Hydrazinylpyridine based highly selective optical sensor for aqueous source of carbonate ions: Electrochemical and DFT studies

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 193; pp. 330 - 337
• Main Authors: Thimaradka, Vikram, Pangannaya, Srikala, Mohan, Makesh, Trivedi, Darshak R.
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15.03.2018
• Subjects: 2-(Arylidenehydrazinyl)pyridines; Carbonate ion sensor; Colorimetric; DFT; Electrochemical study; LOD; LOD; DFT; Carbonate ion sensor; Electrochemical study; 2-(Arylidenehydrazinyl)pyridines; Colorimetric
• ISSN: 1386-1425; 1873-3557
• DOI: 10.1016/j.saa.2017.12.041

A series of new receptors PDZ1–3 based on 2-(arylidenehydrazinyl)pyridines have been designed and synthesized for the detection of biologically and environmentally important ions. The colorimetric detection of CO32− using neutral organic receptor PDZ-1 has been achieved with characteristic visual colour change from yellow to green accompanied by a large redshift of 215nm in absorption maxima. UV–Vis spectroscopic and cyclic voltammetric studies reveal the stoichiometry of binding and electrochemistry of host-guest complex formation. The binding constant was found to be 0.77×104M−2. In addition, electrochemical studies provide an insight into the stability of the complex. DFT studies performed on the PDZ-1 and PDZ-1−CO32− complex reveal the binding mechanism involved in the anion detection process. PDZ-1 is highly selective for carbonate and does not show any colorimetric response towards any other anions or cations, while PDZ-2 and PDZ-3 remain inactive in the ion detection process. The limit of detection (LOD) and limit of quantification (LOQ) of PDZ-1 for carbonate was found to be 0.11mM and 0.36mM respectively. Considerable binding constant and limit of detection make PDZ-1 to be used as a real time sensor for the detection of carbonate in environmental and biological samples. [Display omitted] •2-(arylidenehydrazinyl)pyridines were synthesized by varying the substituents on the aromatic ring.•Effect of substituents on molecular recognition has been visualized.•PDZ-1 is the first ever selective probe towards aqueous source of CO32− ions•Limit of detection was as low as 0.11 mM.•The receptor PDZ-1 was able to differentiate CO32− ions from HCO3− ions.