ABSTRACT
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.
Subject(s)
Oxazoles/chemistry , Polymers/chemistry , Catalysis , Copper/chemistry , Cross-Linking Reagents/chemical synthesis , Cyclopropanes/chemistry , Diazonium Compounds/chemistry , Ligands , Polystyrenes/chemistry , Spectroscopy, Fourier Transform Infrared , Spectrum Analysis, Raman , StereoisomerismABSTRACT
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.
