Carbon-13 NMR spectra of methyl-substituted 1,4-trans-polybutadienes. 1. Method of assignment and spectra of some homopolymers

Sozzani, Piero; Silvestro, Giuseppe Di; Grassi, M.; Farina, Mário

doi:10.1021/ma00142a012

Cited by 30 publications

(31 citation statements)

References 16 publications

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“…The investigation carried out on homopolymerization and copolymerization of diene monomers included in PHTP allowed us to make evident that the same stereochemical control exists for the two processes (17,24 -CH(CH )-CH(CH )-, which are not detectable in the corresponding homopoîymer. ?he disorder existing among the guests probably extends to the host lattice thus making it possible to generate small amougts of usually forbidden sequences.…”

Section: Whenmentioning

confidence: 99%

“…?he disorder existing among the guests probably extends to the host lattice thus making it possible to generate small amougts of usually forbidden sequences. The C NMR spectra of diene homopolymers and copolymers were interpreted on the basis of a fully consistent set of additive parameters (17,24). The presence of methyl groups influences the chemical shift of the chain carbon atoms even when they are four or five bonds away s (δ and e parameters).…”

Section: Whenmentioning

confidence: 99%

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Polymerization in Crystalline Inclusion Compounds

Farina

Silvestro

Sozzani

1987

ACS Symposium Series

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The polymerization of monomers included as guests in the crystal structure of channel-like inclusion compounds extends the fields of application of solid state polymerization far beyond the melting point of pure monomers. Depending on the nature of both host and guest compounds, polymers can be obtained having a wide variety of structural features: regio-and stereospecificity can reach very high values; optical activity is induced by using chiral crystal lattices; extended-chain macroconformations are observed under specific working conditions. Inclusion polymerization proceeds by a radical mechanism and its living character has been demonstrated in some cases. Recent results concern the production of block and statistical copolymers and a new synthesis of polyethylene and polypropylene by high-pressure inclusion polymerization. (1-6). This process belongs to the wider class of solid state polymerization, but possesses some specific features which make it worthy of a separate description. Throughout this article, the polymerization in inclusion compounds will be referred to as "inclusion polymerization" (other names currently used in the scientific literature are channel, canal or tunnel polymerization), and the terms "clathrate" will be used as synonymous with "inclusion compound". When there is no risk of confusion, the more general term of "adduct" will be used for clathrate: in principle a Crystalline inclusion compounds containing unsaturated monomers are effective reactive systems for the production of linear polymers

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Section: Whenmentioning

confidence: 99%

Section: Whenmentioning

confidence: 99%

Polymerization in Crystalline Inclusion Compounds

Farina

Silvestro

Sozzani

1987

ACS Symposium Series

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“…Insight into the polymer microstructure was obtained by 1 H and 13 C solution NMR spectroscopy. The 13 C NMR spectra of PPD polymerized in Ala‐Val (Figure 3 a) featured the characteristic signals of the 1,4‐ trans polymer without regiochemical errors or pendant vinyl groups 10…”

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confidence: 98%

Octupolar Merocyanine Dyes: A New Class of Nonlinear Optical Chromophores

Poronik

Hugues

Blanchard‐Desce

et al. 2012

Chemistry A European J

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A set of new octupolar merocyanine chromophores was designed and synthesized. These compounds were prepared from the reaction of 1,3,5-triformyl-2,4,6-trihydroxybenzene with heterocyclic nucleophiles. Octupolar dyes were formed exclusively in their open-dye form. The one- and two-photon-absorption spectra of the dyes consist of two bands: The long-wavelength band in the two-photon absorption spectrum (a few hundreds GM above 1000 nm) matches well with the intense, long-wavelength-absorption band that is located in the visible region in the linear spectrum. Interestingly, an additional, much-more-intense TPA band in the NIR region is observed at higher energy, which corresponds to a weakly allowed one-photon electronic transition. Changing the peripheral heterocyclic moieties allows tuning of the optical properties to approach the cyanine limit (i.e., polymethine state), thus resulting in a red-shift of the low-energy one-photon-absorption band as well as to the rise of an intense two-photon-absorption band in the NIR region. To the best of our knowledge, this is the first synthesis and TPA characterization of octupolar merocyanine chromophores with typical low-bond-length alternation.

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“…The aliphatic region of the spectrum of entry 11, and entry 8 for comparison, shows several signals due to different sequences of the two co‐monomers in the copolymer. The assignments of these peaks are made on the basis of the additive shift method for methyl‐substituted 1,4‐ trans ‐polybutadienes . The sequences were assigned considering 4MPD in both 1,2‐ and 1,4‐mcrostructure.…”

Section: Resultsmentioning

confidence: 99%

Binary copolymerization of 4-methyl-1,3-pentadiene with styrene, butadiene and isoprene catalysed by a titanium [OSSO]-type catalyst

2016

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Binary copolymerization of 4‐methyl‐1,3‐pentadiene (4MPD) with styrene, butadiene and isoprene promoted by the titanium complex dichloro{1,4‐dithiabutanediyl‐2,2′‐bis[4,6‐bis(2‐phenyl‐2‐propyl)phenoxy]}titanium activated by methylaluminoxane is reported. All the copolymers are obtained in a wide range of composition and the molecular weight distributions obtained from gel permeation chromatographic analysis of the copolymers are coherent with the materials being copolymeric in nature. The copolymer microstructure was fully elucidated by means of 1H NMR and 13C NMR spectroscopy. Differential scanning calorimetry shows an increase of glass transition temperature (Tg) with the amount of 4MPD in the copolymers with butadiene and isoprene, while in the copolymers with styrene Tg is increased on increasing the amount of styrene. © 2016 Society of Chemical Industry

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Carbon-13 NMR spectra of methyl-substituted 1,4-trans-polybutadienes. 1. Method of assignment and spectra of some homopolymers

Cited by 30 publications

References 16 publications

Polymerization in Crystalline Inclusion Compounds

Polymerization in Crystalline Inclusion Compounds

Octupolar Merocyanine Dyes: A New Class of Nonlinear Optical Chromophores

Binary copolymerization of 4-methyl-1,3-pentadiene with styrene, butadiene and isoprene catalysed by a titanium [OSSO]-type catalyst

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