- 6,6-Diphenylfulvene at 140 K
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The title compound, C18H14, crystallizes with two molecules in the asymmetric unit, which differ only in the angle between the phenyl rings and the fulvene moiety. The two double bonds of the cyclopentadiene moiety are shortened [1.352 (2) and 1.353 (2) A] in the title compound compared with the range found in its metal complexes (1.381-1.520 A). The bond joining these two double bonds is generally shorter in the metal complexes than in the title compound [1.467 (2) and 1.468 (2) A], but there are exceptions. A conformational analysis of the title compound with the molecular modelling program MOMO [Bolte, Beck & Egert (1991). Molecular Modelling Program MOMO. University of Frankfurt, Germany] shows only one minimum on the energy hypersurface, where both phenyl rings form an angle of 56.6° with the fulvene moiety.
- Bolte, Michael,Amon, Michael
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Read Online
- In Situ Activation: Chances and Limitations to Form Ultrahigh Molecular Weight Syndiotactic Polypropylene with Metallocene Dichlorides
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Fluorenyl cyclopentadienyl Cs-symmetric ansa-metallocene (M = Zr, Hf) complexes I-IV featuring different bridging motifs (C and Si) were synthesized and subsequently examined in the syndiospecific coordinative polymerization of propylene. All complexes were activated in situ with triisobutylaluminum (TIBA) and [Ph3C][B(C6F5)4] (TrBCF) in order to highlight the benefits of this in situ activation, resulting in a significantly higher molecular weight and a significantly increased productivity in comparison to methylaluminoxane (MAO). The isopropylidene-bridged zirconocene Ia (ZrCl2[Me2C(η5-Flu)( η5-Cp)]) exhibited a high productivity (80000 kgPP (molcat h)-1) and stereoregularity ([rrrr] up to 93%) with a moderate molecular weight of polypropylene (PP), whereas the polymerization with the corresponding hafnocene Ib (HfCl2[Me2C(η5-Flu)( η5-Cp)]) resulted in a lower productivity and stereoregularity but yielded ultrahigh molecular weight polypropylene (Mw = 1100 kg mol-1). The backbone in II (HfCl2[Ph2C(η5-Flu)( η5-Cp)]) was associated with a higher productivity and molecular weight, while the syndiotacticity was not affected. In contrast, SC-XRD revealed a reduced dihedral angle and D value for Si-bridged hafnocenes III (HfCl2[Me2Si(η5-Flu)( η5-Cp)]) and IV (HfCl2[Ph2Si(η5-Flu)( η5-Cp)]), resulting in a more constrained geometry of the catalyst. This led to an increased molecular weight, while the productivity as well as the syndiotacticity decreased due to these structural parameters. Activation of Ib and II-IV with n-octyl-modified methylaluminoxane (MMAO) resulted in a lower molecular weight of the polymer, because the transfer of the growing polymer chain onto the Al center was enhanced. Nevertheless, the stereoregularity of MMAO-activated catalysts was slightly increased, probably due to a coordination of the ill-defined MMAO anion during the polymerization. DSC analysis exposed for syndiotactic polypropylene (sPP) produced by the highly active zirconocene Ia a defined melting transition (Tm up to 145.2 °C), whereas TIBA/TrBCF-activated hafnocenes Ib and II-IV gave polymers with no observable Tm value.
- Stieglitz, Lucas,Henschel, Daniel,Pehl, Thomas,Rieger, Bernhard
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supporting information
p. 4055 - 4065
(2021/09/30)
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- Visible-light-induced [4 + 2] cycloaddition of pentafulvenes by organic photoredox catalysis
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We have developed thioxanthylium photoredox catalyzed [4 + 2] cycloaddition of pentafulvenes at room temperature under green light irradiation, which affords tetrahydrocyclopenta[b]chromenes with high regioselectivities. The present reaction provides a sustainable approach to carry out the cycloaddition of pentafulvenes without the use of transition metal catalysts or high-temperature conditions. This procedure enables a mild and straightforward access to 1,3a,9,9a-tetrahydrocyclopenta[b]chromenes. The quantum yield of the reaction (Φ = 0.15) indicates that the reaction would mainly proceed via photocatalytic pathways.
