Synthesis and properties of 2,2'-di(heteroaryl)-9,9'-spirobifluorenes

Article abstract of DOI:10.1246/bcsj.20090121

A series of 2,2'-di(heteroaryl)-9,9'-spirobifluorenes were prepared by employing Friedlaender reaction of 2,2'- diacetyl-9,9'-spirodifluorene with a series of ortho-aminoarenecarbaldehydes. The compound 2,2'-di(benzo[b]-1,10- phenanthrolin-2-yl)-9,9'-spirofluorene (4e) showed a green light emission at 500 nm upon the excitation of the absorption at 374 nm while 2,2'-di(benzo[h] quinolin-2-yl)-9,9'-spirofluorene (4c), 2,2'-di(1,10-phenanthrolin-2-yl)-9,9'- spirofluorene (4d), 2-(benzo[h]quinolin-2-yl)-2'-(benzo[b]-1,10-phenanthrolin-2- yl)-9,9'-spirofluorene (4g), and 2-(1,10-phenanthrolin- 2-yl)-2'-(benzo[b]-1,10- phenanthrolin-2-yl)-9,9'-spirofluorene (4h) showed emissions at 413, 465, 442, and 442 nm upon excitation of the absorption at 370, 362, 370, and 363 nm, respectively, thus having potential for OLED applications.

Full text of DOI:10.1246/bcsj.20090121

672
Bull. Chem. Soc. Jpn. Vol. 83, No. 6, 672–677 (2010)
© 2010 The Chemical Society of Japan
Synthesis and Properties of 2,2¤-Di(heteroaryl)-9,9¤-spirobifluorenes
Yurngdong Jahng* and A. F. M. Motiur Rahman
College of Pharmacy, Yeungnam University, Gyeongsan 712-749, Korea
Received May 8, 2009; E-mail: ydjahng@ynu.ac.kr
A series of 2,2¤-di(heteroaryl)-9,9¤-spirobifluorenes were prepared by employing Friedländer reaction of 2,2¤-
diacetyl-9,9¤-spirodifluorene with a series of ortho-aminoarenecarbaldehydes. The compound 2,2¤-di(benzo[b]-1,10-
phenanthrolin-2-yl)-9,9¤-spirofluorene (4e) showed a green light emission at 500 nm upon the excitation of the absorption
at 374 nm while 2,2¤-di(benzo[h]quinolin-2-yl)-9,9¤-spirofluorene (4c), 2,2¤-di(1,10-phenanthrolin-2-yl)-9,9¤-spirofluorene
(4d), 2-(benzo[h]quinolin-2-yl)-2¤-(benzo[b]-1,10-phenanthrolin-2-yl)-9,9¤-spirofluorene (4g), and 2-(1,10-phenanthrolin-
2-yl)-2¤-(benzo[b]-1,10-phenanthrolin-2-yl)-9,9¤-spirofluorene (4h) showed emissions at 413, 465, 442, and 442 nm upon
excitation of the absorption at 370, 362, 370, and 363 nm, respectively, thus having potential for OLED applications.
The 9,9¤-spirobifluorene (9,9¤-spirobi[9H-fluorene] ([5,5]-
Some proton resonances of the products were characteristic
enough to afford probes for the structure suggested. The
protons adjacent to nitrogen such as H7¤¤ of 4b and H9¤¤ of
4d are the those of characteristic chemical shifts (¤ 8.99 and
spirobifluorylidene, 1), as well as its derivatives have been
attractive due to the characteristic structure since its first
preparation in 1930.1 Early studies on this molecule were
focused on the molecular recognition of various ¡-amino-
alcohols by 9,9¤-spirobifluorene-based crown ethers,2-10 and
monosaccharides by dendritic cleft receptors,11-20 as well as
by inclusion compounds with hydrocarbons,4,21,22 carbohy-
drate,23,24 and ¡-hydroxycarboxylates.25 However, focus of
studies on compounds with 9,9¤-spirobifluorene especially 9,9¤-
spirobifluorene-based oligomers as well as polymers has been
switched to applications in molecular electronic devices for
light-emitting devices.26-33
3
9.14, respectively) with relatively small J coupling constant
(4.3 Hz).52 In addition, the resonances of H1 of 9,9¤-spirobi-
fluorene moiety generally appeared in the region of ¤ 7.48-7.80
with a characteristic meta-coupling constant (4J = 1.4-1.8 Hz).
