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1.
Cationic Silica‐Supported N‐Heterocyclic Carbene Tungsten Oxo Alkylidene Sites: Highly Active and Stable Catalysts for Olefin Metathesis 下载免费PDF全文
Margherita Pucino Dr. Victor Mougel Roman Schowner Dr. Alexey Fedorov Prof. Dr. Michael R. Buchmeiser Prof. Dr. Christophe Copéret 《Angewandte Chemie (International ed. in English)》2016,55(13):4300-4302
Designing supported alkene metathesis catalysts with high activity and stability is still a challenge, despite significant advances in the last years. Described herein is the combination of strong σ‐donating N‐heterocyclic carbene ligands with weak σ‐donating surface silanolates and cationic tungsten sites leading to highly active and stable alkene metathesis catalysts. These well‐defined silica‐supported catalysts, [(≡SiO)W(=O)(=CHCMe2Ph)(IMes)(OTf)] and [(≡SiO)W(=O)(=CHCMe2Ph)(IMes)+][B(ArF)4?] [IMes=1,3‐bis(2,4,6‐trimethylphenyl)‐imidazol‐2‐ylidene, B(ArF)4=B(3,5‐(CF3)2C6H3)4] catalyze alkene metathesis, and the cationic species display unprecedented activity for a broad range of substrates, especially for terminal olefins with turnover numbers above 1.2 million for propene. 相似文献
2.
Cherif Larabi Kai C. Szeto Yassine Bouhoute Marc O. Charlin Nicolas Merle Aimery De Mallmann Regis M. Gauvin Laurent Delevoye Mostafa Taoufik 《Macromolecular rapid communications》2016,37(22):1832-1836
Ring opening metathesis polymerization (ROMP) of bicyclo[2.2.1]hept‐2‐ene (norbornene) is carried out over silica‐supported catalysts based on tungsten complexes bearing an oxo ligand ( 1 : [(SiO)W(O)(CH2SiMe3)3, 2 : [(SiO)W(O)(CHCMe2Ph)(dAdPO)], dAdPO 2,6 diadamantyl‐4‐methylphenoxide, 3 : [(SiO)2W(O)(CH2SiMe3)2]). The evaluation of the catalytic activities of the aforementioned materials in ROMP indicates that at low reaction time (0.5 min), the highest polymer yield is obtained with catalyst 2 . However, for longer reaction time (>2 min), complex 3 , a model of the industrial catalyst, exhibits a better monomer conversion. The polymers obtained are characterized. Moreover, these catalysts are shown to be rather preferentially selective to give the cis polynorbornene (>65%), characterized by high melting points (≈300 °C). The experimental values of the average molecular weight (Mn) of polynorbornenes are found to be close to the theoretical ones for the polymers prepared using catalyst 2 and higher for those originated from catalyst 3 .
3.
Pavel A. Zhizhko Florian Toth Christopher P. Gordon Ka Wing Chan Wei‐Chih Liao Victor Mougel Christophe Copret 《Helvetica chimica acta》2019,102(10)
5‐Coordinated methoxybenzylidene complexes M(=NAr)(=CH?C6H4?o‐OMe)(OtBuF3)2 (Ar=2,6‐iPr2C6H3; tBuF3=CMe2(CF3)) of Mo ( 1mMo ) and W ( 1mW ) were synthesized by cross‐metathesis from the corresponding neophylidene/neopentylidene precursors and o‐methoxystyrene. 1mMo and 1mW were grafted onto the surface of silica partially dehydroxylated at 700 °C to give well‐defined silica‐supported alkylidenes (≡SiO)M(=NAr)(=CH?C6H4?o‐OMe)(OtBuF3) (M=Mo ( 1Mo ), W ( 1W )). Supported methoxybenzylidene complexes were tested in metathesis of cis‐4‐nonene, 1‐nonene, and ethyl oleate, and compared to their molecular precursors and supported classical analogs (≡SiO)M(=NAr)(=CHCMe2R)(OtBuF3) (M=Mo, R=Ph ( 2Mo ), M=W, R=Me ( 2W )). Both grafted complexes 1Mo and 1W show significantly better performance as compared to their molecular precursors 1mMo and 1mW but are less efficient than the classical 4‐coordinated alkylidenes 2Mo and 2W . Noteworthy, both 1Mo and 1W can reach equilibrium conversion in metathesis of cis‐4‐nonene at catalyst loadings as low as 50 ppm. 相似文献
4.
