Institut Polymerchemie

uni

suche

sitemap

kontakt

Universität Stuttgart

Institut für Polymerchemie

	Lehrstuhl für Makromolekulare Stoffe und Faserchemie
	Prof. Dr. Michael R. Buchmeiser Conjugated, Conductive Polymers via the Cyclopolymerization of 1,6-Heptadiynes and 1,7-Octadiynes

During the last years, we developed on the cyclopolymerization (CP) of 1,6-heptadiynes by “pseudo-halide”-modified Grubbs-Hoveyda initiators of the formula [RuX₂(NHC)(CH-(2-(2-PrO)-C₆H₄)] (NHC=IMesH₂=1,3-dimesitylimidazolin-2-ylidene, 1-3-dimesityl-3,4,5,6-tetrahydropyrimidin-2-ylidene, 1,3-dimesityl-4,5,6,7-tetrahydrodiazepin-2-ylidene; X=CF³COO, CF³CF₂COO, CF₃ (CF₂)2COO, NCO, NCS). A regioselective a-addition could be established for different 1,6-heptadiynes, resulting in the virtually selective (>96%) formation of five-membered repeat units (i.e. cyclopent-1-enylene-2-vinylenes) (Scheme 1). More recently, we confirmed the reactivity of Grubbs-Hoveyda-type initiators bearing pseudo-halide ligands in CP and presented a general concept explaining for the observed regioselectivity in insertion. In cooperation with Prof. E. Klemm, University of Stuttgart, cyclopolymerization-derived conductive polyene-based monolithic materials are currently used in microreactor technology for continuous heterogeneous (bio-) electrocatalysis.

Recently, we were able to extend the regioselective cyclopolymerization to 1,7-octadiynes. Modified Grubbs- Hoveyda initiators and tuned Schrock initiators allow for a high regioselectivity in insertion, i.e. for selective -insertion. Poly(1,7-octadiynes) derived via such a regioselective -insertion can serve as a soluble progenitors to poly(o-phenylenevinylenes)s (OPVs). OPVs are accessible from the corresponding poly(1,2-cyclohex-1-enylenevinylene)s via oxidation or thermally induced elimination of suitable substituents at the 4,5-position. Currently we are working on the elimination conditions and on the nature of different leaving groups to produce thin, transparent and conductive films for smart electronics.

Scheme. Mechanism of the cyclopolymerization of 4,5-R2-1,7-octadiynes.

References:
1) Regioselectivity of Insertion and the Role of the Anionic Ligands in the Ru-Alkylidene Catalyzed Cyclopolymerization of 1,6-Heptadiynes, S. Naumov, M. R. Buchmeiser, Organometallics, 31, 847-856 (2012)
2) Regioselective Cyclopolymerization of 1,7-Octadiynes, S. Naumann, J. Unold, W. Frey, M. R. Buchmeiser, Macromolecules, 44, 8380-8387 (2011), highlighted in SYNFACTS, 8 (2), 0150, 2012 by T. M. Swager and J. R. Cox
3) Cyclopolymerization of N,N-Dipropargyl-3,4-dialkoxyanilines by Schrock and Grubbs-Hoveyda Initiators: Influence of Initiator Structure on the Mode of Insertion, M. R. Buchmeiser, C. Schmid, D. Wang, Macromol. Chem. Phys., 212, 1999–2008 (2011)
4) Factors Relevant for the Regioselective Cyclopolymerization of 1,6-Heptadiynes, N,N-Dipropargylamines, N,N-Dipropargylammonium Salts, and Dipropargyl Ethers by RuIV-Alkylidene-Based Metathesis Initiators, P. Santhosh Kumar, K. Wurst, Michael R. Buchmeiser, J. Am. Chem. Soc., 131, 387-395 (2009)
5) Naumann, S.; Unold, J.; Frey, W.; Buchmeiser, M. R. Macromolecules 2011, 44, 8380-8387
6) Naumann, S.; Unold, J.; Frey, W.; Buchmeiser, M. R. Polym. Prep. (Am. Chem. Soc., Div. Polym. Chem.) 2012, 53, 138-139

All research topics

Lehrstuhl für Makromolekulare Stoffe und Faserchemie

Prof. Dr. Michael R. Buchmeiser Conjugated, Conductive Polymers via the Cyclopolymerization of 1,6-Heptadiynes and 1,7-Octadiynes

Prof. Dr. Michael R. Buchmeiser

Conjugated, Conductive Polymers via the Cyclopolymerization of 1,6-Heptadiynes and 1,7-Octadiynes