Novel dispirobifluorenes and indeno-spirobifluorenes: Syntheses and properties

Article abstract of DOI:10.1016/j.tet.2010.11.092

Novel indeno-spirobifluorene and dispirobifluorene derivatives were synthesized and characterized. Their two positional isomers were unambiguously determined by X-ray crystallography. Preliminary investigations indicated that these indeno-spirobifluorene

Full text of DOI:10.1016/j.tet.2010.11.092

Tetrahedron 67 (2011) 1201e1209
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Novel dispirobifluorenes and indeno-spirobifluorenes: syntheses and properties
*
Yingbo Shi, Qiancai Liu , Guohong Wu, Lingling Rong, Jie Tang
Department of Chemistry, East China Normal University, Shanghai 200062, China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 6 August 2010
Received in revised form 10 November 2010
Accepted 30 November 2010
Available online 8 December 2010
Novel indeno-spirobifluorene and dispirobifluorene derivatives were synthesized and characterized.
Their two positional isomers were unambiguously determined by X-ray crystallography. Preliminary
investigations indicated that these indeno-spirobifluorene and dispirobifluorenes showed blue fluores-
cence with good quantum yields (F>60%) and excellent thermal stabilities.
Ó 2010 Elsevier Ltd. All rights reserved.
Keywords:
Dispirobifluorenes
Indeno-spirobifluorenes
Synthesis
DielseAlder Cycloaddition
1. Introduction
coplanarity, carrier mobility, and excellent luminescence.7 Since
the first report on ladder-type poly(p-phenylene)s in 1991,8 many
efforts have been done to clarify their structureeproperty re-
lationships, 6,12-dihydroindeno[1,2-b]fluorene (called (1,2-b)-IF) is
one of the simplest and ladder-type oligomer widely used as
a building block leading to a strong enhancement of the OLED
properties.9
Attention has also been paid to the ladder-type compounds with
rigid spiro-linked structures. Recent elegant studies on novel
families of dispiro derivatives, such as dispiro fluorene-9,6-indeno
[1,2-b]fluorene-12,9-fluorene (called (1,2-b)-DSF-IF), which
appeared to be highly promising for blue OLED applications, have
been reported.10 Compared with dispirobifluorenes, the indeno
[1,2-b]spirobifluorenes, which could be used as host materials for
electro-phosphorescent organic light-emitting devices (PhOLED)
with unique properties, have been paid less attention.10c However,
to the best of our knowledge, the (2,1-a)-IF positional isomers have
been reported in few instances,11 only (2,1-a)-DSF-(tBu)4-IF and
(2,1-a)-DSF-(aryl)4-IF have been reported so far.10deh Additionally
heterocycle-fused dispirofluorenes have called a lot of attention in
very recently.10iek
The fabrication of the first efficient molecule-based organic
light-emitting diodes (OLEDs), reported by Tang and van Slyke, led
many efforts to bring OLEDs into commercial applications.1
In order to produce high-efficiency OLEDs with saturated color,
low driving voltages as well as high quantum yield, many factors
have to be considered. Conjugated aromatic compounds have been
widely considered as organic semiconductors in fields of organic
thin-film transistors (OTFTs) and organic light-emitting diodes
(OLEDs).2Among all the known organic semiconductors and OLED
applications, the fluorene-based compounds attracted most at-
tention, owing to their unique properties, availability and proc-
essability.3 Nowadays, only the red and green ones have shown
sufficient efficiencies and lifetimes to be of commercial values from
materials based either oligomers or polymers, while that of blue-
emitting materials still remains as a big challenge.4
Research into blue-emitting materials has centered on conju-
gated fluorenes, such as polyfluorenes(PFs), Poly(indeno-fluorenes)
(PIFs).3a,5 Substituted fluorenes are known to have relatively high
€
band gaps and low HOMO levels. As reported by Mullen and Leis-
ing, the block of interchain interaction and the enhancement of the
thermal stability could be approached by introducing bulky groups
at C9 position of polyfluorene.2,4c,6
Particularly ladder-type materials are of great interest as
promising units for organic electronic devices due to their high
The reports on indeno[1,2-a]- or [2,1-c]spirobifluorene and
dispirobifluorene are still rare, it is not until 1999 that a few indeno
[1,2-a]fluorenes and its spiro-derivatives were reported.12 The
above mentioned studies have prompted us to explore novel
indeno-spirobifluorenes and dispirobifluorenes with cores other
than (1,2-b-IF). In this paper, we report the latest progress on rigid
ladder-type molecules of indeno-spiro and dispiro bifluorenes:(1,2-
a)-IF-SF (8a), (2,1-c)-IF-SF (8b), (1,2-a)-DSF-(tBu)4-IF (10a) and (2,1-
c)-DSF-(tBu)4-IF (10b).
* Corresponding author. Tel.: þ86 21 62233490; fax: þ86 21 62232414; e-mail
address: qcliu@chem.ecnu.edu.cn (Q. Liu).
0040-4020/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2010.11.092

1202
Y. Shi et al. / Tetrahedron 67 (2011) 1201e1209
2. Result and discussion
As 5a,b have poor solubilities in common organic solvents,
therefore WolffeKishner reaction was performed to obtain 7a,b
(yields: 62% and 78%), which were easily converted into diethyl-
indenonspirobifluorenes (8a,b) via lithiation and halogen-ex-
change (yields 85% and 90%). The solubility of 8a,b was improved
dramatically compared to that of their precursors 7a,b.
All new intermediates and final products were confirmed by
NMR. In 1H NMR, due to the shielding effect of the carbonyl, the
proton shift of 5a and 6a peaks both appear at ca. 9.5 ppm, which is
larger than those of 5b and 6b (ca. 8.5 ppm) (Fig. 1). This phenom-
enon provides an useful solution to infer the absolute configuration
of positional isomers for different indenofluorene skeletons.
It is noteworthy that synthetic routes described here are easy to
handle with good overall yield, and under transition-metal cata-
lysts free condition, the later has often been involved in cross-
coupling reactions to obtain precursors for other indenofluorenes
or dispirobifluorenes.
2.1. Synthesis
The synthetic routes to novel indeno-spirobifluorene and dis-
pirobifluorene are presented in Scheme 1. Initially the reaction of
ethynylmagnesium chloride with fluorenones afforded 9-ethynyl-9-
fluorenols (1a,b) (yields: 63 and 73%); Then the DieldseAlder
reaction of 1a or 1b with indanocyclone (2) at 240 ꢀC led to the for-
mation of 3a,b and 4a,b, which could easily be separated by column
chromatography (yields: 61% and 71%) (Table 1). The fluorenols 3a,b
and 4a,b were subsequently converted into indeno-spirobiflorenes
5a,b and 6a,b in excellent yields (90e96%) via FriedeleCrafts alkyl-
ation with HOAc/HCl. Compounds 5a and 5b are barely soluble in
polar solvents, such as THF and Et2O, which prevented further
transfer into dispirobifluorene derivatives. In contrast, 6a,b show
higher solubility, and could be converted into the tert-butyl
substituted fluoren-9-ols (9a,b)(yield: 93%). Then the acid promoted
FriedeleCrafts reactions were employed to form dispirobifluorenes
(10a,b) in the presence of HOAc/HCl with isolated yield ca. 85%.
Compounds 9a,b and 10a,b appear to be the first examples of a spiro-
type compounds with [1,2-a]-IF-and [2,1-c]-IF cores.
