Soluções para Sistemas Conjugados e Espectroscopia Ultravioleta

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Solutions for Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy
O
O
H
O
CH2 CH2CH3
O
O
O
CH2CH2CH3
CH2CH2CH3
Cl
Cl
CH2
O
CH
CH3
CH3
CH2CH2CH3
C
H
CH2
CN
CN
H
C
CH
C
COOCH3
HC
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(a) The absorption at 1630 cm–1 suggests a conjugated alkene. The higher temperature allowed for 
migration of the double bond.
(b)
desired actual
(c)
expected:
m/z 79
+ • CH2CH2CH3
actual:
doubly allylic
m/z 122
m/z 122
m/z 93
+ • CH2CH3
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(a) (b) (c)
+ ++
(d) (e) (f)
++ +
mass 29
mass 43
The UV λmax at 261 nm verifies that the two 
double bonds have become conjugated. 
Isolated double bonds absorb at