Journal of Organic Chemistry, volume 70, issue 12, pages 4687-4694

Novel Ruthenium-Based Metathesis Catalysts Containing Electron- Withdrawing Ligands:  Synthesis, Immobilization, and Reactivity

Tobias S. Halbach 1
, 
Stefan Mix 1
, 
Dirk Fischer 1
, 
Simon Maechling 1
, 
Jens O Krause 1
, 
Carsten Sievers 1
, 
Siegfried Blechert 1
, 
Oskar Nuyken 1
, 
Michael R. Buchmeiser 1
Show full list: 9 authors
1
 
Publication type: Journal Article
Publication date: 2005-05-05
scimago Q2
SJR: 0.724
CiteScore: 6.2
Impact factor: 3.3
ISSN: 00223263, 15206904
DOI:  10.1021/jo0477594
PubMed ID:  15932306
Organic Chemistry
Abstract
The syntheses and reactivity of seven different ruthenium-based metathesis catalysts are described. Ru(CF3COO)2(PCy3)(=CH-2-(2-PrO)C6H4) (1), Ru(CF3COO)2(1,3-dimesityldihydroimidazolin-2-ylidene)(=CH-2-(2-PrO)C6H4) (2), and Ru(CF3COO)2(PCy(3))(1,3-dimesityldihydroimidazolin-2-ylidene)(=CHC6H5) (3) were prepared via chlorine exchange by reacting RuCl2(PCy3)2(=CH-2-(2-PrO)C6H4), RuCl2(1,3-dimesityldihydroimidazolin-2-ylidene)(=CH-2-(2-PrO)C6H4), and RuCl2(PCy3)(1,3-dimesityldihydroimidazolin-2-ylidene)(=CHC6H5), respectively, with silver trifluoroacetate (Cy =cyclohexyl). In analogy, Ru(CF3CF2COO)2(1,3-dimesityldihydroimidazolin-2-ylidene)(=CH-2-(2-PrO)C6H4) (4) and Ru(CF3CF2CF2COO)2(1,3-dimesityldihydroimidazolin-2-ylidene)(=CH-2-(2-PrO)C6H4) (5) were prepared from RuCl2(1,3-dimesityldihydroimidazolin-2-ylidene)(=CH-2-(2-PrO)C6H4) via reaction with CF3CF2COOAg and CF3CF2CF2COOAg, respectively. Ru(C6F5COO)2(1,3-dimesityldihydroimidazolin-2-ylidene)(=CH-2-(2-PrO)C6H4) (6) and Ru(C6F5O)2(1,3-dimesityldihydroimidazolin-2-ylidene)(=CH-2-(2-PrO)C6H4) (7) were prepared from RuCl2(1,3-dimesityldihydroimidazolin-2-ylidene)(=CH-2-(2-PrO)C6H4) via reaction with C6F5COOTl and C6F5OTl, respectively. Supported catalysts Ru(PS-DVB-CH2OOCCF2CF2CF2COO)(CF3COO)(PCy3)(1,3-dimesityldihydroimidazolin-2-ylidene)(=CHC6H5) (8), Ru(PS-DVB-CH2OOCCF2CF2CF2COO)(CF3COO)(PCy3)(=CH-2-(2-PrO)C6H4) (9), and Ru(PS-DVB-CH2OOCCF2CF2CF2COO)(CF3COO)(1,3-dimesityldihydroimidazolin-2-ylidene)(=CH-2-(2-PrO)C6H4) (10) were synthesized by reaction of RuCl2(PCy3)(1,3-dimesityldihydroimidazolin-2-ylidene)(=CHC6H5), RuCl2(PCy3)(=CH-2-(2-PrO)C6H4), and RuCl2(1,3-dimesityldihydroimidazolin-2-ylidene)(=CH-2-(2-PrO)C6H4), respectively, with a perfluoroglutaric acid-derivatized poly(styrene-co-divinylbenzene) (PS-DVB) support (silver form). Halogen exchange in PCy3-containing systems had to be carried out in dichloromethane in order to suppress precipitation of AgCl.PCy3. The reactivity of all new catalysts in ring-closing metathesis (RCM) of hindered electron-rich and -poor substrates, respectively, at elevated temperature (45 degrees C) was compared with that of existing systems. Diethyl diallylmalonate (DEDAM, 11), diethyl allyl(2-methylallyl)malonate (12), N,N-diallyl-p-toluenesulfonamide (13), N-benzyl-N-but-1-en-4-ylbut-2-enecarboxylic amide (14), and N-allyl-N-(1-carboxymethyl)but-3-en-1-yl-p-toluenesulfonamide (15) were used as educts. Supported catalysts were prepared with high loadings (2.4, 22.1, and 160 mg of catalyst/g PS-DVB for 8, 9, and 10, respectively). Catalyst 8 showed higher and catalysts 9 and 10 sowed significantly reduced activities in RCM compared to their homogeneous analogues. Thus, with 8, turnover numbers (TONs) up to 4200 were realized in stirred-batch (carousel) RCM experiments. To elucidate the nature of the bound species, catalysts 8-10 were subjected to 13C- and 31P-MAS NMR spectroscopy. These investigations provided evidence for the proposed structures. Leaching of ruthenium into the reaction mixture was low, resulting in ruthenium contents <85 ppb (ng/g) in the final RCM-derived products.
