Sistemas Conjugados e Espectroscopia UV

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Solutions for Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy
39 Look for extended conjugation, meaning an unbroken string of sp hybridized atoms, noted here with 2
a large dot on carbon atoms. Other sp2 atoms, like O and N, are designated with a *.
O
∗
O
∗
I
Na+ –O
I
I
I
COO– Na+
N
∗N
∗
OH
N
∗
Na+ –OOC
N
∗
SO3
– Na+
Na+ –O3S
O
∗
N
∗
N ∗
CH3
CH3
Cl–
HO
∗
O ∗
N
∗
N
∗
OH
∗
HO
∗
Na+ –O3S
O
HO OH
COOH
H3CO
O
N(CH3)2
O
∗
O
∗
OH
∗
OH
∗
HO
∗
CH3
COOH
OH
∗
NO2
HO
ONH2OH
Cl
Cl
Cl
Cl
O∗
O ∗
(a)
(c)
(e)
(g)
(i)
(j)
(b)
(d)
(f)
(h)
(k)
NOT COLORED—
no extended conjugation
NOT COLORED—
no extended conjugation
NOT COLORED—
no extended conjugation
NOT COLORED—
no extended conjugation
All 4 N and COO– are also sp2.
food dye:
FD&C Red #3
food dye:
FD&C Yellow #5
rhodoxanthin, a purple dye
found in plants and bird feathers
Acid Alizarin 
Violet N, a 
violet dye
kermesic acid,
a red dye from insects
p-naphtholbenzein, 
a red indicator
Basic Blue 6,
aka Meldola Blue,
a biological stain
358