Synthesis of Fluorogenic Arylureas and Amides and Their Interaction with Amines: A Competition between Turn-on Fluorescence and Organic Radicals on the Way to a Smart Label for Fish Freshness

Javier García-Tojal,Mateo M Salgado,José García-Calvo,Tomás Torroba,José V Cuevas,Carla Hernando-Muñoz,Borja Díaz De Greñu,María-Josefa Rojo

doi:10.3390/molecules26051404

Javier García-Tojal, Mateo M Salgado + Show 6 more

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https://doi.org/10.3390/molecules26051404

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Journal: Molecules	Publication Date: Mar 5, 2021
Citations: 2	License type: CC BY 4.0

Affiliation: University of Burgos

Abstract

We describe the synthesis of fluorogenic arylureas and amides and their interaction with primary or secondary amines under air and light in organic-aqueous mixtures to give rise to a new class of persistent organic radicals, described on the basis of their electron paramagnetic resonance (EPR), as well as UV–vis, fluorescence, NMR, and quantum mechanics calculations, and their prospective use as multi-signal reporters in a smart label for fish freshness.

Highlights

Persistent organic radicals are of immense importance for the preparation of new hybrid materials with spin-probe and spin-label functions [1], magnetic materials [2], electrical transport [3], molecular spintronics [4], and surface-confined electroactive molecules for single-molecule switching devices [5], and they remain integral in classical areas such as catalysis for the oxidation of organic molecules [6] and DNA damage [7]
We present an unusual family of new fluorogenic aminoaryl-indane-based probes that are able to form persistent radical species in the presence of primary or secondary amines, and we describe their prospective use as multiple-signal fluorogenic reporters for the detection of volatile amines
The synthesis of arylureas used in this study was performed using an easy Suzuki reaction between 5-bromoindanone and 4-aminobenzeneboronic acid pinacol ester, followed by a Knoevenagel reaction with malononitrile and a reaction with selected mono- and Molecules 2021, 26, 1404 reaction between 5-bromoindanone and 4-aminobenzeneboronic acid pinacol ester, followed by a Knoevenagel reaction with malononitrile and a reaction with selected monoand bis-isocyanates

Summary

Introduction

Persistent organic radicals are of immense importance for the preparation of new hybrid materials with spin-probe and spin-label functions [1], magnetic materials [2], electrical transport [3], molecular spintronics [4], and surface-confined electroactive molecules for single-molecule switching devices [5], and they remain integral in classical areas such as catalysis for the oxidation of organic molecules [6] and DNA damage [7]. Persistent radical cations [8] and radical anions [9], examples of organic mixed-valence compounds [10], are important, along with their neutral organic radical parents, for the discovery of new organic materials and the development of improved devices. Amines and their derivatives are extensively used as chemicals in abuse drugs, cosmetics, polymers, etc. We present an unusual family of new fluorogenic aminoaryl-indane-based probes that are able to form persistent radical species in the presence of primary or secondary amines, and we describe their prospective use as multiple-signal fluorogenic reporters for the detection of volatile amines

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Conclusion