The protons H8, H1¤, and H8¤ of the 9,9¤-spirobifluorene
moiety are the most upfield-shifted due to the anisotropic effect
of the neighboring two phenyl groups, thus were resonated in
the range of ¤ 6.80-6.71. Additionally, the protons at the peri-
position of 4a and 4e (H8¤¤ of 4a, H11¤¤ of 4e) were resonated
at ¤ 8.30 and 8.70, respectively, and H10¤¤ of the benzo[h]-
quinoline moiety of 4c was resonated at ¤ 9.36 as a doublet of
Although a few pyridine-derived monomeric 2,2¤-di(hetero-
aryl)-9,9¤-spirobifluorenes such as 2,2¤-di(benzo[h]quinolin-2-
yl)-9,9¤-spirobifluorene (4c),34 2,2¤-di(1,10-phenanthrolin-2-
yl)-9,9¤-spirobifluorene (4d),35-37 and 2,2¤,7,7¤-tetra(benzo[h]-
quinolin-2-yl)-9,9¤-spirobifluorene38 have been reported to
show promising photophysical properties for OLED applica-
tions, systematic approaches either for the preparation or for the
examination of their properties of systems with heteroaromatics
have not yet been pursued.39,40 Additionally, benzo[b]-1,10-
phenanthroline (bphen) and related compounds show promis-
ing light emission with improved stability.41
4
doublet (3J = 9.0 Hz and J = 1.2 Hz), which experienced the
anisotropic effect of neighboring pyridine as well as the
electronic effects of lone pair electrons on N1¤¤ most seriously.
The same Friedländer reaction of 2 with one equivalent of 3c
afforded mono-condensed products 5a in 89% yield along with
a trace of doubly condensed 4c, which were readily separable
(Scheme 2). Consecutive condensation of 5a with second o-
aminoaldehydes 3d and 3e afforded 4f and 4g in 92% and 95%
yield, respectively. However, a reaction of 2 with 3d afforded
an inseparable mixture of 2, 5b, and 4d. The three component
mixture thus was subjected to second condensation reaction
with 3e to lead to three expected compounds 4e, 4h, and 4d in a
ratio of 1:5:2 which were separated by column chromatography
on silica gel eluting with CH2Cl2:CH3OH (97:3).
Our interest in the preparation and properties of bphen42,43
and related polydentates44 spurred us to study a series of 9,9¤-
spirobifluorene-derived N-heterocycles.
Results and Discussion
Synthesis of the pyridine-derived 2,2¤-di(heteroaryl)-9,9¤-
spirobifluorenes was straightforward as shown in Scheme 1.
The Friedländer condensation of 2,2¤-diacetyl-9,9¤-spirobifluo-
rene (2)2 with a series of o-aminoarenecarbaldehydes (3)45-49
afforded a series of heteroaromatics with 9,9¤-spirobifluorene
skeleton in 82-99% yields. The starting 2,2¤-diacetyl-9,9¤-spiro-
bifluorene was prepared in 51% yield by Friedel-Craft acylation
of 9,9¤-spirobifluorene. Prerequisite 9,9¤-spirobifluorene was
readily prepared in 3 steps from commercially available 2-
bromobiphenyl and fluorenone in 35% overall yield.1,4,50,51
Since 2,2¤-disubstituted 9,9¤-spirobifluorenes are chiral, the
compounds prepared can be considered to have an additional
chiral axis through the aryl-aryl bond. When free rotation of the
two aryl-aryl bonds of 4 is restricted, such conformational
rigidity may lead to two rotameric diastereomers. However, the
energy barrier between the two rotamers is not expected to be
high enough leading to a separation of the two rotamers at room
temperature. 1H NMR spectra of all the mixed heterocycles (4f,
4g, and 4h) showed only one set of each proton resonance
implying that the aryl-aryl bond is free to rotate in each case.
Published on the web May 28, 2010; doi:10.1246/bcsj.20090121

Y. Jahng et al.
Bull. Chem. Soc. Jpn. Vol. 83, No. 6 (2010)
673
CHO
NH2
X
3a X = CH
b
X = N
N
X
X
N
H7"
1
4a
b
X = CH
X = N
CHO
CH3COCl AlCl3
NH2
X
6
5
4
3
CH3
O
7
X
3c
d
X = CH
X = N
N
8
1
8'
1'
N
O
X
H9"
7'
CH3
3' 4'
5' 6'
CHO
NH2
2
4c
d
X = CH
X = N
N
N
3e
N
N
N
H11
"
4e
Scheme 1. Synthesis of symmetric 2,2¤-di(heteroaryl)-9,9¤-spirobifluorenes.
N
N
N
3c/3d
3d
2
N
O
X
CH3
5a
b
X = CH
X = N
4f
3e
N
N
N
X
4g
X = CH
h X = N
Scheme 2. Synthesis of unsymmetric 2,2¤-di(heteroaryl)-9,9¤-spirobifluorenes.