Found 17
By date By citations
Wiley
Novel Metathesis Catalysts Based on Ruthenium 1,3-Dimesityl-3,4,5,6-tetrahydropyrimidin-2-ylidenes: Synthesis, Structure, Immobilization, and Catalytic Activity
Yang L., Mayr M., Wurst K., Buchmeiser M.R.
Chemistry - A European Journal scimago Q1 wos Q2 , 
2004-11-19,  citations by CoLab: 166 ,  Abstract  
The synthesis of novel ruthenium-based metathesis catalysts containing the saturated 1,3-bis(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene ligand, that is, [RuCl2(NHC)[=CH-2-(2-PrO)-5-NO(2)-C6H3]] (1) and [Ru(CF3COO)2(NHC)[=CH-2-(2-PrO)-5-NO2-C6H3]] (2) (NHC=1,3-bis(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene) is described. Both catalysts are highly active in ring-closing metathesis (RCM) and ring-opening cross-metathesis (ROCM). Compound 1 shows moderate activity in enyne metathesis. Compound 2 is not applicable to enyne metathesis since it shows high activity in the cyclopolymerization of diethyl dipropargylmalonate (DEDPM). Poly(DEDPM) prepared by the action of 2 consists of 95% five-membered rings, that is, poly(cyclopent-1-enevinylene)s, and 5 % of six-membered rings, that is, poly(cyclohex-1-ene-3-methylidene)s. The polymerization proceeds in a nonliving manner and results in polyenes with broad polydispersities (1.9< or =PDI< or =2.3). Supported analogues of 2 were prepared by immobilization on hydroxymethyl-Merrifield resin and a monolithic support derived from ring-opening-metathesis polymerization (ROMP). Catalyst loadings of 1 and 2.5%, respectively, were obtained. Both supported versions of 2 showed excellent reactivity. With 0.24-2% of the supported catalysts, yields in RCM and ROCM were in the range of 76-100%. Leaching of ruthenium was low and resulted in Ru contaminations of the products of less than 0.000014% (0.14 ppm).
American Chemical Society (ACS)
Ortho- and Para-Substituted Hoveyda−Grubbs Carbenes. An Improved Synthesis of Highly Efficient Metathesis Initiators
Bujok R., Bieniek M., Masnyk M., Michrowska A., Sarosiek A., Stȩpowska H., Arlt D., Grela K.
Journal of Organic Chemistry scimago Q2 wos Q1 , 
2004-08-27,  citations by CoLab: 72 ,  Abstract  
A novel highly efficient and general route to various 3- and 5-substituted 2-alkoxystyrenes, required for the preparation of Hoveyda-Grubbs catalysts, is described.
American Chemical Society (ACS)
Nitro-Substituted Hoveyda−Grubbs Ruthenium Carbenes:  Enhancement of Catalyst Activity through Electronic Activation
Michrowska A., Bujok R., Harutyunyan S., Sashuk V., Dolgonos G., Grela K.
