Electrochemically reduced tungsten‐based active species as catalysts for cross‐metathesis reactions: cross‐metathesis of erucic acid with 2‐octene

et al. 2004

Applied Organom Chemis

The ring-opening metathesis polymerization of cyclododecene using an electrochemically reduced tungsten-based catalyst (WCl 6 -e − -Al-CH 2 Cl 2 ) is described. In addition, the influence of reaction conditions on the polymerization yield was determined. The resulting polymer has been characterized by NMR, IR, gel permeation chromatography and differential scanning calorimetry. The glass transition temperature and melting point of the polydodecenamer are 19.6 • C and 70.0 • C respectively. Furthermore, cyclododecene has been polymerized into a low-molecular-weight polymer (12.0 × 10 3 ) with a polydispersity of 2.06 in high yields (94%). IR and NMR analysis indicate that the polydodecenamer has a high trans content (60%).

Ring‐opening metathesis polymerization of cyclododecene using an electrochemically reduced tungsten‐based catalyst

Karabulut

Çetinkaya

et al. 2004

Applied Organom Chemis

Synthesis and characterization of polyoctenamer with WCl₆e⁻AlCH₂Cl₂ catalyst system via ring‐opening metathesis polymerization

Çetinkaya

Karabulut

et al. 2005

Applied Organom Chemis

Self Cite

A typical low-strain monomer, cyclooctene, was polymerized via ring-opening metathesis polymerization with electrochemically produced active species. The structural properties of the polyoctenamer were determined by NMR, gel-permeation chromatography and differential scanning calorimetry. Analysis of the polyoctenamer microstructure by 1 H and 13 C NMR spectroscopy indicates that the polymer contains a highly cis stereoconfiguration of the double bonds (σ c = 0.75). The resulting polymer is of low molecular weight and has a reasonably broad molecular weight distribution (M w = 18 000, PDI = 1.9). The glass transition temperature and melting point of the polyoctenamer are −11.3 • C and 36.5 • C respectively.

Application of electrochemically generated molybdenum-based catalyst system to the ring-opening metathesis polymerization of norbornene and a comparison with the tungsten analogue

Dereli

Aydoğdu

Appl. Organometal. Chem.

et al. 2005

Self Cite

This study describes the application of the electrochemically generated molybdenum-based catalyst system MoCl 5 -e − -Al-CH 2 Cl 2 to ring-opening metathesis polymerization of bicyclo[2.2.1]hept-2-ene (norbornene). The results are compared with those previously obtained by the WCl 6 -e − -Al-CH 2 Cl 2 system. The polymer product has been characterized by 1 H and 13 C NMR, IR and gelpermeation chromatography techniques. This molybdenum-based catalyst system has led to a mainly trans stereoconfiguration (ca 60%) of the double bonds, in contrast to the polymer obtained with the tungsten-based analogue, where the cis content is 60%. Analysis of the poly(1,3-cyclopentylenevinylene) microstructure by 13 C NMR spectroscopy revealed that the polymer having σ c = 0.41 (fraction of double bonds with cis configuration) contains a slightly blocky distribution (r t r c > 1) of the double-bond dyads (r t r c = 1.44). In addition, the influence of reaction parameters, e.g. reaction time, electrolysis time and catalyst aging time, on conversion has been analysed in detail.