2.2. X-ray single crystal determination
Due to their good solubility in the common organic solvents, the
suitable crystals of 8a,b and 10a,b for X-ray structure determination
R
R
R
R
OH
Ph
R
R
O
OH
O
1. HCCMgCl,
THF, heat
HOAc
240°C
R = H (1a); R = tBu (1b)
R
R
HCl(Cat.)
reflux
Ph
2. sat. NH4Cl
R
R
R
R
O
O
Ph
Ph
OH
O
O
2
O
R = H (5a) and (5b)
R = tBu (6a) and (6b)
R = H(3a) and (3b)
R = tBu (4a) and (4b)
1.BuLi/-78°C
2.EtBr
Ph
NH2NH2/ KOH
180°C
Ph
or
Ph
Ph
for 5a or 5b
or
(7a)
(7b)
(8a)
(8b)
R
R
R
R
R
R
R
Ph
R
R
Ph
Ph
R
Ph
R
/-78°C
R
1.
HOAc
or
Li
o
r
OH
for 6a or 6b
2.sat. NH4Cl
HCl (cat.)
reflux
HO
R
R
(10b)
R
R
(10a)
(9b)
(9a)
R = tBu for 9a-9b and 10a, 10b
Scheme 1.
were obtained. Fine crystals of compounds 8a,b were obtained from
CHCl3/EtOH; while those of 10a and 10b were grown from EtOAc/EtOH,
Toluene/EtOH, respectively. The X-ray structure determinations con-
firmed their structures in accordance with their NMR (Fig. 2). The
crystallizations of 10a,b were more difficult than those of 8a,b.
Table 1
The DielseAlder reaction yield of 3a,b and 4a,b
Rf Data (PE/DCM¼1:1)
Yield (%)
Total yield (%)
71
3a
3b
4a
4b
0.78
0.64
0.75
0.56
21
50
21
40
It is interesting to find, there are two strong CeH/
p effect,
which impacts on the conjugate plane of the molecule in 8b (the
distance between H on aromatics to the centers of coplanar
61

Y. Shi et al. / Tetrahedron 67 (2011) 1201e1209
1203
2.3. Optical studies
Table 2 shows the 8a,b and 10a,b’s Optical data and thermo-
analysis data.
Table 2
The optical data and thermo-analysis data of 8a,b and 10a,b
lAbs (nm)a
lem,solution
(nm)b
lem,solid
(nm)c
F
(%)d
Tm (ꢀC)e
Td (ꢀC)f
8a
8b
10a
10b
278,299
261,310
273,303,315
272,316
400
370
395
372
398
395
394
370
62
83
60
70
223
264
327
362
333
337
373
375
a
In dichloromethane(1.0ꢂ10ꢁ6 M).
b
c
In dichloromethane(1.0ꢂ10ꢁ6 M).
The solid emission spectrum was measured with solid powder.
d
The relative quantum yield
F was measured using standard procedures with
reference to 9,10-diphenyl anthracene (1.0ꢂ10ꢁ6 M in cyclo-hexane,
F
¼90%).
e
Read from DSC.
f
Decomposition temperature Td is defined as the temperature at which 5% loss
occurs during heating.
Fig. 1. Comparison of 5a,b’s 1H NMR.
Due to the structural similarities, there are no significant dif-
ference in the UVevis spectra (Fig. 4a) of compounds 8a,b and
10a,b, their absorption wavelengths peak between 250 and 340 nm
are assigned to the p/p transitions.
*
The emission spectra (Fig. 4b) of the (1,2-a)-DSF-(tBu)4-IF (10a) and
(1,2-a)-IF-SF (8a) in solution are shown at 395 nm and 400 nm, re-
spectively, both at visible light area, while those of (2,1-c)-DSF-(tBu)4-IF
10b and (2,1-c)-IF-SF 8b are around 370 nm, which are compared
to those of their isomers reported in literatures (ca. 360 nm).10deh
Both dispirobifluorenes and indeno-spirobifluorenes show high
quantum yields (60e83%) related to 9,10-diphenyl anthracene as
reference. It is also quite interesting to find that the quantum yields
of (1,2-a)-IF compounds (60e62%) are lower than their (2,1-c)-IF
analogue (70e83%), and the Stokes shift of (1,2-a)-IF compounds is
higher compared to the (2,1-c)-IF analogue.
The broaden peak appears on 8b with red-shift to visible area,
while the solid photoluminescent intensity decreased (Fig. 4c). The
difference of emission spectra in 8b’s solution and solid state is ca.
25 nm, this phenomenon might be due to the effect of CeH/p in
solid state, which may enhance the energy transfer and non-radi-
ative transition between the molecules. However, the solid emis-
sions of dispirobifluorenes 10a,b and 8a are similar to those in
solutions with wavelength shift 1e2 nm only. The comparison of
the solution and solid emission spectra shows that the steric con-
gestions and rigid spiro-skeletons could prevent the formation of
dimmer in solid state, and therefore lead emissions more stable.
Fig. 2. Crystal structures of compound 8a,b and 10a,b.
2.4. HOMO and LUMO studies
phenyl-rings of dimeric spirobifluorene ranges from 3.024 to
3.085 A) (Fig. 3). These results proved that the double spiro-
ꢀ
Cyclic voltammetry (CV) and calculations by the Gaussian-03 at
skeletons would prevent crystallization and avoid interactions
between molecules.
13
B3LYP/6-31G
*
level are useful tools for studying the front orbital
energy. CV shows compounds 8a,b and 10a,b have a good elec-
trochemical stability both in the reduction and the oxidation pro-
cess (Fig. 5). The reversible monoelectric oxidation for 8a,b and
10a,b occurs at 1.80 to 1.91V, and reversible monoelectric reduction
for them occurs at ꢁ1.94V to ꢁ2.00V. It is reasonable to assign the
first oxidation and reduction process of 8a,b and 10a,b to the
indenofluorene centered electron transfer as described previously.
Thus the HOMO and LUMO energy levels were estimated at
ꢁ5.75 eV to ꢁ5.88 eV, ꢁ1.97 eV to ꢁ2.01 eV, respectively. These
values are closed to the HOMO of (1,2-b)-IF(ꢁ5.62 eV) and (2,1-a)-
DSF-(tBu)4-IF(ꢁ5.48 eV) to those of (1,2-b)-DSF-IF(ꢁ5.76 eV), and
(1,2-b)-DSF-(tBu)4-IF(ꢁ5.61eV).10 So, the results indicate there is
little difference of orbital energy between the (1,2-a)-IF and (2,1-c)-
IF isomers, and almost all indenofluorene compounds have a low
HOMO energy level and high LUMO energy level.
Fig. 3. The CeH/p affection of 8b.

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Y. Shi et al. / Tetrahedron 67 (2011) 1201e1209
Fig. 4. (a). UVevis spectra of 8a,b and 10a,b. (b) Liquid photoluminescence spectra of 8a,b and 10a,b (in CH2Cl2, 1.0ꢂ10ꢁ6 M). (c) Solid photoluminescence spectra of 8a, b and 10a,b;
(d) The photoluminescence photos of 8a,b and 10a,b (under 365 nm).
2.18V
2.25V
2.01V
10
5
10a
8a
10
5
-1.94V
-1.98V
0
0
1.88V
1.64V
1.96V
-5
-10
-5
1.722V
-2.47V
-10
-2.47V
-3.0 -2.5 -2.0 -1.5
1
2
-3.0 -2.5 -2.0 -1.5
1
2
E (Volt)
E (Volt)
2.16V
10
5
8b
-2.08V
10b
10
5
-1.93V
-1.89V
0
0
-1.79V
-5
-10
-5
1.70V
2
-2.35V
-2.38V
-10
-3.0-2.5-2.0-1.5
1
2
-3.0 -2.5 -2.0 -1.5
1
E (Volt)
E (Volt)
Fig. 5. Cylcicvoltammograms of 8a,b; 10a,b. Anodic oxidation of a 2ꢂ10ꢁ3 M solution in CH2Cl2þBu4NPF6 0.1 M, 100 mV/s; Cathode reduction of a 2ꢂ10ꢁ3 M solution in
THFþBu4NPF6 0.1 M, 100 mV/s.
