Versatile post-polymerization functionalization of poly(p-phenylene vinylene) copolymers containing carboxylic acid substituents: development of a universal method towards functional conjugated copolymers

A novel conjugated copolymer of poly(2-methoxy-5-(3,7-dimethyloctyloxy)-1,4-phenylene vinylene) (MDMO-PPV) and poly(1,4-(2-(5-carboxypentyloxy)-5-methoxyphenylene) vinylene) (CPM-PPV), which can be used as a platform for further post-polymerization functionalization, is presented. This copolymer is soluble in common organic solvents, such as CHCl3, CH2Cl2, and THF. Post-polymerization functionalization of the acid-groups of this copolymer has been successfully performed via an optimized DCC/DMAP-procedure with the desired alcohol. Several examples have been prepared to demonstrate the versatility of the developed functionalization methodology. PPV-copolymers have been prepared with vinyl groups, propynylphenyl groups, methacrylate groups, ATRP initiator groups, dithiocarbamate initiator groups and propargyl groups. The latter group can be utilized to do "click" chemistry, which has been demonstrated with an azide-functionalized reagent. In all cases, analytical data are consistent with a quantitative conversion of the functional groups. It is demonstrated that no substantial degradation of the conjugated system occurs even after consecutive post-polymerization functionalization reactions.