Neutral and Cationic Molybdenum Imido Alkylidene N‐Heterocyclic Carbene Complexes: Reactivity in Selected Olefin Metathesis Reactions and Immobilization on Silica 下载免费PDF全文
Suman Sen Roman Schowner Dominik A. Imbrich Dr. Wolfgang Frey Prof. Michael Hunger Prof. Michael R. Buchmeiser 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(39):13778-13787
The synthesis and single‐crystal X‐ray structures of the novel molybdenum imido alkylidene N‐heterocyclic carbene complexes [Mo(N‐2,6‐Me2C6H3)(IMesH2)(CHCMe2Ph)(OTf)2] ( 3 ), [Mo(N‐2,6‐Me2C6H3)(IMes)(CHCMe2Ph)(OTf)2] ( 4 ), [Mo(N‐2,6‐Me2C6H3)(IMesH2)(CHCMe2Ph)(OTf){OCH(CF3)2}] ( 5 ), [Mo(N‐2,6‐Me2C6H3)(CH3CN)(IMesH2)(CHCMe2Ph)(OTf)]+ BArF? ( 6 ), [Mo(N‐2,6‐Cl2C6H3)(IMesH2)(CHCMe3)(OTf)2] ( 7 ) and [Mo(N‐2,6‐Cl2C6H3)(IMes)(CHCMe3)(OTf)2] ( 8 ) are reported (IMesH2=1,3‐dimesitylimidazolidin‐2‐ylidene, IMes=1,3‐dimesitylimidazolin‐2‐ylidene, BArF?=tetrakis‐[3,5‐bis(trifluoromethyl)phenyl] borate, OTf=CF3SO3?). Also, silica‐immobilized versions I1 and I2 were prepared. Catalysts 3 – 8 , I1 and I2 were used in homo‐, cross‐, and ring‐closing metathesis (RCM) reactions and in the cyclopolymerization of α,ω‐diynes. In the RCM of α,ω‐dienes, in the homometathesis of 1‐alkenes, and in the ethenolysis of cyclooctene, turnover numbers (TONs) up to 100 000, 210 000 and 30 000, respectively, were achieved. With I1 and I2 , virtually Mo‐free products were obtained (<3 ppm Mo). With 1,6‐hepta‐ and 1,7‐octadiynes, catalysts 3 , 4 , and 5 allowed for the regioselective cyclopolymerization of 4,4‐bis(ethoxycarbonyl)‐1,6‐heptadiyne, 4,4‐bis(hydroxymethyl)‐1,6‐heptadiyne, 4,4‐bis[(3,5‐diethoxybenzoyloxy)methyl]‐1,6‐heptadiyne, 4,4,5,5‐tetrakis(ethoxycarbonyl)‐1,7‐octadiyne, and 1,6‐heptadiyne‐4‐carboxylic acid, underlining the high functional‐group tolerance of these novel Group 6 metal alkylidenes. 相似文献
5.
Stefano C. G. Biagini Vernon C. Gibson Matthew R. Giles Edward L. Marshall Michael North 《Journal of polymer science. Part A, Polymer chemistry》2008,46(24):7985-7995
The block and random copolymerization of a series of amino acid and amino ester functionalized norbornenes by ring‐opening metathesis polymerization (ROMP) induced by the well‐defined molybdenum [Mo(?N‐2,6‐iPr? C6H3)(?CHCMe2)Ph)(OCMe3)2] or ruthenium [Ru(PCy)2Cl2(?CHPh)] based initiators is described. The monomers are derived from the amino acids glycine, alanine, and isoleucine or the methyl esters of these amino acids and either endo‐ or exo‐norborn‐5‐ene‐2,3‐dicarboxylic anhydride. Enantiomerically pure monomers afforded optically active polymers, and the mechanism and kinetics of the copolymerizations are investigated. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7985–7995, 2008 相似文献
6.
Karin Wewerka Alf Wewerka Franz Stelzer Bernard Gallot Luisa Andruzzi Giancarlo Galli 《Macromolecular rapid communications》2003,24(15):906-910
We prepared new varied diblock copolymers by ring‐opening metathesis polymerization of functionalized norbornenes and cyclooctene in the presence of Schrock‐type initiators, either [Mo(CHCMe2Ph)(N‐2,6‐iPr2Ph)(OCCH3(CF3)2)2] or [Mo(CHCMe2Ph)(N‐2,6‐iPr2Ph)(OC(CH3)3)2]. The block copolymers were microphase separated and presented the individual phases of each polymer block constituent, that were amorphous/amorphous, amorphous/semicrystalline, or semicrystalline/liquid‐crystalline. One example of such a block copolymer is shown.