- Asada, Yosuke,Honda, Kiyoshi,Hoshino, Yujiro,Tanaka, Kenta
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supporting information
p. 8074 - 8078
(2020/11/03)
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- Preparation method of substituted cyclopentadienyl metallocene compound
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The invention relates to a preparation method of a substituted cyclopentadienyl metallocene compound. The preparation method comprises the following steps that a cyclopentadienyl compound and an aldehyde-ketone compound are adopted to carry out reaction to produce a fulvene compound, then the fulvene compound is acted with metal hydride to produce substituted cyclopentadienyl salt, and the substituted cyclopentadienyl salt is further reacted with group IV metal halide to produce the metallocene compound. Compared with the prior art, the preparation method has the advantages of high product yield, convenience in operation, good economy and the like and is suitable for industrial production.
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Paragraph 0084; 0085; 0086
(2017/11/30)
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- (Planar-Chiral) Ferrocenylmethanols: From Anionic Homo Phospho-Fries Rearrangements to α-Ferrocenyl Carbenium Ions
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The reaction of FcCH2OH with chlorophosphates gave ferrocenyl phosphates FcCH2OP(O)(OR)2 [Fc = Fe(η5-C5H5)(η4-C5H4)], which readily separate into phosphate anions and ferrocenyl carbo-cations. The latter species undergoes consecutive reactions, for example, electrophilic aromatic substitutions. When nitriles, instead of alcohols, are treated with FcLi or tBuLi and chlorophosphates, chiral-pool based ferrocenylimino phosphoramidates Fc-CR=N-P(O)(OR*)2 are formed, which are promising candidates for anionic homo phospho-Fries rearrangements. Moreover, the sterically demanding chiral chlorophosphate with R* enabled oxidative couplings of the imines to form a diferrocenylazine. Similarly, the reaction of Fc–Li with 9-anthrylnitrile produced a 10-ferrocenyl-substituted product, contrary to a reaction at the C≡N functionality. A planar-chiral ortho-P(S)Ph2-functionalized ferrocenylmethanol also gave carbo-cations under acidic conditions. These species can be sulfurized in a unique way giving thio ethers, whereby the in situ formed 1,2-P(S)Ph2,CH2+ ferrocene cation acts as the sulfur and electron source. However, lowering the substrate concentration prevents sulfur migration, resulting in electrophilic substitution reactions with aromatic solvents. Planar-chiral ferrocenylmethyl thio or anisyl derivatives were applied as ligands in Pd-catalyzed Suzuki–Miyaura C,C cross-couplings for the atroposelective synthesis of hindered biaryls with up to 26 % ee at low catalyst loadings (1 mol-% Pd).
- Korb, Marcus,Mahrholdt, Julia,Lang, Heinrich
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supporting information
p. 4028 - 4048
(2017/09/20)
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- Method for producing fulvene
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PROBLEM TO BE SOLVED: To provide a method for producing a fulvene in which the reaction efficiently proceeds regardless of the nature of the substituent group which a raw-material ketone, especially a ketone not having an α-proton, possesses. SOLUTION: Provided is a method for producing a fulvene including a step to condense a ketone not possessing an α-proton, and an alkali metal salt of cyclopentadiene in the presence of a Lewis acid. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0037
(2017/03/08)
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- METALLOCENE COMPOUNDS, CATALYST COMPOSITIONS COMPRISING THE SAME, AND METHOD FOR PREPARING OLEFIN POLYMERS USING THE SAME
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The present invention relates to a transition metal compound which can usefully adjust characteristics of synthesized olefin polymers such as chemical structures, molecular weight distribution, mechanical properties, etc. while exhibiting high activity during olefin polymerization reaction; to a catalyst composition comprising the same; and a preparation method of olefin polymer using the catalyst composition. The novel transition metal compound of the present invention can provide polyolefin with medium-low molecular weight for improving processability and is represented by chemical formula 1.COPYRIGHT KIPO 2016
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Paragraph 0118-0121
(2017/01/09)
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- METALLOCENE COMPOUNDS, CATALYST COMPOSITIONS COMPRISING THE SAME, AND METHOD FOR PREPARING OLEFIN POLYMERS USING THE SAME (AS AMENDED)
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The present invention relates to a transition metal compound that may exhibit high activity in olefin polymerization, and easily control the properties of synthesized olefin polymer such as a chemical structure, molecular weight distribution, a mechanical property, and the like, a catalyst composition comprising the same, and a method for olefin polymerization using the catalyst composition.
