Polyethylenes bearing a terminal porphyrin group

Abstract

An α-[Cu(II)-porphyrin]-polyethylene was synthesized for the first time using copper catalyzed 1,3-dipolar azide-alkyne Huisgen cycloaddition yielding highly colored moiety-substituted polyethylene.Polyolefins, including polyethylene (PE) and isotactic polypropylene (iPP), are commercially the most important family of polymers with annual production exceeding 100 Mt.1 Polyolefins have reached wide application, since they combine excellent mechanical, physical and chemical properties. However, their use in certain applications is limited by their low polarity, leading to a lack of adhesion, dyeability, paintability, and compatibility with other polymers.2 Also, their chemical inertness precludes post-synthesis functionalisation with colorants or other useful moieties. We have recently shown3 that PE chains of controlled length, obtained by using the catalytic system (C5Me5)2NdCl2Li(OEt2)2/MgR2, could be highly functionalized with a variety of reactive groups including azide end groups3c (PE–N3, 1 in Scheme 1). As a result, azide–alkyne 1,3-dipolar Huisgen cycloaddition4 could be performed permitting conversion of these PE building blocks into macromonomers using acrylate and methacrylate propargyls.3c The high efficiency of these PE-end group functionalizations led us to further investigate the synthesis of PE chains by the same 1,3-dipolar Huisgen cycloaddition of azido PE with various alkyne containing reagents. Here we report for the first time the end-functionalization of PE with organic chromophores of the porphyrin type.