Synthesis of Novel Complex with Bridged Bis(indenyl) Ligand and its Polymerization Behavior of Propylene

Kato, Taku; Uchino, Hideshi; Iwama, Naoshi; Imaeda, Kaori; Kashimoto, Masami; Osano, Yasuko T.; Sugano, Toshihiko

doi:10.1007/978-3-642-60178-1_18

Cited by 9 publications

(7 citation statements)

References 9 publications

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“…Extensive spectroscopic investigations of their excimers, such as biradicals of α,ω‐diarylalkanes, have therefore been performed 2. α,ω‐Diarylalkanes are now also in demand as ligands for metal complexes,3 precursors of cyclophanes/calixarenes,4 polymerization initiators,5 and as agents for improving the viscosity index of lubricants, especially in high‐temperature nuclear‐radiation‐resistant hydraulic fluids 6. In addition, α,ω‐diarylalkanes are important model compounds for elucidating the mechanism of coal liquefaction 7.…”

Section: Methodsmentioning

confidence: 99%

Synthesis and Characterization of Mixed‐Valent Manganese Phosphonate Cage Complexes

Shanmugam

Chastanet

Mallah

et al. 2006

Chemistry A European J

106

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The reaction of phenylphosphonic acid (PhPO(3)H(2)) with the mixed-valent basic oxo-centered manganese triangle [Mn(3)O(O(2)CCMe(3))(6)(py)(3)] (1; where py=pyridine) in the presence of a suitable base gives four different manganese clusters depending on the identity of the base. The syntheses and structural characterization of [Mn(18)(mu(3)-O)(8)(PhPO(3))(14)(O(2)CCMe(3))(12)(py)(6)(H(2)O)(2)] (2), [Mn(7)(mu(3)-O)(3)(O(3)PPh)(3)(O(2)CCMe(3))(8)(py)(3)] (3), [Mn(9)Na(mu(3)-O)(4)(mu(4)-O)(2)(O(3)PPh)(2)(O(2)CCMe(3))(12)(H(2)O)(2)(H(2)O)(0.67)(Py)(0.33)] (4), and [Mn(13)(mu(3)-O)(8)(OMe)(8)(O(3)PPh)(4)(O(2)CCMe(3))(10)] (5) are described. Complexes 4 and 5 are homovalent Mn(III) cages, while 2 and 3 contain divalent, trivalent, and/or tetravalent ions. All the manganese centers are valence-localized, the octahedral Mn(III) sites being recognizable by marked Jahn-Teller distortions. The magnetic properties of compounds 2-5 have been investigated in the polycrystalline state by magnetic susceptibility and high-field magnetization measurements, which reveal that spin ground states vary from 0< or =S > or =8. AC susceptibility measurements performed on 4 and 5, in the 1.6-10.0 K ranges show the presence of out of AC susceptibility signal (chi(M)'') for 4, and an effective energy barrier (U(eff)) for the re-orientation of the magnetization is found to be 17 K, but for 5, the chi(M)'' maximum is found to be below 1.5 K.

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Section: Methodsmentioning

confidence: 99%

Synthesis and Characterization of Mixed‐Valent Manganese Phosphonate Cage Complexes

Shanmugam

Chastanet

Mallah

et al. 2006

Chemistry A European J

106

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“…Many efforts have been focused on improving the polymerization performance in terms of activity, melting point, and molecular weight of the polymer. During the development of a large number of bridged bis-indenyl and bis-cyclopentadienyl systems, it was found that stereoselectivity (stereodefect) and regioselectivity (regioinversion) of the inserted propylene monomer are influenced by the steric effect of the substituents on the indenyl or cyclopentadienyl moieties. − In particular, it was elucidated that both the 2- and 4-positions of the bridged bis-indenyl system are important, and for this reason, extensive development and optimization of 2,4-substitutents were examined in order to obtain higher melting point isotactic polypropylene. As previously reported, we have synthesized the bis-azulenyl zirconocenes bearing methyl groups at the 2-position and phenyl groups at the 4-position of the azulenyl rings: Me 2 Si(2-Me-4-Ph-4 H -Azu) 2 ZrCl 2 .…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Structure, and Polymerization Behavior of Novel Azulenyl Metallocenes Producing Propylene-Ethylene Pseudo-Copolymer

Iwama

Osano

2004

Organometallics

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Novel bridged bis-azulenyl metallocenes bearing substituents at the 2-, 4-, and 8-positions, dichlorodimethylsilylenebis(2-methyl-4-phenyl-8-n-butyl-8H-azulenyl)hafnium and dichlorodimethylsilylenebis(2-methyl-4,8-diphenyl-8H-azulenyl)hafnium, were synthesized. The structure of the former compound was determined by X-ray crystallographic analysis to have C 2 symmetry. When activated with methylaluminoxane (MAO), both compounds gave an active propylene polymerization catalyst. In propylene homopolymerization, propylene-ethylene pseudo-copolymer was obtained unexpectedly. Although the metallocene has C 2 symmetry, the obtained polypropylene was elastomeric and showed no melting point on measurement by differential scanning calorimetry (DSC). The 13C NMR analysis of the polymer showed the presence of a large amount of regioinversion.

