Synthesis of dialkoxydiphenylsilanes via the rhodium-catalyzed hydrosilylation of aldehydes

The commercially available rhodium(I) complex [RhCl(CO)₂]₂ (1) was shown to be an effective catalyst for the reduction of carbonyls with organosilanes under mild conditions. This study focusses on the hydrosilylation of aldehydes with diphenylsilane leading to the isolation of a series of dialkoxydiphenylsilanes with low catalytic loading of complex 1.     

FeIII–Salen-Based Probes for the Selective and Sensitive Detection of E450 in Foodstuff

Inorganic pyrophosphate (PPi) is considered as a diagnostic marker for various diseases such as cancer and vascular calcification. PPi also plays an important preservative role as an additive E450 in foodstuff. In this work, a selective Fe^III–salen-based probe for PPi is described; this probe disassembles in the presence of the target analyte into its molecular blocks, 1,2-propanediamine and 3-chloro-5-formyl-4-hydroxybenzenesulfonic acid. The latter signaling unit leads to a fluorometric response. Compared with a related prototype, the new complex shows a 2.3-times stronger emission at 500 nm and a 155-times better selectivity of PPi over adenosine triphosphate (ATP). Importantly, the new probe was successfully applied for detecting E450 in foodstuff.     

1,3-Dipolar cycloaddition of vinyloxy quinolines with α-alkoxy carbonyl aldonitrones or cyclic surrogates: A comparative study for an asymmetric access to trans 4-quinolinoxy oxaprolines

The asymmetric access to unreported trans 4-quinolinoxy oxaproline precursors is investigated here in a comparative way by 1,3-dipolar cycloaddition of vinyloxy quinolines with chiral α-alkoxycarbonyl aldonitrones and chiral cyclic surrogates.     

Catechol Thioesters: Ligands for Hierarchically Formed Lithium-Bridged Titanium(IV) Helicates and Helicate-Based Switches

The thioester moiety is introduced as a lithium binding unit for the hierarchical formation of titanium(IV) catecholate-based lithium-bridged helicates. In solution, the coordination compounds show a monomer–dimer equilibrium which —in comparison to the oxo esters— is significantly shifted towards the monomers. In addition, the influence of the thioester side chain on the dimerization behavior is investigated and an expansible/compressible molecular switch is synthesized. In the latter case expansion and compression are performed reversibly in methanol, whereas in DMSO spontaneous expansion occurs.     

Coverages on inverse semigroups

Semigroup Forum - First we give a definition of a coverage on an inverse semigroup that is weaker than the one given by Lawson and Lenz and that generalizes the definition of a coverage on a...     

Hetero-Substituted αβ-Fused BODIPY

Here, we report the synthesis and properties of heterosubtituted αβ-fused BODIPY fluorophores. The compounds were obtained in good yields by sequential and selective Stille cross-coupling reactions from 2,3,5,6-tetrahalo-BODIPY, allowing the introduction of different substituents at the 3,5 and 2,6 positions of the BODIPY ring. The final fused compounds were synthesized using oxidative cyclisation with ferrous chloride. The fully fused compounds show a strong bathochromically shifted emission along with a hyperchromic shift of the absorption maxima. The fluorescence quantum yields remain relatively large for compounds emitting in this wavelength range. Computational studies have been carried out to fully understand the photophysical behaviour of these dyes.