Chirality induction of π-conjugated chains through chiral complexation

Article abstract of DOI:10.1016/j.tet.2006.10.016

Chirality induction of π-conjugated polyanilines through chiral complexation with the chiral palladium(II) complexes was demonstrated to afford the chiral conjugated polymer complexes. Complexation of the emeraldine base of poly(o-toluidine) (POT) with th

Full text of DOI:10.1016/j.tet.2006.10.016

Tetrahedron 62 (2006) 12237–12246
Chirality induction of p-conjugated chains
through chiral complexation
*
Toshiyuki Moriuchi, Xiuliang Shen and Toshikazu Hirao
Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Yamada-oka, Suita, Osaka 565-0871, Japan
Received 5 August 2006; revised 5 October 2006; accepted 6 October 2006
Available online 30 October 2006
Abstract—Chirality induction of p-conjugated polyanilines through chiral complexation with the chiral palladium(II) complexes was
demonstrated to afford the chiral conjugated polymer complexes. Complexation of the emeraldine base of poly(o-toluidine) (POT) with
the chiral palladium(II) complex bearing one labile coordination site led to the formation of the chiral conjugated polymer complex, which
exhibited an induced circular dichroism (ICD) based on the chirality induction into a p-conjugated backbone. The mirror image of the CD
signal was observed with the chiral conjugated polymer complex, which was obtained from the chiral palladium(II) complex possessing the
opposite configuration. The chirality of the podand ligand moieties of the palladium complex is considered to induce a propeller twist of the
p-conjugated molecular backbone. The crystal structure of the chiral conjugated complex of N-bis(40-dimethylaminophenyl)-1,4-benzo-
quinonediimine (L3) as a model compound of the polyaniline revealed a chiral propeller twist conformation of the p-conjugated backbone.
Furthermore, chiral complexation with the cationic palladium(II) complexes provided the ionic chiral conjugated complexes.
Ó 2006 Elsevier Ltd. All rights reserved.
1. Introduction
The polymer complex can effectively serve as an oxidation
catalyst.7a,b,d Furthermore, we have already demonstrated
that the controlled complexation of polyanilines with palla-
dium(II) compounds by changing the coordination mode
is achieved to afford the single-strand or cross-linked net-
work conjugated complexes, in which the quinonediimine
moieties serve as bridging coordination sites.7f Also, con-
trolled complexation with the redox-active quinonediimine
derivative has been achieved to afford the conjugated poly-
meric complex, the conjugated trimetallic macrocycle, or
the conjugated bimetallic complex, depending on the coordi-
nation mode.7g,h,8 The introduction of chiral complexes
is considered to be a strategy to induce chirality into a
p-conjugated backbone of polyanilines, giving the chiral
conjugated complexes.7h We herein describe a full scope
of chirality induction of polyaniline derivatives through
complexation with chiral palladium(II) compounds.
p-Conjugated polymers have received extensive interest
because of the potential application to electronic materials
depending on their electrical properties.1 Much progress has
been made in understanding the chemistry and physics of
the p-conjugated polymers. One of the most important
p-conjugated polymers, polyaniline, is redox-active and ex-
ists in various redox states from leucoemeraldine in a high
reduction state to pernigraniline in a high oxidation state.
The redox properties have been demonstrated to be con-
trolled by the introduction of an acceptor unit.2 The struc-
tural and chiral control is to be investigated for further
functionalization. Chiral polyaniline has been focused on
due to their potential applications in molecular recognition
and chiral separation.3 Chiral polyaniline and its derivatives
were synthesized only by doping with a chiral acid,4 poly-
merization of aniline in the presence of a chiral acid dopant,5
or template polymerization of aniline in the presence of a
chiral molecular template.6 Another interesting function of
polyanilines is coordination properties of two nitrogen atoms
of the quinonediimine moiety. In a previous paper, the emer-
aldine base form of polyanilines, which contains the quino-
nediimine unit, has been revealed to coordinate to transition
metals, affording the conjugated polymer complex systems.7
2. Results and discussion
Chiral palladium(II) complexes, ((S,S)-L1)Pd(MeCN)
((S,S)-1) and ((R,R)-L1)Pd(MeCN) ((R,R)-1), were designed
and prepared by the treatment of the N-heterocyclic tri-
dentate podand ligands, N,N0-bis[(S)-1-methoxycarbonyl-
2-phenylethyl]-2,6-pyridinedicarboxamide ((S,S)-L1H2) and
N,N0-bis[(R)-1-methoxycarbonyl-2-phenylethyl]-2,6-pyri-
dinedicarboxamide ((R,R)-L1H2), respectively, with
Pd(OAc)2 in acetonitrile as shown in Scheme 1. This similar
synthetic method was also used for the synthesis of chiral
Keywords: Polyaniline; Quinonediimine; Palladium complex; Chiral conju-
gated complex; Chirality induction.
* Corresponding author. Tel.: +81 6 6879 7413; fax: +81 6 6879 7415;
e-mail: hirao@chem.eng.osaka-u.ac.jp
0040–4020/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2006.10.016

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T. Moriuchi et al. / Tetrahedron 62 (2006) 12237–12246
O
O
O
O
O
O
N
N
N
R
N
N
NH
HN
*
R
R
Pd
Cl
Cl
R
R
Pd(OAc)2
*
*
*
*
CH2Cl2, Et3N, Ar
MeCN, rt, Ar
NH2
N
C
Me
R = COOMe, (S,S)-L1H2: 70%
(R,R)-L1H2: 67%
R = COOMe, (S,S)-1: 90%
(R,R)-1: 95%
R = CONHPh, (S,S)-L2H2: 60%
(R,R)-L2H2: 68%
R = CONHPh, (S,S)-2: 98%
(R,R)-2: 95%
Scheme 1.
palladium complexes, ((S,S)-L2)Pd(MeCN) ((S,S)-2) and
((R,R)-L2)Pd(MeCN) ((R,R)-2), bearing the amide moieties
instead of the ester ones. These palladium(II) complexes
have one interchangeable coordination site through ex-
change of acetonitrile. p-Conjugated polymers with poten-
tial metal-coordination sites are expected to coordinate to
the palladium center by displacement of this labile ligand.
p-conjugated backbone of POT is achieved by the chiral
complexation. A similar absorption spectrum was observed
in the case of the amide (S,S)-4 as shown in Figure 1.
