Undecoupled and decoupled high resolution nuclear magnetic resonance study of poly(vinyl chloride)

Satoh, Shiroh

doi:10.1002/pol.1964.100021218

Cited by 31 publications

(7 citation statements)

References 10 publications

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“…Another interesting fact obtained from the spectra of the three-unit models is concerned with the CH resonances. When, in the polymer, the C H proton was decoupled from the CH2 protons, three peaks were seen, 5,18919 and these were assigned by Bovey et al and also by Satoh et al to the syndiotactic, heterotactic, and isotactic CH resonances, respectively, from the low field. This assignment is supported by the three-unit model compounds.…”

Section: Analysis Of the Nmr Spectra Of Pvcmentioning

confidence: 89%

NMR spectra of model compounds of poly(vinyl chloride)

Abe

Tasumi

Shimanouchi

et al. 1966

J. Polym. Sci. A‐1 Polym. Chem.

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SynopsisThe NMR spectra of three stereoisomers of 2,4,&trichloroheptane 3s model compounds of poly(viny1 chloride) have been studied. Spectra were observed at 60 and 100 Mc./ sec., both at room temperature and at high temperatures. A spin-decoupling experiment was performed. Computational analysis of the spectra was carried out on an IBM 7090 computer. The difference of the chemical shifts of the two meso methylene protons a t 60 McJsec. was found to be ca. 7 cps. for the isotactic three-unit model while it was ca. 16 cps. for the isotactic two-unit model or heterotactic three-unit model. The spectra of poly(viny1 chloride) were interpreted reasonably on the basis of this result. Observed values of vicinal coupling constants of model compounds were interpreted as the weighted means of those for several conformations, and the stable conformatiorrs of the models were determined.

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Section: Analysis Of the Nmr Spectra Of Pvcmentioning

confidence: 89%

NMR spectra of model compounds of poly(vinyl chloride)

Abe

Tasumi

Shimanouchi

et al. 1966

J. Polym. Sci. A‐1 Polym. Chem.

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“…The spectrum of polyvinyl chloride solutions is very complex and its form depends markedly on the frequency of the measurement, the solvent, and the temperature and the data of different investigators do not agree completely [197,199,238,269,270,271,380,597,691,744]. Different methods have been used to interpret the spe~tra of polyvinyl chloride.…”

Section: Polymethyl Methacrylatementioning

confidence: 99%

“…Different methods have been used to interpret the spe~tra of polyvinyl chloride. These include comparison of the spectrum of the polymer with the spectra of model compounds (d,l-2,4-dichloropentane and meso-2,4-dichloropentane [269][270][271]597]), plotting the spectra of deuterated polymers [199,744] and eliminating the spin-spin interaction between the methyne and methylene protons by the double resonance method [197,597,744].…”

Section: Polymethyl Methacrylatementioning

confidence: 99%

The NMR of Polymers

Slonim¹,

Lyubimov²

1995

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“…We took into account the magnetic anisotropies of the C-C and C-Cl bonds, but neglected Llxc-H because of its small contribution. 30 ( 6) where R is a distance between any specified proton and an atom (X) bonded to it, q the charge on the atom (X), and Ez is the component of a uniform electric field E in the bond direction of any specified proton. Ez and E were estimated from the charge distributions obtained by the extended Hiickel method as described below.…”

Section: Theoreticalmentioning

confidence: 99%

The Chemical Shifts of Poly(vinyl chloride) and Its Model Compounds

Ando

Nishioka

Watanabe

1972

Polym J

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ABSTRACT:The proton chemical shifts of meso and racemic 2, 4-dichloropentanes (DCP) were calculated by taking into account the diamagnetic shielding, bond anisotropy and polar effects, using preferred comformations of TG and G'T forms for meso DCP, and TT and GG forms for racemic DCP. The TT form was found to be more stable the GG one by 1.97 kcal/mol. It is predicted theoretically that the anti methylene proton would appear at higher field than the syn proton. Also the orders of the excess charges of the 2p electrons and the total charges on the carbon atoms of meso and racemic DCP's coincide with the order of the observed C-13 chemical shifts of those DCP's.The proton chemical shifts of poly(vinyl chloride) (PVC) were calculated assuming the preferred conformations, (TG)n and (G'T)n for isotactic PVC and (TT)n for syndiotactic PVC. The calculated chemical shifts of racemic methylene and isotactic methine protons appear at a higher field than the meso methylene and syndiotactic methine protons, respectively. As for the isotactic PVC the anti proton appears at higher field than the syn proton just as for DCP.KEY WORDS Poly(vinyl chloride) / Dichloropentane / Chemical Shift / Conformation / Extended Hiickel Method / The proton NMR spectrum of poly(vinyl chloride) (PVC) in solution has long been studied for the stereochemical structure of this polymer, sometimes using decoupling and selective deuteration techniques. 1 -16 Recently Heatley, 16 et al., have studied the vicinal coupling constants of PVC, using a 220-MHz NMR spectrometer and have suggested that in thermodynamically good solvents, the isotactic dyads are in approximate equilibrium between the conformations which result in a 31 helix, whereas syndiotactic dyads are probably in a planar zigzag structure. Also, as the model compounds of PVC, the molecular structure of meso and racemic 2, 4-dichloropentanes (DCP) and isotactic, heterotactic and syndiotactic 2, 3, 6-trichloroheptanes have been studied by infra-red and NMR methods 17 -24 and it has been proposed that the TG and G'T forms are preferred for meso DCP, whereas the preferred form for racemic DCP are predominantly TT, and also GG with some probabilities. Flory, et al.,25 have pointed out the existence of less-favoured conformations. However, these may be almost ignored in our discussion described below.As described above, the molecular structures of DCP and PVC have been studied in detail, but the relationship between the chemical shifts and molecular structures of these compounds have been scarcely studied theoretically. In this paper the calculation of the proton and C-13 chemical shifts of these model compounds in their preferred conformations are described.At first, in the cases of DCP's the extended Hiickel theory 26 was applied to calculate the total electron energies, the total net charges and the excess charges of 2p electrons. Then the proton chemical shifts of these compounds were calculated by taking into account the contributions from diamagnetic shielding, magnetic anisotropy and po...

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Undecoupled and decoupled high resolution nuclear magnetic resonance study of poly(vinyl chloride)

Cited by 31 publications

References 10 publications

NMR spectra of model compounds of poly(vinyl chloride)

NMR spectra of model compounds of poly(vinyl chloride)

The NMR of Polymers

The Chemical Shifts of Poly(vinyl chloride) and Its Model Compounds

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