RESUMEN
The chlorine radical is a strong HAT (Hydrogen Atom Transfer) agent that is very useful for the functionalization of C(sp3)-H bonds. Albeit highly attractive, its generation from the poorly oxidizable chloride ion mediated by an excited photoredox catalyst is a difficult task. We now report that 8Rf8-4CzIPN, an electron-deficient fluorous derivative of the benchmark 4CzIPN photoredox catalyst belonging to the donor-acceptor carbazole-cyanoarene family, is not only a better photooxidant than 4CzIPN, but also becomes an excellent host for the chloride ion. Combining these two properties ultimately makes the self-assembled 8Rf8-4CzIPNâ¢Cl- dual catalyst highly reactive in redox-neutral Giese-type C(sp3)-H bond alkylation reactions promoted by the chlorine radical. Additionally, because of its fluorous character, the efficient separation/recovery of 8Rf8-4CzIPN could be envisioned.
RESUMEN
The templated clipping of a ferrocene-grafted isophthalic acid derivative to encircle a hydrogen-bonding axle through the reaction with 1,4-bis(aminomethyl)benzene is described. The constituent electroactive macrocycle of the resultant [2]rotaxane is a homologue of the versatile benchmark tetraamide variant developed by Leigh and co-workers. The relative templating effect of different hydrogen-bonding motifs in rotaxane and pseudorotaxane generation is compared, with yields varying from 0 to 41%. The electrochemical properties and single crystal X-ray structure of a doubly ferrocene-decorated [2]rotaxane are further reported.
RESUMEN
Trans-1,2-di(1-pyrenylamino)cycloxexane was found to display circularly polarized excimer emission (glum = 0.016) both in polar and non-polar solvents that is assigned to charge separation symmetry breaking on the basis of its large transition state dipole moment (12.1 D).
Asunto(s)
Luminiscencia , SolventesRESUMEN
Reversible electronic energy transfer and photoinduced electron transfer conspire in the light-driven dethreading of a molecular piston, showing the potential of combining these processes in supramolecular systems.
RESUMEN
The fluorinated double-tailed triblock surfactant 1-Na represents a new type of gelator for perfluorocarbons which can gelate at low concentration (1.5 wt%) both bromoperfluorooctane and perfluorodecalin, two of the most appealing perfluorinated fluids for pharmaceutical applications.