Calculations models of 8a,b and 10a,b based on the CIF data
from their X-ray structures. Compared to (1,2-b)-DSF(tBu)4-IF and
(2,1-a)-DSF(tBu)4-IF, the HOMO levels of 8a,b, 10a,b are lower
while LUMO levels seem to be slight higher, while they both hold
bigger band gaps. The HOMO and LUMO levels of compounds
10a,b shows at ꢁ5.78 V and ꢁ5.75 V; ꢁ1.97 and ꢁ2.02 eV, while
those of compounds 8a,b lie at ꢁ5.88 V, ꢁ5.82 V, ꢁ2.01 and
ꢁ2.01 eV, respectively. The similar electrochemical band gaps of

Y. Shi et al. / Tetrahedron 67 (2011) 1201e1209
1205
Table 3
calculation HOMO levels of 8a and 10a are slight higher than 8b and
10b which might be explained by the different type of indeno-fused
structures. However, The band gaps of 10a,b are smaller than those
of 8a,b might be due to combination of the spiro-effect and the
increase of molecular weights (Table 3).
Electrochemical properties and HOMO/LUMO levels of 8a,b; 10a,b
Electrochemical data
Calculation data
EOx ERed (V)b HOMO LUMO
DE D
el (eV, nm)e HOMOcal LUMOcal Ecal
(V)a
(eV)c
(eV)d
(eV)f
(eV)f
(eV)f
We should emphasize that the large variation between the
experimental and calculated LUMO data was due to the different
calculation methods and conditions. The LUMO data from the CV
was calculated from experiential equation and the DFT calculation
was based on the Koopmans’ theory, which ignored the electron
gain and loss affect on other electrons. On the other hand, the
effect between the molecules has not been considered in DFT
calculation.
8a 1.91 ꢁ1.96
8b 1.84 ꢁ1.96
10a 1.80 ꢁ2.00
10b 1.78 ꢁ1.94
ꢁ5.88 ꢁ2.01 3.87, 320
ꢁ5.82 ꢁ2.01 3.81, 325
ꢁ5.78 ꢁ1.97 3.81, 325
ꢁ5.75 ꢁ2.02 3.73, 332
ꢁ5.31
ꢁ5.52
ꢁ5.21
ꢁ5.25
ꢁ1.05
ꢁ0.96
ꢁ0.98
ꢁ1.00
4.26
4.56
4.23
4.25
a
In CH2Cl2.
In THF.
b
c
From the onset oxidation potential.
From the reduction potential.
D
d
e
f
Eel¼︱HOMOeLUMO︱;
l¼h
n/(
DE
el,eV)¼1237.5/
DE
el(nm)from redox data.
Fig. 6 shows the visual frontier molecular orbitals of the four
Using Gaussian 03 B3LYP/6-31G calculation on models of the CIF documents;
*
D
Ecal¼︱HOMOeLUMO︱.
products. Their
p system established typical conjugated systems of
indenofluorenes with (1,2-a)-IF and (2,1-c)-IF skeletons. Compared
to 8b and 10b, the phenyl group of 8a and 10a partly conjugated
with the indenofluorenyl moiety, this may be the reason for 8a and
10a with longer emission wavelengths than those of 10a and 10b.
However, the partial conjugation of phenyl group has little impact
on their frontier orbitals.
compounds 10a,b and 8a,b range 3.73e3.87 eV(310e320 nm),
which are accordance with their UVevis spectra. Both of the
electrochemical band gaps and theoretical calculation values
(4.23e4.56 eV) and are also close to the energy band gaps of other
blue-emitting materials.
The calculation band gaps of (1,2-a)-IF products (8a and 10a) are
smaller than those of (2,1-c)-IF congeners (8b and 10b), but the
2.5. Thermo analysis
Thermo-gravimetric analysis confirmed the good thermal sta-
bility of 10a,b and 8a,b (Td of 373 and 375, 333, 337 ꢀC, respectively)
(Table 2) as expected by the presence of the rigid, spiro-fused or-
thogonal linkages and indeno-fused spirobiflurenes. Such behavior
is very important to extend the lifetime of blue OLEDs. However,
the ways of aromatic ring fused have strong influence on their
molten temperatures (Tm); the values of (1,2-a)-IF compounds are
always lower (ca. 40 ꢀC) that those of (2,1-c)-IF analogue.4b,14
3. Conclusion
In summary, we developed well-defined synthetic routes to
two families of aryl-substituted dispirobifluorene and indeno-
spirobifluorene luminophores. These molecules are large band gap
compounds with a high photoluminescence quantum yield both in
solution and solid and are thermally stable. This method appears
to be promising for preparing compounds with (1,2-a)-IF and (2,1-
c)-IF skeletons. And the above results provided efficient routes to
introduce indeno and indeno-spiroflurene fused at 1,2 or 3,4-po-
sitions of spirobifluorenes. The products appeared to be promising
blue emission materials with excellent thermal stability and good
quantum yields. Moreover, the indeno and indeno-spiroflurene
units fused at 1,2 or 3,4-positions of spirobifluorene might also be
considered to improve hole injection and transport properties, and
might be potentially used as PhOLED materials as shown by (1,2-
b)-IF congeners. The thermal and photo-physical properties of
DSF-IFs and IF-SBFs indicated that they could be considered as
promising for OLED applications. Further investigations will be
focused on the application of different dispiro and indeno-spiro
compounds ascribed here for OLED and PhOLED devices. This re-
search is current underway in our laboratory.
4. Experimental
4.1. General information
Commercially available reagents, solvents, and other materials
were used without further purification other than stated below. THF
was distilled from Na/benzophenone prior to use. Pet. ether refers to
the fraction with bp 60e90 ꢀC fractions. All of operations were
performed by standard Schlenk techniques unless otherwise stated.
TLC was carried out by using silica gel 60 GF254 and visualized under
Fig. 6. Visual frontier molecular orbital of compounds 8a,b and 10a,b.

1206
Y. Shi et al. / Tetrahedron 67 (2011) 1201e1209
UV lights (254 and 365 nm). Melting point was measured on X-4
micrographic measuring apparatus. 1H NMR and 13C NMR spectra
were measured on a Bruker DRꢂ500 spectrometer (1H NMR
500 MHz, 13C NMR 125 Hz). Element analyses were measured on
Vario EL element analysis instrument. IR spectra were recorded on
an Infrared Spectrophotometer (Nicolet Nexus 670). High resolution
mass spectra were recorded on the GCT Premier TM. All chemical
are obtained from commercial sources and used as received.
4.2. Crystal data for 8a,b and 10a,b
Crystal data for 8a: C42H32
M¼536.68, colorless diamond,
,
0.52ꢂ0.47ꢂ0.25 mm, Monoclinic, space group: P2(1)/c, a¼11.1520
(3) A, b¼ꢀ10.7208(3) A, c¼24.2998(7) A,
a
¼90.00ꢀ,
b
¼97.0770(10)ꢀ,
ꢀ
ꢀ
ꢀ
g
¼90.00 , V¼2883.11(14) A; Z¼4; Dc¼1.236 Mg/mmꢁ3; T¼173(2) K;
ꢀ
Final R (I>2
s
(I)): R1¼0.0391, wR2¼0.0957; R indices (all data):
R1¼0.0456, wR2¼0.1017. Crystal data for 8b: C43H33 Cl3, M¼656.04,
The crystal data were collected by Bruker SMART CCD area
colorless diamond, 0.56ꢂ0.31ꢂ0.15 mm, Orthorhombic, space group:
ꢀ
ꢀ
ꢀ
ꢀ
a
detector with Mo K
a
radiation (
l
¼0.71073 A). The structure so-
P2(1), a¼22.9225(7ꢀ) A, b¼13.3503(4) A, c¼11.1714(4) A,
¼90.00ꢀ,
ꢁ3
lution and refinement were solved on the computer by the Bruker
SHELXTL. The structures were solved by direct methods and re-
fined by full-matrix least-squares on F2 values of all data.
