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

• Synthesis of 1-[(5-benzyl-1,3-thiazol-2-yl)diazenyl]naphthalene-2-ol.
• Structural description and spectroscopic characterization of the new azo dye.
• Evaluation of the dissociation constant by the Yasuda–Shedlovsky method.
• Development of a method for Hg(II) determination with BnTAN.

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, 1H, 13C, COSY and HSQC NMR spectra. The pKa 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 pKa 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.

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