Chemistry Reference
In-Depth Information
R
1
hydroquinone
Cs
2
CO
3
,CsF
Pd
2
(dba)
3
,P(
t
Bu)
3
1,4-dioxane,
R
1,2
X
R
1,2
Br
Br
R
1,2
X
R
1,2
n
R
2
96a
:R
1
,R
2
=C
6
H
4
N(C
16
H
33
)
2
96b
:R
1
=C
6
H
4
N(C
16
H
33
)
2
R
2
=C
6
H
4
NO
2
96c
:R
1
=C
6
H
4
N(C
16
H
33
)
2
R
2
=OC
16
H
33
96d
:R
1
,R
2
= TIPS
P96a
P96b
P96c
P96d
Scheme 26 Polymerization of bis-functionalized monomers 96 to ladder polymers P96 [
105
]
Table 10 Yield and molecular weights of ladder polymers P96a-d [
105
]
Polymer
Yield (%) M
n
a
PDI
a
onset
b
em
b
red
ox
l
(nm)
l
(nm)
E
p
(V)
E
p
(V)
P96a
92
11,000
1.23
831
453, 500
-
0.56
P96b
89
7,200
1.29
805
478, 509
1.69
0.52
P96c
90
18,000
1.44
681
457, 549
-
0.56
P96d
68
2,400
1.27
587
452, 526
2.07
1.45
a
Molecular weights determined by THF-GPC using a polystyrene standard
b
Absorption and emission measured in THF
easily than linear 70a. An amorphous thin film of 70a exhibited high hole mobilities
of 1.8
10
3
cm
2
V
1
s
1
. Bulk heterojunction solar cells constructed from 70a as
the donor and fullerene as the acceptor layer had a power conversion efficiency
(PCE) of 0.94% and an open circuit voltage (
V
OC
) of 0.96 V.
The electrochemical and optical properties of 5,10-diphenyl-dibenzo[
a,e
]-
pentalene (74a) and multiple pentalene-containing 81-84 are summarized in Table
9
[
98
]. The reductions of dipentalenes 81 and 82 are shifted to slightly more positive
potentials than that of monopentalene 74a. As expected, the absorbance spectra of
81 and 82 also underwent the largest bathochromic shift. This observation is
analogous to the trend seen in [N]phenylenes in which linear annelation results in
larger decreases in the HOMO-LUMO gap.
3.3 Diaryl[a,e]pentalene Ladder Polymers
Although conducting polymers containing the DAP framework have been reported
previously [
104
], synthetic access to fully conjugated ladder structures remains a
challenge. Traditionally, a single strand polymer precursor is generated first
followed by an intramolecular cyclization to form the second strand of the ladder.
However, this two-step process allows additional opportunities for defects to occur
in the polymer backbone.