674
Bull. Chem. Soc. Jpn. Vol. 83, No. 6 (2010)
2,2¤-Di(heteroaryl)-9,9¤-spirobifluorene
Table 1. UV Absorption and Emission Spectral Data of 1 and 2,2¤-Heteroaryl-9,9¤-spirobifluorenes
Compd
-abs/nm (log ¾)
-
excit/nm
-em/nm
1
223 (4.65), 239 (4.40), 272 (4.29), 296 (3.92), 308 (4.11)
222 (4.55), 253 (4.30), 281 (4.37), 341 (4.39), 351 (4.34)
223 (4.50), 256 (4.24), 275 (4.20), 298 (4.15), 348 (4.42)
230 (4.58), 302 (4.38), 331 (4.35), 351 (4.18), 370 (4.17)
232 (4.61), 267 (4.28), 299 (4.33), 331 (4.36), 344 (4.27), 362 (4.17)
227 (4.72), 255 (4.83), 285 (4.02), 336 (4.67), 357 (4.52), 373 (4.39)
233 (4.62), 333 (4.40), 350 (4.27), 365 (4.23)
308
351
350
370
362
373
365
370
363
388
391
4a
4b
4c
4d
4e
4f
382, 398
397, 413
442, 465, 498
500
378, 396
442
4g
4h
235 (4.71), 252 (4.67), 335 (4.59), 353 (4.23), 370 (4.39)
234 (4.72), 255 (4.65), 334 (4.63), 363 (4.44)
442
1.0
0.5
1.0
To our surprise, an additional compound (Rf = 0.25,
CH2Cl2) was isolated from the reaction mixture along with
the compound 4f (Rf = 0.28, CH2Cl2), by preparative TLC.
Although the 1H NMR spectrum of this species was very
similar to that of 4f, the region ¤ 7.88-7.58 is significantly
different (see Supporting Information). The major difference
lay in the resonances of H1 and H1¤. H1 and H1¤ of the less
polar compound resonate at ¤ 7.56 and ¤ 7.53 (could be
reversed) while these protons of the more polar compound
resonate at ¤ 7.71. Although 13C NMR spectrum of the less
polar compound showed 50 carbon resonances corresponding
to the structure, we failed to get good 13C NMR spectrum due
to instability of the corresponding rotamer. Although attempts
to measure the energy barrier by 1H NMR temperature variation
were not successful due to rapid conversion of one to another at
the temperature of 35-50 °C, the energy barrier range between
the two rotamers was calculated by using a previously reported
equation53 to give 16.5-17.6 kcal mol¹1. Even though the
restricted rotation of aryl-aryl bonds in 4f may result in
rotational isomerism, we cannot explain why only 4f has such a
high energy barrier compared to the other congeners. Such an
immature premise may not rule out the possible presence of as
yet unidentified intermediates based on the broadening of the
1
4c 4g 4d 4e
4e
4h
4h
0.5
4g
4d
4c
1
250
300
350
400
Wavelength/nm
450
500
550
Figure 1. Absorption and photoluminescence (PL) spectra
of 9,9¤-spirobifluorene (1) and selected 2,2¤-di(heteroaryl)-
9,9¤-spirobifluorenes 4 in EtOH (1.21 © 10¹5 M) at 298 K.
light to show emissions in the range of 398-500 nm. The
observed emission wavelength (Table 1) is highly dependent
on the heterocycles on 9,9¤-spirobifluorene and is bathochro-
matically shifted from 388 nm for 9,9¤-spirobifluorene to 400-
500 nm. The compound 4e showed a green light emission at
500 nm upon the excitation of the absorption at 374 nm while
4c, 4d, 4g, and 4h showed emissions at 413, 465, 442, and
442 nm upon excitation of the absorption at 370, 362, 370,
and 363 nm, respectively, thus to have a potential for OLED
applications. The emission wavelength (-em = 388 nm) of
bphen is coincidently matched to that of 9,9¤-spirobifluorene.
In conclusion, a series of 9,9¤-spirobifluorene-derived
heterocycles were prepared by employing Friedländer reaction
of 2,2¤-diacetyl-9,9¤-spirobifluorene with a series of ortho-
aminoaldehydes. The compound, 2,2¤-di(benzo[b]-1,10-phen-
anthrolin-2-yl)-9,9¤-spirofluorene (4e) showed a green light
emission at 500 nm upon the excitation of the absorption at
374 nm while 4c, 4d, 4g, and 4h showed emissions at 413, 465,
442, and 442 nm upon excitation of the absorption at 370, 362,
370, and 363 nm, respectively, thus to have potential for OLED
applications. Studies on asymmetric synthesis of the ligands
employing optically active 2,2-diacetyl-9,9¤-spirobifluorene as
well as metal complex chemistry of the ligands are in progress,
which will be due in the future.
1
peaks at ¤ 9.19, 8.65, and 8.23 in the H NMR spectrum. It
should be noted that attempts to resolve the enantiomers of 4 by
conventional methods have not been successful as of yet.
UV absorption spectra of 4, bphen, and the parent 9,9¤-
spirobifluorene (1) were taken in EtOH (1.21 © 10¹5 M) and
are summarized in Table 1. Three major absorption maxima
originating from the ³-³* transition were observed in the
regions of 224-233, 255-267, 276-293, 330-339, and 350-
374 nm. The absorptions in the range of 330-370 nm were not
observed in the parent compound 9,9¤-spirobifluorene, thus
such absorptions were from ³-³* transition of the heterocyclic
rings of the system. Two rotamers of 4f showed the same
absorption as expected. The absorption maximum is highly
dependent on the nature of the heterocycles attached to 9,9¤-
spirobifluorene. Annulation of an additional benzene ring (4d
vs. 4e) not only led to bathochromic shift of the absorptions at
331, 344, and 362 nm to 336, 357, and 373 nm, respectively,
but also increased corresponding intensity due to the expansion
of conjugated ³-bonds.
