Because anions play significant roles in life processes and in the environment, the development of new anion receptors is of great interest and significance in host-guest chemistry. [1][2][3][4][5][6][7][8][9][10][11] In an effort to develop selective host molecules for applicationsoriented studies of key anionic environmental pollutants, we have recently turned our focus to amide-based receptors. [12][13][14] In this communication we report the synthesis of a new mixed amide/ amine macrocycle L 1 and promising results from initial binding studies, which indicate extremely high affinities for sulfate and phosphate. For sulfate, crystallographic findings indicate a new type of sandwich complex, in which just one sulfate ion is held between two neutral macrocycles by hydrogen bonds to eight amides.

A new class of tetraamide macrocyclic receptors for anions with two quaternized amine functionalities exhibited higher affinities for anions compared with the corresponding neutral amides. In two crystal structures of halide complexes of the prototypes with phenyl and pyridine spacers, the anions are held by hydrogen bonding with the amide hydrogens. The pyridine analogues display higher affinities in general than the phenyl systems, a phenomenon which is attributed to the anion version of the chelate effect.

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Turbidity imparts a great problem in water treatment. Moringa oleifera, Cicer arietinum, and Dolichos lablab were used as locally available natural coagulants in this study to reduce turbidity of synthetic water. The tests were carried out, using artificial turbid water with conventional jar test apparatus. Optimum mixing intensity and duration were determined. After dosing water-soluble extracts of Moringa oleifera, Cicer arietinum, and Dolichos lablab reduced turbidity to 5.9, 3.9, and 11.1 nephelometric turbidity unit (NTU), respectively, from 100 NTU and 5, 3.3, and 9.5, NTU, respectively, after dosing and filtration. Natural coagulants worked better with high, turbid, water compare to medium, or low, turbid, water. Highest turbidity reduction efficiency (95.89%) was found with Cicer arietinum. About 89 to 96% total coliform reduction were also found with natural coagulant treatment of turbid water. Using locally available natural coagulants, suitable, easier, and environment friendly options for water treatment were observed.

Highlights d Elucidation of the interface of full-length STAT1 and a viral interferon antagonist d The viral protein-STAT1 interface involves multiple distinct surfaces d Ablation of the interaction requires multiple mutations at distinct sites d Loss of viral protein-STAT1 interaction attenuates a rabies virus street strain

Two fluoride ions in a single azacryptand: The two fluoride ions are bridged by a water molecule (see structure) to give an anion‐based cascade complex, which mimics the analogous transition‐metal cascade complexes with these ligands.

A urea-based tripodal receptor L substituted with p-cyanophenyl groups has been studied for halide anions by 1H NMR spectroscopy, density functional theory (DFT) calculations and X-ray crystallography. The 1H NMR titration studies suggest that the receptor forms a 1:1 complex with an anion, showing the binding trend in the order of fluoride > chloride > bromide > iodide. The interaction of fluoride anion with the receptor was further confirmed by 2D NOESY and 19F NMR spectroscopy in DMSO-d6. DFT calculations indicate that the internal halide anion is held by six NH…X interactions with L, showing the highest binding energy for the fluoride complex. Structural characterization of the chloride, bromide, and silicon hexafluoride complexes of [LH+] reveals that the anion is externally located via hydrogen bonding interactions. For the bromide or chloride complex, two anions are bridged with two receptors to form a centrosymmetric dimer, while for the silicon hexafluoride complex, the anion is located within a cage formed by six ligands and two water molecules.