(SHELXTL, version 6.1, G. M. Sheldrick, Bruker AXS, Madison, WI,
2001).
b
¼90.00ꢀ,
g
¼90.00 , V¼3418.70(19) A; Z¼4; Dc¼1.275 Mg/mm
;
ꢀ
T¼296(2) K; Final R (I>2 (I)): R1¼0.0530,wR2¼0.1486; R indices (all
s
data): R1¼0.0610, wR2¼0.1583. Crystal data for 10a: C132H124
,
M¼1710.31, colorless diamond 0.55ꢂ0.12ꢂ0.07 mm, Triclinic, space
ꢀ
ꢀ
ꢀ
group: P-1, a¼10.8743(5) A, b¼21.2176(9) A, c¼22.4523(10) A,
ꢀ
UVevis spectra were recorded using a UVevis spectrophotom-
eter (Carey-100). Photo-luminescence spectra were recorded at
room temperature with a spectrofluorimeter (HITACHI F-4500)
using a xenon lamp. Quantum yields (Fsol) were calculated relative
to 9,10-diphenyl anthracene (1ꢂ10ꢁ6 M in cyclohexane, Fsol¼90%)
as standard procedures. Fsol was determined according to the fol-
lowing equation:15
a
¼79.8000(10)ꢀ,
b
¼86.8900(10)ꢀ,
g
¼86.8020(10) , V¼5085.3(4) A;
ꢀ
Z¼2; Dc¼1.117 Mg/mmꢁ3; T¼173(2) K; Final R (I>2
(I)): R1¼0.0640,
s
wR2¼0.1696; R indices (all data): R1¼0.1021, wR2¼0.1964. Crystal data
for 10b: C73H70, M¼947.29, colorless diamond 0.52ꢂ0.48ꢂ0.42 mm,
ꢀ
ꢀ
Monoclinic, space group: P2(1)/c, a¼13.3610(5) A, b¼15.3118(5) A,
ꢀ
c¼15.8483(5) A,
a
¼111.4840(10)ꢀ,
b
¼98.9620(10)ꢀ,
g
¼111.4840(10)ꢀ,
V¼2912.20(17) A; Z¼2; Dc¼1.080 Mg/mmꢁ3; T¼296(2) K; R1¼0.0668,
ꢀ
wR2¼0.1860, wR2¼0.0957;
wR2¼0.2117.
R
indices (all data): R1¼0.0859,
ꢀ
ꢁ
2
ðFs ꢂ ArÞ
ðFr ꢂ AsÞ
ns
nr
Fsol
¼
Fref ꢂ 100 ꢂ
ꢂ
4.3. General procedure for synthesis of 1a,b17
where, subscripts ‘s’ and ‘r’ refer, respectively to the sample and
reference. The integrated area of the emission peak in arbitrary
units is given as ‘F’, ‘n’ is the refracting index of the solvent
(ns¼1.4244 for DCM; nr¼1.4264 for cyclohexane) and A is the ab-
sorbance. The emission spectra were recorded in solution in cy-
clohexane. The solid emission spectrum was measured by their
solid powders.
All electrochemical experiments were performed using a Pt disk
electrode (diameter 1 mm), the counter electrode was a vitreous
carbon electrode (diameter 3 mm) and the reference electrode was
AgI/Ag. The redox cyclic voltammograms were measured with
electrochemical workstation (CH Instruments, CHI-840C), scan rate
is 100 mV/s. All solvents must be dried. The experiment should be
preceded by passing dry nitrogen gas for 5 min to remove oxygen in
the system. With nBu4NtPF6 (0.1 M) as supporting electrolyte, the
oxidation process was measured in CH2Cl2 and reduction process
was measured in THF. All samples were prepared into a solution of
2ꢂ10ꢁ3 M. The ferrocene/ferrocenium (Fcþ/Fc) couple served as
internal standard and all reported potentials are referenced to its
reversible formal potential.
To the solution of fluorenone (100 mmol) in dry THF (50 mL)
was added dropwise a solution of acetylene magnesium chloride in
dry THF (250 mL, 0.6 M in THF,150 mmol), the reaction mixture was
heated to reflux for 12 h. After cooling to room temperature, the
reaction was quenched by carefull addition of saturated ammonium
chloride solution (200 mL). The mixture was extracted by dichlor-
methane (3ꢂ100 mL), then the combined organic phase was dried
over anhydrous Na2SO4. The filtrate was evaporated to dryness, and
the residue was chromatographed to give the fluoren-9-ols as
white powders.
4.3.1. 9-Ethynyl-9-fluorenol (1a). Fluorenone (18 g, 100 mmol) was
employed; product: 15 g (73%) elueted with CH2Cl2/PE¼1:1. mp
102e104 ꢀC (Ref.17:108e109 ꢀC); 1H NMR (CDCl3, 500 MHz, ppm)
d
7.72 (dd, J¼7.6, 1.4 Hz, 2H), 7.63 (dd, J¼7.6, 1.4 Hz, 2H), 7.42 (td,
J¼7.6,1.8 Hz, 2H),7.35 (td, J¼7.6,1.8 Hz, 2H), 2.53 (s,1H), 2.48 (s,1H);
13C NMR (CDCl3, 125 MHz, ppm): 146.52, 193.05. 129.83, 128.60,
124.24, 120.22, 83.78, 74.52, 71.37.
The HOMO and LUMO can be calculated according to the fol-
4.3.2. 2,7-Di-tert-butyl-9-ethynyl-9-fluorenol (1b). 2,7-Di-tert-butyl-
fluorenone (29.2 g, 100 mmol) was employed; product: 20 g (63%)
elueted with CH2Cl2/PE¼1:2, mp170e172 ꢀC (Ref.17: 158e159 ꢀC);
lowing equation:16
HOMO ¼ ½ ꢁ ðEOx
LUMO ¼ ½ ꢁ ðERed
ꢁ
ꢁ
J
J
Þ ꢁ 4:8ꢃeV
Þ ꢁ 4:8ꢃeV
1H NMR (CDCl3, 500 MHz, ppm):
d
7.77 (d, J¼1.4 Hz, 2H), 7.53 (dd,
J¼8.0,1.8 Hz, 2H), 7.46 (dd, J¼7.6,1.8 Hz, 2H), 2.53 (s,1H), 2.48 (s,1H);
13C NMR (CDCl3, 125 MHz, ppm): 155.61, 146.65, 136.40, 126.84,
121.07, 119.48, 84.24, 74.73, 71.33, 35.02, 31.44.
D
Eel ¼ HOMO ꢁ LUMO
j
j
In the equation,
versus AgI/Ag, the value of
J
is the onset potential of ferrocene (Fcþ/Fc)
is 0.6761 V. EOx is the onset potential
J
of oxidation process; ERed is the onset potential of reduction pro-
cess. The constant 4.8 is the vacuum energy level of ferrocene.
Density functional theory (DFT) calculations were performed
with the hybrid Becke-3 parameter exchange functional and the
LeeeYangeParr non-local correlation functional (B3LYP)13 imple-
4.4. General procedure for synthesis of 3a,b and 4a,b
The mixture of 9-ethynyl-fluoren-9-ol (1a) or 2,7-di-tert-butyl-9-
ethynylfluoren-9-ol (1b)9b and indanocyclone 2 was heated up to
240 ꢀC for10 min. Aftercooling, thebrownresiduewas eluented with
PE/DCM (v/v¼1:1) to afford compounds above, which were crystal-
lized from different solvents to give analytical pure samples. For 9-
(1,4-diphenylfluorenon-2-yl)fluoren-9-ol (3a) and 9-(1,4-diphenyl-
fluorenon-3-yl)fluoren-9-ol (3b); 9-ethynylfluoren-9-ol (1a) (2.1 g,
10 mmol) and indanocyclone (2) (3.3 g,10 mmol) were employed. For
2,7-di-tert-butyl-9-(1,4-diphenylfluorenon-2-yl)fluoren-9-ol (4a)
mentedin the Gaussian 03 (Revision B.01) using the 6-31G basis set.
*
Thermo-gravimetric analyses (TGA) have been performed with
a Thermal analyzer (Mettler Toledo TGA851e/SF/1100) under a ni-
trogen atmosphere. TGA measurements were carried out between
20 and 800 ꢀC with a heating rate of 10 ꢀC/minꢁ1. The differential
scanning calorimetry (DSC) thermogram was collected from the
heat process.
and
2,7-di-tert-butyl-9-(1,4-diphenylfluorenon-3-yl)fluoren-9-ol

Y. Shi et al. / Tetrahedron 67 (2011) 1201e1209
1207
(4b): 2,7-di-tert-butyl-9-ethynylfluoren-9-ol (1b) (3.2 g, 10 mmol)
and indanocyclone (2) (3.3 g, 10 mmol) were employed.
and washed with cold methanol for several times and dried under
vacuum to afford desired products.
4.4.1. 9-(1,4-Diphenylfluorenon-2-yl)fluoren-9-ol
(3a). Rf¼0.75,
4.5.1. 50-Phenyl-indeno[1,2-a]spiro[fluorene-9,70] fluorene (5a). 9-
(1,4-Diphenylfluorenon-2-yl) fluoren-9-ol (2.6 g, 5 mmol) was
employed to afford 2.2 g product (90%); mp: 269e270 ꢀC; IR (KBr)/
recrystallized from CH2Cl2/hexanes; 1.1 g (21%) mp 235e237 ꢀC;
HRMS (ESI): C38H24O2þNa requires 535.1674; Found [MþNaþ],
535.1669; IR (KBr)/cmꢁ1
:
n
¼3571 (OH), 3060, 2925, 2854, 1712,
cmꢁ1
:
n
¼3064, 2924, 2854, 1704, 1604, 1431; 1H NMR (CDCl3,
1604, 1445,1049; 1H NMR (CDCl3, 500 MHz, ppm):
d
8.53(s,1H), 7.68
500 MHz, ppm):
d
9.44 (d, J¼7.8 Hz, 1H), 7.84 (d, J¼7.5 Hz, 2H), 7.78
(d, J¼6.8 Hz, 2H), 7.60e7.53 (m, 3H), 7.36 (d, J¼7.0 Hz, 2H), 7.29e7.28
(m, J¼7.6 Hz, 2H), 7.22e7.29 (m, J¼7.6 Hz, 4H), 7.72 (m, 3H), 7.12 (t,
J¼8.27 Hz, 1H), 6.88 (t, J¼7.4 Hz, 1H), 6.82 (d, J¼7.6 Hz, 1H), 6.65(t,
J¼7.8 Hz, 2H), 5.96 (d, J¼7.4 Hz, 2H), 2.26 (s, 1H); 13C NMR (CDCl3,
125 MHz, ppm): 192.43,149.67,143.10,140.37,140.16,136.89,134.75,
134.43, 134.38, 133.89, 129.07, 128.83, 128.68, 128.48, 128.27, 128.06,
127.90, 126.20, 125.38, 124.03, 123.67, 122.82, 120.18, 82.22.
(d, J¼7.2 Hz, 1H), 7.53 (t, J¼7.6 Hz, 1H), 7.42e7.38 (m, 5H), 7.34e7.32
(m, 2H), 7.29e7.26 (m, 2H), 7.18 (m, 3H),
d6.86 (d, J¼7.6 Hz, 2H), 6.77
(d, J¼7.5 Hz, 2H), 6.66 (d, J¼7.1 Hz, 2H); 13C NMR (CDCl3, 125 MHz,
ppm): 194.37, 150.93, 148.36, 144.27, 141.57, 139.9, 139.47, 137.25,
134.43, 134.08, 131.26, 129.71, 128.87, 128.49, 128.45, 128.14, 127.95,
127.90, 126.87, 124.07, 123.93, 123.51, 122.92, 120.05, 65.67.
4.5.2. 60-Phenyl-dihydroindeno[2,1-c]spiro
[fluorene-9,80]fluorene
4.4.2. 9-(1,4-Diphenylfluorenon-3-yl)fluoren-9-ol
(3b). Rf¼0.56,
(5b). 9-(1,4-Diphenylfluorenon-3-yl) fluoren-9-ol (2.6 g, 5 mmꢁo1l)
recrystallized from CH2Cl2/hexanes; 2 g (40%); mp 269e270 ꢀC; HRMS
(ESI): C38H24O2þH requires 513.1855; Found [MþH]þ, 513.1849; IR
to afford 2.3 g product (93%); mp: 193e195 ꢀC; IR (KBr)/cm
:
n
¼3062, 2920, 2854, 1710, 1601, 1446; 1H NMR (CDCl3, 500 MHz,
(KBr)/cmꢁ1
NMR (CDCl3, 500 MHz, ppm):
:
n
¼3548 (OH), 3054, 2920,1710, 1693, 1603, 1450, 1037; 1H
ppm):
d
8.53 (d, J¼7.9 Hz, 1H), 8.44 (d, J¼7.6 Hz, 1H), 7.88 (d,
d
8.46(s,1H), 7.76 (d, J¼7.4 Hz, 2H), 7.54 (t,
J¼7.6 Hz, 2H), 7.69 (td, J¼7.6, 1.2 Hz, 1H), 7.54 (t, J¼6.9 Hz, 1H),
7.45e7.41 (m, 3H), 7.39e7.34 (m, 5H), 7.27 (t, J¼7.6 Hz, 1H), 7.19 (td,
J¼8.0, 1.0 Hz, 1H), 6.89 (d, J¼7.6 Hz, 2H), 6.85 (d, J¼7.4 Hz, 1H), 6.54
(s, 1H); 13C NMR (CDCl3, 125 MHz, ppm): 192.53, 157.05, 149.64,
148.29, 143.90, 141.70, 141.64, 139.93, 137.56, 135.19, 134.38, 129.09,
129.03, 127.70, 128.07, 127.95, 127.87, 127.58, 126.72, 124.58, 124.42,
124.07, 123.77, 123.57, 120.17, 66.03.
J¼8.0 Hz, 2H), 7.48 (t, J¼7.6 Hz, 2H), 7.32 (d, J¼7.4 Hz, 1.8 Hz, 2H),
7.22e7.26 (m, 4H), 7.15 (d, J¼7.9 Hz, 2H), 7.02 (t, J¼7.4 Hz, 1H), 6.99 (t,
J¼7.5 Hz, 2H), 6.85 (t, J¼7.4 Hz, 1H), 6.72 (t, J¼7.5 Hz, 2H), 6.04 (d,
J¼8.0 Hz, 2H), 5.20 (d, J¼7.9 Hz, 1H), 2.32 (s, 1H); 13C NMR (CDCl3,
125 MHz, ppm): 192.75, 149.58, 147.21, 144.12, 140.72, 140.23, 137.90,
135.64, 134.89, 133.82, 130.01, 129.41, 129.22, 128.91, 128.14, 128.10,
128.00, 127.80, 127.23, 126.01, 124.21, 123.39, 123.10, 120.20, 82.46.