The photoluminescence (PL) of 1, 4, and bphen was studied
in EtOH (1.21 © 10¹5 M) to evaluate their potentials as a key
structure for further OLED applications and are presented in
Figure 1. All the ligands could be well excited by 365-405 nm
Experimental
Melting points were determined using a Fischer-Jones

Y. Jahng et al.
Bull. Chem. Soc. Jpn. Vol. 83, No. 6 (2010)
675
melting point apparatus and are not corrected. UV spectra were
recorded on a JASCO-V550 spectrophotometer and emission
spectra on a F-4500 Fluorescence Spectrophotometer, Rigong
International, Japan. FT-IR spectra were recorded on a JASCO
FT-IR 300E spectrophotometer. The NMR spectra were
recorded on a Bruker-250 spectrometer 250, 300, or 600 MHz
for 1H NMR and 62.5 MHz for 13C NMR and are reported
as parts per million (ppm) from the internal standard tetra-
methylsilane (TMS). The starting 9,9¤-spirobifluorene,1,50-51
2,2¤-Di(benzo[h]quinolin-2-yl)-9,9¤-spirobifluorene (4c).
Yellow crystalline solid (86%): Unreported physical and
spectral data are as follows, mp > 300 °C. 1H NMR
(250 MHz, CDCl3): ¤ 9.36 (2H, dd, J = 9.0, 1.2 Hz, H10 of
bq), 8.62 (2H, dd, J = 8.0, 1.2 Hz, H4 of bq), 8.10 (2H, d,
J = 8.0 Hz, H3 of bq), 8.04 (2H, d, J = 8.5 Hz, H5/H6), 7.98
(2H, d, J = 7.5 Hz, H5 and H5¤), 7.83 (2H, dd, J = 8.2, 1.5 Hz,
H4 and H4¤), 7.76 (2H, d, J = 8.5 Hz, H6/H5), 7.70 (2H, d,
J = 8.5 Hz, H8 of bq), 7.66 (2H, ddd, J = 8.5, 7.5, 1.2 Hz, H6
and H6¤), 7.59 (2H, d, J = 9.0 Hz, H7 of bq), 7.56 (2H, d,
J = 1.7 Hz, H1 and H1¤), 7.22 (2H, td, J = 7.5, 1.0 Hz, H7 and
H7¤), 6.82 (2H, d, J = 7.5 Hz, H8 and H8¤). 13C NMR (62.5
MHz, CDCl3): ¤C 155.29, 149.40, 146.08, 143.10, 141.29,
139.63, 136.27, 133.78, 131.63, 128.25, 128.05, 127.96,
127.90, 127.70, 127.30, 126.81, 125.01, 124.63, 124.21,
122.91, 120.64, 120.44, 119.16, 66.23. MS (ESI): m/z = 671
[M + H]+.
2,2¤-diacetyl-9,9¤-spirobifluorene,2
o-aminobenzaldehyde,45
2-aminonicotinaldehyde,46
1-aminonaphthalene-2-carbalde-
hyde,48 8-aminoquinoline-7-carbaldehyde,47,48 and 4-amino-
acridine-3-carbaldehyde49 were prepared by employing previ-
ously reported methods. Chemicals and solvents were
commercial reagent grade and used without further purification.
Electrospray ionization mass spectrometry (MS/ESI) experi-
ments were performed on a LCQ advantage-trap mass
spectrometer (Thermo Finnigan, San Jose, CA, USA). Ele-
mental analyses were taken on a Hewlett-Packard Model 185B
elemental analyzer. Abbreviations q, naph, bq, and phen were
introduced for quinoline, 1,8-naphthyridine, benzo[h]quino-
line, and 1,10-phenanthroline, respectively.
2,2¤-Di(1,10-phenanthrolin-2-yl)-9,9¤-spirobifluorene (4d).
Yellow crystalline solid (82%), mp > 300 °C. (lit.35 mp >
1
300 °C). H NMR (250 MHz, CDCl3): ¤ 9.14 (2H, dd, J = 4.3,
1.5 Hz, H9 of phen), 8.60 (2H, dd, J = 8.0, 1.2 Hz, H4 of
phen), 8.17 (2H, dd, J = 7.9, 1.7 Hz, H7 of phen), 8.12 (2H, d,
J = 8.4 Hz, H8 and H8¤ of phen), 8.06 (2H, d, J = 8.1 Hz, H4
and H4¤), 7.93 (2H, d, J = 7.8 Hz, H5 and H5¤), 7.83 (2H, d,
J = 8.3 Hz, H3 and H3¤), 7.68 (4H, AB quartet, H5 and H6 of
phen), 7.57 (2H, dd, J = 8.0, 4.3 Hz, H8 of phen), 7.48 (2H, d,
J = 1.3 Hz, H1 and H1¤), 7.38 (2H, td, J = 6.8, 1.0 Hz, H6 and
H6¤), 7.11 (2H, td, J = 7.5, 1.8 Hz, H7 and H7¤), 6.77 (2H, d,
J = 7.5 Hz, H8 and H8¤). MS (ESI): m/z = 673 [M + H]+.