To gain further insight into chirality induction, the chiral
complexation with a model unit of polyaniline, N,N0-bis(40-
dimethylaminophenyl)-1,4-benzoquinonediimine (L3),9 was
investigated. The complexation of L3 with 2 molar equiv
of (S,S)-1 or (R,R)-1 afforded the chiral conjugated 1:2 com-
plex, ((S,S)-L1)Pd(L3)Pd((S,S)-L1) ((S,S)-5) or ((R,R)-
L1)Pd(L3)Pd((R,R)-L1) ((R,R)-5), respectively (Scheme 3).
The chiral conjugated complexes, ((S,S)-L2)Pd(L3)Pd((S,S)-
L2) ((S,S)-6) and ((R,R)-L2)Pd(L3)Pd((R,R)-L2) ((R,R)-6),
were also prepared from (S,S)-2 or (R,R)-2, respectively, by
the same complexation route. The electronic spectra of
(S,S)-5 and (S,S)-6 in dichloromethane exhibited a broad
absorption at around 600–900 nm based on the similar chiral
complexation as mentioned above (Fig. 2).
Treatment of the emeraldine base form of poly(o-toluidine)
(POT)7g with the chiral palladium(II) complex (S,S)-1 or
(S,S)-2 in THF led to the formation of the conjugated poly-
mer complex, POT–((S,S)-L1Pd) ((S,S)-3) or POT–((S,S)-
L2Pd) (S,S)-4, respectively, as shown in Scheme 2. The
electronic spectrum of (S,S)-3 in THF exhibited broad
absorption at around 500–800 nm, which is probably due
to a low-energy charge-transfer transition with significant
contribution from palladium (Fig. 1). This result indicates
the coordination of the quinonediimine nitrogen atoms to
the palladium centers. It should be noted that the complex
(S,S)-3 exhibits an induced circular dichroism (ICD) at
around 500–800 nm. Furthermore, the mirror image of
the CD signal was observed with (R,R)-3, which was ob-
tained from the complexation of POT with (R,R)-1 (Fig. 1).
These findings suggest that the chirality induction of a
1
Variable temperature H NMR studies of the conjugated
complex (S,S)-5 indicated interesting molecular dynamics
in solution (Fig. 3). The protons of the quinonediimine
moiety of the syn-isomer at 233 K were observed at 9.14
and 7.14 ppm as singlet peaks, whereas the anti isomer
O
O
N
Me
Me
Me
Me
N
N
R
R
H
N
H
N
Pd
+
N
N
*
*
THF, rt, Ar
N
C
n
Me
R = COOMe, (S,S)-1 or (R,R)-1
R = CONHPh, (S,S)-2 or (R,R)-2
(Lx)Pd
Me
Me
Me
Me
O
O
N
H
N
H
N
N
N
N
N
R
R
Pd
(Lx)Pd
n
=
*
*
(Lx)Pd
R = COOMe, (S,S)-3 or (R,R)-3
R = CONHPh, (S,S)-4 or (R,R)-4
Scheme 2.

T. Moriuchi et al. / Tetrahedron 62 (2006) 12237–12246
12239
40
20
0
3.0
2.0
(S,S)-5
(S,S)-3
(S,S)-2
(S,S)-6
(R,R)-3
(S,S)-1
3
1.0
0.0
L
-20
-40
3.0
2.0
1.0
0.0
(S,S)-4
400
600
nm
800
1000
(S,S)-3
POT
Figure 2. UV–vis spectra of L3, (S,S)-1, (S,S)-2, (S,S)-5, and (S,S)-6 in
dichloromethane (5.0ꢂ10ꢀ5 M).
200
300
400
500
nm
600
700
800
Figure 1. CD spectra (top) of (S,S)-3 and (R,R)-3 in THF (1.3ꢂ10ꢀ3 M of
the monomer unit), and UV–vis spectra (bottom) of (S,S)-3, (S,S)-4, and
POT in THF (1.3ꢂ10ꢀ3 M of the monomer unit).
was observed between (S,S)-5 and (R,R)-5 as shown in Fig-
ure 5. The ICD at around 600–800 nm appears to be reflected
by the chirality of the palladium(II) complexes. Such ICD
was not observed in the case of 1. Similar chiral complexa-
tion was also observed in the case of the chiral complexes 6
(Fig. 6). These results indicate the chirality induction into
the quinonediimine moiety through the chiral complexation.
exhibited doublet peaks of those protons at 7.84 and
6.92 ppm. As the temperature was lowered, the peaks of
(S,S)-5syn increased gradually. The equilibrium constant
Keq between (S,S)-5syn and (S,S)-5anti was calculated
from variable temperature 1H NMR spectra shown in
Figure 3. The temperature dependence of Keq is used to
construct the van’t Hoff plot of ln Keq versus Tꢀ1 (Fig. 4).
The syn configuration is enthalpically more favorable than
the anti one in CD2Cl2 by 2.3 kcal molꢀ1, but entropically
Further structural information was obtained by the single-
crystal X-ray structure determination. The crystal structure
of (R,R)-5 indicates that the two (L1)Pd units are bridged
by the quinonediimine moiety of L3 to form the C2-symmet-
rical 2:1 complex (R,R)-5syn with the Pd–Pd separation
less favorable by 11.0 cal molꢀ1 Kꢀ1
.