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Paragraph 0076-0077
(2016/10/31)
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- POLYMERIZATION CATALYSTS FOR PRODUCING POLYMERS WITH LOW MELT ELASTICITY
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The present techniques relate to catalyst compositions, methods, and polymers encompassing a Group 4 metallocene compound comprising bridging η5-cyclopentadienyl-type ligands, typically in combination with a cocatalyst, and a activator. The compositions and methods presented herein include ethylene polymers with low melt elasticity.
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Paragraph 0205
(2013/09/26)
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- An improved pathway to 6,6-disubstituted fulvenes
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Pentafulvenes with alkyl and/or aryl substituents at the exocyclic position are formed rapidly in high yields through reaction of crystalline sodium cyclopentadienide directly with the appropriate ketones.
- Chajara, Khalil,Ottosson, Henrik
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p. 6741 - 6744
(2007/10/03)
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- Cs-symmetric hafnocene complexes for synthesis of syndiotactic polypropene
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Three new C s-symmetric ansa-hafnocene complexes such as dichloro[η10-2,4-cyclopentadienyl-1-ylidenebis (4-methyldiphenyl-methylen)[2,7-bis(1,1-di-methylethyl)-9H-fluorene-9- ylidene]]hafnium (2) were synthesized which produce partiell syndiotactic polypropylenes with very high molecular weights. The influence of the methyl and methoxy substitution in the bridge was studied on the activity, tacticity, and molar mass. The hafnocene-MAO catalysts (1-4) were active up to polymerisation temperatures of 90 °C and produces 55 000 kg polymer in 1 h by 1 mol of hafnocene. The molecular weight of the obtained elastic polypropylene reaches 2.2 million g mol-1.
- Kaminsky, Walter,Hopf, Andreas,Piel, Christian
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p. 200 - 205
(2007/10/03)
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- Antifungal properties of novel N- and α,β-substituted succinimides against dermatophytes
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The synthesis and antifungal properties of a series of new N-aryl α,β-substituted succinimides against a panel of dermatophytes of clinical relevance are reported. Among those compounds possessing a N-phenyl substituent, 7-thia-2-azabicyclo[2,2,1]hept-2-en-3-amine[5,6-c]succinimide was the better inhibitor of Trichophyton rubrum, the major ethiological agent of all infections produced by dermatophytes. In contrast, succinimides containing a N-(p-sulfonylphenyl) substituent, only inhibited Epidermophyton floccosum, all active compounds possessing an oxabicyclo group in positions α,β of the imide. Substituents on the oxabicyclo group were important for the activity. Regarding the mechanism of action, N-(p-N′-4-methoxyphenylsulfamoylphenyl) -8-oxabicyclo[2,2,1]hept-4-en-3-methyl[5,6-c]succinimide produced a mottled inhibition halo in the Neurospora crassa assay, showing that it would act by inhibiting the synthesis or assembly of the fungal cell wall.
- Lopez, Silvia N.,Sortino, Maximiliano,Escalante, Andrea,De Campos, Fatima,Correa, Rogerio,Cechinel Filho,Nunes, Ricardo J.,Zacchino, Susana A.
