These novel single-site ruthenium metathesis catalysts lead to high performances in various reactions of this type, particularly in cross-metathesis (cm), enyne metathesis, ring-closing metathesis (rcm), ring-opening metathesis (rom) and ring-opening metathesis polymerisation (romp. Skip to main content journals books register sign in books register sign in. Ty - jour t1 - a novel class of ruthenium catalysts for olefin metathesis au - weskamp,t au - schattenmann,w c au - spiegler,m au - herrmann,w a. The catalyst's main point of activity with regard to olefin metathesis is the ru=c bond, commonly called a ruthenium carbene 30-32 this catalyst has a greater tolerance for water and air than many previous ruthenium- and molybdenum-based.
The decomposition of a series of ruthenium metathesis catalysts has been examined using methylidene species as model complexes all of the phosphine-containing methylidene complexes decomposed to generate methylphosphonium salts, and their decomposition routes followed first-order kinetics. Abstract sixteen novel, ru-based olefin metathesis catalysts bearing ph responsive ligands were synthesized the ph-responsive groups employed with these catalysts included dimethylamino (nme 2) modified nhc ligands as well as n-donor dimethylaminopyridine (dmap) and 3-(o-pyridyl)propylidene ligands. Two new ru-based metathesis catalysts, 3 and 4, have been synthesized for the purpose of comparing their catalytic properties to those of their cis-selective nitrate analogues, 1 and 2. Novel η 3-vinylcarbene complexes derived from ruthenium-based olefin metathesis catalysts tina m trnka , michael w day , and robert h grubbs arnold and mabel beckman laboratory of chemical synthesis, division of chemistry and chemical engineering, california institute of technology, pasadena, california 91125.
Next article in issue: the stability of the oxidation state +4 in group 14 compounds from carbon to element 114 next article in issue: the stability of the oxidation state +4 in group 14 compounds from carbon to element 114. Of ruthenium and rhodium complexes jun 26, 1998 the present invention relates to novel metathesis catalysts with an imidazolidine-based ligand and to. Grubbs' catalysts are a series of transition metal carbene complexes used as catalysts for olefin metathesis they are named after robert h grubbs , the chemist who supervised their synthesis several generations of the catalyst have been developed. Novel metathesis chemistry : well-defined initiator systems for specialty chemical synthesis, tailored polymers, and advanced material applications . 1) stable hoveyda-type olefin metathesis catalyst nitro-grela is a ruthenium complex developed by grela et al and is effectively used for trans-selective olefin metathesis reactions nitro-grela has an isopropoxy group on a phenylvinylidene moiety offering coordination to a ruthenium metal while bearing an electron-withdrawing nitro group.
Ring-closing metathesis is a variant of the olefin metathesis reaction in which alkylidene moieties are exchanged to form a ring the most common catalysts for this reaction are complexes of molybdenum or ruthenium. The present invention relates to a novel class of ruthenium and osmium olefin metathesis catalysts having a general formula (a) or (b) and isomers thereof: wherein (i) m is ruthenium or osmium, preferably ruthenium. Olefin metathesis is an organic reaction that entails the redistribution of fragments of alkenes (olefins) by the scission and regeneration of carbon-carbon double bonds   because of the relative simplicity of olefin metathesis, it often creates fewer undesired by-products and hazardous wastes than alternative organic reactions.
15 ruthenium-indenylidene and other alkylidene containing olefin metathesis catalysts 417 césar a urbina-blanco, stefano guidone, steven p nolan, and catherine s j cazin 16 hoveyda-type olefin metathesis complexes 437. In 1999, a new class of olefin metathesis catalysts with an isopropoxy group on the benzylidene moiety, [ru]3, was reported by hoveyda and coworkers soon thereafter, the second-generation hoveyda-grubbs catalysts were reported, all incorporating an nhc ligand ( [ru]4 is one example. Ruthenium-based metathesis catalysts introduction olefin metathesis is now a well-entrenched synthetic technique, and is a powerful method for the clean construction of innumerable classes of chemical architectures.
In olefin metathesis reactions, the disclosed catalysts provide a high catalytic activity combined with the capability to generate higher yields of the olefin metathesis product the present invention refers to novel ruthenium-based catalysts for olefin metathesis reactions, particularly to fast initiating catalysts having stereoselective. Ruthenium-based catalysts for olefin metathesis have attained enormous attention during the past years recently we have shown that the application of n-heterocyclic carbenes extends and. The potential catalytic behaviour of a novel class of olefin metathesis catalysts, 1 and we wish to use density functional theory (dft) based calculations to characterize a new catalyst.
 this invention relates to a novel class of olefin metathesis catalysts, methods of preparation, and to processes using the olefin metathesis catalysts background of the invention  in organic synthesis, a metathesis reaction is a catalytic reaction in which recombination of the double bonds occurs between two kinds of olefins or. Ruthenium-based olefin metathesis catalysts, known for their functional group tolerance and broad applicability in organic synthesis and polymer science, continue to evolve as an enabling technology in these areas. Olefin metathesis in organic synthesis wendy jen macmillan group meeting january 17, 2001 i well-defined alkene metathesis catalysts ii applications of olefin metathesis.