Syndiotactic 1,2‐polybutadiene with Co‐CS2 catalyst system. III.1H‐ and 13C‐NMR study of highly syndiotactic 1,2‐polybutadiene

Ashitaka, Hidetomo; Inaishi, Kazutoshi; Ueno, Haruo

doi:10.1002/pol.1983.170210708

Cited by 43 publications

(36 citation statements)

References 23 publications

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“…13 C and 1 H NMR measurements were carried out on a Bruker AVANCE 400 spectrometer, operating at 400 MHz for 1 H and 100.58 MHz for 13 C. The spectra were obtained in C 2 D 2 Cl 4 at 103 • C (hexamethyldisiloxane, HMDS, as internal standard). The concentration of polymer solutions was about 10 wt %.…”

Section: Polymer Characterizationmentioning

confidence: 99%

“…As an example, the 13 C NMR spectrum of the poly(1,2-propadiene) obtained with (η 3 -C 4 H 7 )(η 4 -C 4 H 6 )Co(PMePh 2 ) ( Table 3, run 2) is shown in Figure 7c. It is worth noting that complex 3 was more active than 1 and 2, likely due to its lower stability and/or greater reactivity toward the interaction with MAO.…”

Section: Polymerization Of 12 Propadienementioning

confidence: 99%

“…Powder X-ray Diffraction (PXRD) (a); Differential Scanning Calorimetry (DSC) (b) and 13 C NMR (c) spectra of poly(1,2-propadiene) ( Table 3, entry 2).…”

Section: Figurementioning

confidence: 99%

“…The concentration of polymer solutions was about 10 wt %. 13 C NMR conditions were the following: 10 mm probe; 14.50 µs as 90 • pulse, relaxation delay 18 s; acquisition time 1.87 s. Proton broad-band decoupling was achieved with a 1D sequence using bi_waltz_16_32 power-gated decoupling. DSC scans were carried out on a Perkin Elmer Pyris 1 Instrument (Perkin Elmer, Milano, Italy) equipped with a liquid nitrogen sub-ambient device.…”

Section: Polymer Characterizationmentioning

confidence: 99%

“…Allyl derivatives of other transition metals (Ti, Zr, Mo, W, Ru, Rh, U, Nd) were later found to be effective catalysts [8][9][10]. More recently, the allyl cobalt compound (η 4 -C4H6)(η 5 -C8H13)Co, alone or in presence of CS2, was reported to be highly active and stereoselective in the polymerization of 1,3-butadiene to 1,2 syndiotactic polymer [11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

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Novel Allyl Cobalt Phosphine Complexes: Synthesis, Characterization and Behavior in the Polymerization of Allene and 1,3-Dienes

et al. 2017

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Abstract:Novel allyl cobalt complexes, i.e., (η 3 -C 4 H 7 )(η 4 -C 4 H 6 )Co(PCyPh 2 ) (1), (η 3 -C 4 H 7 )(η 4 -C 4 H 6 )Co(PMePh 2 ) (2) and (η 3 -C 5 H 9 )(η 4 -C 5 H 8 )Co(PMePh 2 ) (3), were synthesized by reacting CoCl 2 (PRPh 2 ) 2 (R = methyl, cyclohexyl) with 1,3-butadiene or isoprene in presence of metallic zinc. The complexes were fully characterized by Nuclear Magnetic Resonance (NMR) spectroscopy ( 1 H and 2D experiments); in case of 1, single crystals, suitable for X-ray analysis, were obtained and the molecular structure was determined. The allyl cobalt phosphine complexes alone gave highly crystalline 1,2 polymers from 1,2-propadiene, but they did not polymerize 1,3-dienes. Nevertheless, in the presence of a stoichiometric amount of methylaluminoxane (MAO), they were able to polymerize 1,3-butadiene and substituted 1,3-butadienes such as isoprene, (E)-1,3-pentadiene, (E)-1,3-hexadiene, and (E)-3-methyl-1,3-pentadiene. Specifically, 1/MAO gave predominantly syndiotactic 1,2 polymers from 1,3-butadiene and terminally substituted 1,3-butadienes (e.g., 1,3-pentadiene and 1,3-hexadiene), but it was practically not active in the polymerization of internally substituted 1,3-butadienes (e.g., isoprene and 3-methyl-1,3-pentadiene); 2/MAO and 3/MAO exhibited instead an opposite behavior, giving predominantly isotactic 1,2 polymers from 3-methyl-1,3-pentadiene, and showing very low activity in the polymerization of 1,3-butadiene, 1,3-pentadiene and 1,3-hexadiene. The results obtained are interesting from the mechanistic point of view, and some hypotheses to explain this particular behavior were formulated.

