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Byrd Dawson posted an update 6 months, 4 weeks ago
While β,γ-unsaturated carbonyl compounds have been widely used as γC- or αC-nucleophiles, their potential αC,αC-bisnucleophilic reactivity is still underdeveloped. Herein, a phosphine-catalysed (4+1) annulation of β’-acetoxy allenoate and a β,γ-unsaturated carbonyl compound is reported, wherein β’-acetoxy allenoate is the 1,4-biselectrophilic component while the β,γ-unsaturated carbonyl compound serves as an αC,αC-bisnucleophile. The process not only provides a new reaction mode of β,γ-unsaturated carbonyl compounds under mild conditions but also broadens the scope of Lewis base-catalysed annulation of acetoxy allenoate.Microplastics from the North Atlantic Gyre deposited on Guadeloupe beaches were sampled and characterized. A new method is developed to identify which elements were present as additives in these microplastics. The method used both acidic leaching and acidic digestion. Several elements (Al, Zn, Ba, Cu, Pb, Cd, Mn, Cr) were identified as pigments. Furthermore, some elements used as additives to plastics (especially the non-essential elements) seem to contribute to most of the acidic leaching, suggesting that these additives can leach and adsorb onto the surface microplastics, becoming bioavailable. Based on the acidic leaching element content, only Cd should represent a danger for fish when ingested. However, further studies are needed to determine the potential synergetic effect on health caused by the ingestion of several elements and microplastics.Three novel cicada-like nickel(ii) clusters, formulated as ·4MeCN (SD/Ni6b), ·MeOH (SD/Ni5a) and ·2NO3·2MeCN (SD/Ni4a), were obtained by tuning the auxiliary carboxylic acids, where H2bdped = 1,2-bis-(3,5-dimethylpyrazol-1-yl)-ethane-1,2-diol; Hmba = 2-methylbenzoic acid; Hdmpz = 3,5-dimethyl-1H-pyrazole; Htca = 3-thiophenecarboxylic acid; and Hba = benzoic acid. The structures of SD/Ni6b, SD/Ni5a and SD/Ni4a are built from a central Ni4O4 opened cube, appending two to zero NiNO5 octahedra. The solution behaviours of SD/Ni6b, SD/Ni5a and SD/Ni4a were studied in detail via an ESI-MS technique and their solution stabilities were confirmed. ML349 clinical trial Magnetic analysis indicated the presence of Ising-type anisotropy D = -13, -10, and -11 cm-1 for SD/Ni6b, SD/Ni5a, and SD/Ni4a, respectively; moreover, dominantly ferromagnetic interactions were found between magnetic centers J1 = 6.5 cm-1, J2 = -0.44 cm-1 and J1 = 5.9 cm-1, J2 = 2.6 cm-1 for SD/Ni5a and SD/Ni4a, respectively. Besides, the photocurrent signals were observed and they reached the maximum very quickly for these three nickel(ii) clusters and then their current intensities remained almost constant, which provide a possibility to be used for light-harvesting and photo-related catalysis.The design and synthesis of efficient sensor materials with fast-responsive and ultrasensitive detection ability is critical to monitor ecological safety, supervise human health, control industrial wastes, and govern food quality among others. Metal-organic frameworks (MOFs) or coordination polymers (CPs) are a new class of porous crystalline materials that have emerged in several potential applications in last two decades. In particular, applications of MOFs as sensory scaffolds for the detection of hazardous pollutants have attracted researchers due to their fabulous structural characteristics and wide range of pore environment tunability. Among several transducer procedures, the luminescence detection of a particular analyte is immensely desirable as it is easy to handle and cost effective, where visual changes in physicochemical attributes can be comprehended via a quick naked eye detection. The porous nature of MOFs facilitates the pre-concentration of target analytes within the pore structure and provides superior host-guest interaction with good detection limits when compared to conventional materials. To this end, guest-induced fluorescence switching in sensory MOFs with good recyclability and unique detectable fingerprints are of particular importance to benefit futuristic monitoring aptitudes and promises environmental remediation. In this review, we present the latest literature based on the analyte-responsive modulation of fluorescence intensity in MOFs towards the detection of target pollutants and discuss the underlying sensing mechanism, which can assist in developing new useful nano-scale devices and sensors.Probing the rotational and translational diffusion and colloidal stability of nanorods is of significant fundamental interest with implications for many different applications. Recently R. Nixon-Luke and G. Bryant presented a method to analyze angle-dependent depolarized dynamic light scattering data allowing for the clear separation of the translational and rotational diffusion coefficients of gold nanorods in dilute suspension (R. Nixon-Luke and G. Bryant, Part. Part. Syst. Charact., 2018, 36, 1800388). In the present work we applied this analysis to gold nanorods decorated with high molecular weight, thermoresponsive poly-N-isopropylacrylamide ligands, which results in particles with lower effective aspect ratios. The temperature response of the ligand shell is studied. We precisely determine the translational and rotational diffusion coefficients over a broad range of temperatures and the results are compared to theoretical predictions. The results show that as temperature increases the ligands collapse, and the effective aspect ratio increases as the particle shape transitions from prolate spheroid at low temperatures to more cylindrical at high temperatures.We report the first ESIPT-based probe ABTB, for the highly sensitive and selective imaging of formaldehyde (FA). The various theoretical calculations have been systematically performed, and clearly unravel the lighting mechanism of the fluorescent probe for FA. Additionally, the probe was successfully applied in monitoring endogenous FA in the brain of AD mice.A novel mitochondria-targeting molecular rotator FD was designed to visualize changes in viscosity under hypoxic conditions in vitro and in vivo. Importantly, FD can be used to detect changes in the blood viscosity of liver cancer and liver cirrhosis patients, and also rehabilitation of liver disease.