3
˚
7.59 A, as depicted in Figure 7. Each phenylene ring of L
has an opposite dihedral angle of 47.3ꢁ with respect to the
quinonediimine plane, resulting in a propeller twist of 75.6ꢁ
between the planes of the two phenylene rings. Schematic
The mirror image relationship of the CD signals around the
CT band of the quinonediimine moiety in dichloromethane
O
O
N
N
N
R
R
Me
Me
Pd
Me
Me
*
*
N
N
N
N
2
+
N
CH2Cl2, rt, Ar
C
Me
L3
R = COOMe, (S,S)-1 or (R,R)-1
R = CONHPh, (S,S)-2 or (R,R)-2
Me
O
O
O
N
Me
N
N
N
O
R
R
O
R
O
R
R
R
N
N
N
Pd
Pd
Pd
*
*
*
N
*
N
*
N
R
*
N
N
N
N
*
N
Pd
*
N
O
R
N
Me
N
N
Me
Me
N
Me
O
Me
Me
Anti-isomer
Syn-isomer
R = COOMe, (S,S)-5 or (R,R)-5
R = CONHPh, (S,S)-6 or (R,R)-6
Scheme 3.

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T. Moriuchi et al. / Tetrahedron 62 (2006) 12237–12246
6.0
25 °C
(R,R)-1
4.0
(R,R)-5
2.0
0
0 °C
-2.0
-15 °C
(S,S)-5
-4.0
(S,S)-1
-6.0
200
300
400
500
nm
600
700
800
-30 °C
-45 °C
Figure 5. CD spectra of 1 (1.0ꢂ10ꢀ4 M) and 5 (5.0ꢂ10ꢀ5 M) in dichloro-
methane.
30
(S,S)-2
9.0
8.0
ppm
7.0
20
10
Figure 3. Variable temperature 1H NMR spectrum of (S,S)-5 in CD2Cl2.
(S,S)-6
0
-0.4
-10
(R,R)-6
-20
-0.6
-0.8
-1.0
-1.2
-1.4
(R,R)-2
-30
200
300
400
500
nm
600
700
800
Figure 6. CD spectra of 2 (4.0ꢂ10ꢀ5 M) and 6 (2.0 ꢂ 10ꢀ5 M) in dichloro-
methane.
complexes. In order to obtain further insight, the complexa-
tion with the cationic palladium complexes 710 possessing
weak Pd–N coordination bonds instead of Pd–N covalent
bonds in the complexes 1 and 2 was investigated (Fig. 9).
The cationic palladium complexes, ((S,S)-L4)Pd(MeCN)
((S,S)-7) and ((R,R)-L4)Pd(MeCN) ((R,R)-7), were prepared,
respectively, by the treatment of the N-heterocyclic tridentate
podand ligand, 2,6-bis[(S)-40-isopropyloxazolin-20-yl]-
pyridine ((S,S)-L4H2) and 2,6-bis[(R)-40-isopropyloxazolin-
20yl]pyridine ((R,R)-L4H2), with Pd(MeCN)4(BF4)2 in
acetonitrile (Scheme 4).
1/T
Figure 4. Plot of ln Keq versus Tꢀ1 for (S,S)-5 in CD2Cl2.
representation of the crystal structure of (R,R)-5syn is shown
in Figure 8. The chirality of the podand moieties of (L1)Pd
is considered to induce a propeller twist in the p-conjugated
chain. Similar complexation behavior is considered to be the
case with the polymer complexation. Therefore, the random
twist conformation of POT might be transformed into the
helical conformation with a predominant screw sense
through the chiral complexation. Furthermore, these find-
ings strongly indicate that the chiral structure of quinonedi-
imines is controlled by chiral complexation.
The complexation of L3 with 2 molar equiv of (S,S)-7
or (R,R)-7 led to the formation of the chiral conjugated
1:2 complex, ((S,S)-L4)Pd(L3)Pd((S,S)-L4) ((S,S)-8) or
((R,R)-L4)Pd(L3)Pd((R,R)-L4) ((R,R)-8), respectively, as
shown in Scheme 5. The complexes 8 are more stable in
the coordination solvent, acetonitrile. In the 1H NMR spec-
trum of the conjugated complex (S,S)-8, two sets of peaks
based on syn and anti isomers were observed at 298 K
in CD3CN. The electronic spectra of 8 in acetonitrile ex-
hibited a broad absorption at around 600–900 nm (Fig. 10),
probably due to the chiral complexation of the quinonedi-
imine moiety as observed in the conjugated complexes 5
and 6.
Chirality induction was realized by the complexation of
polyanilines and oligoanilines with the chiral palladium

T. Moriuchi et al. / Tetrahedron 62 (2006) 12237–12246
12241
Figure 7. (a) Top view and (b) side view of the X-ray crystal structure of (R,R)-5syn (hydrogen atoms are omitted for clarity).
O
O
O
O
OMe MeO
N
N
101.6°
O
O
N
N
P
d
Pd
Pd
N
N
O
O
N
MeO
97.9°
N
N
OMe
N
N
+47.3°
–47.3°
N
Me
N
N Me
75.6°
Me
Me
Figure 8. Schematic representation of (R,R)-5syn.
3. Conclusion
2+
O
O
O
O
N
N
Chirality induction of a p-conjugated backbone of the
emeraldine base of poly(o-toluidine) and the quinonedi-
imine derivative through chiral complexation with the chiral
palladium(II) complexes bearing one interchangeable co-
ordination site was achieved to afford the chiral conjugated
complexes. The crystal structure of the chiral conjugated
complex 5 with the quinonediimine derivative revealed a
chiral propeller twist conformation of the p-conjugated moi-
ety. The chirality of the podand ligand is considered to reg-
ulate a propeller twist of the p-conjugated backbone. Our
strategy for chirality induction through chiral complexation
provides an efficient and feasible route to chiral d,p-conju-
gated complexes, in which the introduced metals are envi-
sioned to play an important role as a metallic dopant and
interact with each other through p-conjugation. These chiral
conjugated complexes are considered to be potent as
promising functionalized materials and asymmetric redox
catalysts.
