mz9b01025_si_001.pdf (2.39 MB)
Heteronuclear, Monomer-Selective Zn/Y Catalyst Combines Copolymerization of Epoxides and CO2 with Group-Transfer Polymerization of Michael-Type Monomers
journal contribution
posted on 2020-03-27, 18:05 authored by Alina Denk, Sebastian Kernbichl, Andreas Schaffer, Moritz Kränzlein, Thomas Pehl, Bernhard RiegerTerpolymerizations
of cyclohexene oxide (CHO), CO2, and the Michael-type monomer
2-vinylpyridine (2VP) are presented. The combination of two distinct
polymerization mechanisms was enabled by the synthesis of a heterobifunctional
complex (3). Its β-diiminate zinc moiety allows
the ring-opening copolymerization of CHO and CO2, whereas
the yttrium metallocene catalyzed the rare earth metal-mediated group-transfer
polymerization of the polar vinyl monomer. Both units were connected
via the CH-bond activation of a pyridyl-alkoxide linker. Matrix-assisted
laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS)
revealed the successful transfer of the linker to the end-group of
the respective homopolymers poly(cyclohexene carbonate) (PCHC) and
poly(2VP) (P2VP) being the prerequisite for copolymer formation. Aliquot
gel-permeation chromatography (GPC) analysis and solubility behavior
tests confirmed the P2VP-block(b)-PCHC terpolymer formation via two pathways, a sequential and a
one-pot procedure. Furthermore, the versatility of the method was
demonstrated by introducing 2-isopropenyl-2-oxazoline (IPOx) as the
second Michael-type monomer that yielded the terpolymer poly(IPOx)-b-PCHC.