[zeoblade]

If both borneol and isoborneol have 10 signals in the 13CNMR slightly differing in the values, would a mixture of borneol and isoborneol give 20 peaks of those same corresponding values? Would the peaks be too difficult to resolve?

I'm not sure if my conclusion is correct.

[johnnyd]

Generally, you'd be considered very unlucky to have overlapping signals in your carbon spectra. It's  a question of resolution though. A 400MHz spectrometer or better would prob distinguish between all 20 signals. The proton spectrum will be an awful mess though! Characterise as one big multiplet 1-2ppm

[zeoblade]

Great, thanks, for confirming.

What frequency would be unable to distinguish all the peaks from each other?

[johnnyd]

Thats one of those how long is a piece of string questions!

You can't know unless you know how close the signals are to each other. You might be really unlucky and have two signals right on top of each other. An 800MHz machine wont differentiate them in this case.

For these 2 compounds, and I'm guessing here, I'd say 400MHZ is prob the limit. Maybe 300 at a push?

[zeoblade]

Sorry to ask that kind of question.

Isn't 800MHz better resolution and can distinguish between those 20 peaks and low resolution (100MHz) unable to distinguish between those 20 peaks?

[johnnyd]

Absolutely right.

I was just making the point that if you are unlucky enough to have signals appearing at exactly the same frequency, no spectrometer will be able to differentiate between them.

If you're concerned that you have overlapping signals, 2d NMR may help. If you can run a CH COSY or long range CH COSY experiment, you should be able to tell which carbon signals are which.

[OC pro]

Even an old machine like a 300 MHz spectrometer can easily differentiate between Borneol and Isoborneol. I assume most of the carbon atoms will have similar chemical shifts. But at the CH-group on which the alcohol is attached has a different chemical shift in 13C. Even the 1H NMR will look quite different.

[zeoblade]

thanks johnnyd

yeah some of them differ by 0.05

thanks for your confirmation