Grafting of Vinyl‐Type Polynorbornene on Polybutadiene and Polyisoprene

Schroers, Michael; Demeter, Jürgen; Dehnicke, Kurt; Greiner, Andreas

doi:10.1002/macp.200290046

Cited by 5 publications

(4 citation statements)

References 19 publications

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“…Bulky substituents are capable of controlling chain transfer reactions. As a result, Ni-159 produced higher molecular weight polymers than Ni-157 [151].…”

Section: Oo-chelate Ligandsmentioning

confidence: 99%

“…The tetranuclear nickel complex [NiBr(NPMe 3 )] 4 Ni-42, in which the Ni-and N-atoms form a heterocubane, required MAO to create an active species [149]. The catalytic activity depended on the monomer/Ni ratio, which was varied from 5000 to 60 000.…”

Section: Nn-chelate and Bis(n) Ligandsmentioning

confidence: 99%

“…In addition, it was shown that the molar masses could be controlled by addition of styrene after certain reaction times. The MAO [150] or B(C 6 F 5 ) 3 [151] activated complex [NiBr(NPMe 3 )] 4 was also applied for the copolymerization of norbornene with different olefins to produce olefin-terminated polynorbornene chains.…”

Section: Nn-chelate and Bis(n) Ligandsmentioning

confidence: 99%

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Metal catalysts for the vinyl/addition polymerization of norbornene

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Janiak

2009

Coordination Chemistry Reviews

329

208

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“…Bulky substituents are capable of controlling chain transfer reactions. As a result, Ni-159 produced higher molecular weight polymers than Ni-157 [151].…”

Section: Oo-chelate Ligandsmentioning

confidence: 99%

Section: Nn-chelate and Bis(n) Ligandsmentioning

confidence: 99%

See 1 more Smart Citation

Metal catalysts for the vinyl/addition polymerization of norbornene

Blank

Janiak

2009

Coordination Chemistry Reviews

329

208

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“…In the literature electronwithdrawing ligands or substituents are usually viewed as activity enhancing in complexes activated for NB polymerization. [35][36][37][38][39][40][41][42] Aromatic nitrogen ligands are stronger and electron-withdrawing ligands in the spectrochemical series than aliphatic amine ligands due to their modest p-accepting character whereas aliphatic amines are pure s-donor ligands. Hence, our activity order is counterintuitive.…”

Section: Norbornene Polymerizationmentioning

confidence: 99%

Palladium(ii) complexes with pentafluorophenyl ligands: structures, C6F5 fluxionality by 2D-NMR studies and pre-catalysts for the vinyl addition polymerization of norbornene

et al. 2010

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The palladium(II) complex [Pd(C(6)F(5))Cl(bpzm*)] (5) [bpzm* = bis(3,5-dimethylpyrazol-1-yl)methane] was characterized by (1)H,(1)H-TOCSY, (1)H-NOE difference spectra, (1)H,(19)F-HOESY and (13)C,(1)H-HMBC 2D-NMR techniques. Chemical exchange of the methylene protons from (1)H,(1)H-NOESY cross peaks and exchange of the ortho- and meta-fluorine atoms, respectively, from (19)F,(19)F-EXSY cross peaks indicates that the Pd-bpzm* chelate ring boat-to-boat inversion occurs at a rate slower than the NMR time scale together with a concomitant change of the C(6)F(5) atom positions. The presence of three (19)F-NMR signals for 2F(o) : 1F(p) : 2F(m) of the C(6)F(5) ligand for complexes [Pd(C(6)F(5))Cl(tmeda)] (1) and [Pd(C(6)F(5))Cl(bipy)] (3) (tmeda = N,N,N',N'-tetramethylethylenediamine; bipy = 2,2'-bipyridine) is interpreted as being due to identical hemi-spaces above and below an apparent symmetry plane coinciding with the Pd-coordination plane instead of free ring rotation. The molecular structures of 1, 3 and 5 from single-crystal studies suggest that the hindered C(6)F(5) rotation is not limited to 5 but is also present in 1 and 3 due to ligand repulsion. Complexes [Pd(C(6)F(5))Cl(tmeda)] (1), [Pd(C(6)F(5))OH(tmeda)] (2), [Pd(C(6)F(5))Cl(bipy)] (3), [Pd(C(6)F(5))OH(bipy)] (4) and [Pd(C(6)F(5))Cl(bpzm*)] (5) have been applied as pre-catalysts for the vinyl homopolymerization of norbornene in combination with the cocatalyst methylaluminoxane (MAO). Activities of more than 10(6) g(polymer)/(mol(Pd) h) could be reached with these catalytic systems. Based on the spectrochemical series, pre-catalysts 1 and 2 with the pure sigma-donor and more weakly bound aliphatic amine ligands showed higher polymerization activities than compounds 3-5 with modest pi-accepting and stronger bound aromatic substituents. This is reasoned with a kinetic activation effect through a faster removal of the more weakly bound ligands upon reaction with MAO together with the chloro or hydroxo ligands to give the active, almost "naked" Pd(2+) cations. For the activation mechanism, (1)H-, (13)C- and (19)F-NMR studies of the MAO activated complex 5 showed about 13% chlorine-to-methyl exchange for a molar Pd : Al ratio of 1 : 10. For 5 : MAO at a Pd : Al ratio of 1 : 100 abstraction of C(6)F(5) takes place with a redox reaction giving Pd metal and C(6)F(5)-CH(3) in the absence of norbornene monomer.

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Synthesis and Rheological Properties of Poly(5‐n‐hexylnorbornene)

Müller¹,

Kreiling²,

Dehnicke³

et al. 2006

Macro Chemistry & Physics

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Summary: Poly(5‐n‐hexylnorbornene) (PHNB) was obtained in high molecular weight and high yields by vinyl‐type polymerization of 5‐n‐hexyl‐2‐norbornene (endo/exo = 77/23) with [NiBr(NPMe3)]4/B(C6F5)3 as catalyst precursor. The combination of size exclusion chromatography with on‐line light scattering and intrinsic viscosity measurements allowed the Mark‐Houwink expressions to be evaluated in tetrahydrofuran. The unperturbed chain dimensions for poly(5‐n‐hexylnorbornene) were estimated via the extrapolation procedure of Burchard‐Stockmayer‐Fixman. This evaluation of the unperturbed chain dimension in turn permits the calculation of the entanglement molecular weight and the plateau modulus via the packing length model. This allows the determination of rheological properties for these materials where conventional rheology measurements are difficult, or impossible.[η]‐M data for PHNB in THF at 35 °C.magnified image[η]‐M data for PHNB in THF at 35 °C.

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Grafting of Vinyl‐Type Polynorbornene on Polybutadiene and Polyisoprene

Cited by 5 publications

References 19 publications

Metal catalysts for the vinyl/addition polymerization of norbornene

Metal catalysts for the vinyl/addition polymerization of norbornene

Palladium(ii) complexes with pentafluorophenyl ligands: structures, C6F5 fluxionality by 2D-NMR studies and pre-catalysts for the vinyl addition polymerization of norbornene

Synthesis and Rheological Properties of Poly(5‐n‐hexylnorbornene)

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