4.5.3. 50-Phenyl-2,7-di-tert-butylindeno[1,2-a]spiro[fluorene-9,70]
fluorene (6a). 2,7-Di-tert-butyl-9-(1,4-diphenylfluorenon-2-yl)flu-
oren-9-ol (3.1 g, 5 mmol) was empꢁlo1yed to afford 2.9 g product
4.4.3. 2,7-Di-tert-butyl-9-(1,4-diphenylfluorenon-3-yl)fluoren-9-ol
(4a). Rf¼0.78, recrystallized from CH2Cl2/MeOH; 1.3 g (21%); mp:
183e184 ꢀC; HRMS (ESI): C46H40O2þNa requires 647.2926; Found
(96%); mp: 282e284 ꢀC; IR (KBr)/cm
:
n
¼3060, 2962, 2904, 2868,
[MþNaþ], 647.2921; IR (KBr)/cmꢁ1
:
n
¼3533 (OH), 2962, 2902, 2867,
1708, 1604, 1469, 1252; 1H NMR (CDCl3, 500 MHz, ppm):
d 9.42 (d,
1712, 1605, 1478, 1363, 1252, 1183; 1H NMR (CDCl3, 500 MHz, ppm):
J¼7.8 Hz, 1H), 7.75 (d, J¼7.2 Hz, 1H), 7.68 (d, J¼8.0 Hz, 2H), 7.50 (t,
J¼7.4 Hz, 1H), 7.39e7.37 (m,5H), 7.29e7.22 (m, 4H), 7.15 (t, J¼7.4 Hz,
1H), 6.74 (d, J¼7.4 Hz, 3H), 6.64 (d, J¼4.6 Hz, 2H), 1.17 (s, 18H); 13C
NMR (125 MHz, CDCl3, ppm): 194.56, 151.88, 150.97, 150.71, 148.59,
144.43, 141.17, 139.87, 139.72, 139.09, 137.19, 134.02, 131.41, 129.67,
128.90, 128.50,128.36, 127.92, 127.89,126.62, 124.95, 123.90, 123.77,
122.88, 120.65, 119.13, 66.01, 34.84, 31.41.
d
7.74 (d, J¼7.2 Hz, 2H), 7.59 (t, J¼7.3 Hz, 2H), 7.54 (d, J¼7.4 Hz, 1H),
7.36 (d, J¼6.9 Hz, 1H), 7.25e7.22 (m, 4H), 7.15 (td, J¼7.5, 1.0 Hz, 1H),
7.10 (t, J¼7.3 Hz, 1H), 7.02 (d, J¼7.8 Hz, 2H), 6.85 (t, J¼7.4 Hz, 2H),
6.62 (t, J¼7.3 Hz, 2H), 5.89 (d, J¼6.4 Hz, 2H), 2.24 (s, 1H), 1,31(s,
18H); 13C NMR (CDCl3, 125 MHz, ppm): 192.65, 151.01, 149.72,
143.28, 142.27, 140.29, 139.39, 137.55, 136.86, 134.51, 133.89, 132.45,
129.18,128.66,128.44,128.32,128.05,126.07,125.74,125.30,123.68,
120.80, 119.54, 82.43, 34.86, 31.45.
4.5.4. 60-Phenyl-2,7-di-tert-butyl-indeno[2,1-c]spiro[fluorene-9,80]
fluorene (6b). 2,7-Di-tert-butyl-9-(1,4-diphenylfluorenon-3-yl)flu-
oren-9-ol (3.1 g, 5 mmol)ꢁw1 as employed to afford 2.9 g (96%); mp:
4.4.4. 2,7-Di-tert-butyl-9-(1,4-diphenylfluorenon-3-yl)fluoren-9-ol
(4b). Rf¼0.64; recrystallized from CH2Cl2/MeOH; 3.1 g (50%); mp
299e300 ꢀC; HRMS (ESI): C46H40O2þNa requires 647.2926; Found:
275e276 ꢀC; IR (KBr)/cm
:
n
¼3065, 2962, 2902, 1711, 1604, 1466,
1363, 1252; 1H NMR (CDCl3, 500 MHz, ppm):
d
8.53 (d, J¼7.6 Hz,
[MþNaþ], 647.2921; IR (KBr)/cmꢁ1
:
n
¼3599 (OH), 2960, 2867, 1710,
8.51
1H), 8.47 (d, J¼7.6 Hz,1H), 7.73(t, J¼7.4 Hz, 3H),7.68 (t, J¼7.6 Hz,1H),
7.51 (t, J¼7.4 Hz, 1H), 7.43e7.40 (m, 3H), 7.32e7.26 (m, 5H), 7.23 (t,
J¼7.4 Hz, 1H), 6.82 (d, J¼7.6 Hz, 1H), 6.79 (s, 1H), 6.52(s, 1H), 1.19(s,
18H); 13C NMR (CDCl3, 125 MHz, ppm): 192.62, 157.94, 151.10,
150.46, 148.58, 144.13, 141.64, 139.90, 139.16, 137.81, 135.38, 134.27,
129.06, 128.98, 128.63, 127.90, 127.63, 127.59, 126.94, 125.16, 124,84,
124.35, 123.93, 123.45, 120.61, 119.27, 66.38. 34.87, 31.42.
1601, 1552, 1478, 1251, 1183; 1H NMR (CDCl3, 500 MHz, ppm):
d
(s, 1H),
d7.84 (d, J¼7.5 Hz, 2H), 7.60 (t, J¼7.4, 2H), 7.52 (t, J¼6.4 Hz,
2H), 7.32e7.28 (m, 4H), 7.06 (t, J¼6.5 Hz, 3H), 6.98 (t, J¼7.3 Hz, 1H),
6.88 (t, J¼7.6 Hz, 1H), 6.72 (t, J¼7.5 Hz, 2H), 6.00 (d, J¼7.4 Hz, 2H),
5.25 (d, J¼7.7 Hz, 1H), 2.32 (s, 1H), 1.36 (s, 18H); 13C NMR (CDCl3,
125 MHz, ppm): 192.84, 151.20, 149.62, 144.05, 143.77, 140.66,
137.95, 137.61, 135.70, 135.37, 135.02, 133.76, 130.06, 129.51, 129.25,
128.13, 127.80, 127.09, 125.90, 125.85, 123.42, 123.06, 120.93, 119.55,
82.68, 34.88, 31.46.
4.6. General procedure for the synthesis of 7a,b
4.5. General procedure for synthesis of 5a,b and 6a,b
To a suspension of indeno-spirobifluorene (0.49 g, 1 mmol) in
diethylene glycol (50 mL) was added dropwise hydrazine hydrate
(85%, 0.9 mL, 15.8 mmol); the resulting mixture was heated at
180 ꢀC for 2 h. After cooling, solid potassium hydroxide1.69 g
(30mmol) was added, then the mixture was heated at 180 ꢀC with
azeotropic distillation of water for 2 h. Then the solution was cooled
and poured into water (100 mL) and the solution was neutralized to
pH 7e8 with 1 N HCl and extracted with dichloromethane
(3ꢂ20 mL). The combined organic extract was washed with water
9-(1,4-Diphenylfluorenonyl)fluoren-9-ol (3a or 3b) or 2,7-di-
tert-butyl-9-(1,4-diphenylfluorenonyl)fluoren-9-ol (4a or 4b)
(5 mmol) was dissolved in glacial acetic acid (100 mL) and the
solution was heated at reflux, then 2 mL of hydrochloric acid was
added dropwise, the yellow solid was formed spontaneously. After
addition, the suspension was heated to reflux for another hour,
then cooling to room temperature, the yellow crystals were filtered

1208
Y. Shi et al. / Tetrahedron 67 (2011) 1201e1209
and dried over anhydrous MgSO4. After workup, the residue was
chromatographed with DCM/PE (1:1;v/v).
127.53, 127.29, 127.23, 127.11, 126.95, 126.35, 124.72, 124.15, 124.13,
123.53, 122.89, 122.12, 119.86, 65.90, 57.72, 32.36, 8.32.
4.6.1. 60-Phenyl-dihydroindeno[1,2-a]spiro
[fluorene-ꢁ91,80]fluorene
4.8. General procedure for synthesis of 9a,b
(7a). Yield 0.30 g (6 2%); mp:>300 ꢀC; IR (KBr)/cm
:
n
¼3062,
2920, 2854,1604,1431, 1100,1016; 1H NMR (CDCl3, 500 MHz, ppm):
To a solution of 4,40-di-tert-butyl-2-bromobiphenyl (0.7 g,
2 mmol) in THF (20 mL), was added BuLi (0.8 mL, 2.5 M; 2.0 mmol)
at ꢁ78 ꢀC the mixture was stirred for half an hour at the same
temperature, then the solution of indeno-spirobifluorene (0.6 g,
1 mmol) in THF (15 mL) was added dropwise with stirring; the re-
action was continued for another half an hour and slowly warmed
up to room temperature and kept for 2 h, then quenched with
saturated aqueous ammonium chloride. The mixture was extracted
with DCM (3ꢂ15 mL), the combined organic phase was washed
with water and dried over Na2SO4. After workup, the residue was
mixed with methanol (30 mL) and heated to reflux for several
minutes followed by filtration to obtain white crystalline product.
d
8.74 (d, J¼7.8 Hz, 1H), 8.67 (d, J¼7.9 Hz, 1H), 7.87 (d, J¼7.6 Hz, 2H),
7.62 (d, J¼7.4 Hz, 1H), 7.58 (t, J¼7.6 Hz, 1H), 7.51 (t, J¼7.6 Hz, 1H),
7.45e7.37 (m, 7H), 7.33e7.31 (m, 1H), 7.16 (t, J¼7.48 Hz, 2H), 6.87 (d,
J¼7.6 Hz, 2H), 6.83 (d, J¼7.5 Hz, 1H), 6.67 (s, 1H), 4.05 (s, 2H); 13C
NMR (CDCl3, 125 MHz, ppm): 149.97, 149.82, 149.45, 144.66, 142.33,
142.13, 142.01, 141.96, 141.14, 138.39, 137.52, 136.25, 128.85, 128.50,
128.13, 127.91, 127.75, 127.38, 127.01, 126.82, 125.26, 124.52, 124.40,
123.80, 123.06, 120.21, 66.35, 37.78.
4.6.2. 50-Phenyl-dihydroindeno[2,1-c]spiro
(7b). Yield 0.38 g (77.6%); mp 294e295 ꢀC; IR (KBr)/cmꢁ1
2924, 2854,1604,1433,1088, 1016; 1H NMR (CDCl3, 500 MHz, ppm):
[fluorene-9,70]fluorene
:
n¼3064,
d
8.07 (d, J¼7.6 Hz, 1H), 7.88 (d, J¼7.6 Hz, 2H), 7.72 (d, J¼7.4 Hz, 1H),
4.8.1. 50-Phenyl-120-hydroxy-120-(200,700-di-tert-butylfluoren-9-yl)-
2,7-di-tert-butylindeno[1,2-a]spiro[fluorene-9,70]fluorene (9a). Yield
7.52 (t, J¼7.5 Hz, 1H), 7.42e7.40 (m, 7H), 7.31 (t, J¼7.7 Hz,1H), 7.21 (t,
J¼7.5 Hz,1H), 7.18e7.11 (m, 3H), 7.03 (d, J¼7.8 Hz,1H), 6.87e6.84 (m,
3H), 6.67 (s, 1H), 4.43(s, 2H); 13C NMR (CDCl3, 125 MHz, ppm):
149.67, 148.98, 147.21, 143.66, 141.71, 141.69, 141.25, 137.36, 136.94,
136.92, 129.22, 128.25, 127.84, 127.70, 127.58, 127.36, 126.36, 124.90,
124.58, 124.20, 124.11, 122.82, 122.10, 119.98, 66.12, 36.21.
0.8 g (93%), mp:>300 ꢀC; IR (KBr)/cmꢁ1
:
n
¼3556 (OH), 3062, 2962,
2903, 2867, 1479, 1362, 1253; 1H NMR (CDCl3, 500 MHz, ppm):
7.99(d, J¼7.8 Hz, 1H), 7.74(d, J¼8.1 Hz, 1H), 7.69(d, J¼8.0 Hz, 1H),
d
7.46(dd, J¼8.1, 1.7 Hz, 1H), 7.37(td, J¼8.0, 1.9 Hz, 2H), 7.30e7.28(m,
4H), 7.17e7.11(m, 3H), 7.04(td, J¼7.33, 0.8Hz, 2H), 6.90 (m, 2H),
6.85(d, J¼7.8 Hz, 1H), 6.75(d, J¼7.5 Hz, 2H), 6.69(d, J¼7.4 Hz, 1H),
6.33(d, J¼1.4 Hz, 1H), 6.47(d, J¼7.8 Hz, 1H), 6.43(s, 2H), 5.87(s, 1H),
2.74(s, 1H), 1.67(s, 9H), 1.29(s,9H), 1.15(s, 9H), 1.13(s, 9H); 13C NMR
(CDCl3, 125 MHz, ppm): 150.76, 149.93, 149.59, 140.42, 138.93,
132.01, 129.01, 128.03, 127.55, 127.44, 127.28, 127.17, 126.69, 125.19,
125.06, 124.61, 124.45, 123.95, 123.32, 122.67, 120.55, 120.25,
119.19, 118.92, 82.75, 66.29, 35.03, 34.86, 34.80, 34.16, 31.65, 31.61,
31.42, 31.21.
4.7. General procedure for synthesis of 8a,b
To a dihydroindeno-spirobifluorene (0.2 g, 0.4 mmol) in dry THF
(10 mL) was added slowly with BuLi (2.5 M, 0.24 mL, 0.6 mmol) at
ꢁ78 ꢀC, the reaction mixture was kept at that temperature with
stirring for half an hour, then ethyl bromide (0.45 mL, 0.6 mmol)
was added slowly and stirring was continued for another hour.
Then again the above operation was repeated once. The final
mixture was stirred for further 6 h, then the reaction was quenched
with saturated ammonium chloride and extracted with dichloro-
methane (2ꢂ10 mL); the combined organic phase was washed with
water and solvents were evaporated. The residue was chromat-
graphed with PE/DCM (1:1,v/v) to afford white crystalline solid.
4.8.2. 50-Hydroxy-50-((200,700-di-tert-butylfluoren-9-yl))-60-phenyl-
2,7-di-tert-butyl-indeno[2,1-c] spiro[fluorene-9,80]fluorene (9b). Yield
0.8 g (93%), mp:>300 ꢀC; IR (KBr)/cmꢁ1
:
n
¼3060, 2962, 2904, 2868,
1708, 1604, 1469, 1252; 1H NMR (CDCl3, 500 MHz, ppm):
d
8.27(d,
J¼7.8 Hz, 1H), 8.08 (d, J¼7.4 Hz, 1H), 7.71 (d, J¼8.0 Hz, 1H), 7.67 (d,
J¼8.05 Hz, 1H), 7.57(s, 1H), 7.44e7.33 (m, 4H), 7.27 (t, J¼7.4 Hz, 1H),
7.21(d, J¼7.2 Hz, 1H), 7.17e7.11(m, 3H), 7.05(t, J¼7.5 Hz, 3H), 6.85(d,
J¼7.0 Hz, 2H), 6.78(m, 4H), 6.65(d, J¼1.2 Hz, 1H), 6.36(s, 1H), 6.15(br
s, 1H), 6.03(d, J¼7.9 Hz, 1H), 2.58(s, 1H), 1.31(s, 9H), 1.24 (s, 9H), 1.16
(s, 9H), 1.08(s, 9H); 13C NMR (CDCl3, 125 MHz, ppm): 151.75, 151.38,
150.82, 150.73, 149.29, 148.82, 139.88, 130.94, 129.21, 128.17, 127.82,
127.52, 127.25, 127.21, 126.89, 125.95, 124.67, 124.44, 124.36, 123.93,
123.69, 123.40, 121.02, 120.47, 119.03, 82.86, 66.01, 34.96, 34.83,
34.57, 31.66, 31.45, 31.14.
