I) CONJUGATED DIENE CORRELATIONS:

a) Homoannular Diene:-Cyclic diene having conjugated double bonds in same ring.

b) Heteroannular Diene:-Cyclic diene having conjugated double bonds in different rings.

c)Endocyclic double bond:-Double bond present in a ring.

d)Exocyclic double bond: -Double bond in which one of the doubly bonded atoms is a part of a ring system.

Here Ring A has one exocyclic and endocyclic double bond. Ring B has only one endocyclic double bond.

PARENT VALUES AND INCREMENTS FOR DIFFERENT SUBSTITUENTS/GROUPS:

I) CONJUGATED DIENE CORRELATIONS:

i) Base value for homoannular diene = 253 nm

ii) Base value for heteroannular diene = 214 nm

iii) Alkyl substituent or Ring residue attached to the parent diene = 5 nm

iv) Double bond extending conjugation = 30 nm

v) Exocyclic double bonds = 5 nm

vi) Polar groups: a) OAc = 0 nm

b) OAlkyl = 6 nm

c) Cl, Br = 5 nm

Eg:

Base value = 214 nm

Ring residue = 3 x 5 = 15 nm

Exocyclic double bond = 1 x 5 = 5 nm

Î»max= 214+15+5=234 nm

II) Î±, Î² UNSATURATED CARBONYL COMPOUNDS OR KETONES:

1. Base value: a) Acyclic Î±, Î² unsaturated ketones = 214 nm

b) 6 membered cyclic Î±, Î² unsaturated ketones = 215 nm

c) 5 membered cyclic Î±, Î² unsaturated ketones = 202 nm

d) Î±, Î² unsaturated aldehydes = 210 nm

e) Î±, Î² unsaturated carboxylic acids & esters = 195 nm

2. Alkyl substituent or Ring residue in Î± position = 10 nm

3. Alkyl substituent or Ring residue in Î² position = 12 nm

4. Alkyl substituent or Ring residue in Î³ and higher positions = 18 nm

5. Double bond extending conjugation = 30 nm

6. Exocyclic double bonds = 5 nm

7. Homodiene compound = 39 nm

8. Polar groups: a) â€“OH in Î± position = 35 nm

â€“OH in Î² position = 30 nm

â€“OH in Î´ position = 50 nm

b) â€“OAc in Î±, Î², Î³, Î´ positions = 6 nm

c) â€“OMe in Î± position = 35 nm

â€“OMe in Î² position = 30 nm

â€“OMe in Î³ position = 17 nm

â€“OMe in Î´ position = 31 nm

d) â€“Cl in Î± position = 15 nm

â€“Cl in Î² position = 12 nm

e) â€“Br in Î± position = 25 nm

â€“Br in Î² position = 30 nm

f) â€“NR2in Î² position = 95 nm

Eg:

Î²- Substituents = 1 x 12 = 12 nm

Î´- Substituents = 1 x 18 = 18 nm

Double bond extending conjugation =1 x 30 = 30 nm

Exocyclic double bond = 5 nm

Î»max= 279 nm

III) AROMATIC COMPOUNDS:

1)Base value: for a) ArCOR = 246 nm

b) ArCHO = 250 nm

c) ArCO2H = 230 nm

d) ArCO2R = 230 nm

2) Alkyl group or ring residue in ortho and meta position = 3 nm

3) Alkyl group or ring residue in para position =10 nm

4)Polar groups: a) â€“OH, â€“OCH3, â€“OAlkyl in o, m position = 7 nm

b) â€“OH, â€“OCH3, â€“OAlkyl p position = 25 nm

c) â€“O (oxonium) in o position = 11 nm

d) â€“O (oxonium) in m position = 20 nm

e) â€“O (oxonium) in p position = 78 nm

f) â€“Cl in o, m position = 0 nm

g) â€“Cl in p position = 10 nm

h) â€“Br in o, m position = 2 nm

i) â€“Br in p position = 15 nm

j) â€“NH2in o, m position = 13 nm

k) â€“NH2in p position = 58 nm

l) â€“NHCOCH3in o, m position = 20 nm

m) â€“NHCOCH3in p position = 45 nm

n) â€“NHCH3in p position = 73 nm

o) â€“N(CH3)2in o, m position = 20 nm

p) â€“N(CH3)2in p position = 85 nm

Eg:

Base value =246 nm

Ring residue in o- position = 1 x 3 = 3 nm

Polar group -OCH3in p- position = 25 nm

Î»max= 274 nm

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