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p. 280 - 288
(2007/10/03)
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- Catalyst system for the polymerization of alkenes to polyolefins
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The invention provides metallocene catalyst systems for the controlled polymerization of alkenes to a wide variety of polyolefins and olefin coplymers. Catalyst systems are provided that specifically produce isotactic, syndiotactic and steroblock polyolefins. The type of polymer produced can be controlled by varying the catalyst system, specifically by varying the ligand substituents. Such catalyst systems are particularly useful for the polymerization of polypropylene to give elastomeric polypropylenes. The invention also provides novel elastomeric polypropylene polymers characterized by dyad (m) tacticities of about 55% to about 65%, pentad (mmmm) tacticities of about 25% to about 35%, molecular weights (Mw)in the range of about 50,000 to about 2,000,000, and have mmrm+rrmr peak is less than about 5%.
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- Synthesis of bis-cyclopentadienyl compounds with a 9,9-fluorenylidene bridge. Crystal and molecular structure of [μ-9,9-Flu(η5-Cp)2]ZrCl2
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An efficient synthetic approach to 9,9-bis(cyclopentadienyl)fluorenes was developed. The two corresponding ansa-zirconocenes were synthesized. The structure of one of these compounds was established by X-ray diffraction analysis.
- Ivchenko,Ivchenko,Nifant'ev,Bagrov,Kuz'mina
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p. 1287 - 1291
(2007/10/03)
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- On the Reaction of Bis(trimethylphosphane)titanocene with Ketones
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Fulvenes are the products of the reaction of aliphatic and aromatic ketones with bis(trimethylphosphane)titanocene in nonpolar solvents, but no formation of pinacols is observed.The mechanism is discussed. - Key Words: Titanocenes / Fulvenes / Solvent effect / Ketyls
- Gleiter, Rolf,Wittwer, Wolfgang
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p. 1797 - 1798
(2007/10/02)
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- Isolation, Structure and Reaction of Selenobenzophenones. X-Ray Molecular Structure of 4,4'-Dimethoxyselenobenzophenone and of 4,4-Diphenyl-2,3-diselenabicyclooct-7-ene
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4,4'-Dimethoxy- 1a and 4,4'-dimethyl-selenobenzophenone 1b could be isolated in moderate yields by the reaction of the corresponding ylides 3 with elemental selenium in benzene at 80 deg C.Their spectral data are described.Attempted isolation of unsubstituted selenobenzophenone afforded only its dimer 5.Compound 1a crystallizes in space group P21/n with unit-cell parameters a = 7.191(3), b = 7.505(4=, c = 24.856(4) Angstroem, β = 90.32(1) deg, Z = 4, R = 0.055.The oxidation and thiation of 4,4'-dimethoxyselenobenzophenone 1a afforded the corresponding benzophenone and thiobenzophenone in good yields.The reaction of compound 1 with cyclopentadiene afforded the corresponding cycloadducts 7 (3,3-diaryl-2-selenabicyclohept-5-enes), whereas bicyclic diselenides 8 (4,4-diaryl-2,3-diselenabicyclooct-7-enes were obtained by using an excess of selenium and a higher temperature.Oxidation of compound 8c gave the corresponding diol 12, aldehyde 13, and diphenylfulvene 11.The reaction of compound 1a with benzenediazonium carboxylate afforded 2,2-bis-(4-methoxyphenyl)-4H-3,1-benzooxaselenin-4-one 17.
- Okuma, Kentaro,Kojima, Kazuki,Kaneko, Isao,Tsujimoto, Yoshikazu,Ohta, Hiroshi,Yokomori, Yoshinobu
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p. 2151 - 2160
(2007/10/02)
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- Tandem Reactions of N,N-Dialkylamides with Organolithium Compounds and Cyclopentadiene. A New Efficient Synthesis of Pentafulvenes
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Reactions of N,N-dialkylamides with organolithium compounds followed by addition of cyclopentadiene furnish 6-mono- or 6,6-di-substituted pentafulvenes in moderate to high yields, providing a new and simple pentafulvene synthesis.