7.
Janis V. Musso Jordan De Jesus Silva Mathis J. Benedikter Jonas Groos Wolfgang Frey Christophe Copret Michael R. Buchmeiser 《Chemical science》2022,13(29):8649
Cationic d0 group 6 olefin metathesis catalysts have been recently shown to display in most instances superior activity in comparison to their neutral congeners. Furthermore, their catalytic performance is greatly improved upon immobilization on silica. In this context, we have developed the new family of molecular cationic molybdenum oxo alkylidene complexes stabilized by N-heterocyclic carbenes of the general formula [Mo(O)(CHCMe3)(IMes)(OR)[X−]] (IMes = 1,3-dimesitylimidazol-2-ylidene; R = 1,3-dimesityl-C6H3, C6F5; X− = B(3,5-(CF3)2C6H3)4−, B(ArF)4, tetrakis(perfluoro-t-butoxy)aluminate (PFTA)). Immobilization of [Mo(O)(CHCMe3)(IMes)(O-1,3-dimesityl-C6H3)+B(ArF)4−] on silica via surface organometallic chemistry yields an active alkene metathesis catalyst that shows the highest productivity towards terminal olefins amongst all existing molybdenum oxo alkylidene catalysts.The first cationic molybdenum oxo complexes were synthesized and immobilized on partially dehydroxylated silica. Vastly enhanced catalytic activity for terminal olefins was found compared to their neutral congeners. 相似文献
8.
The reaction of stoichiometric MeLi with the 1:1 mixture of (?5‐C5H5)Fe(CO)2I/P(OR)3 (R = Me, Et, and Ph) at ?78°C changes the bonding mode between metal and ring from (?5‐C5H5) to (?4‐exo‐MeC5H5) and the oxidation state of metal from Fe(II) to Fe(O), the novel complexes (?4‐exo‐MeC5H5)Fe(CO)2P(C)R)3 being obtained in 45‐57% yields. The reaction of trace MeLi with the 1:1 mixture of (?5‐C5H5)Fe(CO)2I/P(OMe)3 at ?78°C results in 70% yield of the phosphonate complex (?5‐C5H5)Fe(CO)2P(O)(OMe)2 which is an Arbuzov‐like dealkylation product from the cationic intermediate [(?5‐C5H5)Fe(CO)2P(OMe)3+] and the iodide. The amines could assist the Arbuzov‐like dealkylation of [(?5‐C5H5)Fe(CO)2P(OMe)3+] [PF6?] where iron‐carbamoyl intermediates are likely involved in the case of primary amines. 相似文献
9.
Coleen Pugh Pukun Zhu Guehyun Kim Joe X. Zheng Michael J. Rubal Stephen Z. D. Cheng 《Journal of polymer science. Part A, Polymer chemistry》2006,44(13):4076-4087
(±)‐exo,endo‐5,6‐Bis{[[11′‐[2″,5″‐bis[2‐(3′‐fluoro‐4′‐n‐alkoxyphenyl)ethynyl]phenyl]undecyl]oxy]carbonyl}bicyclo[2.2.1]hept‐2‐ene (n = 1–12) monomers were polymerized by ring‐opening metathesis polymerization in tetrahydrofuran at room temperature with Mo(CHCMe2Ph)(N‐2,6‐iPr2Ph)(OtBu)2 as the initiator to produce polymers with number‐average degrees of polymerization of 8–37 and relatively narrow polydispersities (polydispersity index = 1.08–1.31). The thermotropic behavior of these materials was independent of the molecular weight and therefore representative of that of a polymer at approximately 15 repeat units. The polymers exhibited an enantiotropic nematic mesophase when n was 2 or greater. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4076–4087, 2006 相似文献
10.
Monolithic polymeric materials are prepared via ring‐opening metathesis copolymerization of norborn‐2‐ene with 1,4,4a,5,8,8a‐hexahydro‐1,4,5,8‐exo,endo‐dimethanonaphthalene in the presence of macro‐ and microporogens, that is, of n‐hexane and 1,2‐dichloroethane, using the Schrock catalyst Mo(N‐2,6‐(2‐Pr)2‐C6H3)(CHCMe2Ph)(OCMe3)2. Functionalization of the monolithic materials is accomplished by either terminating the living metal alkylidenes with various functional aldehydes or by post‐synthesis grafting with norborn‐5‐en‐2‐ylmethyl‐4‐(4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolan‐2‐yl)benzoate. Finally, boronate‐grafted monolithic columns (100 × 3 mm i.d.) are successfully applied to the affinity chromatographic separation of cis‐diol‐based biomolecules. 相似文献
11.
