Sr(II) based one-dimensional coordination polymer as an efficient optical sensor for the detection of nitroaromatic explosives in aqueous medium

Abstract

The detection of explosive materials holds significant importance due to their profound impact on various aspects such as environmental and biological systems, homeland security, and forensic investigations. Metal-organic frameworks (MOFs) and coordination polymers (CPs) have emerged as promising candidates for the selective and sensitive detection of small molecules. In this study, we synthesized a novel oxydiacetic acid functionalized strontium (II) coordination polymer, termed SDGA, using a cost-effective method known as the gel diffusion technique. The crystal structure, characterization, thermal stability, and photoluminescence properties of SDGA were thoroughly investigated by using single crystal X-ray diffraction, FTIR, UV–visible, TG/DTG, and fluorescence spectroscopy. The results revealed that SDGA crystallizes in a monoclinic crystal system with the P21/c space group. SDGA exhibits an emission peak at 340 nm under an excitation wavelength of 301 nm, attributed to the inter-ligand n-π* transition. Leveraging this photoluminescence behaviour, sensing experiments were conducted to detect nitrobenzene and p-nitrophenol within a concentration range of 0-10−20 M. The results indicate a decrease in fluorescence intensity with increasing concentrations of nitrobenzene and p-nitrophenol, indicative of a ‘turn-off’ mechanism.