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Modern-day environmental pollution does not end with only air pollution by harmful gases. Issues also arise due to dust particles released by industry and motor vehicles. Regular use of herbicides, fungicides, and pesticides to increase the production of foodstuffs in agricultural fields also enhances the risk of soil and aquatic environmental pollution. Therefore, the systematic development of multi-functional materials for the catalytic conversion of toxic gases and hydrocarbons into value-added products under mild conditions, selective detection, and quantification of toxic organic pollutants in environmental water bodies are crucial to maintaining a sustainable environment. Herein, we have strategically engineered a highly robust, fluorine-rich, Zr(IV)–organic framework (1) and, desolvated (1′) to address three emerging environmental issues. This is the first recyclable metal–organic framework (MOF) catalyst (1′) where the Lewis basic nature of fluorine atoms and the Lewis acidic nature of the Zr(IV) sites are utilized for the mild pressure, solvent-free entrapping of CO2 to epoxides with various kinetic dimensions in high yields. The hydrophobic cavity of 1′ also facilitated better conversions of hydrocarbons into their respective alcohols/ketones compared to non-hydrophobic MOF under aerobic oxidation conditions with recyclability. Notably, for the first time, selective, rapid (response time <5 s) and nanomolar (LOD = 1.1 nM) fluorescence-based detection of aclonifen (ACF) herbicide was performed using 1′ in various environmental water samples, at different pH conditions, and also in variety of food and vegetable extracts. Moreover, a reusable 1′@starch@cotton composite was fabricated for the on-site, naked-eye detection of ACF under UV light. Additionally, a detailed investigation of the mechanistic pathways of all the proposed applications was performed experimentally and theoretically. [ABSTRACT FROM AUTHOR]

We report the solvothermal synthesis of a dansyl anchored hafnium based fluorescent metal–organic framework (MOF) having the formula [Hf6O4(OH)4(L)6]·H2O·6DMF (H2L = 2-((5-(dimethylamino)naphthalene)-1-sulfonamido)terephthalic acid). The synthesized material showed high fluorescence emission properties as well as high thermal (stable up to 330 °C) and chemical stability. It also exhibited a wide range of pH tolerance as well as a high BET surface area of 703 m2 g−1. The activated MOF showed ultra-fast (detection time < 10 s) and ultra-sensitive sensing properties towards Cu(II) and the biologically important biomarker 3-nitrotyrosine (3-NTyr) in a HEPES medium at a physiological pH of 7.4. Along with high selectivity, very low detection limits of 229 nM and 539 nM were obtained for Cu(II) and 3-NTyr respectively. Furthermore, this probe was utilised for the detection and quantification of Cu(II) and 3-NTyr in biosamples (urine and serum) with very low RSD values (2.3–4.8%). Additionally, this probe was employed to detect the presence of Cu(II) as a pollutant in various environmental water samples. Furthermore, for rapid economic detection of Cu(II), a MOF coated fluorescent paper strip was demonstrated. Thorough mechanistic investigations displayed that a complexometric interaction between Cu(II) and the probe is the main reason for the quenching of fluorescence intensity. This proposed mechanism was well supported by experimental evidence. On the other hand, the FRET mechanism is proposed based on the experimental observations for dynamic quenching of the fluorescence intensity of the probe in the presence of 3-NTyr. [ABSTRACT FROM AUTHOR]