Journal ArticleDOI
W(CO)6/CBr4/hv — a new system for metathesis polymerisation
B Gita,G. Sundararajan +1 more
TLDR
In this paper, an optimization study of W(CO) 6 CBr 4 / hv is presented, where the active species are characterised by reaction with acetophenone and copolymers of phenylacetylene and norbornene.Abstract:
Metathesis polymerisation can be effected with many catalysts under a variety of conditions. The system described here, viz., W(CO) 6 CBr 4 / hv , induces polymerisation by in situ generation of the active species and has not been reported in the literature so far. In this paper, optimisation studies of this system, yields obtained with various monomers and characterisation of the active species are discussed. Variation of different parameters such as the ratio of W(CO) 6 :CBr 4 , the time of photolysis and the effect of solvents as well as that of the metal carbonyls have been studied. In addition, copolymers of phenylacetylene and norbornene have been synthesised. We have also attempted to characterise the active species responsible for the polymerisation by reaction with acetophenone.read more
Citations
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Journal ArticleDOI
Interactions of M(CO)6 (M=Cr, Mo, W) with surface sites of Al2O3: a theoretical study
TL;DR: In this article, the first interaction steps of Group VI hexacarbonyls with different surface sites of alumina were modelled by a computational, non-local, density-functional theory method.
Book ChapterDOI
Tungsten Compounds with CO or Isocyanides
Murray V. Baker,David Brown +1 more
TL;DR: A critical review of tungsten compounds containing carbonyl and/or isocyanide ligands is presented in this paper, where the compounds containing heteroatom or carbon π- and σ-donor ligands are covered within donor type groupings.
Book ChapterDOI
Polymerisation of Cyclic Olefins and Alkynes by Sevencoordinate Tungsten (II) and Molybdenum (II) Compounds
TL;DR: In this article, a review summarises the most interesting approaches in the polymerisation of alkynes and the ring opening metathesis polymerization of cyclic olefins catalysed by seven-coordinate tungsten and molybdenum(II) compounds.
Journal ArticleDOI
Tungsten Oxo and Tungsten Imido Alkylidene N-Heterocyclic Carbene Complexes for the Visible-Light-Induced Ring-Opening Metathesis Polymerization of Dicyclopentadiene
TL;DR: In this article , a system for the visible-light-controlled ring-opening metathesis polymerization (ROMP) of endo,endo-dicyclopentadiene (DCPD) was developed by combining thermally latent group 6 olefin initiators, whose vacant binding site is occupied by N-heterocyclic carbene (NHC), with a photoredox catalyst.
References
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Journal ArticleDOI
A novel route to block copolymers by changing the mechanism from living ring-opening metathesis polymerization of cyclic olefins to aldol condensation polymerization of silyl vinyl ethers
Wilhelm Risse,Robert H. Grubbs +1 more
TL;DR: Synthese de polynorbornene et poly(exodicyclopentadiene) avec un groupe terminal aldehyde par polymerisation puis reaction avec le terephtalaldehyde as discussed by the authors.
Journal ArticleDOI
Block and graft copolymers by living ring-opening olefin metathesis polymerization
Wilhelm Risse,Robert H. Grubbs +1 more
TL;DR: A review of titanacyclobutane-initiated "living" olefin metathesis polymerization for the preparation of new polymer structures is given in this paper, where the same type of reaction was used to link preformed polymer blocks to give ABA-type triblock copolymers and graft Copolymers.
Journal ArticleDOI
Reaction de metathese des olefines induite photochimiquement en presence d'un complexe de metal de transition : VI. Existence probable d'un metallodichlorocarbene primaire
TL;DR: In this paper, a mechanism for the formation of these compounds is outlined, and the mechanism for their formation is described in terms of the insertion of metalladichlorocarbene moieties into the carbon double bond.
Journal ArticleDOI
The photoinduced metathesis of olefin catalyzed by W(CO)5L-AXn system
TL;DR: In this article, the metathesis of internal and terminal olefins was investigated in photocatalytic systems containing tungsten compounds of the type W(CO)5L (L = CO, py, PPh3, Cl−).
Journal ArticleDOI
From the reaction of metal—carbene complexes with cyclic enol ethers to the synthesis and structure of μ-alkylidene complexes of tungsten and their possible implication in the olefin metathesis reaction
TL;DR: The reaction of a metathesis catalyst prepared from W(CO) 6 /CCl 4 /hν with cyclic enol ethers gives products arising from the probable insertion of a dichlorocarbene complex of tungsten into the carbon-carbon double bond.