Journal of the American Chemical Society scimago Q1 wos Q1 , 
2004-07-13,  citations by CoLab: 434 ,  Abstract  
The design, synthesis, stability, and catalytic activity of nitro-substituted Hoveyda-Grubbs metathesis catalysts are described. The highly active and stable meta- and para-substituted complexes are attractive from a practical point of view. These catalysts operate in very mild conditions and can be successfully applied in various types of metathesis [ring-closing metathesis, cross-metathesis (CM), and enyne metathesis]. Although the presence of a NO(2) group leads to catalysts that are dramatically more active than both the second-generation Grubbs's catalyst and the phosphine-free Hoveyda's carbene, enhancement of reactivity is somewhat lower than that observed for a sterically activated Hoveyda-Grubbs catalyst. Attempts to combine two modes of activation, steric and electronic, result in severely decreasing a catalyst's stability. The present findings illustrate that different Ru catalysts turned out to be optimal for different applications. Whereas phosphine-free carbenes are catalysts of choice for CM of various electron-deficient substrates, they exhibit lower reactivity in the formation of tetrasubstituted double bonds. This demonstrates that no single catalyst outperforms all others in all possible applications.
Royal Society of Chemistry (RSC)
Recent advances in the synthesis of supported metathesis catalysts
Buchmeiser M.R.
New Journal of Chemistry scimago Q2 wos Q2 , 
2004-05-10,  citations by CoLab: 125 ,  Abstract  
The state of the art and recent developments in the synthesis of supported, well-defined metathesis catalysts are reviewed. In this context, their synthesis, selected properties and application to both polymer and organic chemistry are summarised. Special consideration will be given to aspects of activity [discussed in terms of turnover numbers (TONs) and turn over frequencies (TOFs)], regioselectivity and enantioselectivity as well as stability. The general applicability of these supported catalysts to either high-throughput technology or to the manufacture of continuous flow systems is discussed.
Wiley
Cyclopropane-Annelated Azaoligoheterocycles by Ti-Mediated Intramolecular Reductive Cyclopropanation of Cyclic Amino Acid Amides
Gensini M., de Meijere A.
Chemistry - A European Journal scimago Q1 wos Q2 , 
2004-02-06,  citations by CoLab: 31 ,  Abstract  
Starting from pyrrole- and indole-2-carboxylic acids 5 a and 5 b, the tri- and tetracyclic N,N-dibenzylcyclopropylamines 7 a and 7 b have been synthesized in 52 and 33 % overall yield, respectively. The synthesis of the enantiopure tetracyclic diamine 10 has been achieved applying the established set of reactions to N-tert-butoxycarbonylindoline-2-carboxylic acid (8) in 46 % overall yield. The amide 15 could not be prepared in the same way starting from the N-tert-butoxycarbonylproline 11. In fact, in the allylation step the stereogenic center was deprotonated and the doubly alkylated amide 13 was formed. However, the desired intermediate 15 could be obtained from L-proline in 49 % yield performing first the N-allylation step, then the introduction of the amide function. From 15, the cyclopropane-annelated pyrrolizidine 16 was obtained in 70 % yield as a mixture of (1aS,6aS,6bR)-16 and (1aR,6aS,6bS)-16 diastereoisomers in a ratio of 1:2.9.
Wiley
Heterogenization of a Modified Grubbs–Hoveyda Catalyst on a ROMP-Derived Monolithic Support
Krause J.O., Lubbad S.H., Nuyken O., Buchmeiser M.R.
Macromolecular Rapid Communications scimago Q1 wos Q2 , 
2003-10-22,  citations by CoLab: 96 ,  Abstract  
A ring-opening metathesis polymerization- (ROMP-) based monolith was synthesized using a Grubbs' first generation catalyst. The living termini were used for surface grafting of norborn-5-ene-2-ylmethyl hexafluoroglutarate. The free carboxylic acid groups of the graft polymer were converted into the corresponding silver salt and reacted with the Grubbs-Hoveyda catalyst [RuCl 2 -(=CH-(2-iPrO-)C 6 H 4 )(IMesH 2 )] (IMesH 2 = 1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene) to yield a stable heterogeneous version of this catalyst for use in ring-closing metathesis (RCM) under continuous flow condition. The monolith-supported Grubbs-Hoveyda catalyst.
Elsevier
Ruthenium olefin metathesis catalysts with modified styrene ethers: influence of steric and electronic effects
Zaja M., Connon S.J., Dunne A.M., Rivard M., Buschmann N., Jiricek J., Blechert S.
Tetrahedron scimago Q3 wos Q2 , 
2003-08-12,  citations by CoLab: 137 ,  Abstract  
A series of olefin metathesis catalysts with modified isopropoxybenzylidene ligands were synthesised, and the effects of ligands on the rate of metathesis investigated. Increased steric hinderance ortho to the isopropoxy group enhanced reaction rates. In the case of N -heterocyclic carbene complexes, decreasing electron density at both the chelating oxygen atom and the RuC bond accelerated reaction rates appreciably. Catalysts containing a tricyclohexylphosphane ligand, followed the same trend with regard to benzylidene electrophilicity, while higher electron density at oxygen enhanced reaction rates.
