ccr.2023.215385
M3 - Review article
AN - SCOPUS:85168456160
SN - 0010-8545
VL - 495
JO - Coordination Chemistry Reviews
JF - Coordination Chemistry Reviews
M1 - 215385
ER -