Fluorescence Quenching and the Chamber of Nitroaromatics: A Dinaphthoylated Oxacalix[4]arene’s(DNOC) Adventure Captured through Computational and Experimental Study

Abstract

This research introduces Dinaphthoylated Oxacalix[4]arene (DNOC) as a novel fluorescent receptor for selective detection of nitroaromatic compounds (NACs). DNOC was characterized using 1H-NMR, 13C-NMR, and ESI-MS spectroscopic techniques. The receptor exhibited remarkable selectivity in acetonitrile towards various nitroaromatic analytes, including MNA; 2,4-DNT; 2,3-DNT; 1,3-DNB; 2,6-DNT and 4-NT as confirmed through emission spectra analysis. Investigation of binding constants, Stern-volmer analysis, lowest of detection limit (3σ/Slope) and fluorescence quenching sheds light on DNOC's inclusion behaviour. Additionally, Density Functional Theory (DFT) calculations using Gaussian 09 program elucidate the selectivity trend of the ligand DNOC for NAC detection. Analysing energy gaps between molecular orbitals (HOMO and LUMO) offers insights into electron-transfer mechanisms and electronic interactions. Smaller energy gaps indicate higher selectivity through favourable electron-transfer processes, while larger gaps imply reduced selectivity due to weaker electronic interactions. This interdisciplinary study combines experimental and computational approaches to comprehensively understand DNOC's selective binding behaviour, rendering it a promising chemical sensor for nitroaromatic explosives.