R
N
N
R
N
N
Pd
Pd
*
*
*
*
Ph
Ph
2BF4
( N
N
N
)
( N
N
7
N )
1, 2
Figure 9. Structure of palladium(II) complexes 1, 2, and cationic palla-
dium(II) complex 7.
The CD spectra of (S,S)-8 and (R,R)-8 exhibited ICD at
around 600–800 nm based on the CT band of the quinonedi-
imine moiety, and these are in a good mirror image relation-
ship (Fig. 11). Such ICD was not observed in the case of 7.
These findings indicate the similar complexation behavior as
observed with the chiral conjugated complexes 5 and 6.
2+
Pd(MeCN)4(BF4)2
O
O
O
O
(1 equiv)
N
N
N
N
MeCN, Ar, rt, 5 h
N
N
Pd
4. Experimental
*
*
*
*
N
C
–
2BF4
4.1. General comments
(S,S)-L4 or (R,R)-L4
Me
(S,S)-7 or (R,R)-7
All reagents and solvents were purchased from commercial
sources and were further purified with the standard methods,
Scheme 4.

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T. Moriuchi et al. / Tetrahedron 62 (2006) 12237–12246
2+
O
O
N
Me
Me
Me
Me
N
N
+
N
N
N
N
2
Pd
MeCN, r.t.
*
*
N
C
L3
2BF4
Me
(S,S)-7 or (R,R)-7
4+
4+
Me
O
O
N
O
N
N Me
N
N
N
N
*
O
*
O
O
*
Pd
N
Pd
Pd
N
*
N
*
N
*
N
N
N
*
4BF4
4BF4
N
Pd
O
*
N
O
N
N Me
Me
Me
N
Me
N
Me
Me
Syn-isomer
Anti-isomer
(S,S)-8 or (R,R)-8
Scheme 5.
2.0
(R,R)-7
10
0
(R,R)-8
1.0
0.0
(S,S)-7
(S,S)-8
L3
(S,S)-8
-10
(S,S)-7
200
300
400
500
nm
600
700
800
200
400
600
nm
800
1000
Figure 11. CD spectra of 7 (8.0ꢂ10ꢀ5 M) and 8 (4.0ꢂ10ꢀ5 M) in MeCN.
Figure 10. UV–vis spectra of L3 (4.0ꢂ10ꢀ5 M), (S,S)-7 (4.0ꢂ10ꢀ5 M), and
(S,S)-8 (4.0ꢂ10ꢀ5 M) in MeCN.
4.3. Synthesis of 1
if necessary. Melting points were determined on a Yanagi-
moto Micromelting Point Apparatus and were uncorrected.
Infrared spectra were obtained with a JASCO FT/IR-
480plus. 1H and 13C NMR spectra were recorded on a
JEOL JNM-GSX-400 spectrometer (400 and 100 MHz,
respectively). Mass spectra were run on a JEOL JMS-700
mass spectrometer. Electronic spectra were obtained by
using a Hitachi U-3500 spectrophotometer. CD spectra
were recorded using JASCO J-720 and J-725 spectro-
polarimeters.
To a stirred mixture of phenylalanine methyl ester hydro-
chloride (129.4 mg, 0.6 mmol) and triethylamine (0.21 mL,
1.5 mmol) was added drop-wise 2,6-pyridyldicarbonyl
dichloride (61.2 mg, 0.3 mmol) in dichloromethane (8 mL)
under argon at 0 ꢁC for 7 h and then at room temperature
for 18 h. The resulting mixture was diluted with dichloro-
methane, washed with saturated NaHCO3 aqueous solution
and brine, and then dried over Na2SO4. The solvent was
evaporated in vacuo. The chiral ligands, N,N0-bis[(S)-1-
methoxycarbonyl-2-phenylethyl]-2,6-pyridinedicarboxamide
((S,S)-L1H2) and N,N0-bis[(R)-1-methoxycarbonyl-2-phenyl-
ethyl]-2,6-pyridinedicarboxamide ((R,R)-L1H2), were iso-
lated by recrystallization from acetonitrile.
4.2. Synthesis of poly(o-toluidine)
Poly(o-toluidine) was prepared according to our previous
procedure.7g The molecular weight of poly(o-toluidine)
was estimated to be 4191 as determined by gel permeation
chromatography (GPC) (polystyrene standard with THF as
an eluent). Elemental analysis (C7.00H6.75N1.00) indicated
the emeraldine base structure consisting of the amine and
imine moieties at ca. 1:1 ratio.
4.3.1. (S,S)-L1H2. Yield 70%; mp 124–126 ꢁC (uncor-
rected); IR (KBr, cmꢀ1): 3335, 1754, 1679, 1656, 1548,
1516; 1H NMR (400 MHz, CD3CN, 298 K): d 8.36 (d, 2H,
J¼8.4 Hz, HNH), 8.19 (d, 2H, J¼7.6 Hz, Hpy), 8.03 (t, 1H,
J¼7.6 Hz, Hpy), 7.29–7.18 (m, 10H, Hph), 4.95–4.89 (m,

T. Moriuchi et al. / Tetrahedron 62 (2006) 12237–12246
12243
1
2H, Hethyl), 3.72 (s, 6H, HOMe), 3.34 (dd, 2H, J¼14.0,
5.6 Hz, Hethyl), 3.19 (dd, 2H, J¼14.0, 8.8 Hz, Hethyl); MS
(EI): m/z¼489 (M+). Anal. Calcd for C27H27N3O6: C,
66.25; H, 5.56; N, 8.58. Found: C, 66.37; H, 5.41; N, 8.55.
1559, 1539; H NMR (400 MHz, CDCl3, 298 K): d 8.55
(d, 2H, J¼7.7 Hz, HNH), 8.32 (d, 2H, J¼7.7 Hz, Hpy), 8.01
(t, 1H, J¼7.7 Hz, Hpy), 7.89 (br s, 2H, HNH), 7.42 (d, 4H,
J¼8.0 Hz, Hph), 7.35–7.26 (m, 12H, ph), 7.23 (t, 2H,
J¼7.3 Hz, Hph), 7.10 (t, 2H, J¼7.7 Hz, Hph), 4.96 (dd,
2H, J¼7.7, 7.5 Hz, Hethyl), 3.40–3.31 (m, 4H, Hethyl); MS
(EI): m/z¼611 (M+). Anal. Calcd for C37H33N5O4:
C, 72.65; H, 5.44; N, 11.45. Found: C, 72.37; H, 5.41;
N, 11.35.
4.3.2. (R,R)-L1H2. Yield 67%; mp 124–126 ꢁC (uncor-
rected); IR (KBr, cmꢀ1): 3335, 1754, 1679, 1656, 1548,
1516; H NMR (400 MHz, CD3CN, 298 K): d 8.36 (d, 2H,
1
J¼8.4 Hz, HNH), 8.19 (d, 2H, J¼7.6 Hz, Hpy), 8.03 (t, 1H,
J¼7.6 Hz, Hpy), 7.29–7.18 (m, 10H, Hph), 4.95–4.89 (m,
2H, Hethyl), 3.72 (s, 6H, HOMe), 3.34 (dd, 2H, J¼14.0,
5.6 Hz, Hethyl), 3.19 (dd, 2H, J¼14.0, 8.8 Hz, Hethyl);
MS (EI): m/z¼489 (M+). Anal. Calcd for C27H27N3O6:
C, 66.25; H, 5.56; N, 8.58. Found: C, 66.42; H, 5.29; N,
8.43.
4.4.2. (R,R)-L2H2. Yield 68%; mp 250–252 ꢁC (uncor-
rected); IR (KBr, cmꢀ1): 3292, 1695, 1675, 1646, 1599,
1559, 1539; H NMR (400 MHz, CDCl3, 298 K): d 8.55
1
(d, 2H, J¼7.7 Hz, HNH), 8.32 (d, 2H, J¼7.7 Hz, Hpy), 8.01
(t, 1H, J¼7.7 Hz, Hpy), 7.89 (br s, 2H, HNH), 7.42 (d,
4H, J¼8.0 Hz, Hph), 7.35–7.26 (m, 12H, ph), 7.23 (t, 2H,
J¼7.3 Hz, Hph), 7.10 (t, 2H, J¼7.7 Hz, Hph), 4.96 (dd, 2H,
J¼7.7, 7.5 Hz, Hethyl), 3.40–3.31 (m, 4H, Hethyl); MS (EI):
m/z¼611 (M+). Anal. Calcd for C37H33N5O4: C, 72.65; H,
5.44; N, 11.45. Found: C, 72.26; H, 5.51; N, 11.34.
A
mixture of (S,S)-L1H2 or (R,R)-L1H2 (24.5 mg,
0.05 mmol) and Pd(OAc)2 (11.2 mg, 0.05 mmol) in aceto-
nitrile (5.0 mL) was stirred under argon at room temperature
for 2 h. After evaporation of the solvent, the palladium com-
plex (S,S)-1 or (R,R)-1 was isolated as yellow crystal by
recrystallization from benzene and hexane.
A
mixture of (S,S)-L2H2 or (R,R)-L2H2 (30.6 mg,
0.05 mmol) and Pd(OAc)2 (11.2 mg, 0.05 mmol) in aceto-
nitrile (5.0 mL) was stirred under argon at room temperature
for 2 h. After evaporation of the solvent, the palladium com-
plex (S,S)-2 or (R,R)-2 was isolated as yellow crystal by
recrystallization from benzene and hexane.
4.3.3. (S,S)-1. Yield 90%; mp 200–201 ꢁC (decomp.); IR
1
(KBr, cmꢀ1): 1730, 1594; H NMR (400 MHz, CD3CN,
298 K): d 8.07 (t, 1H, J¼8.0 Hz, Hpy), 7.53 (d, 2H,
J¼8.0 Hz, Hpy), 7.34 (d, 4H, J¼8.1 Hz, Hph), 7.26 (dd,
4H, J¼8.1, 7.5 Hz, Hph), 7.16 (t, 2H, J¼7.5 Hz, Hph), 4.70
(dd, 2H, J¼10.0, 4.2 Hz, Hethyl), 3.69 (s, 6H, HOMe), 3.27
(dd, 2H, J¼13.6, 4.2 Hz, Hethyl), 2.85 (dd, 2H, J¼13.6,
10.0 Hz, Hethyl); MS (FAB): m/z¼594 ((MꢀMeCN)++1).
Anal. Calcd for C29H28N4O6Pd: C, 54.85; H, 4.44; N,
8.82. Found: C, 54.85; H, 4.21; N, 8.60.
4.4.3. (S,S)-2. Yield 98%; mp 202–203 ꢁC (decomp.); IR
(KBr, cmꢀ1): 3280, 1596, 1495; 1H NMR (400 MHz,
CD3CN, 298 K): d 9.07 (s, 2H, HNH), 7.73 (dd, 4H, J¼7.7,
1.0 Hz, Hph), 7.53 (t, 1H, J¼7.7 Hz, Hpy), 7.36–7.30 (m,
8H, Hph and Hph), 7.23 (d, 2H, J¼7.7 Hz, Hpy), 7.10 (t,
6H, J¼7.3 Hz, Hph and Hph), 7.02 (t, 2H, J¼7.3 Hz, Hph),
5.18 (dd, 2H, J¼9.9, 4.4 Hz, Hethyl), 3.42 (dd, 2H, J¼14.1,
4.4 Hz, Hethyl), 2.68 (dd, 2H, J¼14.1, 9.9 Hz, Hethyl); MS
(FAB): m/z¼716 ((MꢀMeCN)++1). Anal. Calcd for
C39H34N6O4Pd: C, 61.87; H, 4.53; N, 11.10. Found: C,
61.77; H, 4.52; N, 11.09.
