NMR 2 Flashcards
What type of multipliity is there in aromatics?
mono/di/tri substitited
what does it mean if the protons are chemically equivilant?
attached to same things- will react in same way
what does it mean if the protons are mechanically equivilant?
prime indicates not mechanically eq
if the coupling is 3J how many hertz is it?
8HZ
if it is 4J coupling how many hertz is it?
3HZ
Why are some signals shifted?
due to sheilding- more sheilded- shift right
also due to lone pairs- electron donating- resonance
if the carbon is delta negative what does that indicate?
high electron density and it is sheilded- right shift- lower PPM
if the carbon is delta positive what does this indicate?
low electron density- left shift- higher PPM
What are the two kinds of EDG?
electron donating through induction
and resonance
what are the two types of EWG?
electron withdrawing through induction and resonance
what does an AX2 system indicate?
- Single bonds and free rotation- chemically and magnetically equivilant( how ha couples with them- 3 bonds each)
- 2 HX=triplet- split once by HX and same again
what is an AX3 bond?
attached to differnt carbons
3 bonds X3
and 1 bond x1
quartet
what is an A2x3 bond?
2as 3xs
as have 2
xhas 3
triplet
what is an AMX
trisubstituted 3 differnt environments ha-4-hm- 3 hertz coupling narrow doublet broad doublet doublet doublet
what are non-first order patterns?
differnce in chemical shift vs J value- if bigger/ 10x
- if not obeyed changes to AB system- rooftop system
