- Thursday, April 5, 1984
- Two-Dimensional Relayed Coherence Transfer Experiments as a Means of Subgrouping Protonated Carbon Resonances of Complex Polynuclear Heteroaromatics on the Basis of Vicinal Proton-Proton Connectivities
- Published at:Not Found
Application of autocorrelated homonuclear (COSY) and proton-carbon chemical shift correlation two-dimensional nmr experiments to the problem of assigning the 'H- and "C-nmr spectra of phenanthro[4,3-aldibenzothiophene fails despite their considerable utility in the assignment of the spectra of the smaller phenanthro[b]thiophenes. The failure of these techniques in the case of phenanthro[4,3-aldibenzothiophene is predominantly due to the inability of the COSY spectrum to provide the means of subgrouping the proton resonances into their component spin subsystems. Two-dimensional relayed coherence transfer nmr experiments which first established coherence between vicinally coupled protons which is then transferred to the carbon spins which are ultimately observed circumvent these problems. The application of two-dimensional relayed coherence transfer to phenanthro[4,3-a]dibenzothiophene is described, the technique leading to the subgrouping of all five of the proton spin subsystems and thus providing a means of beginning the total assignment.