NMR Part 16

Quick correction to this video! I mistakenly said that deuterium isn’t NMR active. That was incorrect — deuterium is NMR active. Here’s why: A nucleus is NMR active if it has a nonzero nuclear spin. A simple rule of thumb is: If a nucleus has an odd number of protons, it’s NMR active. If it has an odd number of neutrons, it’s NMR active. If it has both protons and neutrons even, it’s usually not NMR active. Let’s look at some examples: ¹H (proton): 1 proton, 0 neutrons → odd protons → NMR active. ²H (deuterium): 1 proton, 1 neutron → both odd → NMR active. ¹³C: 6 protons, 7 neutrons → odd neutrons → NMR active. ¹²C or ¹⁶O: even protons and even neutrons → not NMR active. So why do we use deuterated solvents in proton NMR? Even though deuterium is NMR active, it resonates at a completely different frequency than normal hydrogen (¹H). That means the solvent signals won’t overlap with the proton signals we’re interested in. So the correction is: deuterium is NMR active, but we choose deuterated solvents because their signals don’t interfere with ¹H NMR. Hello Viewers, If you like my style of teaching chemistry, please subscribe. If you would like additional help, please see my tutoring link. However, if you are a current student of mine, I can not and will not tutor you through my online tutoring service. I will, however, be more than happy to help you during office hours. https://www.wyzant.com/Tutors/orgochemist Best, Dr. P