Estimation of photolysis halflives of dyes in a c

Authors: Davoud Beiknejad Mohammad Javad Chaichi

Publish Date: 2014/03/24

Volume: 8, Issue: 5, Pages: 683-692

PDF Link

Abstract

In this paper the photolysis halflives of the model dyes in water solutions and under ultraviolet UV radiation were determined by using a continuousflow spectrophotometric method A quantitative structureproperty relationship QSPR study was carried out using 21 descriptors based on different chemometric tools including stepwise multiple linear regression MLR and partial least squares PLS for the prediction of the photolysis halflife t 1/2 of dyes For the selection of test set compounds a Kmeans clustering technique was used to classify the entire data set so that all clusters were properly represented in both training and test sets The QSPR results obtained with these models show that in MLRderived model photolysis halflives of dyes depended strongly on energy of the highest occupied molecular orbital E HOMO largest electron density of an atom in the molecule ED + and lipophilicity logP While in the model derived from PLS besides aforementioned E HOMO and ED + descriptors the molecular surface area S m molecular weight MW electronegativity χ energy of the second highest occupied molecular orbital E HOMO1 and dipole moment µ had dominant effects on logt1/2 values of dyes These were applicable for all classes of studied dyes including monoazo disazo oxazine sulfonephthaleins and derivatives of fluorescein The results were also assessed for their consistency with findings from other similar studies

Keywords: