3.7 Oxygen Compounds
63
Assignment
Range
Comments
Aromatic
Ortho effect with appropriate substituents:
O H
Y
Z
O
Y
+
H
Z
+ .
+ .
with Y–Z as –CO–OR, C–hal, –O–R, and similar
Aliphatic
Aromatic
≈200–210 nm
(log ε ≈3.8)
≈270 nm
(log ε ≈2.4)
No absorption above 200 nm
In alkaline solution, shift to longer wavelength and increase in intensity due to
deprotonation
3.7.2 Ethers
Assignment
Range
Comments
al C–O
50–90 ppm
Oxiranes: outside the normal range
al C–(C–O)
10–60 ppm
Hardly any shift with respect to C–(C–CH 3 )
al C–(C–C–O)
10–60 ppm
Shift with respect to C–(C–C–CH 3 ) ≈-5 ppm
O–C–O
85–110 ppm
(C)=C–O
115–165 ppm
Shift with respect to (C)=C–C ≈+15 ppm
C=(C–O)
70–120 ppm
Shift with respect to C=(C–C) ≈-30 ppm
ar C–O
140–155 ppm
Shift with respect to ar C–H ≈+25 ppm
ar C–(C–O)
100–130 ppm
Shift with respect to ar C–(C–H):
ortho ≈-15 ppm
meta ≈+1 ppm
para ≈-8 ppm
CH 3 –O
CH 2 –O
3.3–4.0 ppm
3.4–4.2 ppm
Singlet
O–CH 2 –O
CH–O
CH(O) 3
4.5–6.0 ppm
3.5–4.3 ppm
≈ 5–6 ppm
H–C(O)=C
H–C=C–O
5.7–7.5 ppm
3.5–5.0 ppm
Shift with respect to H–C(H)=C ≈+1.2 ppm
Shift with respect to H–C(=C–H) ≈-1 ppm
ar CH–C–O
6.6–7.6 ppm
H–C(–O) st
2880–2815 cm -1 For CH 3 –O and CH 2 –O; similar range for
corresponding amines
H–CH(O) 2 st
2880–2750 cm -1 Two bands
C–O–C st
1310–1000 cm -1 Strong, sometimes two bands
MS
UV
13 C
1 H
IR