These later methods allow access to the diiodoterphenyl
DITP patterns and in particular to the 2,2′′-[1,1′,4′,1′′]-
diiodoterphenyl compound (2,2′′-DITP) we were interested
in for further synthetic purposes (route c).
To avoid long and sophisticated multistep syntheses, we
developed an expedient method toward 2,2"-DITPs, which
were the key molecules in our approach, involving original
arylboronic acids bearing a triazene moiety in the ortho
position readily convertible into iodide (Scheme 2). o-
Triazenylboronic acids were obtained in a two-step sequence
from the corresponding substituted diazotyzed o-iodoanilines
5
to a strong enhancement of the OLED properties. Interes-
tingly, a new tendency consists of developing highly
conjugated molecules of well-defined lengths displaying
similar spectroscopic features at the single chromophore
1
-3 in situ quenched by pyrrolidine in basic medium. The
resulting o-iodoaryltriazenes 4-6 were then converted into
their corresponding boronic acids 7-9 by a standard lithia-
tion/borylation sequence involving n-butyllithium and tri-
6
level. To obtain blue light emitting molecules or materials
with long-term stability, we designed a new family of
versatile electropolymerizable chromophores combining both
IF and SBF architectural specificities.
In this communication we report a concrete, well-described
route to dispiro[fluorene-9′,6,9′′,12-indeno[1,2b]fluorenes]
9
methylborate. Suzuki-Miyaura coupling of functionalized
o-triazenylboronic acids with p-diiodobenzene afforded 2,2′′-
bis(triazenyl)terphenyl compounds 10-12, which were con-
verted into 2,2′′-DITPs 13-15 in good isolated yields by a
10
subsequent treatment with excess of methyliodide.
(
DSFIFs) as a new rigid ladder-type family of macromo-
The lithium-iodine exchange of 2,2′′-DITPs 13-15 with
n-butyllithium in THF at low temperature followed by
quenching with a solution of fluorenone in benzene afforded
the corresponding diols 16-18, which were finally heated
to reflux with AcOH/HCl to lead to the corresponding
lecules. Their photophysical and electrochemical characte-
ristics have been evaluated for further OLED applications.
The prototypical DSFIF (Scheme 1) can be considered as
the joining of two SBF moieties through a shared phenyl
ring. Since 9,9′-spirobifluorene can be easily obtained by
7
Clarkson and Gomberg procedure, it seemed reasonable to
adopt a similar strategy starting from either indeno[1,2-b]-
fluorene-6,12-dione (IFD) and 2-lithiodiphenyl (route a) or
8
from dilithioterphenyl and fluorenone (routes b or c) (Scheme
1).
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6
987. (c) Hadizad, T.; Zhang, J.; Wang, Z. Y.; Gorjanc, T. C.; Py, C. Org.
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(
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Org. Lett., Vol. 8, No. 2, 2006