How many resonances would be expected in the broadband proton-decoupled ¹³C spectrum of:

Question

Quizplus · Accepted Answer

The spectrum is proton-decoupled, which means that any coupling between protons and the target carbon (C) is eliminated. The formula for the number of expected resonances in a proton-decoupled carbon spectrum is given by the number of unique carbon environments in the molecule. 
In this case, there are three unique carbons: S1, U1, and P0. Therefore, we can expect three resonances in the spectrum. The other carbons (P1, S2, S3, and S4) are either coupled to protons or are not observed in this experiment. So, the answer is C)3.

How Many Resonances Would Be Expected in the Broadband Proton-Decoupled