Simple admixture of 4-nitrobenzaldehyde and 2,4-dimethylpyrrole for efficient colorimetric sensing of copper(II) ions

Karnan Rajaswathi; Muruganandam Jayanthi; Rajamani Rajmohan; Veerappan Anbazhagan; Pothiappan Vairaprakash

doi:10.1016/j.saa.2019.01.014

Simple admixture of 4-nitrobenzaldehyde and 2,4-dimethylpyrrole for efficient colorimetric sensing of copper(II) ions

Spectrochim Acta A Mol Biomol Spectrosc. 2019 Apr 5:212:308-314. doi: 10.1016/j.saa.2019.01.014. Epub 2019 Jan 14.

Authors

Karnan Rajaswathi¹, Muruganandam Jayanthi¹, Rajamani Rajmohan¹, Veerappan Anbazhagan², Pothiappan Vairaprakash³

Affiliations

¹ Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, Tamil Nadu, India.
² Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, Tamil Nadu, India. Electronic address: [email protected].
³ Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, Tamil Nadu, India. Electronic address: [email protected].

PMID: 30677599
DOI: 10.1016/j.saa.2019.01.014

Abstract

An easily accessible chemo-probe based on physical mixture of 2,4-dimethylpyrrole and 4-nitrobenzaldehyde has been developed. Based on NMR spectroscopic analysis, catalyst free formation of dipyrromethane was observed in the physical mixture of chemo-probe. The probe is utilized in effective colorimetric sensing of copper(II) ions present in environmental solutions by instantaneous appearance of red colour, even in the co-existence of various metal ions. The lowest detection limit of 2.51 μM for this chemo-probe towards copper(II) sensing is significantly lower than the WHO prescribed level (<30 μM of copper(II) ions) in potable water. The sensing mechanism is explained via rapid formation of bis(dipyrrinato)copper(II) complex, as confirmed by Jobs plot, UV-Vis spectroscopy and IR spectroscopy.

Keywords: Bis(dipyrrinato)copper; Chemo-probe; Copper(II) sensor; Naked-eye detection.