4.3.4. (R,R)-1. Yield 95%; mp 200–201 ꢁC (decomp.); IR
1
(KBr, cmꢀ1): 1730, 1594; H NMR (400 MHz, CD3CN,
298 K): d 8.07 (t, 1H, J¼8.0 Hz, Hpy), 7.53 (d, 2H,
J¼8.0 Hz, Hpy), 7.34 (d, 4H, J¼8.1 Hz, Hph), 7.26 (dd,
4H, J¼8.1, 7.5 Hz, Hph), 7.16 (t, 2H, J¼7.5 Hz, Hph), 4.70
(dd, 2H, J¼10.0, 4.2 Hz, Hethyl), 3.69 (s, 6H, HOMe), 3.27
(dd, 2H, J¼13.6, 4.2 Hz, Hethyl), 2.85 (dd, 2H, J¼13.6,
10.0 Hz, Hethyl); MS (FAB): m/z¼594 ((MꢀMeCN)++1).
Anal. Calcd for C29H28N4O6Pd: C, 54.85; H, 4.44; N,
8.82. Found: C, 54.79; H, 4.11; N, 8.56.
4.4.4. (R,R)-2. Yield 95%; mp 202–203 ꢁC (decomp.); IR
(KBr, cmꢀ1): 3280, 1596, 1495; 1H NMR (400 MHz,
CD3CN, 298 K): d 9.07 (s, 2H, HNH), 7.73 (dd, 4H, J¼7.7,
1.0 Hz, Hph), 7.53 (t, 1H, J¼7.7 Hz, Hpy), 7.36–7.30 (m,
8H, Hph and Hph), 7.23 (d, 2H, J¼7.7 Hz, Hpy), 7.10 (t,
6H, J¼7.3 Hz, Hph and Hph), 7.02 (t, 2H, J¼7.3 Hz, Hph),
5.18 (dd, 2H, J¼9.9, 4.4 Hz, Hethyl), 3.42 (dd, 2H, J¼14.1,
4.4 Hz, Hethyl), 2.68 (dd, 2H, J¼14.1, 9.9 Hz, Hethyl); MS
(FAB): m/z¼716 ((MꢀMeCN)++1). Anal. Calcd for
C39H34N6O4Pd: C, 61.87; H, 4.53; N, 11.10. Found: C,
61.80; H, 4.50; N, 10.88.
4.4. Synthesis of 2
To a stirred mixture of phenylalanine–phenylamide hydro-
chloride (144.2 mg, 0.6 mmol) and triethylamine (0.42 mL,
1.5 mmol) was added drop-wise 2,6-pyridyldicarbonyl
dichloride (61.2 mg, 0.3 mmol) in dichloromethane (8 mL)
under argon at 0 ꢁC for 7 h and then at room temperature
for 18 h. The resulting mixture was diluted with dichloro-
methane, washed with saturated NaHCO3 aqueous solution
and brine, and then dried over Na2SO4. The solvent was
evaporated in vacuo. The chiral ligands, N,N0bis[(S)-1-
phenylcarbamoyl-2-phenylethyl]-2,6-pyridinedicarboxamide
((S,S)-L2H2) and N,N0-bis[(R)-1-phenylcarbamoyl-2-phenyl-
ethyl]-2,6-pyridinedicarboxamide ((R,R)-L2H2), were iso-
lated by recrystallization from acetonitrile.
4.5. Synthesis of 3
To POT (2.73 mg, 26 mmol) in THF solution (20 mL) was
added 1 (0.5 molar equiv to the monomer unit of POT,
8.25 mg, 13 mmol) in THF solution. The mixture was stirred
at room temperature for 30 min and filtered through a
membrane under argon. The electronic and CD spectra of
the filtrate 3 in THF were measured. The electronic and
CD spectra were measured in a 0.10 cm quartz cell at
room temperature with 1.3ꢂ10ꢀ3 M concentration of the
monomer unit of POT under argon.
4.4.1. (S,S)-L2H2. Yield 60%; mp 250–252 ꢁC (uncor-
rected); IR (KBr, cmꢀ1): 3292, 1695, 1675, 1646, 1599,

12244
T. Moriuchi et al. / Tetrahedron 62 (2006) 12237–12246
4.6. Synthesis of 4
4.8. Equilibrium measurement of 5
To POT (2.73 mg, 26 mmol) in THF solution (20 mL) was
added 2 (0.5 molar equiv to the monomer unit of POT,
9.84 mg, 13 mmol) in THF solution. The mixture was stirred
at room temperature for 30 min and filtered through a
membrane under argon. The electronic spectrum of the
filtrate 4 in THF was measured. The electronic spectrum
was measured in a 0.10 cm quartz cell at room temperature
with 1.3ꢂ10ꢀ3 M concentration of the monomer unit of
POT under argon.
Measurement of the equilibrium constants at various tem-
peratures was carried out by the integration of the appropri-
ate peaks during 1H NMR spectroscopy. Spectra were taken
in CD2Cl2 from 228 to 298 K. The thermodynamic para-
meters were determined from the van’t Hoff plot of ln Keq
versus Tꢀ1
.
