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Stereoselective Cyclopolymerization of Diynes: Smart Materials for Electronics and Sensors
Author(s) -
Krause Jens O.,
Wang Dongren,
Anders Udo,
Weberskirch Ralf,
Zarka M. Tobias,
Nuyken Oskar,
Jäger Claus,
Haarer Dietrich,
Buchmeiser Michael R.
Publication year - 2004
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200451314
Subject(s) - quinuclidine , tacticity , monomer , catalysis , polymer chemistry , polymerization , chemistry , polymer , medicinal chemistry , materials science , organic chemistry
Abstract A series of heptadiynes was cyclopolymerized by Schrock initiators to produce poly(ene)s exclusively based on one single repetitive unit, i.e. 1,2‐cyclopent‐2‐enylenvinylenes. Polymers containing virtually solely 1,2‐cyclopent‐2‐enylenvinylene units were obtained by various routes, e.g. by low‐temperature‐initiated cyclopolymerization of diethyldipropargyl malonate (DEDPM). A chiral poly(ene) was prepared from 4‐(ethoxycarbonyl)‐4‐(1 S , 2 R , 5 S )‐(+)‐menthoxycarbonyl‐1,6‐heptadiyne (ECMHD) to determine the configuration of the double bonds and the tacticity of the poly(ene) backbone. Poly(ECMHD) consisted of >96% 5‐membered rings and possessed a tactic, alternating cis‐trans structure. Alternatively, poly(DEDPM) exclusively based on 1,2‐(cyclopent‐1‐enylene)vinylene units was prepared using MoCl 5 ‐ n ‐Bu 4 Sn‐EtOH‐quinuclidine (1:1:5:1) and MoOCl 4 ‐ n ‐Bu 4 Sn‐EtOH‐quinuclidine (1:1:2:1). The initiator efficiency of MoOCl 4 ‐ n ‐Bu 4 Sn‐EtOH‐quinuclidine (1:1:2:1) was as high as 91%, the highest value ever reported for such systems. Multistage polymerizations of DEDPM indicated for both initiator systems that the catalytic species were active for at least 6 hours in the presence of monomer yet did not fulfill the criteria of a truly living polymerization. Finally, a new modification of the Grubbs‐Hoveyda catalyst, Ru(CF 3 COO) 2 (CH‐2‐(2,4,5‐(MeO) 3 ‐C 6 H 3 )(SIMes) (SIMes=1,3‐dimesityl‐4,5‐dihydroimidazol‐2‐ylidene) allowed the first ruthenium alkylidene‐catalyzed living cyclopolymerization of DEDPM. The different initiators, their properties, the resulting polymerization systems as well as the physical properties of the resulting poly(ene)s are summarized.