RESUMO
A functionalized chiral bis(oxazoline) is used as a chiral monomer in polymerization reactions leading to homo- and copolymers of different morphology. Polymers with a high content of chiral monomer lead to enantioselectivities that are higher than those obtained with the soluble ligand, but the chiral ligand is not used in an optimal way. A hyperbranched polymer, obtained by using a hexavinyldendrimer as the cross-linker, leads to the same enantioselectivities with a more efficient use of the chiral ligand.
Assuntos
Oxazóis/química , Polímeros/química , Catálise , Cobre/química , Reagentes de Ligações Cruzadas/síntese química , Ciclopropanos/química , Compostos de Diazônio/química , Ligantes , Poliestirenos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , EstereoisomerismoRESUMO
New dipolar and non-dipolar poly(phenylenevinylene) dendrimers bearing electron-donating and electron-withdrawing groups have been efficiently synthesized using Heck and Horner-Wadsworth-Emmons reactions. The photoluminescence of these systems may be tuned in the blue zone by choosing the appropriate peripheral groups. Despite the meta-substitution pattern, large Stokes shifts can be observed when pi-donor and pi-acceptor groups are connected by a m-phenylenevinylene system.
RESUMO
Dendrimeric meta-substituted phenylenevinylene moieties have been incorporated on a chiral binaphthyl core, providing new chiral and photoluminescent molecules.
