NMR Flashcards
How do you figure out which protons are more or less shielded
The less electrons there are around a proton the less shielded it is and vice versa
What are the two energy levels of an NMR?
Alpha (+1/2) aligned with the magnetic field and Beta (-1/2) runs against the magnetic field
What determines the difference between the two energy levels of the NMR?
The strength of the magnet
How is shielding related to how up or downfield protons appear on the NMR?
The more (D)esheilded the more (D)ownfield it will be
What does TMS stand for and what is it?
TMS stands for tetrmethylsiline and it is an “internal standard” (aka TMS = 0)
What do we use instead of water for NMR?
We use deuterated water which will not appear on the NMR
What are the two main rules for equivalent protons when it comes to NMR?
-Protons on the same sp3 carbon are equivalent
-Protons are related to each other by symmetry
What’s the easy method to do spin-spin coupling?
After you pick a proton you look at how many protons are on neighboring carbons and then add 1 to that value.
What is the coupling constant(j)?
It is the distance between spins of protons on an NMR
What ratio does the splitting pattern follow?
Pascal’s triangle (1,1-1,1-2-1,1-3-3-1,etc)
What is fast exchange?
It’s when a hydrogen is switched out with the deuterium
Is TMS the most upfield or downfield signal during H-NMR?
Upfield
Where are peaks where protons absorb longer wavelengths of radio waves found?
Upfield