Wiley
Monolith- and Silica-Supported Carboxylate-Based Grubbs–Herrmann-Type Metathesis Catalysts
Krause J., Lubbad S., Nuyken O., Buchmeiser M.
Advanced Synthesis and Catalysis scimago Q1 wos Q1 , 
2003-08-08,  citations by CoLab: 108 ,  Abstract  
The synthesis of silica- and monolith-supported Grubbs–Herrmann-type catalysts is described. Two polymerizable, carboxylate-containing ligands, exo, exo-7-oxanorborn-2-ene-5,6-dicarboxylic anhydride and 7-oxanorborn-2-ene-5-carboxylic acid were surface-immobilized onto silica- and ring-opening metathesis (ROMP-) derived monolithic supports using “grafting-from” techniques. The “1st generation Grubbs catalyst”, RuCl2(CHPh)(PCy3)2, was used for these purposes. In addition, a poly(norborn-2-ene-b-exo, exo-norborn-2-ene-5,6-dicarboxylic anhydride)-coated silica 60 was prepared. The polymer supported anhydride and carboxylate groups were converted into the corresponding mono- and disilver salts, respectively, and reacted with the Grubbs–Herrmann catalyst RuCl2(CHPh)(IMesH2)(PCy3) [IMesH2=1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene]. Heterogenization was accomplished by exchange of one chlorine ligand with the polymeric, immobilized silver carboxylates to yield monolith-supported catalysts 4, 5, and 6 as well as silica-supported systems 7, 8 and 9. The actual composition of these heterogenized catalysts was proven by the synthesis of a homogeneous analogue, RuCl[7-oxanorbornan-2-(COOAg)-3-COO](CHPh)(IMesH2)(PCy3) (3). All homogeneous and heterogeneous catalysts were used in ring-closing metathesis (RCM) of diethyl diallylmalonate, 1,7-octadiene, diallyldiphenylsilane, methyl trans-3-pentenoate, diallyl ether, N,N-diallyltrifluoracetamide and t-butyl N,N-diallylcarbamate allowing turnover numbers (TON's) close to 1000. In a flow-through set-up, an auxiliary effect of pendant silver carboxylates was observed with catalyst 5, where the silver moiety functions as a (reversible) phosphine scavenger that both accelerates initiation and stabilizes the catalyst by preventing phosphine elution. Detailed catalytic studies were carried out with the monolith-supported systems 4 and 6 in order to investigate the effects of temperature and chain-transfer agents (CTA's) such as cis-1,4-diacetoxybut-2-ene. In all RCM experiments Ru-leaching was low, resulting in a Ru-content of the RCM products ≤3.5 μg/g (3.5 ppm).
Wiley
Grela K., Harutyunyan S., Michrowska A.
Angewandte Chemie , 
2002-11-04,  citations by CoLab: 106 , 
Wiley
Ein selbstgenerierender, hochaktiver und wiederverwendbarer Katalysator für die Olefinmetathese
Connon S.J., Dunne A.M., Blechert S.
Angewandte Chemie , 
2002-10-18,  citations by CoLab: 33 , 
Wiley
Photochemical Sensing of NO2 with SnO2 Nanoribbon Nanosensors at Room Temperature
Law M., Kind H., Messer B., Kim F., Yang P.
Angewandte Chemie , 
2002-07-03,  citations by CoLab: 164 ,  Abstract  
Gute Kandidaten für miniaturisierte, hochempfindliche Gassensoren für viele Anwendungen sind einzelne einkristalline SnO2-Nanobänder. Hier wird gezeigt, dass sie zum Nachweis von NO2 im ppm-Bereich bei Raumtemperatur und Bestrahlung mit UV-Licht geeignet sind. Das Bild illustriert, dass sie bei Licht der Wellenlänge 365 nm sogar nahe der Grenze ihres Nachweisvermögens verlässlich arbeiten.
Elsevier
Synthesis and application of a new polystyrene-supported ruthenium carbene catalyst for alkene metathesis
Nieczypor P., Buchowicz W., Meester W.J., Rutjes F.P., Mol J.C.