- Kurata, Hiroyuki,Ekinaka, Tatsuya,Kawase, Takeshi,Oda, Masaji
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p. 3445 - 3448
(2007/10/02)
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- Novel Photoreactions of Benzhydrylidenequadricyclane and Quadricyclanone: A New Route to Trimethylenemethane and Oxyallyl Derivatives
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The irradiation of 3-benzhydrylidenequadricyclane (1) generated a trimethylenemethane (TMM) derivative, 3-benzhydrilenebicyclohept-6-ene-2,4-diyl (3), which dimerized and could be captured by molecular oxygen and acrylonitrile, but not by furan, methanol, or ethyl vinyl ether.The triplet nature of (3) was confirmed by EPR, emission, and absorption spectra.By contrast, the irradiation of quadricyclanone (2) generated the singlet oxyallyl (OA), 3-oxobicyclohept-6-ene-2,4-diyl (4), which could be captured by furan, methanol, and ethyl vinyl ether, but not by molecular oxygen or acrylonitrile, indicating the zwitterionic and electron-accepting nature of 4.
- Hirano, Takashi,Kumagai, Tsutomu,Miyashi, Tsutomu,Akiyama, Kimio,Ikegami, Yusaku
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p. 1907 - 1914
(2007/10/02)
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- Regioselective synthesis of bicyclic diselenides by the reaction of phosphonium ylides with elemental selenium
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Selenabicyclo[2.2.1]heptenes reacted with elemental selenium to produce unusual bicyclic diselenides in 30-40% yield. The reaction of phosphonium ylides with excess of elemental selenium also afforded bicyclic diselenides in good yields. The reactions might proceed via biradical intermediates.
- Okuma, Kentaro,Kaneko, Isao,Ohta, Hiroshi,Yokomori, Yoshinobu
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p. 2107 - 2110
(2007/10/02)
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- REACTION OF DICYCLOPENTADIENYLYTTRIUM CHLORIDE WITH ALDEHYDES AND KETONES. A NOVEL CLEAVAGE REACTION OF Cp-Y ?-BOND
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Dicyclopentadienylyttrium chloride reacts with aldehydes and ketones at 80 deg C in DME, generating fulvenes in excellent yields, while at lower temperature affording, after hydrolysis, cyclopentadienyl substituted alcohols.
- Qian, Changtao,Qiu, Aineng
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p. 6931 - 6934
(2007/10/02)
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- PREPARATION OF 6,6-DIARYLFULVENE COMPLEXES OF RHODIUM(I) AND THEIR REACTION WITH DIOXYGEN
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Complexes (1+) react with 6,6-diarylfulvenes C5H4C(C6H4X-4)2 to yield products C5H4C(C6H4X-4)2L2>(1+) in which the fulvene is bound to the metal through the five-membered ring.Corresponding reactions with (1+) yield complexesC5H4C(C6H4X-4)22>(1+) containing two fulvene ligands.Atmospheric oxidation of these complexes results in the linking of the exocyclic carbon atoms in the two fulvene ligands by a peroxide bridge.If the initial attack by O2 is on the metal, the subsequent rearrangement may be viewed either as a transfer of singlet oxygen from metal to ligands or as a nucleophilic attack by peroxide on the (probably somewhat positively charged) exocyclic carbon atoms of the fulvene ligands.
- Jeffery, John,Probitts, E. Jane,Mawby, Roger J.
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p. 2423 - 2428
(2007/10/02)
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- 6,6-DIMETHYL-6-SILAFULVENE. GENERATION AND TRAPPING REACTIONS
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6,6-Dimethyl-6-silafulvene generated from (allyl)(cyclopentadienyl)-dimethylsilane reacts with a trapping reagent such as methanol, benzaldehyde, and benzophenone to give (cyclopentadienyl)(methoxy)dimethylsilane, 6-phenylfulvene, and 6,6-diphenylfulvene, respectively.Without a trapping reagent, the silafulvene undergoes dimerization.
- Nakadaira, Yasuhiro,Sakaba, Hiroyuki,Sakurai, Hideki
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p. 1071 - 1074
(2007/10/02)
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