Y-shaped ferrocene/non-ferrocene conjugated quinoxalines for colorimetric and fluorimetric detection of picric acid

Ayilam Viswanathan Rajalakshmi; Nallasamy Palanisami

doi:10.1016/j.saa.2019.117812

Y-shaped ferrocene/non-ferrocene conjugated quinoxalines for colorimetric and fluorimetric detection of picric acid

Spectrochim Acta A Mol Biomol Spectrosc. 2020 Mar 5:228:117812. doi: 10.1016/j.saa.2019.117812. Epub 2019 Nov 19.

Authors

Ayilam Viswanathan Rajalakshmi¹, Nallasamy Palanisami²

Affiliations

¹ Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore, 632014, Tamil Nadu, India.
² Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore, 632014, Tamil Nadu, India. Electronic address: palanisami.n@gmail.com.

PMID: 31787532
DOI: 10.1016/j.saa.2019.117812

Abstract

New Y-shaped ferrocene and non-ferrocene conjugated quinoxaline derivatives {[R-(CH)₂-N=CH-)₂C₁₀H₄], R = C₅H₅-Fe-C₅H₅ (1) and R = C₆H₄-OCH₃ (2)} have been synthesized and characterized using analytical and spectroscopic techniques. The thermal stability of the compounds 1 and 2 were examined by thermogravimetric analysis (TGA), both were stable up to 250 °C. The optical properties were studied using UV-Visible and fluorescence spectroscopic methods and Y-shaped ferrocene appended quinoxaline derivative 1 show a weak emission due to the quenching nature of ferrocene. The compound 2 shows enhanced fluorescence intensity in their aggregation state due to Restricted Intramolecular Rotation (RIR). Hence, the compound 2 have further utilized for the detection of picric acid (PA) by fluorimetric method and the detection limit of 1.37 × 10^-6 M was obtained. Further, paper sensor was made using compound 2 which resulted in the instant 'naked eye' response for trace detection of picric acid. Consequently, the compound 2 acts as a colorimetric sensor and can be used as a new probe for the detection of nitro aromatic explosives.

Keywords: AIE; Ferrocene/non-ferrocene; Picric acid sensing; Quinoxaline.