Highly selective electrosynthesis of biphenols on graphite electrodes in fluorinated media.

The direct and selective phenol coupling reaction that provides biphenols still represents a challenge in organic synthesis. The recently developed electrosynthesis on boron-doped diamond anodes with fluorinated additives was developed further to allow the application to less-expensive electrodes and fluorinated media. This advanced protocol allows the highly selective anodic phenol coupling reaction on graphite with a broad scope.

ortho-Selective phenol-coupling reaction by anodic treatment on boron-doped diamond electrode using fluorinated alcohols.

Enlarged scope by fluorinated mediators: Oxyl radicals are easily formed on boron-doped diamond (BDD) electrodes and can be exploited for the ortho-selective coupling to the corresponding biphenols (see scheme). At partial conversion, a clean transformation is achieved that can be applied to electron-rich as well as fluorinated phenols.

Metal-organic frameworks for sensing applications in the gas phase.

Several metal-organic framework (MOF) materials were under investigated to test their applicability as sensor materials for impedimetric gas sensors. The materials were tested in a temperature range of 120 °C - 240 °C with varying concentrations of O(2), CO(2), C(3)H(8), NO, H(2), ethanol and methanol in the gas atmosphere and under different test gas humidity conditions. Different sensor configurations were studied in a frequency range of 1 Hz -1 MHz and time-continuous measurements were performed at 1 Hz.

Novel template-directed anodic phenol-coupling reaction.

Substituted phenols were anodically coupled to the corresponding 2,2'-biphenols via tetraphenoxy borate derivatives. This electrochemical method is particularly useful for methyl-substituted substrates, such as 2,4-dimethyl phenol. The selective ortho-coupling reaction can be easily performed on a multikilogram scale.

Photoisomerizable bipyridine ligands and macroligands: absorption, photoisomerization properties and theoretical study.

Two 2,2'-bipyridines, substituted at the 4,4'-positions by p-dialkylaminophenylazostyryl moieties p-R2N-C6H4-N=N-C6H4-CH=CH-[6 a, R2N=nBu2N; 6 b, R2N=(nBu)(C4H8OTHP)N; 6 c, R2N=(nBu)(C4H8OH)N], were successfully synthesized by using Wadworth-Emmons reactions. The X-ray structure of 6 a has been determined. Esterification of 6 c with 2-bromoisobutyroylbromide afforded 6 d.