We introduce bis-aryl croconamides as a new member in the family of dual hydrogen bonding anion receptors. In this study a series of croconamides are synthesised, and the selectivity for anion binding is investigated (Cl > Br > I in CHCl). The croconamides exhibit different structures in the crystal phase depending on the substituents on the aromatic rings, and furthermore, the crystal structure revealed the presence of tautomers. DFT calculations elucidated the complex structures formed upon addition of anion to the croconamides, confirming the order of association constants towards the halogen anions. The use of croconamides as organocatalysts in a proof-of-concept study is demonstrated in the formation of THP ethers. In addition to this, construction of a Hammet plot further elucidates the mechanism in action on formation of THP ethers.

Plants used to treat inflammatory ailments, pain, fever and infections in the Pamir Mountains in northeastern Afghanistan, were tested for antibacterial and COX-1 inhibitory activity. Water and ethanol extracts of 20 species were tested for antibacterial activity against two gram positive and two gram negative bacteria. The ethanol extract of Arnebia guttata inhibited Staphylococcus aureus with a MIC of 6 µg/mL. Water and ethanol extracts of Ephedra intermedia and the ethanol extracts of Lagochilus cabulicus and Peganum harmala inhibited Staphylococcus aureus at 0.5 mg/mL,and the P. harmala extract further inhibited the growth of Bacillus subtilis and E. coli, also with MICs of 0.5 mg/mL. Ethanol extracts of Artemisia persica (IC50: 0.5 µg/mL), Dragocephalum paulsenii (IC50: 0.5 µg/mL), Ephedra intermedia (IC50: 3.8 µg/mL), Hyoscyamus pusillus, Nepeta parmiriensis (IC50: 0.7 µg/mL) and Rumex patientia subsp. pamiricus (IC50: 3.5 µg/mL) exhibited COX-1 inhibitory activity. The observed in vitro activities support the use of some of the plant species in the traditional medicine systems of the Pamir Mountains.

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Dynamic combinatorial libraries that equilibrate under thermodynamic control and can be trapped kinetically when desired are key to creating complex systems that can mimic dynamic biological systems, such as the biochemical system of life. A much-sought-after feature is the ability to turn off the dynamic exchange of the system, in order to investigate a transient state away from thermodynamic equilibrium, and then turn on the dynamic exchange again. We describe here the first use of thiosemicarbazone exchange to form dynamic combinatorial libraries. The libraries were found to require a nucleophilic catalyst, or equilibrator, in order to reach thermodynamic equilibrium. This equilibrator approach adds a supramolecular level of control over the dynamic system and allows the dynamic exchange to be turned off by addition of 18-crown-6, which binds the equilibrator in a nonnucleophilic complex. The dynamic exchange can be restarted by addition of potassium ions that competitively bind 18-crown-6, thus liberating the equilibrator. The highly complex thiosemicarbazone-based macrocyclic libraries contain both [2]catenanes and sequence isomers, which can be distinguished by HPLC-MS/MS.

Transmission laser welding of plastic is typically achieved by incorporating a laser absorbing dye into one of the two pieces of plastic one wishes to weld together and mediating the welding process using a laser emitting light at a suitable wavelength. Desirable properties of laser absorbing dyes include: (1) the dye is colorless in the visible region but absorbs strongly in the region at the wavelength where the laser emits, (2) the dye has a good conversion of the energy from the laser to heat, (3) the dye is stable enough to be incorporated into the molten plastic, (4) the dye is soluble in the plastic of choice to give an even distribution in the plastic, and (5) the dye is nontoxic. Here, we explore an alternative approach to achieve laser welding of colorless plastics using a laser dye that is colored, but that can be bleached after the welding process. Nonsymmetrical squaraine dyes were prepared by condensation of squaric acid and two equivalents of various 3,5‐dimethoxy‐N,N‐dialkylanilines. After the incorporation into polyethylene and laser welding, the plastic was bleached either by heat treatment or by irradiation with a high pressure Xe‐lamp giving colorless polyethylene. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2245–2254