2,2¤-Di(benzo[b]-1,10-phenanthrolin-2-yl)-9,9¤-spirofluo-
rene (4e). Yellow crystalline solid (99%), mp 280-282 °C.
1H NMR (250 MHz, CDCl3): ¤ 8.70 (2H, dd, J = 8.0, 1.5 Hz,
H11 of bphen), 8.66 (2H, s, H7 of bphen), 8.56 (2H, d,
J = 8.7 Hz, H4 of bphen), 8.14 (2H, d, J = 8.1 Hz, H8 of
bphen), 8.07 (2H, d, J = 8.4 Hz, H5/H6 of bphen), 7.99 (2H, d,
J = 7.5 Hz, H3 of bphen), 7.97 (2H, d, J = 7.2 Hz, H3 and
H3¤), 7.87 (2H, d, J = 8.4 Hz, H6/H5 of bphen), 7.83 (2H, ddd,
J = 8.4, 7.8, 1.2 Hz, H10 of bphen), 7.73 (2H, d, J = 9.0 Hz,
H5 and H5¤), 7.60 (2H, td, J = 7.2, 1.2 Hz, H9 of bphen), 7.57
(2H, d, J = 9.0 Hz, H4 and H4¤), 7.55 (2H, d, J = 1.2 Hz, H1
and H1¤), 7.41 (2H, td, J = 7.2, 1.2 Hz, H6 and H6¤), 7.14 (2H,
td, J = 7.2, 0.6 Hz, H7 and H7¤), 6.80 (2H, td, J = 7.5 Hz, H8
and H8¤). 13C NMR (62.5 MHz, CDCl3): ¤ 157.11, 149.47,
148.87, 148.11, 146.82, 146.20, 143.22, 141.32, 139.67,
136.50, 135.81, 130.85, 130.00, 128.85, 128.23, 127.97,
127.85, 127.52, 127.23, 126.94, 126.69, 126.48, 125.71,
124.15, 123.30, 121.39, 120.70, 120.49, 66.21. MS (ESI):
m/z = 773 [M + H]+. Anal. Calcd for C57H32N4 (772.9): C,
88.58; H, 4.17; N, 7.25%. Found: C, 88.62; H, 4.14; N, 7.24%.
2-Acetyl-2¤-(benzo[h]quinolin-2-yl)-9,9¤-spirobifluorene
2,2¤-Di(quinolin-2-yl)-9,9¤-spirobifluorene (4a) (General
Procedure). A mixture of 2-aminobenzaldehyde (190 mg,
1.57 mmol) and 2,2¤-diacetyl-9,9¤-spirobifluorene (400 mg,
0.63 mmol) in absolute EtOH (20 mL) with saturated alcoholic
KOH (1 mL) was refluxed for 5 h. Upon cooling the reaction
mixture solid was formed, which was collected as a pure
1
product (300 mg, 83%) as yellow solid, mp 302 °C. H NMR
(250 MHz, CDCl3): ¤ 8.30 (2H, dd, J = 8.6, 1.6 Hz, H8 of q),
8.05-8.00 (6H, m, H4, H5 of q, H3 and H3¤), 7.93 (2H, d,
J = 7.7 Hz, H3 of q), 7.70 (2H, dd, J = 7.5, 1.2 Hz, H4 and
H4¤), 7.65 (2H, d, J = 8.6 Hz, H5 and H5¤), 7.64 (2H, td,
J = 8.6, 1.5 Hz, H7 of q), 7.51 (2H, d, J = 1.5 Hz, H1 and H1¤),
7.42 (2H, td, J = 7.5, 1.5 Hz, H6 of q), 7.37 (2H, t, J = 7.5 Hz,
H6 and H6¤), 7.13 (2H, td, J = 8.6, 1.5 Hz, H7 and H7¤), 6.78
(2H, d, J = 7.5 Hz, H8 and H8¤). 13C NMR (62.5 MHz, CDCl3):
¤ 157.03, 149.35, 148.97, 148.10, 143.20, 141.20, 139.48,
136.49, 129.56, 129.51, 128.29, 127.87, 127.81, 127.32,
127.01, 126.11, 124.21, 123.32, 120.53, 120.45, 119.15,
66.18. MS (ESI): m/z = 571 [M + H]+. Anal. Calcd for
C43H26N2 (570.7): C, 90.50; H, 4.59; N, 4.91%. Found: C,
90.50; H, 4.62; N, 4.88%.
2,2¤-Di(1,8-naphthyridin-2-yl)-9,9¤-spirobifluorene (4b).