Tetrahedron Letters scimago Q3 wos Q3 , 
2001-10-01,  citations by CoLab: 78 ,  Abstract  
A ruthenium carbene complex was permanently immobilised on a functionalised polystyrene resin by reaction with a supported silver salt of a carboxylic acid. The catalyst thus prepared was active in the self-metathesis of internal alkenes as well as in ring-closing metathesis. It was easily separated from the reaction products, which were almost free from ruthenium contamination, and also recycled.
American Chemical Society (ACS)
Enantioselective Ruthenium-Catalyzed Ring-Closing Metathesis
Seiders T.J., Ward D.W., Grubbs R.H.
Organic Letters scimago Q1 wos Q1 , 
2001-09-08,  citations by CoLab: 387 ,  Abstract  
[reaction: see text] The first enantioselective ruthenium olefin metathesis catalysts have been prepared, and high enantiomeric excesses (up to 90%) are observed in the desymmetrization of achiral trienes. A model consistent with the stereochemical outcome of the reactions is described and suggests side-on olefin binding and reorganization of the halide ligands.
Elsevier
Synthesis and metathesis reactions of a phosphine-free dihydroimidazole carbene ruthenium complex
Gessler S., Randl S., Blechert S.
Tetrahedron Letters scimago Q3 wos Q3 , 
2000-12-01,  citations by CoLab: 472 ,  Abstract  
Synthesis and activity in ring closure metathesis (RCM) and cross metathesis (CM) of the phosphine-free 1,3-dimesityl-4,5-dihydroimidazole-2-ylidene (IHMes) ruthenium alkoxybenzylidene complex 6 are reported.
American Chemical Society (ACS)
The Development of L2X2RuCHR Olefin Metathesis Catalysts:  An Organometallic Success Story
Trnka T.M., Grubbs R.H.
Accounts of Chemical Research scimago Q1 wos Q1 , 
2000-11-04,  citations by CoLab: 3279 ,  Abstract  
In recent years, the olefin metathesis reaction has attracted widespread attention as a versatile carbon-carbon bond-forming method. Many new applications have become possible because of major advances in catalyst design. State-of-the-art ruthenium catalysts are not only highly active but also compatible with most functional groups and easy to use. This Account traces the ideas and discoveries that were instrumental in the development of these catalysts, with particular emphasis on (PCy3)2Cl2Ru=CHPh and its derivatives. The discussion includes an analysis of trends in catalyst activity, a description of catalysts coordinated with N-heterocyclic carbene ligands, and an overview of ongoing work to improve the activity, stability, and selectivity of this family of L2X2Ru=CHR complexes.
Found 129
By date By citations
Elsevier
Recovery and Reuse of Metal Complex Catalysts
Cseri L.
2025-01-01,  citations by CoLab: 0 , 
Springer Nature
Ring closing metathesis reaction of citronellene by utilizing simple mesoporous SBA-15-loaded ruthenium alkylidene supercatalyst
Shinde T., Jirimali H.
Research on Chemical Intermediates scimago Q2 wos Q2 , 
2024-06-09,  citations by CoLab: 0 ,  Abstract  
The immobilization of Hoveyda–Grubbs form of metathesis catalyst (Z.C.) exhibited simple non-covalent interactions with the mesoporous SBA-15. It was discovered that the Z.C. catalyst worked well to speed up the citronellene ring closing metathesis reaction. Using cyclohexane as a solvent, the citronellene ring closing metathesis reaction was performed at various temperatures. A very low (almost negligible) catalyst leaching was observed. A high turnover number (TON) was obtained by using a very small amount of catalyst. The activation energy was calculated in the case of ring closing metathesis reaction of citronellene at different temperatures. By using the high concentration of citronellene, a high TON was obtained (4674), which indicates that active catalytic centers were not demolished by a large concentration of citronellene molecule. Turnover number (264) was produced when the Ru/substrate molar ratio 1:300 used in the reaction.
Ring closing metathesis reaction of citronellene by utilising simple mesoporousSBA-15 loaded ruthenium alkylidene supercatalyst
Shinde T., Jirimali H.
2024-02-09,  citations by CoLab: 0 ,  Abstract  
Abstract The immobilization of Hoveyda Grubbs form of metathesis catalyst (Z.C.) exhibited simple non-covalent interactions with the mesoporous SBA-15.It was discovered that the Z.C. catalyst worked well to speed up the citronellene ring closing metathesis reaction. Using cyclohexane as a solvent, the citronellene ring closing metathesis reaction was performed at various temperatures.A very low (almost negligible) catalyst leaching was observed. A high turnover number (TON) was obtained by using a very small amount of catalyst. The activation energy was calculated in the case of ring closing metathesis reaction of citronellene at different temperatures. By using the high concentration of citronellene, a high turnover number was obtained (4674), which indicates that active catalytic centers were not demolished by a large concentration of citronellene molecule. Turnover number (264) was produced when the Ru/substrate molar ratio 1:300 was used.
