Novel anion recognition host molecules, tris-1,10-phenanthroline cobalt(III) and bis-2,2'-bipyridine mono-1,10-phenanthroline ruthenium(II) complexes bearing fused dipyrrolylquinoxaline moieties have been synthesized. As determined by UV-vis spectroscopic and electrochemical studies, these metal complexes bind fluoride with high affinity in polar media both in absolute terms and relative to the metal-free phenanthroline dipyrrolylquinozaline precursor from which they are derived (fluoride is bound to the tris-1,10-phenanthroline cobalt(III) dipyrrolylquinoxaline system with a 1:1 binding constant of 54 000 M-1 in DMSO). The large observed binding constants are ascribed to two factors, (i) the presence of a phenanthroline-coordinated cationic charge that decreases the electron density on the pyrrole NH protons and (ii) pure electrostatic effects.

Pro and anti: Recognition of chloride ion and through‐membrane H+/Cl− ion transport (“symport”) could account for the biological effects (anticancer activity) of prodigiosin, as inferred from model studies involving pyrrole‐based anion receptors designed to mimic the key features of this naturally occurring pigment (see picture).

The diprotonated form of an organic-solubilized cyclo[8]pyrrole derivative, bearing eight undecyl chains on the β-pyrrolic positions, was found to extract sulfate anion effectively from neutral aqueous media into a toluene organic phase. The kinetics of sulfate anion exchange between the two phases were found to be exceedingly slow in the absence of the phase-transfer catalyst, Aliquat 336-nitrate (A336N), but appreciable in its presence. The bisnitrate anion bound form of this cyclo[8]pyrrole could be generated in situ by subjecting the toluene phase containing initially 0.5 mM of the sulfate anion bound form and 0.1 mM trioctylamine (TOA) to successive equilibrations with aqueous 0.1 M HNO3 until sulfate was no longer detected in the aqueous phase. This bisnitrate complex, when studied as a 0.5 mM solution in toluene in the presence of 0.1 mM (TOAH)+(NO3 -), was also found to be an effective extractant for sulfate anion. D SO4 values of 0.001 and 1000 were observed at 1 M NaNO3(aq) and 0.3 mM NaNO3(aq), respectively, and the logarithm of the conditional exchange constant, log( ), was calculated to be 4.9 ± 0.4. The present cyclo[8]pyrrole system is thus noteworthy as being the first synthetic receptor that displays a high selectivity for sulfate anion in the presence of excess nitrate under conditions of solvent extraction.

Doppelt wirksam: Das Erkennen des Chloridions und der H+/Cl−‐Ionentransport („symport“) durch die Membran könnten die biologische Wirkung von Prodigiosin gegen Tumoren erklären, wie aus Modellstudien unter Beteiligung pyrrolbasierter Anionenrezeptoren folgt, die als Mimetika der Schlüsselelemente dieses natürlichen Pigments entworfen wurden (siehe Bild).

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Guiding students to become practicing scientists entails teaching them the specialized ways of collaborating, writing, and thinking that these professionals utilize every day. Laboratory experiences provide unique opportunities for student-centered curricular activities that mimic these skills. The biodiesel laboratory experience described here connects previously published biodiesel exercises in an intentionally scaffolded experience that models for students the types of collaboration and communication skills they will need if they choose to enter a STEM profession. The collaboration is vertically scaffolded to span multiple courses (general chemistry, organic chemistry, and physical chemistry) with opportunities for future connections with additional upperdivision courses. The experience is writing intensive with a focus on both scientific writing through formal laboratory reports and writing for communication with nonscientists. By encountering this experience repeatedly throughout their chemistry coursework, students have the opportunity to develop the habits of working scientists.

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