Yellow crystalline solid (82%), mp > 315 °C. 1H NMR
(250 MHz, CDCl3): ¤ 8.99 (2H, dd, J = 4.3, 1.8 Hz, H7 of
naph), 8.36 (2H, dd, J = 8.1, 1.5 Hz, H5 and H5¤), 8.06 (2H, d,
J = 8.6 Hz, H4 of naph), 8.04 (2H, dd, J = 8.6, 1.8 Hz, H5 of
naph), 8.02 (2H, d, J = 8.4 Hz, H3 of naph), 7.92 (2H, d,
J = 7.8 Hz, H4 and H4¤), 7.84 (2H, d, J = 8.6 Hz, H5 and H5¤),
7.80 (2H, d, J = 1.2 Hz, H1 and H1¤), 7.38 (2H, td, J = 7.5,
1.2 Hz, H6 and H6¤), 7.33 (2H, dd, J = 8.1, 4.3 Hz, H6 of
naph), 7.11 (2H, td, J = 7.5, 1.2 Hz, H7 and H7¤), 6.76 (2H, d,
J = 7.6 Hz, H8 and H8¤). 13C NMR (62.5 MHz, CDCl3): ¤
160.01, 155.88, 153.56, 149.42, 149.02, 144.24, 141.03,
138.04, 137.37, 136.64, 128.47, 128.03, 120.45, 119.88,
66.16. MS (ESI): m/z = 573 [M + H]+. Anal. Calcd for
C41H24N4 (572.7): C, 85.99; H, 4.23; N, 9.78%. Found: C,
86.00; H, 4.20; N, 9.80%.
(5a). Yellow crystalline solid (92%), mp > 300 °C. IR (KBr)
¹1
¯ 1710 cm
.
1H NMR (600 MHz, CDCl3): ¤ 9.33 (1H, d,
J = 7.2 Hz, H10 of bq), 8.55 (1H, d, J = 7.8 Hz, H4 of bq),
8.08-8.02 (3H, m, H3, H5/H6, H7 of bq), 7.98-7.93 (3H, m,
H3 of bq, H5 and H5¤), 7.86 (1H, dd, J = 7.2, 2.0 Hz, H4), 7.74
(1H, d, J = 8.5 Hz, H4¤), 7.73 (1H, d, J = 9.6 Hz, H6/H5 of
bq), 7.70 (1H, t, J = 7.2 Hz, H9 of bq), 7.67 (1H, t, J = 7.2 Hz,
H8 of bq), 7.62 (1H, d, J = 8.4 Hz, H3¤), 7.49 (1H, d, J = 0.8
Hz, H1¤), 7.43 (2H, overlapped t, J = 7.6 Hz, H6 and H6¤), 7.39

676
Bull. Chem. Soc. Jpn. Vol. 83, No. 6 (2010)
2,2¤-Di(heteroaryl)-9,9¤-spirobifluorene
(1H, d, J = 0.8 Hz, H1), 7.20 (1H, td, J = 7.6, 1.0 Hz, H7),
7.15 (1H, td, J = 7.6, 1.0 Hz, H7¤), 6.83 (1H, d, J = 7.6 Hz,
H8), 6.72 (1H, d, J = 7.6 Hz, H8¤), 2.44 (3H, s). 13C NMR
(62.5 MHz, CDCl3): ¤ 197.62, 155.23, 149.94, 148.97, 148.55,
148.26, 146.66, 146.08, 143.05, 141.32, 140.38, 139.68,
136.71, 136.31, 133.78, 131.57, 129.26, 128.82, 128.25,
128.09 (two carbons), 128.07 (two carbons), 127.73, 127.38,
126.82, 125.01, 124.97, 124.55, 124.40, 124.20, 123.93,
122.71, 121.02, 120.71, 120.58, 120.01, 119.06, 66.24,
29.69. MS (ESI): m/z = 536 [M + H]+. Anal. Calcd for
C40H25NO (535.6): C, 89.69; H, 4.70; N, 2.61%. Found: C,
89.71; H, 4.69; N, 2.60%.
8.63 (1H, dd, J = 8.4, 1.8 Hz), 8.57 (1H, d, J = 8.6 Hz), 8.16
(1H, d, J = 8.4 Hz), 8.11 (1H, d, J = 8.4 Hz), 8.09 (1H, d,
J = 8.4 Hz), 8.05 (1H, d, J = 8.0 Hz), 8.02 (1H, d, J = 8.0 Hz),
8.00 (1H, d, J = 8.4 Hz), 7.98 (1H, d, J = 8.4 Hz), 7.89 (1H, d,
J = 8.4 Hz), 7.85 (1H, td, J = 8.4, 1.2 Hz), 7.84 (1H, d, J =
8.4 Hz), 7.78 (1H, d, J = 8.4 Hz), 7.77 (1H, d, J = 9.0 Hz),
7.71 (1H, td, J = 8.4, 1.2 Hz), 7.70 (1H, d, J = 8.4 Hz), 7.65
(1H, td, J = 8.4, 1.2 Hz), 7.63 (1H, t, J = 8.4 Hz), 7.61-7.58
(4H, m), 7.43 (2H, overlapped td, J = 8.4, 1.2 Hz), 7.16 (1H, t,
J = 8.4 Hz), 7.15 (1H, t, J = 8.4 Hz), 6.83 (1H, d, J = 8.4 Hz),
6.82 (1H, d, J = 8.4 Hz). 13C NMR (62.5 MHz, CDCl3): ¤
157.21, 155.35, 149.50, 149.48, 149.06, 148.92, 148.36,
147.04, 146.56, 146.09, 143.23, 143.15, 141.35, 141.33,
139.79, 139.67, 136.53, 136.28, 135.70, 133.78, 131.68,
131.06, 129.94, 128.86, 128.26, 128.22, 128.02 (two carbons),
127.95, 127.88 (two carbons), 127.67, 127.54, 127.33, 127.24,
127.05, 126.81, 126.73, 126.63, 125.74, 125.02 (two carbons),
124.70, 124.25, 124.16, 123.32, 123.00, 121.41, 120.71,
120.59, 120.52, 120.41, 119.18, 66.28. MS (ESI): m/z = 722
[M + H]+. Anal. Calcd for C54H31N3 (721.8): C, 89.85; H,
4.33; N, 5.82%. Found: C, 89.78; H, 4.32; N, 5.84%.