Alkyne Metathesis with Silica‐Supported and Molecular Catalysts at Parts‐per‐Million Loadings 下载免费PDF全文
Deven P. Estes Martin Casey Alexey Fedorov Matthias Tamm Christophe Copéret 《Angewandte Chemie (International ed. in English)》2016,55(45):13960-13964
Improvement of the activity, stability, and chemoselectivity of alkyne‐metathesis catalysts is necessary before this promising methodology can become a routine method to construct C≡C triple bonds. Herein, we show that grafting of the known molecular catalyst [MesC≡Mo(OtBuF6)3] ( 1 , Mes=2,4,6‐trimethylphenyl, OtBuF6=hexafluoro‐tert‐butoxy) onto partially dehydroxylated silica gave a well‐defined silica‐supported active alkyne‐metathesis catalyst [(≡SiO)Mo(≡CMes)(OtBuF6)2] ( 1 /SiO2‐700). Both 1 and 1 /SiO2‐700 showed very high activity, selectivity, and stability in the self‐metathesis of a variety of carefully purified alkynes, even at parts‐per‐million catalyst loadings. Remarkably, the lower turnover frequencies observed for 1 /SiO2‐700 by comparison to 1 do not prevent the achievement of high turnover numbers. We attribute the lower reactivity of 1 /SiO2‐700 to the rigidity of the surface Mo species owing to the strong interaction of the metal site with the silica surface. 相似文献
12.
From an Isolable Acyclic Phosphinosilylene Adduct to Donor‐Stabilized SiE Compounds (E=O,S, Se) 下载免费PDF全文
Kerstin Hansen Dr. Tibor Szilvási Dr. Burgert Blom Dr. Elisabeth Irran Prof. Dr. Matthias Driess 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(52):18930-18933
Reaction of the arylchlorosilylene‐NHC adduct ArSi(NHC)Cl [Ar=2,6‐Trip2C6H3; NHC=(MeC)2(NMe)2C:] 1 with one molar equiv of lithium diphenylphosphanide affords the first stable NHC‐stabilized acyclic phosphinosilylene adduct 2 (ArSi(NHC)PPh2), which could be structurally characterized. Compound 2 , when reacted with one molar equiv selenium and sulfur, affords the silanechalcogenones 4 a and 4 b (ArSi(NHC)(?E)PPh2, 4 a : E=Se, 4 b : E=S), respectively. Conversion of 2 with an excess of Se and S, through additional insertion of one chalcogen atom into the Si?P bond, leads to 3 a and 3 b (ArSi(NHC)(?E)‐E‐P(?E)Ph2, 3 a : E=Se, 3 b : E=S), respectively. Additionally, the exposure of 2 to N2O or CO2 yielded the isolable NHC‐stabilized silanone 4 c , Ar(NHC)(Ph2P)Si?O. 相似文献
13.
Hosein Tafazolian Sudarsan VenkatRamani Charlene Tsay Richard R. Schrock Peter Müller 《Helvetica chimica acta》2020,103(6):e2000068
3,3′,5,5′-Tetra-tert-butyl-2′-sulfanyl[1,1′-biphenyl]-2-ol (H2[tBu4OS]) was prepared in 24 % yield overall from the analogous biphenol using standard techniques. Addition of H2[tBu4OS] to Mo(NAr)(CHCMe2Ph)(2,5-dimethylpyrrolide)2 led to formation of Mo(NAr)(CHCMe2Ph)[tBu4OS], which was trapped with PMe3 to give Mo(NAr)(CHCMe2Ph)[tBu4OS](PMe3) ( 1 (PMe3)). An X-ray crystallographic study of 1 (PMe3) revealed that two structurally distinct square pyramidal molecules are present in which the alkylidene ligand occupies the apical position in each. Both 1 (PMe3)A and 1 (PMe3)B are disordered. Mo(NAd)(CHCMe2Ph)(tBu4OS)(PMe3) ( 2 (PMe3); Ad=1-adamantyl) and W(NAr)(CHCMe2Ph)(tBu4OS)(PMe3) ( 3 (PMe3)) were prepared using analogous approaches. 1 (PMe3) reacts with ethylene (1 atm) in benzene within 45 minutes to give an ethylene complex Mo(NAr)(tBu4OS)(C2H4) ( 4 ) that is isolable and relatively stable toward loss of ethylene below 60 °C. An X-ray study shows that the bond distances and angles for the ethylene ligand in 4 are like those found for bisalkoxide ethylene complexes of the same general type. Complex 1 (PMe3) in the presence of one equivalent of B(C6F5)3 catalyzes the homocoupling of 1-decene, allyltrimethylsilane, and allylboronic acid pinacol ester at ambient temperature. 1 (PMe3), 2 (PMe3), and 3 (PMe3) all catalyze the ROMP of rac-endo,exo-5,6-dicarbomethoxynorbornene (rac-DCMNBE) in the presence of B(C6F5)3, but the polyDCMNBE that is formed has a random structure. 相似文献
14.
