Assignment of the 1H‐ and 13C‐NMR spectra of phenanthro[1,2‐b]thiophene through the concerted application of two‐dimensional NMR spectroscopic techniques

Two‐dimensional nmr spectroscopy, by virtue of its second frequency domain which permits the segregation of spectral information along two frequency axes, considerably simplifies many assignment problems and facilitates others which may be impossible using conventional nmr methodology. A compound which falls into the latter category of assignment problem is phenanthro[1,2‐b]thiophene. The assignment of the 1H‐ and 13C‐nmr spectra of phenanthro[1,2‐b]thiophene are, however, reported through the concerted application of two‐dimensional nmr techniques. Experiments utilized in making the assignments included: auto‐correlated homonuclear (COSY) two‐dimensional spectroscopy; heteronuclear two‐dimensional J‐resolved spectroscopy; proton‐carbon chemical shift correlation two‐dimensional spectroscopy; and two‐dimensional 13C‐13C double quantum coherence spectroscopy.