| Abstract: | Two-dimensional (2-D) NMR results are presented for all-trans-retinal. 2-D J-resolved 1H-NMR separated the multiplets of the olefinic protons and accurately determined their chemical shifts. 2-D shift-correlated 1H-NMR gave the connectivities between scalar coupled protons. From the observed H,H long-range couplings the assignment of the methyl resonances was possible. 2-D J-resolved 13C-NMR separated overlapping C,H-multiplets and allowed analysis of the C,H long-range couplings, 2-D shift-correlated 13C-NMR related each directly bonded C,H-pair in this molecule. The potential of 2-D NMR in resolving and identifying individual resonances in polyene spectra is discussed. |
