Imidazole-Functionalized Y-Shaped Push-Pull Dye for Nerve Agent Sensing as well as a Catalyst for Their Detoxification

Dey, N and Kulhánek, J and Bureš, F and Bhattacharya, S (2021) Imidazole-Functionalized Y-Shaped Push-Pull Dye for Nerve Agent Sensing as well as a Catalyst for Their Detoxification. In: Journal of Organic Chemistry, 86 (21). pp. 14663-14671.

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Abstract

A Y-shaped push-pull dye (1) with N,N-dimethylanilino donors and a benzonitrile acceptor connected via an imidazole-based π-conjugated spacer was designed. It showed a dark yellow color in solution due to facile intramolecular charge-transfer interaction, but no fluorescence was detected, presumably due to the photo-induced electron transfer effect of the imidazole moiety. However, addition of nerve agents such as diethyl chlorophosphate (DCP, sarin mimic) and diethyl cyanophosphate (DCNP, Tabun mimic) resulted in a blue-colored fluorescence with fading of the native dark yellow color. Mechanistic studies indicated nucleophilic attack of imidazole at the phosphorus of DCP or DCNP, leading to the formation of a phosphorylated intermediate, which undergoes time-dependent hydrolysis (∼24 h) in aqueous medium. This process recovers the free probe (enzyme-like behavior) and releases a less-toxic organophosphate compound as the byproduct. The phosphorylated derivative of 1, formed during such interaction, shows a different electronic behavior, which reduces the extent of charge-transfer interaction as well as nonradiative decay and supports emissive properties. Considering the high sensitivity of 1 towards DCP and DCNP with LOD 35 and 42 ppb, we prepared easy test strips for on-site vapor-phase detection of nerve agents. © 2021 American Chemical Society.

Item Type:	Journal Article
Publication:	Journal of Organic Chemistry
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to American Chemical Society
Keywords:	Aromatic compounds; Charge transfer; Fluorescence; Phosphorylation, Benzonitriles; Dark yellow; Functionalized; Imidazol; Intramolecular charge-transfer interactions; Nerve agents; No fluorescences; Push pull; Y-shaped; ]+ catalyst, Detoxification, imidazole derivative; organophosphate, alkalinity; aqueous solution; Article; catalyst; chemical structure; controlled study; detoxification; electron transport; electrospray mass spectrometry; nucleophilicity; photon correlation spectroscopy; scanning electron microscopy; stoichiometry; time resolved fluorescence spectroscopy; ultraviolet visible spectroscopy
Department/Centre:	Division of Chemical Sciences > Organic Chemistry
Date Deposited:	25 Feb 2023 07:33
Last Modified:	25 Feb 2023 07:33
URI:	https://eprints.iisc.ac.in/id/eprint/80592

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