Synthesis and Crystal Structure of Multifunctional Tosylate as Basis for Star-shaped Poly(2-ethyl-2-oxazoline)s

Hoogenboom, Richard; Fijten, Martin W. M.; Kickelbick, Guido; Schubert, Ulrich S.

Abstract:

The synthesis of well-defined polymer architectures is of major importance for the development of complex functional materials. In this contribution, we discuss the synthesis of a range of multifunctional star-shaped tosylates as potential initiators for the living cationic ring-opening polymerization (CROP) of 2-oxazolines resulting in star-shaped polymers. The synthesis of the tosylates was performed by esterification of the corresponding alcohols with tosyl chloride. Recrystallization of these tosylate compounds afforded single crystals, and the X-ray crystal structures of di-, tetra- and hexa-tosylates are reported. The use of tetra- and hexatosylates, based on (di)pentaerythritol as initiators for the CROP of 2-ethyl-2-oxazoline, resulted in very slow initiation and illdefined polymers, which is most likely caused by steric hindrance in these initiators. As a consequence, a porphyrin-cored tetratosylate initiator was prepared, which yielded a well-defined star-shaped poly(2-ethyl-2-oxazoline) by CROP as demonstrated by SEC with RI, UV and diode-array detectors, as well as by 1H NMR spectroscopy.

Year:

2010

Type of Publication:

Article

Journal:

Beilstein Journal of Organic Chemistry

Volume:

6

Pages:

771 - 783