A DFT-Based QSAR study of the toxicity of 2-(3,4,5-trichlorophenoxy) acetic acid and 2-(2,3,4-trichlorophenoxy)acetic acid derivatives

Quantitative structure – activity relationships (QSARs), as one of the most important areas in chemometrics, QSAR models are mathematical equations relating chemical structure to their activity [1]. QSAR are attempts to correlate molecular structure, or properties derived from molecular structure with a particular kind of chemical activity [2]. All quantum-chemical calculations are carried out at DFT/B3LYP level of theory with 6-311++G* basis set quantum-chemical calculations have been applied for electronic properties and wave function computations as implemented in Gaussian 09. QSAR studies have been performed on 2-(3,4,5-trichlorophenoxy)acetic acid and 2-(2,3,4-trichlorophenoxy)acetic acid compounds. To confirm the predictive power of the models, an external set of molecules was used. High correlation between experimental and predicted activity values was observed, indicating the validation and the good quality of the derived QSAR models. We have observed a high relationship between experimental and predicted activity values, indicating the validation and the excellent quality of the derived QSAR model. The application of rules on the studied 2-(3,4,5-trichlorophenoxy)acetic acid and 2-(2,3,4-trichlorophenoxy)acetic acid derivatives shows that all descriptors have significant relationships with observed activity. We have observed a high relationship between experimental and predicted activity values, indicating the validation and the excellent quality of the derived QSAR model. This study shows that the nature of substituents has very important determining role in toxicity of these compounds.