Synthesis of Well-Defined Phthalimide Monofunctional Hyperbranched Polyglycerols and Its Transformation to Various Conjugation Relevant Functionalities

Phthalimide monofunctional hyperbranched polyglycerols (HbPG) were successfully synthesized, for the first time, by applying a new, highly efficient phthalimide/potassium phthalimide (PhthIm/K-PhthIm) initiating system for the anionic ring-opening multibranching polymerization of glycidol. As the analyses of the resulting polymers by UV and NMR spectroscopies, vapor pressure osmometry, aqueous and organic phase GPCs and ESI-MS proved, well-defined HbPGs with one phthalimide moiety, predetermined average molar masses, and narrow molar mass distributions were formed. The phthaloyl group was quantitatively cleaved by hydrazinolysis to form a monoamine functional HbPG. The amine functionality of the HbPG molecules at the initiating site was transformed into carboxylic, maleimide, and chloroacetamide groups. All functionalization reactions were quantitative as proved by multidimensional NMR spectroscopy. These findings indicate that the PhthIm/K-PhthIm combination can be utilized in the polymerization and subsequent derivatizations of other epoxides as well. In addition, the selectively modifiable reactive headgroup can be applied for obtaining various novel functionalized materials