Tuning the reduction potential of quinones by controlling the effects of hydrogen bonding, protonation and proton-coupled electron transfer reactions.

An all-organic cell comprising 2,3-dimethyl-1,4-napthoquinone and pyrano[3,2-f]chromene as electroactive elements exhibited a good combination of large cell voltage and stability of the reduced quinone upon the addition of diethyl malonate (a weak organic acid), as compared to the addition of trifluoroethanol (which led to a high cell potential but low stability via strong hydrogen bonding interactions) and the addition of trifluoroacetic acid (which led to a lower cell potential but high stability through proton transfer).

Tetrathiafulvalene aids in the atomic spectroscopic determination of total mercury.

The determination of mercury simultaneously with other elements via inductively coupled plasma-mass spectrometry (ICP-MS) in airborne particulate matter (PM) is still challenging due to the lack of accuracy for the low level mercury concentrations as a result of its volatility and tendency to adhere to the walls of the sample introduction system. This study investigated the effect of existing (gold and methionine) and new (lithium tetrathiafulvalene carboxylate (LiCTTF)) preservation agents in order to improve the determination of trace mercury in PM samples. Statistical analysis revealed that a concentration of 10 μg mL of LiCTTF was sufficient to obtain highly accurate results with t values of 0.

Sulfoxidation of alkenes and alkynes with NFSI as a radical initiator and selective oxidant.

Sulfoxides are important functional molecules. We develop a short-route (one-pot) synthesis of this class of molecules by reacting thiols with alkenes or alkynes under mild and metal-free conditions. N-Fluorobenzenesulfonimide (NFSI) is used to play dual roles: as a radical initiator for a thiol-ene/-yne reaction to form sulfide adducts, and as efficient oxidant for conversion of the sulfides formed in situ to sulfoxides.

Primary-Colored Electrochromism of 1,4-Phenylenediamines.

Ten 1,4-phenylenediamines were studied using electrochemical techniques (voltammetry and controlled potential electrolysis) and UV/Vis spectroscopy under ambient conditions. All compounds demonstrated vibrant color changes upon one-electron electrochemical oxidation in acetonitrile, with most displaying a primary color (red, green, blue, or yellow) in their oxidized state. The four electrochromes that exhibited the most intense color changes were examined by using a gold micromesh electrode laminated inside a polymer film to determine their electrochromic properties in solution (contrast ratios, chromatic efficiency, and cycle life).

Brønsted acid-catalyzed cycloisomerization of but-2-yne-1,4-diols with or without 1,3-dicarbonyl compounds to tri- and tetrasubstituted furans.

A Brønsted acid-catalyzed method to prepare tri- and tetrasubstituted furans efficiently from cycloisomerization of but-2-yne-1,4-diols with or without 1,3-dicarbonyl compounds is described. By taking advantage of the orthogonal modes of reactivity of the alcoholic substrate through slight modification of the reaction conditions, a divergence in product selectivity was observed. At room temperature, p-TsOH·H(2)O-mediated tandem alkylation/cycloisomerization of the propargylic 1,4-diol with the β-dicarbonyl compound was found to selectively occur to provide the tetrasubstituted furan product.

Silver triflate catalyzed tandem heterocyclization/alkynylation of 1-((2-tosylamino)aryl)but-2-yne-1,4-diols to 2-alkynyl indoles.

Don't cross me! 2-Alkynyl indoles were prepared efficiently by the AgOTf-catalyzed tandem heterocyclization/alkynylation of 1-(2-tosylamino)aryl)but-2-yne-1,4-diols under mild conditions (see scheme). The attractiveness of this approach lies in the fact that both the indole ring and alkyne side chain of the N-heterocycle are sequentially formed from low cost, readily available, and ecologically benign starting materials. It also provides the first route to this synthetically valuable class of compounds that is not based on a cross-coupling strategy.