2-(Benzo[h]quinolin-2-yl)-2¤-(1,10-phenanthrolin-2-yl)-
9,9¤-spirobifluorene (4f). The more polar compound (19%)
(Rf = 0.25, CH2Cl2): Yellow crystalline solid, mp > 300 °C.
1H NMR (600 MHz, CDCl3): ¤ 9.38 (1H, d, J = 8.1 Hz), 9.19
(1H, br s), 8.70-8.65 (1H, m), 8.62 (1H, dd, J = 8.4, 1.8 Hz),
8.23 (1H, d, J = 7.8 Hz), 8.14 (1H, d, J = 8.4 Hz), 8.12 (1H, d,
J = 8.4 Hz), 8.10 (1H, d, J = 8.4 Hz), 8.07 (1H, d, J = 8.4 Hz),
7.98 (1H, dd, J = 7.2, 1.2 Hz), 7.97 (1H, d, J = 7.2 Hz), 7.88
(1H, d, J = 8.4 Hz), 7.86 (1H, dd, J = 7.8, 1.3 Hz), 7.78 (1H, d,
J = 9.0 Hz), 7.74-7.70 (4H, m), 7.66 (1H, td, J = 7.8, 1.8 Hz),
7.62 (2H, d, J = 9.0 Hz), 7.56 (1H, d, J = 1.2 Hz, H1/H1¤),
7.53 (1H, d, J = 1.2 Hz, H1¤/H1), 7.42 (2H, td, J = 7.2, 1.0
Hz), 7.16 (1H, td, J = 7.2, 1.0 Hz), 7.15 (1H, d, J = 7.2 Hz),
6.81 (2H, td, J = 7.2, 1.0 Hz). MS (ESI): m/z = 672 [M +
H]+. Anal. Calcd for C50H29N3 (671.8): C, 89.39; H, 4.35; N,
6.26%. Found: C, 89.42; H, 4.33; N, 6.25%. The less polar
compound (76%) (Rf = 0.28, CH2Cl2): Yellow crystalline
2-(Benzo[b]-1,10-phenanthrolin-2-yl)-2¤-(1,10-phenanthro-
lin-2-yl)-9,9¤-spirobifluorene (4h).
Pale yellow needles
[Rf = 0.4 (CH2Cl2:CH3OH = 97:3), Rf values of 4d and 4e are
0.1 and 0.7, respectively], mp 235 °C. 1H NMR (600 MHz,
CDCl3): ¤ 9.17 (1H, dd, J = 4.8, 1.8 Hz, H9 of phen), 8.70
(1H, dd, J = 8.4, 1.8 Hz, H11 of bphen), 8.68 (1H, s, H7 of
bphen), 8.66 (1H, dd, J = 8.4, 1.8 Hz, H4 of bphen), 8.57 (1H,
d, J = 8.5 Hz, H4 of phen), 8.18 (1H, dd, J = 8.0, 1.8 Hz, H7
of phen), 8.14 (1H, d, J = 8.4 Hz, H3 of bphen), 8.115 (1H, d,
J = 8.4 Hz), 8.110 (1H, d, J = 8.4 Hz), 8.087 (1H, d, J = 8.4
Hz), 8.02 (1H, dd, J = 8.4, 0.6 Hz), 7.98 (1H, d, J = 8.4 Hz),
7.97 (1H, d, J = 8.4 Hz), 7.88 (1H, d, J = 8.4 Hz), 7.852 (1H,
td, J = 8.4, 1.8 Hz), 7.847 (1H, d, J = 8.4 Hz), 7.76 (1H, d,
J = 9.0 Hz), 7.68 (2H, AB quartet), 7.62 (1H, td, J = 8.4,
1.2 Hz), 7.59 (1H, d, J = 8.4 Hz), 7.58 (1H, d, J = 8.4, 4.2 Hz),
7.56 (1H, d, J = 1.8 Hz), 7.52 (1H, d, J = 1.8 Hz), 7.42 (1H,
td, J = 8.4, 0.6 Hz, H6/H6¤), 7.41 (1H, td, J = 8.4, 0.6 Hz,
H6¤/H6), 7.16 (1H, td, J = 8.4, 1.2 Hz, H7/H7¤), 7.15 (1H, td,
J = 8.4, 1.2 Hz, H7¤/H7), 6.81 (2H, d, J = 8.3 Hz, H8 and
H8¤). 13C NMR (62.5 MHz, CDCl3): ¤ 157.82, 157.48, 150.44
(two carbons), 149.75, 149.74, 149.17, 149.05, 148.59, 147.30,
146.77, 146.48, 146.13, 143.49, 143.46, 141.58, 141.57,
136.80 (two carbons), 136.28, 135.93, 131.28, 130.19,
129.20, 129.16, 126.09, 128.48 (two carbons), 128.26,
128.09 (two carbons), 127.78, 127.62, 127.56, 127.29,
126.96, 126.82, 126.57 (two carbons), 126.24, 126.01,
124.43, 124.41, 123.60, 123.56, 123.03, 121.70, 121.33,
120.95, 120.93, 120.73 (two carbons), 66.50. MS (ESI):
m/z = 723 [M + H]+. Anal. Calcd for C53H30N4 (722.8): C,
88.07; H, 4.18; N, 7.75%. Found: C, 88.14; H, 4.16; N, 7.68%.
