Computational simulation of the molecular structure and properties of heterocyclic organic compounds with possible corrosion inhibition properties

The damages by corrosion generate not only high costs for inspection, repairing and replacement, but in addition these constitute a public. risk. Thus the necessity of developing novel substances that behave like corrosion inhibitors. In general. the organic compounds have demonstrated a great effectiveness in inhibiting the watery corrosion of many metals and alloys. It has been demonstrated that the compounds that have nitrogen and sulfur in their structure provide a greater inhibition than those than only contain one of the atoms at a time. being this property attributable to its molecular structure. The objective of this work is to provide information about the electronic and molecular structure of several-heterocyclic organic compounds: 1,3,4-thiadiazole and its derivatives, with different nucleophilic and ellectrophilic alkyl substituents (R1 and R2), obtained through quantum-chemistry calculations conducted by means of the (GAUSSIAN) 03W set of programs. It is an attempt to find the correlation between the molecular structure of these compounds and their possible behavior like corrosion inhibitors. It is important to take into account the effect of films formed by products of corrosion. Thus, the incorporation of metalic atoms in the calculations provides greater information about the relation between the reactivity of compounds and the metallic surface. in addition to the formation of stable complexes. The behavior of these organic substances in the presence of several solvents, among them water, faeffitates the understanding of the processes of inhibition of the corrosion. (C) 2004 Elsevier B.V. All fights reserved.