THE DIPROPENYL ETHERS: VIBRATIONAL AND 13C NMR SPECTRA

Article abstract of DOI:10.1016/0022-2860(82)80034-3

The infrared vapor phase and solution spectra and the Raman liquid phase spectra as well as the 13C NMR absorption have been examined for the dipropenyl ether isomers, i.e. cis, cis (I), cis, trans (II) and trans, trans (III).Evidence based on double bond vibrational coupling, the simple nature of the spectra and the assignment of most of the fundamentals shows only one planar s-trans, s-trans conformations for each isomers.The strong double bond coupling probably indicates that substantial "through space" electron delocalization between the double bonds must be involved, and that this reduces or takes precedence over oxygen electron delocalization in the order I > II > III.The "cis effect" is explained by a dipolar interaction of β-methyl hydrogen with ether oxygen, which is absent in the trans-propenyl structures.