Emma Thorn-Csányi Peter Kraxner Adam Strachota 《Macromolecular rapid communications》1998,19(4):223-228
In this paper we report on the synthesis of all-trans oligomers of 2,5-diheptyloxy-p-phenylenevinylene (2,5-diheptyloxy-PV) via olefin metathesis condensation of 2,5-diheptyloxy-1,4-divinylbenzene 1 The correct IUPAC name is 1,4-bis(heptyloxy)-2,5-divinylbenzene. The name 2,5-diheptyloxy-1,4-divinylbenzene is used in order to underline the structural similarity to 2,5-diheptyloxy-p-phenylenevinylene oligomers. (2,5-diheptyloxy-DVB). The preparation of the monomer is also described. The Schrock type molybdenum alkylidene complex Mo(NPhMe2)(CHCMe2Ph)(OCMe[CF3]2)2 was used as metathesis catalyst. The oligomer product obtained was characterized by means of 1H NMR, IR and UV/Vis spectroscopy and gel permeation chromatography. 相似文献
15.
Solid‐State NMR and DFT Studies on the Formation of Well‐Defined Silica‐Supported Tantallaaziridines: From Synthesis to Catalytic Application 下载免费PDF全文
Bilel Hamzaoui Dr. Jérémie D. A. Pelletier Dr. Edy Abou‐Hamad Dr. Yin Chen Dr. Mohamed El Eter Dr. Edrisse Chermak Prof. Luigi Cavallo Prof. Jean‐Marie Basset 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(9):3000-3008
Single‐site, well‐defined, silica‐supported tantallaaziridine intermediates [≡Si‐O‐Ta(η2‐NRCH2)(NMe2)2] [R=Me ( 2 ), Ph ( 3 )] were prepared from silica‐supported tetrakis(dimethylamido)tantalum [≡Si‐O‐Ta(NMe2)4] ( 1 ) and fully characterized by FTIR spectroscopy, elemental analysis, and 1H,13C HETCOR and DQ TQ solid‐state (SS) NMR spectroscopy. The formation mechanism, by β‐H abstraction, was investigated by SS NMR spectroscopy and supported by DFT calculations. The C?H activation of the dimethylamide ligand is favored for R=Ph. The results from catalytic testing in the hydroaminoalkylation of alkenes were consistent with the N‐alkyl aryl amine substrates being more efficient than N‐dialkyl amines. 相似文献
16.
Kotohiro Nomura Ichiro Sakai Yukio Imanishi Michiya Fujiki Yoshitaka Miyamoto 《Macromolecular rapid communications》2004,25(4):571-576
Summary: Homopolymers and diblock copolymers that contain maltose or glucose residues have been prepared by ring‐opening metathesis polymerization of norbornene derivatives using a molybdenum–alkylidene initiator, Mo(CHCMe2Ph)(N‐2,6‐iPr2C6H3)(OtBu)2 ( A ). These polymerizations took place not only in a living fashion ( = < 1.2) but also with almost quantitative initiation. Two types of ruthenium initiators, (Cy3P)2RuCl2(CHPh) ( B ) and (IMesH2)(Cy3P)RuCl2(CHPh) ( C ), have also been used to compare initiator performance under the same conditions.
17.
