Structural analysis Flashcards
IR stretch c=o
1780-1650
IR stretch c=n
2260-2220
benzene / phenyl
1600 and 1500-1430
1600 and 1500-1430
benzene / phenyl
2260-2220
IR stretch c=n
1780-1650
IR stretch c=o
o-h alcohol
3650-3200
o-h carboxylic acid
3300- 2500
3300- 2500
o-h carboxylic acid
3650-3200
o-h alcohol
if a mass spec has two lines for m+ it means …
it has a atom with an isotope (maybe br or cl is present)
mass spec : 29 means ….
ch2-ch3 chain (ethyl group)
mass spec : 127 means ….
iodine
mass spec: to signify iodine we may see…
127 and a large gap to the next group
if br or cl is present , the m+ line is likely to look like what?
two lines for m+ because they can have an isotope
mass spec : 77 means ….
phenyl group
m*+1 = x . how do we work out how many carbons?
x/1.1
HNMR: how can we work out if its a ch, ch2 or ch3 easily?
use the integration. if we know what one integral represents, we can compare this value to work out how many Hs are present in the others.
mass spec : 91 means ….
tropylium aka benzene with a ch2
HNMR: when two protons are coupled, the coupling constant is …
the same for both protons.
(therefore we can tell which peaks on hnmr are potentially coupled).
HNMR: if the signals are zoomed in but look different, this is because…
they may be taken at different frequencies. look carefully to see if they have been taken under different equipment.
HMRS (High resolution mass spectrometry)
sum of the exact values of the masses of the most common isotope eg c-12.00000 h+1.007825
HNMR: isopropyl group looks like …
septuplet
very small coupling constants mean that its a…
long range coupling