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Section: Polymer Characterizationmentioning

confidence: 99%

Section: Polymerization Of 12 Propadienementioning

confidence: 99%

“…Powder X-ray Diffraction (PXRD) (a); Differential Scanning Calorimetry (DSC) (b) and 13 C NMR (c) spectra of poly(1,2-propadiene) ( Table 3, entry 2).…”

Section: Figurementioning

confidence: 99%

Section: Polymer Characterizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Novel Allyl Cobalt Phosphine Complexes: Synthesis, Characterization and Behavior in the Polymerization of Allene and 1,3-Dienes

et al. 2017

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Polybutadiene

Halasa

Massie

2000

Kirk-Othmer Encyclopedia of Chemical Technology

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The discovery of rubbery elastomers based on 1,3‐butadiene and its derivatives was made in 1926. I. G. Farben developed a process to use sodium polymerization on a commercial scale. The resulting polymer, Buna, made from butadiene and natrium, was tested in passenger car tires, and the results were fairly encouraging since it showed equivalent wear properties to natural rubber compounds. The work on emusion polymerization of butadiene and copolymerization of butadiene and styrene or acrylonitrile began in the 1920s in the United States under the government established Rubber Reserve program. Under this program, Gr‐s and SBR became general‐purpose rubbers even though their tire properties were inferior to natural rubber compounds. Great improvements were made in the emulsion polymerization of 1,3‐butadiene and isoprene, especially with the discovery of chain‐transfer agents used for molecular weight control. Nevertheless, the search for a natural rubber replacement continued in many research laboratories worldwide especially in the United States.

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Stereoselective Polymerization of Conjugated Dienes

Takeuchi

2013

Encyclopedia of Polymer Science and Technology

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Stereospecific polymerization of conjugated dienes, especially 1,3‐butadiene and isoprene, is summarized. Various transition metal catalysts are utilized for the stereospecific polymerization of conjugated dienes. For example, Ti, V, Co, Ni, and lanthanides for cis ‐1,4‐polymerization of 1,3‐butadiene, V, Cr, Fe, and lanthanides for trans ‐1,4‐polymerization of 1,3‐butadiene, and Cr, Co, and Fe for 1,2‐polymerization of 1,3‐butadiene. Lanthanide catalysts are very effective for stereospecific polymerization of isoprene. Stereospecific living polymerization of conjugated dienes is also achieved. A mechanism of the polymerization affording stereoregular polymers and stereospecific polymerization of other diene monomers is also mentioned.

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Syndiotactic 1,2‐polybutadiene with Co‐CS₂ catalyst system. III.¹H‐ and ¹³C‐NMR study of highly syndiotactic 1,2‐polybutadiene

Cited by 43 publications

References 23 publications

Novel Allyl Cobalt Phosphine Complexes: Synthesis, Characterization and Behavior in the Polymerization of Allene and 1,3-Dienes

Novel Allyl Cobalt Phosphine Complexes: Synthesis, Characterization and Behavior in the Polymerization of Allene and 1,3-Dienes

Polybutadiene

Stereoselective Polymerization of Conjugated Dienes

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