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Elucidating the Mode of Action of a Corrosion Inhibitor for Iron
Author(s) -
Frey Marcus,
Harris Steven G.,
Holmes Jeremy M.,
Nation David A.,
Parsons Simon,
Tasker Peter A.,
Winpenny Richard E. P.
Publication year - 2000
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/(sici)1521-3765(20000417)6:8<1407::aid-chem1407>3.0.co;2-k
Subject(s) - carboxylate , hydrogen bond , chemistry , adsorption , oxide , corrosion inhibitor , iron oxide , corrosion , carboxylic acid , crystal structure , inorganic chemistry , crystallography , stereochemistry , molecule , polymer chemistry , organic chemistry
Two polymetallic iron( III ) complexes 1 and 2 have been synthesised from the known corrosion inhibitor 3‐(4‐methylbenzoyl)‐propionic acid HL 1 and their crystal structures determined. Coordination geometries extracted from these structures have been used as the basis for molecular modelling onto idealised iron( III ) oxide surfaces as an aid to understanding the efficacy of inhibitors of the 4‐keto acid type. The proposed mode of action involves 1,3‐bridging didentate coordination of the carboxylate function of L 1 to two Fe III ions, hydrogen‐bond formation between the 4‐keto group of L 1 and a bridging surface hydroxy group, as well as close packing of the aromatic end groups, which should generate a hydrophobic barrier on the surface. Adsorption isotherm experiments have been used to compare the strengths of binding of related carboxylic acids onto iron( III ) oxide surfaces and indicate that the presence of the 4‐keto function leads to the formation of significantly more stable surface complexes.