4.9. X-ray structure analysis of (R,R)-5syn
All measurements for (R,R)-5 were made on a Rigaku
RAXIS-RAPID Imaging Plate diffractometer with graphite
monochromated Mo Ka radiation. The structure of (R,R)-5
was solved by heavy-atom Patterson Methods and expanded
by using Fourier techniques. The non-hydrogen atoms were
refined anisotropically. The final cycle of full-matrix least-
squares refinement was based on 6478 observed reflections
(I>2s(I)) and 451 variable parameters.
4.7. Synthesis of 5
N,N0-Bis(40-dimethylaminophenyl)-1,4-benzoquinonediimine
(L3) was prepared according to the literature procedure.9 A
mixture of L3 (13.8 mg, 0.04 mmol) and (S,S)-1 or (R,R)-1
(50.8 mg, 0.08 mmol) was stirred in dichloromethane
(10 mL) under argon at room temperature for 4 h. After
evaporation of the solution, the chiral complex (S,S)-5 or
(R,R)-5 was isolated by recrystallization from chloroform
and ethyl ether.
4.9.1. Crystal data for (R,R)-5syn. C76H74O12N10Pd2,
Fw¼1532.28, monoclinic, space group C2 (#5), a¼
ꢁ
˚
33.1760(1), b¼15.3324(4), c¼18.1523 A, b¼155.9623(8) ,
3
4.7.1. (S,S)-5. Yield 90%; mp 180–181 ꢁC (decomp.); IR
(KBr, cmꢀ1): 1731, 1591, 1362, 1162; 1H NMR
(600 MHz, CD2Cl2, 233 K, syn:anti¼1:2): d 9.14 (s, 2H,
phenylenesyn), 8.09 (t, 2H, J¼7.2 Hz, pyanti), 8.08 (t, 2H,
J¼7.2 Hz), 7.84 (d, 2H, J¼9.6 Hz, phenyleneanti), 7.73–
7.69 (m, 8H, pysyn and pyanti), 7.26 (d, 4H, J¼9.3 Hz, phsyn),
7.18 (d, 4H, J¼9.3 Hz, phanti), 7.14 (s, 2H, phenylenesyn),
7.11–6.95 (m, 24H, phsyn and phanti), 6.92 (d, 2H, J¼9.6 Hz,
phenyleneanti), 6.86–6.83 (m, 8H, phsyn), 6.78–6.76 (m, 8H,
phanti), 6.56 (d, 4H, J¼9.3 Hz, phanti), 6.52 (d, 4H,
J¼9.3 Hz, phsyn), 3.52–3.48 (m, 2H, ethylenesyn), 3.40 (s,
6H, OMe), 3.38 (s, 6H, OMe), 3.33 (s, 6H, OMe), 3.32 (s,
6H, OMe), 3.24–3.20 (m, 4H, ethyleneanti), 3.15–3.13 (m,
2H, ethylenesyn), 3.12 (br s, 24H, CH3(amine)), 3.05–3.00
V¼3761.1(1) A , Z¼2, T¼4.0 C, Dcalcd¼1.353 g cmꢀ3
,
ꢁ
˚
m (Mo Ka)¼5.44 cmꢀ1, Mo Ka radiation (l¼0.71069 A),
R1¼0.066, wR2¼0.177. Crystallographic data (excluding
structure factors) for the structure reported in this paper
were deposited with the Cambridge Crystallographic Data
Centre as supplementary publication no. CCDC 223573.
Copies of the data can be obtained free of charge on applica-
tion to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK
[fax: (internat.) +44 1223/336 033; e-mail: deposit@ccdc.
cam.ac.uk].
˚
4.10. Synthesis of 6
A mixture of L3 (13.8 mg, 0.04 mmol) and (S,S)-2 or (R,R)-2
(60.4 mg, 0.08 mmol) was stirred in acetonitrile (10 mL) un-
der argon at room temperature for 4 h. After evaporation of
the solution, the chiral complex (S,S)-6 or (R,R)-6 was iso-
lated by recrystallization from chloroform and ethyl ether.
(m, 4H, ethyleneanti), 2.94–2.87 (m, 8H, ethylenesyn
,
ethylenesyn and ethyleneanti), 2.71–2.69 (m, 2H, ethylenesyn),
2.38–2.36 (m, 2H, ethylenesyn); MS (FAB): m/z¼1532
(M+). Anal. Calcd for C76H74N10O12Pd2$0.5CHCl3:
C, 57.72; H, 4.72; N, 8.80. Found: C, 57.86; H, 4.67;
N, 9.11.
4.10.1. (S,S)-6. Yield 85%; mp 207–208 ꢁC (decomp.); IR
(KBr, cmꢀ1): 3387, 1677, 1594, 1518; 1H NMR (400 MHz,
CD2Cl2, 273 K, syn:anti¼1.6:1): d 10.01 (s, 4H, NHanti),
9.77 (s, 4H, NHsyn), 8.32 (s, 2H, phenylenesyn), 8.14 (t,
4H, J¼7.7 Hz, pysyn and pyanti), 8.00 (d, 1H, J¼9.5 Hz,
phenyleneanti), 7.87 (d, 4H, J¼7.7 Hz, pyanti), 7.79 (d, 4H,
J¼7.7 Hz, pysyn), 7.71 (d, 1H, J¼9.5 Hz, phenyleneanti),
7.45 (d, 4H, J¼7.9 Hz, NHphanti), 7.39 (d, 4H, J¼7.9 Hz,
NHphsyn), 7.29–7.15 (m, 26H, NHphanti, NHphsyn and phanti),
7.08–6.95 (m, 44H, ethylene-phanti, ethylene-phsyn, and
phsyn), 6.84 (d, 1H, J¼9.5 Hz, phenyleneanti), 6.79 (d, 1H,
J¼9.5 Hz, phenyleneanti), 6.72 (s, 2H, phenylenesyn), 6.57
(d, 4H, J¼8.4 Hz, phanti), 6.44 (d, 4H, J¼8.4 Hz, phsyn),
3.76–3.20 (m, 24H, ethylene), 3.09 (s, 6H, Meanti), 3.05 (s,
6H, Meanti), 2.80 (s, 6H, Mesyn), 2.76 (s, 6H, Mesyn);
MS (FAB): m/z¼1777 (M++1). Anal. Calcd for
C96H86N14O8Pd2$0.5CHCl3: C, 64.32; H, 4.89; N, 10.88.
