A selective turn-on fluorescent chemosensor 1,1-diaminoazine for azinphos-methyl

Financiaciado para publicación en acceso aberto: Universidade de Vigo/CISUGDetection of organophosphorus pesticides (OPPs) is an important challenge in environmental chemistry, because their exposure to humans can cause severe health problems. In the current study, organic nanoparticles of (E)-(4-chlorophenyl)-1,1-diamino-2,3-diazabutadiene were developed using eco-friendly approach which was found to be in the range of 15–20 nm. These synthesized species exhibited both U.V. Visible and “turn-on” fluorescence responses in aqueous media for the selective detection of the extremely hazardous pesticide azinphos-methyl. These organic nanoparticles also exhibit a good linear relationship in the range of 1–100 μM and the limit of detection (LOD) is 7.4 µM. The selective fluorescence response was also observed in RO water, tap water and orange juice. The FT-IR and DFT studies helped in identifying the specific H-bonding interactions responsible for the selective detection of Azinphos-methylDepartment of Science and Technology, New-Delhi, India | Ref. SP/YO/2021/231

Keto - enol, imine - enamine, and nitro - aci-nitro tautomerism and their interrelationship in substituted nitroethylenes. Keto, imine, nitro, and vinyl substituent effects, and the importance of H-bonding

Tautomeric isomers and conformers of 2-nitrovinyl alcohol (1), 2-nitrovinylamine (2), and 1-nitropropene (3) are reported at the MP2 and B3LYP levels of theory, using the 6-31G* basis set, with energy evaluation at B3LYP/6-311+G** and G2MP2. The nitroalkenes are the global minima on their respective potential energy surfaces. The barriers for the concerted 1,5-H transfer to the corresponding nitronic acids amount to only 5.0 kcal/mol for 1, 13.2 kcal/mol for 2, and a sizable 37.8 kcal/mol for 3. Whereas the aci-nitro tautomer of 2-nitrovinyl alcohol is easily accessible, β-iminonitronic acid has little kinetic stability. H-bonding is a strong stabilizing factor in these nitroalkenes, estimated at 7.0 and 3.7 kcal/mol for the OH and N