MDPI
Tuning the Latency by Anionic Ligand Exchange in Ruthenium Benzylidene Phosphite Complexes
Alassad N., Phatake R.S., Baranov M., Reany O., Lemcoff N.G.
Catalysts scimago Q2 wos Q2 Open Access , 
2023-11-02,  citations by CoLab: 1 ,  PDF,  Abstract  
Recently discovered cis-dichloro benzylidene phosphite complexes are latent catalysts at room temperature and exhibit exceptional thermal and photochemical activation behavior in olefin metathesis reactions. Most importantly, the study of these catalysts has allowed their introduction in efficient 3-D printing applications of ring-opening metathesis derived polymers and the control of chromatically orthogonal chemical processes. Moreover, their combination with plasmonic Au-nanoparticles has given rise to novel smart materials that are responsive to light. Given the importance of the ligand shell in the initiation and reactivity behavior of this family of complexes, we set out to investigate the effect of anionic ligand exchange. Thus, we report herein two new ruthenium benzylidene benzylphosphite complexes where the chloride anionic ligands have been replaced by bromide and iodide anions (cis-Ru-Phos-Br2 & cis-Ru-Phos-I2). The thermal and photochemical activations of these dormant catalysts in a variety of ring-closing and ring-opening metathesis polymerization (RCM and ROMP) reactions were thoroughly studied and compared with the previously known chloride precatalyst. Photochemical RCM studies provided similar results, especially in non-hindered reactions, with the UV-A wavelength being the best in all cases. On the other hand, the thermal activation profile exposed that the anionic ligand significantly affects reactivity. Notably, cis-Ru-Phos-I2 disclosed particularly impressive initiation efficiency compared to the other members of the family.
Elsevier
Heterogeneous catalysts for olefin metathesis
Barteczko N., Grymel M., Chrobok A.
Catalysis Communications scimago Q2 wos Q2 Open Access , 
2023-04-06,  citations by CoLab: 13 ,  Abstract  
Over the past 30 years, many strategies have been developed to immobilize well-defined metathesis catalysts on solid supports. The use of heterogeneous catalysis resulted in increased purity of the product and the possibility of recycling the catalyst. This review presents the short history of heterogeneous catalysts used in numerous types of olefin metathesis with particular emphasis on examples from recent years. The main focus was put on immobilized ruthenium alkylidene complexes based on ionic liquids, as a new promising approach, which includes noncovalent immobilization that gained interest recently. Methods of attaching catalysts and types of carriers are also presented. Homogeneous catalysts are discussed in order to emphasize the influence and potential of immobilization on the activity and selectivity of heterogeneous catalysts in olefin metathesis.
Wiley
Ring‐Opening Metathesis Polymerization: Mechanisms
Herz K., Elser I., Buchmeiser M.R.
2022-03-04,  citations by CoLab: 3 ,  Abstract  
Abstract This article covers the basic principles of modern, well‐defined group 6 and group 8 metal alkylidene catalysts and their use in ring‐opening metathesis polymerization (ROMP). In this context, the expression “well‐defined” refers to catalytic systems that are characterized by a uniform and stoichiometric composition and for which the actual propagating species is well known and characterized. Such catalysts allow for the controlled, sometimes living, ROMP, which is of advantage for a variety of purposes. Generally, one particularity of ROMP is the formation of either cis ‐ or trans ‐double bonds along the polymer chain. Their formation during ROMP is strongly related to the catalyst used. In addition, tactic ROMP‐derived polymers are accessible. The influence of the alkylidene configuration and chirality of the catalysts on the microstructure of the resulting polymers as well as the different mechanisms that lead to tactic structures are outlined.
Polymers Incorporating Ru Complexes
Schubert U.S., Winter A., Newkome G.R.
2021-06-17,  citations by CoLab: 0 ,  Abstract  
Ru complexes might represent integral parts of a polymer—either within the backbone, the side chains or at the chain ends. Such polymers can be prepared via different synthetic routes, which have been adapted from conventional polymer science. The different synthetic strategies and types of Ru-containing polymers are discussed, taking also their characterization, properties and (potential) applications into account. In this respect, opto-electronics, photovoltaics, catalysis, and medicine have to be named as prominent areas of research.
