13C nuclear magnetic resonance studies on the stereochemical configurations of 2,4-dimethoxypentane and poly(alkyl vinyl ethers)

¹³C nuclear magnetic resonance (CMR) spectra were obtained for 2,4-dimethoxypentane, which is a model compound of poly(methyl vinyl ether), and the effects of the solvent and temperature on the chemical shifts were investigated. CMR spectra of poly-(alkyl vinyl ethers) were also determined and analyzed. The diad tacticities were obtained from β-methylene carbon resonances of poly(methyl vinyl ether), poly(ethyl vinyl ether), and poly(isobutyl vinyl ether), but not from those of poly(isopropyl vinyl ether) and poly(tert-butyl vinyl ether). The methoxyl carbon resonance of poly(methyl vinyl ether) and the ethoxyl methylene carbon resonance of poly(ethyl vinyl ether) showed splittings corresponding to pentad and triad sequences, respectively. The α-methine and quaternary carbon resonances of poly(tert-butyl vinyl ether) showed splittings corresponding to pentad and triad sequences, respectively.