Quantum Chemistry Studies on Mechanism of Corrosion Inhibition for Amido Phosphonic Acids

The structure and activity relationships(SAR) of amido phosphonic acids were studied systemically by using Density Functional Theory(DFT) method at B3LYP/6-31G* level.Results of quantum chemical calculations indicated that the orbital energies and the electrophilic fukui indices of the benzene of the six compounds have great relationships with the corrosion efficiency,The abilities of incepting electron of the benzene ring in amido phosphonic acids have great relationship of the corrosion inhibition efficiency.The inhibition efficiency of the six compounds is due to the π bond formed by the benzene and the metal.