1
solid, mp > 300 °C. H NMR (600 MHz, CDCl3): ¤ 9.35 (1H,
d, J = 7.8 Hz, H10 of bq), 9.15 (1H, d, J = 4.2 Hz, H9 of
phen), 8.64 (1H, dd, J = 7.8, 1.5 Hz, H4 of bq), 8.61 (1H, dd,
J = 7.2, 1.5 Hz, H4 of phen), 8.21 (1H, dd, J = 8.1, 2.0 Hz, H7
of phen), 8.14 (1H, d, J = 8.1 Hz, H7 of bq), 8.12 (1H, d,
J = 8.1 Hz, H3 of bq), 8.10 (1H, d, J = 8.4 Hz, H3 of phen),
8.07 (1H, d, J = 8.4 Hz, H5/H6 of bq), 7.98 (1H, d, J =
7.5 Hz, H5/H5¤), 7.97 (1H, d, J = 7.5 Hz, H5¤/H5), 7.88 (1H,
d, J = 9.0 Hz, H5/H6 of bq), 7.87 (1H, t, J = 8.4 Hz, H8 of
bq), 7.78 (1H, d, J = 8.4 Hz, H6/H5 of phen), 7.72-7.70 (4H,
m, H9 of bq, H4, H3¤, H4¤), 7.66 (1H, td, J = 8.1, 0.6 Hz, H8 of
bq), 7.61 (1H, d, J = 9.0 Hz, H6/H5 of phen), 7.60 (1H, dd,
J = 7.5, 4.2 Hz, H3 of phen), 7.54 (1H, d, J = 1.3 Hz, H1/H1¤),
7.51 (1H, d, J = 1.3 Hz, H1¤/H1), 7.42 (2H, td, J = 7.5, 1.5 Hz,
H6 and H6¤), 7.16 (1H, td, J = 7.2, 1.2 Hz, H7/H7¤), 7.15 (1H,
td, J = 7.2, 1.2 Hz, H7¤/H7), 6.81 (2H, dd, J = 7.5, 1.8 Hz, H8
and H8¤). 13C NMR (62.5 MHz, CDCl3): ¤ 157.56, 155.30,
150.13, 149.45, 149.41, 149.01, 148.73, 146.04, 145.76,
143.23, 143.10, 141.29, 141.25, 139.71, 139.63, 136.55,
136.29, 136.19, 133.75, 131.63, 128.97, 128.95, 128.25,
128.20, 128.02, 127.93, 127.86 (three carbons), 127.67,
127.37, 127.24, 126.81, 126.35, 126.01, 125.02, 125.00,
124.62, 124.24, 124.11, 123.24, 122.96, 122.81, 121.11,
120.74, 120.59, 120.52, 120.40, 119.18, 66.21. MS (ESI):
m/z = 672 [M + H+]. Anal. Calcd for C50H29N3 (671.8): C,
89.39; H, 4.35; N, 6.26%. Found: C, 89.40; H, 4.32; N, 6.28%.
2-(Benzo[h]quinolin-2-yl)-2¤-(benzo[b]-1,10-phenanthro-
lin-2-yl)-9,9¤-spirobifluorene (4g). Pale yellow crystalline
solid, mp 244 °C. 1H NMR (600 MHz, CDCl3): ¤ 9.38 (1H, dd,
J = 8.0, 1.8 Hz), 8.71 (1H, dd, J = 8.0, 1.8 Hz), 8.69 (1H, s),
Financial support form Korean Research Foundation Grant
(KRF-2008-521-E00189) is gratefully acknowledged.
Supporting Information
1H NMR spectra of the two diastereomers of 4f are available.
This material is available free of charge on the web at http://
www.csj.jp/journals/bcsj/.

Y. Jahng et al.
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