Modeling of the Co-Mn-Br catalyzed liquid phase oxidation of p-xylene to terephthalic acid and m-xylene to isophthalic acid

Simultaneous spectrophotometric determination of Co (II) and Co (III) in acidic medium with partial least squares regression and artificial neural networks

This study aims at the application of two chemometric techniques to visible spectra of acetic acid solutions of Co (II) and Co (III) for simultaneous determination thereof. Spectral data of 145 samples in the range of 400-700 nm were used to build the models. Partial least squares regression models were developed for which latent variables were determined using internal cross-validation with a leave-one-out strategy and 3 and 2 latent variables were selected for Co(II) and Co(III) based on root mean square error of cross-validation. For these models, root mean square errors of prediction were 1.16 and 0.536 mM and coefficients of determination were 0.975 and 0.892 for Co (II) and Co (III). As an alternate method, artificial neural networks consisting of three layers, with 10 neurons in hidden layer, were trained to model spectra and concentrations of cobalt species. Levenberg-Marquardt algorithm with feed-forward back-propagation learning resulted root mean square errors of prediction of 0.316 and 0.346 mM for Co (II) and Co (III) respectively and coefficients of determination were 0.996 and 0.988.

Chromogenic detection of xylene isomers and luminogenic chemosensing of o-xylene employing a new macrocyclic cobalt complex: synthesis, and X-ray crystallographic, spectroscopic and computational studies

A new binuclear Co(ii) complex, coordinating via two pyridine side-arms linked to two dinaphtho-diazacrown ether macrocyclic ligands, was synthesized and used as a colourimetric and fluorogenic sensor as well as an oxidation catalyst of xylene isomers at room temperature.