Elsevier
Metal-Carbon Bonds of Heavier Group 7 and 8 Metals (Tc, Re, Ru, Os): Mononuclear Tc/Re/Ru/Os Complexes With Metal-Carbon Bonds
Wei W., Jia G.
2021-05-21,  citations by CoLab: 1 ,  Abstract  
The coordination chemistry of ruthenium, osmium, technetium and rhenium with carbon-based ligands covering the literature from 2003 to 2018 is discussed. These metals form a vast number of coordination compounds with carbon-based ligands ranging from a single carbon atom (a carbido ligand) to polydentate hydrocarbon chains, and from monodentate organometallic ligands such as carbenes to multidentate ligands such as pincers and macrocycles. Particular focus of this review is given to syntheses, properties and applications of complexes with popular carbon-based ligands such as monodentate N-heterocyclic carbenes (NHCs), cyclometallated bidentate ligands, tridentate pincers and porphyrin-like macrocycles.
Autonomous Non-profit Organization Editorial Board of the journal Uspekhi Khimii
Fluorine-containing ruthenium-based olefin metathesis catalysts
Masoud S.M., Vorobyeva D.V., Petropavlovskikh D.A., Bruneau C., Osipov S.N.
Russian Chemical Reviews scimago Q1 wos Q1 Open Access , 
2021-04-01,  citations by CoLab: 6 ,  Abstract  
The review summarizes literature data on the methods for the introduction of fluorine atoms and fluoralkyl groups into different ligands to construct metathesis-active ruthenium carbene complexes. It also analyzes the influence of fluorinated ligands on the catalytic activity of the complexes. The choice, structure and positions of fluorinated substituents in NHC ligands are generally dictated by the desire to increase the electrophilicity of the ruthenium atom due to the electron-withdrawing effect of fluorine atoms and fluoroalkyl groups, resulting, as a rule, in an increase in the activity of the ruthenium complex. In catalysts with unsymmetrical fluorine-containing NHC ligands, there is a possibility of additional Ru–F coordination, making the complexes much more stable and, consequently, more active. The presence of fluorine in chelating alkylidene ligands provides an increase in the catalyst initiation rate due to a weakening of the ruthenium – heteroatom bond. Besides, the introduction of polyfluoroalkyl groups into ligands solves the problem of catalyst recovery using fluorous biphasic systems for reuse. The bibliography includes 172 references.
Springer Nature
Modern Approaches to the Creation of Immobilized Metal-Complex Catalysts for Hydrogenation, Alkene Metathesis, and Cross-Coupling Processes: A Review
Ivanytsya M.O., Ryabukhin S.V., Volochnyuk D.M., Kolotilov S.V.
Theoretical and Experimental Chemistry scimago Q3 wos Q4 , 
2020-11-28,  citations by CoLab: 6 ,  Abstract  
The approaches to immobilization of metal-complex catalysts for organic processes of hydrogenation, alkene metathesis, and cross-coupling on silica and polymeric and other carriers are considered. The advantages and lack of modern approaches to the creation of such systems are analyzed. It was shown that the stability of the catalyst with immobilized metal complex in the respective process was directly related to the mechanism of its catalytic action, namely, ligand cleavage in the catalytic cycle. Among the considered catalysts for various types of reactions, the catalysts for hydrogenation processes had the highest stability; this peculiarity is associated with specific features of their action.
Pleiades Publishing
Ion-Functionalized Silver(I) Carboxylates: Synthesis and Application in Ru-Catalyzed Olefin Metathesis Reaction
Chen X., Li X., Li S., Bai X., Li T., Goud E.Y., Zhong C., Zuo Y.
Russian Journal of General Chemistry scimago Q4 wos Q4 , 
2020-11-01,  citations by CoLab: 1 ,  Abstract  
The Grubbs–Hoveyda catalysts have a wide range of applications in catalyzed formation of the carbon-carbon double bonds. In this study, several imidazolium- functionalized or pyridinium-functionalized silver carboxylates have been prepared, and their reaction with Grubbs–Hoveyda 2nd generation (G–H 2nd) catalyst leads a new type of processes. Activity and selectivity of the catalysts have been preliminarily evaluated using cross olefin metathesis reactions.
