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Studies on the tacticity of polyacrylonitrile. III. NMR spectra of stereoisomers of 2,4,6‐tricyanoheptane as model compounds of polyacrylonitrile

1968; Inderscience Publishers; Volume: 6; Issue: 4 Linguagem: Inglês

10.1002/pol.1968.150060413

1542-9350

Masao Murano, Reizô Yamadera,

Advanced Battery Materials and Technologies

Abstract The three stereoisomers of 2,4,6‐tricyanoheptane were separated and their NMR spectra were studied as the three‐unit model compounds of polyacrylonitrile. The chemical shifts and coupling constants obtained from the NMR spectra were compared to those of the two‐units model compounds. The geminal protons for the isotactic methylene are not equivalent, but the difference of the chemical shifts is smaller than that in the meso two‐unit model. The racemic methylene signals appear at higher field than the meso methylene in the heterotactic three‐unit model as in the case of the racemic and the meso two‐unit models. The signals of the methinic protons in triads appear in the order: isotactic CH, heterotactic CH, and syndiotactic CH from the high field. From the observed values of the vicinal coupling constants, the chain conformations of the model compounds are also discussed.