Segmented oligomers consisting of polyoctenylene hard segments and unsaturated polytetrahydrofuran soft segments were prepared using acyclic diene metathesis (ADMET) copolymerization techniques. These are the first such segmented materials prepared via metathesis chemistry. Two different molecular w
Acyclic diene metathesis (ADMET) polymerization using a well-defined ruthenium based metathesis catalyst
✍ Scribed by Krystyna Brzezinska; Patrick S. Wolfe; Mark D. Watson; Kenneth B. Wagener
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 422 KB
- Volume
- 197
- Category
- Article
- ISSN
- 1022-1352
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✦ Synopsis
Abstract
A series of α,ω‐dienes have been exposed to Ru(Cl~2~)(CHPh)(PCy~3~)~2~, [Ru] 3, metathesis catalyst under acyclic diene metathesis (ADMET) conditions, and the products were compared with those obtained previously using Schrock's well defined Mo and W alkylidenes. High molecular weight polymers can be synthesized using [Ru] 3 if lower monomer to catalyst ratios with respect to [Mo] 1 and [W] 2 are used. Monomer structure plays a role since 1,9‐decadiene produces molecular weights typical of ADMET chemistry, whereas 1,5‐hexadiene produces only oligomers. This decrease in reactivity is attributed to a manifestation of intramolecular π‐complexation of the tethered olefin in 1,5‐hexadiene polymerizations. Substituents at the 2‐position of α,ω‐dienes also affects polymerization in that only dimers can be produced from 2‐methyl‐1,5‐hexadiene, a result similar to the same reaction performed with [W] 2. Diallyl ether oligomerizes effectively in the presence of [Ru] 3 with a ratio of cyclics to oligomers comparable to results obtained with [Mo] 1 and [W] 2.
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## Abstract The polymerization of (2‐isopropoxyphenyl)acetylene was investigated using a wide range of well‐defined ruthenium‐alkylidene complexes and related olefin metathesis initiators. In view of its superior activity, the second generation Hoveyda–Grubbs catalyst was singled out for further st
## Abstract The application of the WCl~6~–e^−^–Al–CH~2~Cl~2~ system to acyclic diene metathesis polymerization of 1,9‐decadiene is reported. The polyoctenamer formed is of a weight‐average molecular weight of 9000 with a polydispersity of 1.92. IR and NMR spectral analyses indicate the retention of