American Chemical Society (ACS)
Integrated Batch and Continuous Flow Process for the Synthesis of Goniothalamin
Pastre J.C., Murray P.R., Browne D.L., Brancaglion G.A., Galaverna R.S., Pilli R.A., Ley S.V.
ACS Omega scimago Q2 wos Q2 Open Access , 
2020-07-17,  citations by CoLab: 18 ,  PDF,  Abstract  
An integrated batch and continuous flow process has been developed for the gram-scale synthesis of goniothalamin. The synthetic route hinges upon a telescoped continuous flow Grignard addition followed by an acylation reaction capable of delivering a racemic goniothalamin precursor (16) (20.9 g prepared over 3 h), with a productivity of 7 g·h-1. An asymmetric Brown allylation protocol was also evaluated under continuous flow conditions. This approach employing (-)-Ipc2B(allyl) provided an (S)-goniothalamin intermediate in 98% yield and 91.5% enantiomeric excess (ee) with a productivity of 1.8 g·h-1. For the final step, a ring-closing metathesis reaction was explored under several conditions in both batch and flow regimes. In a batch operation, the Grubbs second-generation was shown to be effective and highly selective for the desired ring closure product over those arising from other modes of reactivity, and the reaction was complete in 1.5 h. In a flow operation, reactivity and selectivity were attenuated relative to the batch mode; however, after further optimization, the residence time could be reduced to 16 min with good selectivity and good yield of the target product. A tube-in-tube reactor was investigated for in-situ ethylene removal to favor ring-closing over cross-metathesis, in this context. These results provide further evidence of the utility of flow chemistry for organometallic processing and reaction telescoping. Using the developed integrated batch and flow methods, a total of 7.75 g of goniothalamin (1) was synthesized.
Wiley
Buchmeiser‐Grubbs‐Hoveyda catalyst
Elsner C.
2020-04-16,  citations by CoLab: 0 ,  Abstract  
Buchmeiser-Grubbs-Hoveyda catalyst C. Elsner, C. ElsnerSearch for more papers by this author C. Elsner, C. ElsnerSearch for more papers by this author First published: 16 April 2020 https://doi.org/10.1002/9783527809080.cataz02572 Read the full textAbout ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Catalysis from A to Z: A Concise EncyclopediaBrowse other articles of this reference work:BROWSE A-Z RelatedInformation
Elsevier
Multifunctional conjugated 1,6-heptadiynes and its derivatives stimulated molecular electronics: Future moletronics
Magisetty R., Hemanth N.R., Kumar P., Shukla A., Shunmugam R., Kandasubramanian B.
European Polymer Journal scimago Q1 wos Q1 , 
2020-02-01,  citations by CoLab: 9 ,  Abstract  
Over the past decade conducting polymers have been studied for electronic applications, among them, molecular electronics: the study and investigation of molecular building blocks is a next-generation demanded area of research. Hence, the moletronic equivalent multi-functional advantages of cyclopolymerized 1,6-heptadiyne (HD) systems explored in this review. Further, this report elucidates physical properties via conditional cyclopolymerization methodologies, it describes the chemistry of tethering molecular-chains facilitated intrinsic-conductivity. HD and its derivatives induce superior conductivity characteristics via doping elements, wherein, significant electronic conductivity mechanism is attributable to the solitons and anti-solitons, which was described in this context. HD and their derivatives molecular mechanism, its compatibility are expounded for moletronic application, which is new insight of the article. Moreover, required inherent characteristics, for e.g., thermal-stability, chemical-resistance, mechanical properties, magnetic, and electronic properties have been discussed. Furthermore, failures, physical limitations, and its realizable similarity solutions for moletronics have described. Though electronic or moletronic components having failures and other physical limitations, HDs offers excellent conductivity with wide functional and physical properties that could lead to potential candidates to deliver efficient and low-cost moletronic devices.
Royal Society of Chemistry (RSC)
Supported Ru olefin metathesis catalysts via a thiolate tether
Renom-Carrasco M., Mania P., Sayah R., Veyre L., Occhipinti G., Gajan D., Lesage A., Jensen V.R., Thieuleux C.
Dalton Transactions scimago Q1 wos Q2 , 
2019-02-01,  citations by CoLab: 5 ,  Abstract  
Ruthenium alkylidene complexes can be successfully immobilized on hybrid mesostructured silica via thiolate tethers to give heterogeneous, thiolate-coordinated olefin metathesis catalysts.

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Journal of Organometallic Chemistry
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Chemical Reviews
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