452
9 UV/Vis
9.4.3 Aromatic Carbonyl Compounds
Scott rules for estimating the position of the K band (solvent: ethanol; λ max in
nm, ε = 10000–30000)
Parent systems
O
H
250
O
OH
230
O
alk
246
O
OR
230
Increments
Substituent
ortho
meta
para
–alkyl
3
3
10
–cycloalkyl
3
3
10
–Cl
0
0
10
–Br
2
2
15
–OH
7
7
25
–O–alkyl
7
7
25
–O –
11
20
78
–NH 2
13
13
58
–N(CH 3 ) 2
20
20
85
–NHCOCH 3
20
20
45
Example: Estimation of the absorption maximum (K band) for
O
O
base value
246
ortho-cycloalkyl
3
para-O–alkyl
25
estimated
274
experimental
276