Chemistry Reference
In-Depth Information
O
Ar
Ar
Ar
O
Ar
glacial
AcOH
O
O
O
O
O
OH
Ar
Ar
Ar
O
Ar
46
47
48
TsOH
O
Ar
Ar
TIPS
Ar
Ar
Ar
O
Ar
1. TIPS-C
2
MgCl
2. SnCl
2
49
Ar
Ar
Ar =
CF
3
50
TIPS
Fig. 24 Synthesis of substituted heptacene 50 [
57
]
O
51
52
O
Fig. 25 Aryl substituted heptacenes 51 and 52 investigated by Chun et al. [
56
]
p
band are rather broad [
56
]. The more soluble derivative 52 is immediately
oxidized upon exposure to air and light. As the color of the solution turns from
brown to orange, the presence of a tetracene species was suggested [
56
].
The 2008 investigation by Chun et al. [
56
] nicely demonstrates that the intro-
duction of bulky groups such as phenyl that may protect the acene from dimeriza-
tion are not sufficient for stabilizing the heptacene core towards air oxidation in the
presence of laboratory light. Two more aryl substituted heptacenes (53 and 54)
were prepared and investigated by the Miller group in 2009 (Fig.
26
)[
58
].