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“…The discovery that group 4 metallocenes catalyze stereospecific polymerization to isotactic polypropylene (IPP) , according to the enantiomorphic site-controlled model resulted in a lot of research targeting better catalyst activities, improved stereo- and regioselectivities, and higher polypropylene molecular weights . Structural modifications to a prototype rac- Me 2 Si[indenyl] 2 ZrCl 2 ( 1 ) 5 led to promising catalysts with higher efficiencies, higher molecular weight polymers, stereospecificities approaching those of commercial catalysts, and higher regiospecificities. , This quest for a “rational design” of catalysts has focused on the trends seen from comparison of polymerization results to catalyst structural parameters that affect the nonbonded energies in preinsertion and termination assemblies was adopted in this contribution as a benchmark for comparisons with similarly substituted cyclopenta[ b ]thiophenes and cyclopenta[ b ]pyrroles.…”

Section: Introductionmentioning

confidence: 99%

Chiral Ansa Metallocenes with Cp Ring-Fused to Thiophenes and Pyrroles: Syntheses, Crystal Structures, and Isotactic Polypropylene Catalysts

Ewen¹,

Elder

Jones

et al. 2001

J. Am. Chem. Soc.

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Syntheses, crystal structures, and polymerization data for new isospecific metallocenes (heterocenes) having cyclopentenyl ligands b-fused to substituted thiophenes (Tp) and pyrroles (Pyr) are reported. The C2- and C1-symmetric heterocenes are dimethylsilyl bridged, have methyl groups adjacent to the bridgehead carbon atoms, and have aryl substituents protruding in the front. rac-Me2Si(2,5-Me2-3-Ph-6-Cp[b]Tp)2ZrCl2/MAO (MAO = methyl alumoxanes) is the most active metallocene catalyst for polypropylene reported to date. rac-Me2Si(2,5-Me2-3-Ph-6-Cp[b]Tp)2ZrCl2 and rac-Me2Si(2,5-Me2-1-Ph-4-Cp[b]Pyr)2ZrCl2 have the same structure, and the former is 6 times more active, produces half the total enantiofacial errors, and is 3.5 times less regiospecific in propylene polymerizations at the same conditions. rac-Me2Si(2-Me-4-Ph-1-Ind)2ZrCl2/MAO is 3.5 times lower in activity than rac-Me2Si(2,5-Me2-3-Ph-6-Cp[b]Tp)2ZrCl2 catalyst, and while the former is the more stereospecific and the less regiospecific, the sum of these two enantioface errors is the same for both species. Fine-tuning the heterocene sterics by changing selected hydrogen atoms on the ligands to methyl groups influenced their catalyst activities, stereospecificites, regiospecificites, and isotactic polypropylene (IPP) Mw. Thus, both substituting a hydrogen atom adjacent to the phenyl ring with a methyl group on an azapentalenyl ligand system and replacing one and then two hydrogens on the phenyl ring with methyls on thiopentalenyl ligands provided increased polymer Tm and Mw with increasing ligand bulk. Polymer molecular weights are sensitive to and inversely proportional to MAO concentration, and the catalyst activities increase when hydrogen is added for molecular weight control. The polymer Tm values with the thiopentalenyls as TIBAL/[Ph3C][B(C6F5)4] systems were higher than with MAO as catalyst activator. A racemic C1, pseudo-meso complex with a hybrid dimethylsilyl-bridged 2-Me-4-Ph-1-Ind/2,5-Me2-4-Ph-1-Cp[b]Pyr ligand produced the first sample of IPP with all the steric pentad intensities fitting the enantiomorphic site control model. Speculative mechanistic considerations are offered regarding electronic effects of the heteroatoms and steric effects of the ligand structures, the preferred phenyl torsion angles, and anion effects.

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Synthesis of Novel Complex with Bridged Bis(indenyl) Ligand and its Polymerization Behavior of Propylene

Cited by 9 publications

References 9 publications

Synthesis and Characterization of Mixed‐Valent Manganese Phosphonate Cage Complexes

Synthesis and Characterization of Mixed‐Valent Manganese Phosphonate Cage Complexes

Synthesis, Structure, and Polymerization Behavior of Novel Azulenyl Metallocenes Producing Propylene-Ethylene Pseudo-Copolymer

Chiral Ansa Metallocenes with Cp Ring-Fused to Thiophenes and Pyrroles: Syntheses, Crystal Structures, and Isotactic Polypropylene Catalysts

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