[rjb641]

Hello,

Perhaps this is a silly question, but I shall ask nevertheless...
I understand that when looking at 1H NMR spectra, 13C signals are so small (4 orders of magnitude smaller than 1H signals) they are effectively invisible. However when viewing 13C NMR spectra, how come signals (not splitting) from protons atoms are not visible? Are they supressed or am I missing something really obvious?

Thanks in advance!

Richard

[McCoy]

okay, remember that proton and carbon resonate at different frequencies. Proton resonance occurs at frequency outside the carbon 13 frequncy range.

[Johnny010]

See the above post.

Also C13 would cause coupling with other C13 atoms, but the chance of them being "close enough" to resonate is low (1 in 100 C atoms are the 13 isotope), the effect is then not seen to such a degree.