%0 journal article
%@ 1022-1352
%A Mendez, J.D., Schroeter, M., Weder, C.

%D 2007
%J Macromolecular Chemistry and Physics
%N 15
%P 1625-1636 
%R doi:10.1002/macp.200700133
%T Hyperbranched Poly(p-phenylene ethynylene)s
%U https://doi.org/10.1002/macp.200700133
15 
%X Hyperbranched poly(p-phenylene ethynylenes) (HB-PPEs) were synthesized in an A2 + B3 one-pot approach by the Pd/Cu-catalyzed cross-coupling reaction of 1,4-diethynyl-2,5-bis-(octyloxy)benzene and 1,2,4-tribromobenzene. Reaction conditions were varied with the objective to obtain well-defined HB-PPEs of different molecular weights. HB-PPEs with  from 11 000 to 237 000 g · mol-1 and PDIs of 1.5-10.7 were prepared. All polymers that comprised unreacted ethynyl groups eventually became insoluble upon drying, presumably as a result of solid-state cross-linking. This reaction could be prevented by endcapping the polymers with an excess of 4-iodotoluene.