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Lehrstuhl für Makromolekulare Stoffe und Faserchemie |
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Prof. Dr. Michael R. Buchmeiser |
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Both the vinyl insertion polymerization (VIP) of olefins and the ring-opening metathesis polymerization (ROMP) of cyclic olefins are
well-established polymerizations techniques in polymer chemistry and those are based on the insertion of a monomer between a
transition metal (ion) and the growing polymer chain. Mechanistic studies show that a cationic VIP-active catalyst and a ROMP-active
one may be interconverted through a simple α-proton elimination/addition process. In order to realize this process, we have designed
and synthesized a sophisticated ligand containing a Lewis-acid and -base pair (B-N), e.g., 6-(2-(Diethylboryl)phenyl)pyridin-2-amine
(1), which should be able to capture/release a proton between the growing metal-alkyl chain and the metal alkylidene moiety
(ROMP type) via a simple α-proton elimination/addition under given conditions during the polymerization reaction.
A series of novel early transition metal compounds (Ti, Zr and Hf) based on this ligand have been synthesized and used for the polymerization of cyclic olefins such as norborn-2-ene or cis-cyclooctene (COE) in the presence of ethylene. The 1H-, 13C-NMR, and GPC results of the obtained polymers show that they contain both cyclic olefin-derived saturated and unsaturated moieties within the same polymer. The obtained new polymers hold great potential in materials chemistry, since they allow for the synthesis of functional polyolefins without the need of copolymerizing polar monomers in extra condition. Current research focusus on extending both the catalysts' and monomers' base and on the realization of novel polymer architectures. Concomitatantly, mechanistic studies including low-temperature NMR and the polymerization of labelled compounds are carried out.  Figure 1: Synthesis of Ti-catalyst (left); 13C-NMR of poly(NBE)ROMP-co-poly(NBE) VIP-co-poly(E) (in C2D2Cl4) (right).  Figure 2: Structure References [1] M. R. Buchmeiser, S. Camadanli, D. Wang, Y. Zou, U. Decker, C. Kühnel, I. Reinhardt, Angew. Chem. 2011, 123, 3628-3633; Angew. Chem. Int. Ed. 2011, 50, 3566-3571. [2] S. Camadanli, Y. Zou, V. N. Gurram, D. Wang, M. R. Buchmeiser, Polym. Prepr. (Am. Chem. Soc., Div. Polym. Chem.) 2011, 52, 217-218. [3] S. Camadanli, U. Decker, C. Kühnel, I. Reinhardt, M. R. Buchmeiser, Molecules 2011, 16, 567-582. [4] Y. Zou, D. Wang, K. Wurst, C. Kühnel, I. Reinhardt, U. Decker, V. Gurram, S. Camadanli, M. R. Buchmeiser, Chem. Eur. J. 2011, 17, 13832-13846. 
All research topics |
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Letzte Änderung 06.06.2012
( JP) | © Universität Stuttgart |
Impressum |