1-[(5-Benzyl-1,3-thiazol-2-yl)diazenyl]naphthalene-2-ol: X-ray structure, spectroscopic characterization, dissociation studies and application in mercury(II) detection

A new thiazolylazo reagent, 1-[(5-benzyl-1,3-thiazol-2-yl)diazenyl]naphthalene-2-ol, has been synthesized for the first time. Single crystals of the azo dye were grown from a saturated solution by the vapour diffusion technique. The compound was analyzed using the single-crystal X-ray diffraction technique, and the chemical structure was also confirmed by ATR-IR, H-1, C-13, COSY and HSQC NMR spectra. The pK(a) dissociation constant of the substance was determined in volumes of methanol (MeOH), dioxane and acetonitrile (MeCN)] by means of the potentiometric method. The Yasuda-Shedlovsky extrapolation procedure was employed to obtain the value of pK(a) in aqueous solution. The chelate complex of the azo dye with mercury(II) was studied spectrophotometrically. A method for Hg(II) ion determination with the new reagent was elaborated and the limit of detection calculated. (C) 2016 Elsevier B.V. All rights reserved.