Acylthiourea ligands have applications in both synthetic and applied chemistry. The skeleton of the ligand contains several heteroatoms which offer variable coordination modes in their complexes. Herein, we report one such erratic behavior of these types of complexes upon crystallization. Six Ru­(II)–benzene complexes (B1–B6) containing the acylthiourea ligand were synthesized and adequately characterized using analytical and spectroscopic techniques. In contrast to the spectroscopic data confirming the monodentate coordination of the ligands to the Ru­(II) ion, the bidentate version in the crystal structure of their Ru­(II)–benzene complexes was observed. To the best of our knowledge, this is the only report as of now on N,S-coordinated acylthiourea ligands forming a four-membered ring in Ru­(II)–benzene complexes, while the same ligands in the Ru­(II)–p-cymene system showed a monodentate coordination. The complexes (B1–B6) exhibited good anticancer potential in A549, overcame cisplatin resistance in cisRA549, but unfortunately exhibited toxicity toward normal human umbilical vein endothelial cell lines. An increase in chain length at the C-terminal and the conjugation at the N-terminal of the acylthiourea ligands seemed to improve the cytotoxic profile of the complexes. 5-Ethynyl-2′-deoxyuridine staining helped to visualize the interruption of DNA synthesis by the active complexes B4 and B5, which was further authenticated using flow cytometry, wherein the complexes arrested the cell cycle in the S phase. The latter also proved the apoptosis mode of cell death induced by the active complexes, and the morphological changes due to apoptosis were visualized using acridine orange/ethidium bromide staining.

Selective and sensitive detection of highly toxic chemicals by a suitable, fast, inexpensive, and trustworthy method is vital due to its serious health threats to humankind and breach of public security caused by unexpected terrorist attacks and industrial accidents. Phosgene or carbonyl dichloride is widely employed in many chemical industries and pharmaceuticals, and in pesticide production, which is extremely toxic by severe (short-term) inhalation exposure. Because of the non-existence of a phosgene sensor in aqueous solution and the immense emphasis gained by nanomaterials, especially carbonaceous materials, augmented attention has been given to the development of a fluorophore-functionalized carbon-based method to detect this noxious substance. In this study, surfactant free 1,8-diaminonaphthalene (DAN)-functionalized graphene quantum dots (DAN-GQDs) were prepared to detect phosgene in aqueous solution. The FESEM (field emission scanning electron microscopy) and HRTEM (high-resolution transmission electron microscopy) analyses confirm the as-prepared DAN-GQD morphology as nanobuds (NBs) with an average diameter of ca. 35–40 nm. The crystalline nature, elemental composition, and chemical state of DAN-GQDs were analyzed by standard physiochemical techniques. The edge-termination at the carboxyl functional group of GQDs with DAN was examined by XPS, Raman, FT-IR, and 1H NMR spectroscopy analyses. The aqueous solution of DAN-GQDs (4.89 × 10–9 M) exhibits a strong emission peak at 423 nm upon excitation at 328 nm. The addition of the phosgene molecule (0 → 88 μL) quenches the initial fluorescence intensity of DAN-GQDs (ΦF 53.6 → 34.6%) through the formation of a stable six-membered cyclized product. The DAN-GQDs displayed excellent selectivity and sensitivity for phosgene (K a = 3.84 × 102 M–1 and LoD (limit of detection) = 2.26 ppb) over other competing toxic pollutants in water. The time-resolved fluorescence analysis confirms that the quenching of DAN-GQDs follows nonradiative relaxation of excited electrons. Furthermore, bioimaging experiments of phosgene in living human breast cancer (HeLa) cells and cell viability test successfully demonstrated the practicability of DAN-GQDs.

Diuron is a herbicide that has been classified as an environmental pollutant because of its harmful effects on living beings and environment. In the present work, the OH-initiated oxidation reaction of diuron is investigated by performing electronic structure calculations based on density functional theory (DFT) methods, M06-2X, ωB97X-D, and MPWB1K using the 6-31G(d,p) basis set. The CBS-QB3 method is used to validate the results obtained from the DFT methods. All possible initial hydrogen and chlorine atom abstraction reaction pathways involved in the oxidation of diuron were studied, and the favorable reaction pathways were found by analyzing the potential energy surface and thermochemistry of the reactions. The results obtained from the present work show that hydrogen atom abstraction from methyl and amine groups of diuron are energetically favorable, which leads to the formation of diuron radical intermediate and water molecule. The rate constant is calculated for most favorable reaction pathways by using canonical variation transition state theory (CVT) with small curvature tunnelling (SCT) correction over the temperature range 298−1000 K. The atmospheric lifetime of diuron is found to be around 15 days. The subsequent reaction of most favorable diuron radical intermediate with other atmospheric reactive species, such as O 2 , H 2 O, HO 2 , and NO x (x = 1, 2) radicals are studied. The time-dependent DFT calculation is performed to study the photolysis of diuron and favorable diuron radical intermediates. This study provides thermochemical and kinetic data for the oxidation of diuron initiated by OH radical through H atom abstraction reaction.

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The •OH-initiated reaction mechanism and kinetics of sulfoxaflor were investigated by using electronic structure calculations. The possible hydrogen atom and cyano group abstraction reaction pathways were studied, and the calculated thermochemical parameters show that the hydrogen atom abstraction from the C7 carbon atom is the more favorable reaction pathway. The subsequent reactions for the favorable intermediate (I4) with other atmospheric reactive species, such as O 2 , H 2 O, HO 2 •, and NO x • (x = 1, 2), were studied in detail. The products identified from the subsequent reactions could contribute to secondary organic aerosol (SOA) formation in the atmosphere. The intermediates and products formed from the initial and subsequent reactions are equally as toxic as the parent sulfoxaflor. At 298 K, the rate constant calculated for the formation of the favorable intermediate I4 is 2.54 × 10 −12 cm 3 molecule −1 s −1 , which shows that the lifetime of sulfoxaflor is 54 h. The excited-state calculation performed through time-dependent density functional theory shows that the photolysis of the title molecule is unlikely in the atmosphere. The global warming potentials (GWPs) for different time horizons, photochemical ozone creation potential (POCP), and ecotoxicity analysis were also studied for the insecticide sulfoxaflor.