Marino Basato Prof. Cristina Tubaro Dr. Andrea Biffis Dr. Marco Bonato Dr. Gabriella Buscemi Dr. Filippo Lighezzolo Dr. Pamela Lunardi Dr. Chiara Vianini Dr. Franco Benetollo Dr. Alessandro Del Zotto Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(6):1516-1526
The reaction of diazo compounds with alkenes catalysed by complex [RuCl(cod)(Cp)] (cod=1,5‐cyclooctadiene, Cp=cyclopentadienyl) has been studied. The catalytic cycle involves in the first step the decomposition of the diazo derivative to afford the reactive [RuCl(Cp){?C(R1)R2}] intermediate and a mechanism is proposed for this step based on a kinetic study of the simple coupling reaction of ethyl diazoacetate. The evolution of the Ru–carbene intermediate in the presence of alkenes depends on the nature of the substituents at both the diazo N2?C(R1)R2 (R1, R2=Ph, H; Ph, CO2Me; Ph, Ph; C(R1)R2=fluorene) and the olefin substrates R3(H)C?C(H)R4 (R3, R4=CO2Et, CO2Et; Ph, Ph; Ph, Me; Ph, H; Me, Br; Me, CN; Ph, CN; H, CN; CN, CN). A remarkable reactivity of the complex was recorded, especially towards unstable aryldiazo compounds and electron‐poor olefins. The results obtained indicate that either cyclopropanation or metathesis products can be formed: the first products are favoured by the presence of a cyano substituent at the double bond and the second ones by a phenyl. 相似文献
18.
Julia Beerhues Suman Sen Roman Schowner Gergely Mate Nagy Dongren Wang Michael R. Buchmeiser 《Journal of polymer science. Part A, Polymer chemistry》2017,55(18):3028-3033
Three novel molybdenum imido alkylidene N-heterocyclic carbene (NHC) pre-catalysts, that is, Mo(N-t-Bu)(1-(2,6-diisopropylphenyl)-3-isopropyl-4-phenyl-1H-1,2,3-triazol-5-ylidene)(CHCMe2Ph)(OTf)2 ( I1 , OTf = CF3SO3), Mo(N-t-Bu)(1-(2,6-diisopropylphenyl)-3-isopropyl-4-phenyl-1H-1,2,3-triazol-5-ylidene)(CHCMe2Ph)(OTf)(t-BuO) ( I2 ) and Mo(N-2,6-Me2-C6H3)(1,3,4-triphenyl-4,5-dihydro-1H-1,2,4-triazol-5-ylidene)(CHCMe2Ph)(OTf)2 ( I3 ) are presented. Compared to complexes based on imidazol-2-ylidenes or imidazolin-2-ylidenes, (1-(2,6-diisopropylphenyl)-3-isopropyl-4-phenyl-1H-1,2,3-triazol-5-ylidene) used in precatalysts I1 and I2 exerts a comparably strong trans effect to the triflate groups trans to the NHC, while (1,3,4-triphenyl-4,5-dihydro-1H-1,2,4-triazol-5-ylidene) used in I3 has a weaker trans effect on the triflate. In combination with a suitable second anionic ligand at molybdenum, that is, OTf, t-BuO, compounds I1 – I3 require higher temperatures to become active and can thus be used as truly room temperature latent pre-catalysts, even for a highly reactive monomer such as dicyclopentadiene (DCPD). When used as latent precatalysts, I1 – I3 offer access to poly-DCPD with different degrees of cross-linking and glass-transition temperatures (Tg). © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3028–3033 相似文献
19.
Ulrich Siemeling Richard R. Schrock Anja Stammler Hans‐Georg Stammler Oliver Kuhnert 《无机化学与普通化学杂志》2001,627(5):925-928
[(FcdippN)2MoCl2(DME)] ( 1 ) was used as starting material for the synthesis of the novel ferrocenyl‐functionalised complexes [(FcdippN)2Mo(CH2CMe2Ph)2] ( 2 ), [(FcdippN)2Mo(OTf)2(DME)] ( 3 ), and [(FcdippN)Mo(CHCMe2Ph)(OtBu)2] ( 4 ) (Fcdipp = 4‐ferrocenyl‐2,6‐diisopropylphenyl). The crystal structure of 2 was determined. Electrochemical investigations by cyclic voltammetry suggest a communication of the ferrocenyl unit and the molybdenum centre in these compounds. The monoalkylation of [(DippN)2MoCl2(DME)] ( 5 ) to [(DippN)2Mo(CH2CMe2Ph)Cl] ( 6 ) (Dipp = 2,6‐diisopropylphenyl) was achieved. 相似文献