The Nuclear Magnetic Resonance Spectrum of Vinylene Carbonate

The H and 13C spectra of vinylene carbonate have been studied by double-resonance techniques. It was found that J(13C—H) = ±220.15 ± 0.15 c/s, J(13C—C—H) = ±17.47 ± 0.12 c/s, and J(H—C—C′—H′) = ±1.47 ± 0.03 c/s. A long-range coupling of 9.26 ± 0.10 c/s was observed between the carbon nucleus of the carbonate group and the vinyl protons. The magnitudes and signs of the geminal 13C—C—H couplings are discussed in terms of the molecular orbital theory of Pople and Bothner-By.