4.7.1. 120, 120-Diethyl-50-phenyl-dihydroindeno [1,2-a]spiro[fluorene-
9,70]fluorene (8a). Yield 0.2 g (90%); Found: C, 93.73; H, 6.27;
C42H32 requires C, 93.99; H, 6.01%; HRMS (ESI): C42H32þNa requires
559.2402; Found: [MþNaþ], 559.2396; IR (KBr)/cmꢁ1
:
n
¼3056,
2962, 2929, 2872, 1599, 1446, 1380; 1H NMR (CDCl3, 500 MHz,
ppm):
d
8.38 (d, J¼7.9 Hz, 1H), 7.83(d, J¼7.6 Hz, 1H), 7.43(m, 2H),
7.37e7.30(m, 7H), 7.25(d, J¼7.8 Hz, 1H), 7.13(t, J¼7.5 Hz, 3H), 6.98(t,
J¼7.5 Hz, 1H), 6.79(d, J¼7.5 Hz, 2H), 6.76e6.73(m, 2H), 6.53(s, 1H), 2
99(m, 2H), 2.30(m, 1H), 0.45(t, J¼7.3 Hz, 6H); 13C NMR (CDCl3,
125 MHz, ppm): 150.98, 149.42, 148.04, 141.70, 141.37, 141.25,
141.03, 137.27, 129.26, 128.20, 127.87, 127.63, 127.46, 127.27, 127.19,
126.71, 126.14, 124.95, 124.93, 124.30, 124.10, 122.37, 122.04, 119.96,
65.83, 57.21, 29.98, 9.02.
4.9. General procedure for the synthesis of 10a,b
General procedure for acid-catalyzed FriedeleCrafts intra-
molecular alkylation of tert-fluoren-9-ols to form dispirobi-
fluorenes: 4,40-di-tert-butyl-2-bromobiphenyl to indeno-spiro-
bifluorenes: tert-fluoren-9-ols (0.5 g, 0.6 mmol) was suspended in
glacial acetic acid (50 mL) and heated to reflux, hydrochloric acid
(1 mL) was added stepwise and continued to reflux for 8 h, after
cooling, the resulting solid was filtered and mixed with ethanol
(30 mL) and heated to reflux for half an hour. The mixture was
filtered while hot to afford white crystals.
4.7.2. 5,50-Diethyl-60-phenyl-dihydroindeno[2,1-c]spiro[fluorene-
9,80]fluorene (8b). Yield 0.19 g (85%); C42H32 requires C, 93.99; H,
6.01%; Found: C, 93.84; H, 6.16%; HRMS (ESI): C42H32þNa requires
559.2402; Found: [MþNaþ], 559.2396; IR (KBr)/cmꢁ1
:
n
¼3062,
2961, 2930, 2872,1600,1447,1374; 1H NMR (CDCl3, 500 MHz, ppm):
d
8.64(t, J¼7.0 Hz, 2H), 7.78(d, J¼7.5 Hz, 2H), 7.49e7.42(m, 2H), 7.39
4.9.1. 2,200,7,700-tetra-tert-butyl-50-phenyldispiro
[fluorene-9,70-in-
(t, J¼7.5 Hz, 1H), 7.34(t, J¼7.2 Hz, 3H), 7.25e7.23(m, 3H), 7.12(m,
5H), 6.84(d, J¼8 Hz, 2H), 6.74(d, J¼7.5 Hz, 1H), 6.37(s, 1H), 1.75(m,
4H), 0.28(t, J¼7.2 Hz, 6H); 13C NMR (CDCl3, 125 MHz, ppm): 151.58,
149.85, 149.31, 142.02, 141.67, 141.46, 141.38, 138.81, 128.81, 127.79,
deno[1,2-a]fluorene-120,900-fluorene (10a). Yield 0.4 g (85%); C66H62
requires C, 92.69; H, 7.31%; Found: C, 92.44%; H, 7.56; HRMS (ESI):
C66H62þNa requires 877.4749; Found: [MþNaþ], 877.4744; IR (KBr)/
cmꢁ1
:
n
¼3062, 2960, 2903, 2867, 1469, 1362, 1201; 1H NMR (CDCl3,

Y. Shi et al. / Tetrahedron 67 (2011) 1201e1209
1209
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500 MHz, ppm)
d
7.99(d, J¼7.8 Hz, 1H), 7.66(d, J¼8.0 Hz, 2H), 7.50(d,
J¼7.4 Hz, 2H), 7.44e7.40(m, 5H), 7.34(dd, J¼7.9, 1.6 Hz, 2H), 6.96(d,
J¼1.2 Hz, 2H), 6.93e6.90(m, 3H), 6.76(t, J¼7.5 Hz, 1H), 6.66(t,
J¼7.6 Hz, 1H), 6.64e6.60(m, 2H), 6.55(d, J¼1.8 Hz, 2H), 6.47(d,
J¼7.3 Hz, 1H), 6.25(d, J¼7.9 Hz, 1H), 1.14(s, 18H), 1.12 (s, 18H); 13C
NMR (CDCl3, 125 MHz, ppm): 151.30, 151.21, 150.84, 149.84, 149.73,
148.28, 141.96, 141.59, 140.31, 140.26, 139.84, 139.43, 138.16, 137.11,
129.80, 128.59, 127.71, 127.37, 126.98, 126.88, 126.28, 124.92, 124.15,
123.58, 123.43, 122.87, 120.88, 120.69, 119.88, 119.31, 66.74, 66.34,
35.07, 34.96, 31.64, 31.59.
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cmꢁ1
500 MHz, ppm):
:
n
¼3060, 2960, 2903, 2868, 1468, 1368, 1252; 1H NMR (CDCl3,
d
8.83(d, J¼7.8 Hz, 2H), 7.63 (d, J¼8.0 Hz, 2H), 7.56
(t, J¼7.5 Hz, 1H), 7.51(t, J¼7.9 Hz, 1H), 7.32(d, J¼7.9 Hz, 2H),
7.25e7.12(m, 6H), 6.86e6.78(m, 5H), 6.72e6.69(m, 2H), 6.44(t,
J¼7.6 Hz, 2H), 6.26(s, 1H), 5.80(d, J¼7.1 Hz, 2H), 1.16(s, 36H); 13C
NMR (CDCl3, 125 MHz, ppm): 150.68, 150.10, 149.38, 148.86, 139.50,
139.22, 128.44, 127.52, 127.47, 127.28, 126.96, 125.91, 125.17, 125.02,
124.64,124.54, 124.33,123.95,123.64,123.48, 120.88,120.47,118.99,
66.32, 66.05, 34.83, 34.73, 31.49, 31.46.
Acknowledgements
The authors acknowledge the Shanghai Natural Science foun-
dation of China (09ZR1409400) and the Sino-French Institute of
ECNU for financial support, Shanghai Committee of Science and
Technology of China (10520710100) and French Institute of ECNU
for funding.
Supplementary data
Supplementary data related to this article can be found online at
doi:10.1016/j.tet.2010.11.092. These data include MOL files and
InChIKeys of the most important compounds described in this
article.
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