Skip To Content

Logic Puzzle #35: Assigning Chemical Shifts

Coupling information is very useful in locating the position of an atom in relation to other atoms. This puzzle covers one such example.

For an unknown compound1, a di-substituted phenyl ring with a fluorine substituent was deciphered. The 13C NMR spectrum below shows two 13C signals split due to 19F-13C coupling. Which carbon, chemical shift at 116 or 134 ppm, is adjacent to the C-F group?

Thank you Walter for your comment on puzzle #34. I missed it in the last post.

  1. Cohen, D.T., Eichman, C.C., Phillips, E.M., Zarefski, E.R., Scheidt, K.A., Angew. Chemie. Int. Ed. 2012, 51, 7309-7313.