Found: C, 64.12; H, 4.67; N, 10.92.
4.7.2. (R,R)-5. Yield 95%; mp 180–181 ꢁC (decomp.); IR
(KBr, cmꢀ1): 1731, 1591, 1362, 1162; 1H NMR
(600 MHz, CD2Cl2, 233 K, syn:anti¼1:2): d 9.14 (s, 2H,
phenylenesyn), 8.09 (t, 2H, J¼7.2 Hz, pyanti), 8.08 (t, 2H,
J¼7.2 Hz), 7.84 (d, 2H, J¼9.6 Hz, phenyleneanti), 7.73–
7.69 (m, 8H, pysyn and pyanti), 7.26 (d, 4H, J¼9.3 Hz, phsyn),
7.18 (d, 4H, J¼9.3 Hz, phanti), 7.14 (s, 2H, phenylenesyn),
7.11–6.95 (m, 24H, phsyn and phanti), 6.92 (d, 2H,
J¼9.6 Hz, phenyleneanti), 6.86–6.83 (m, 8H, phsyn), 6.78–
6.76 (m, 8H, phanti), 6.56 (d, 4H, J¼9.3 Hz, phanti), 6.52 (d,
4H, J¼9.3 Hz, phsyn), 3.52–3.48 (m, 2H, ethylenesyn), 3.40
(s, 6H, OMe), 3.38 (s, 6H, OMe), 3.33 (s, 6H, OMe), 3.32
(s, 6H, OMe), 3.24–3.20 (m, 4H, ethyleneanti), 3.15–3.13
(m, 2H, ethylenesyn), 3.12 (br s, 24H, CH3(amine)), 3.05–
3.00 (m, 4H, ethyleneanti), 2.94–2.87 (m, 8H, ethylenesyn
,
ethylenesyn, and ethyleneanti), 2.71–2.69 (m, 2H ethylenesyn),
2.38–2.36 (m, 2H, ethylenesyn); MS (FAB): m/z¼1532
(M+). Anal. Calcd for C76H74N10O12Pd2$0.5CHCl3: C,
57.72; H, 4.72; N, 8.80. Found: C, 57.62; H, 4.75; N, 8.95.
4.10.2. (R,R)-6. Yield 87%; mp 207–208 ꢁC (decomp.);
IR (KBr, cmꢀ1): 3387, 1677, 1594, 1518; 1H NMR

T. Moriuchi et al. / Tetrahedron 62 (2006) 12237–12246
12245
(400 MHz, CD2Cl2, 273 K, syn:anti¼1.6:1): d 10.01 (s, 4H,
NHanti), 9.77 (s, 4H, NHsyn), 8.32 (s, 2H, phenylenesyn), 8.14
(t, 4H, J¼7.7 Hz, pysyn and pyanti), 8.00 (d, 1H, J¼9.5 Hz,
phenyleneanti), 7.87 (d, 4H, J¼7.7 Hz, pyanti), 7.79 (d, 4H,
J¼7.7 Hz, pysyn), 7.71 (d, 1H, J¼9.5 Hz, phenyleneanti),
7.45 (d, 4H, J¼7.9 Hz, NHphanti), 7.39 (d, 4H, J¼7.9 Hz,
NHphsyn), 7.29–7.15 (m, 26H, NHphanti, NHphsyn, and
4.87–4.79 (m, 16H, Oxsyn and Oxanti), 3.95–3.88 (m, 2H,
Oxsyn), 3.80–3.73 (m, 2H, Oxanti), 3.58–3.50 (m, 2H, Oxsyn),
3.32–3.24 (m, 2H, Oxanti), 3.18 (br s, 24H, NCH3), 1.49–
1.42 (m, 8H, CH), 0.84–0.75 (m, 24H, CH3), 0.67–0.58 (m,
24H, CH3); MS (FAB): m/z¼1420 ((MꢀBF4)+). Anal. Calcd
for C56H70N10O4Pd2(BF4)4: C, 44.62;H, 4.68;N, 9.29. Found:
C, 44.64; H, 4.41; N, 9.18.
phanti), 7.08–6.95 (m, 44H, ethylene-phanti, ethylene-phsyn
,
and phsyn), 6.84 (d, 1H, J¼9.5 Hz, phenyleneanti), 6.79
(d, 1H, J¼9.5 Hz, phenyleneanti), 6.72 (s, 2H, phenylenesyn),
6.57 (d, 4H, J¼8.4 Hz, phanti), 6.44 (d, 4H, J¼8.4 Hz, phsyn),
3.76–3.20 (m, 24H, ethylene), 3.09 (s, 6H, Meanti), 3.05
(s, 6H, Meanti), 2.80 (s, 6H, Mesyn), 2.76 (s, 6H, Mesyn);
MS (FAB): m/z¼1777 (M++1). Anal. Calcd for
C96H86N14O8Pd2$0.5CHCl3: C, 64.32; H, 4.89; N, 10.88.
Found: C, 64.03; H, 4.75; N, 10.95.
4.12.2. (R,R)-8. Yield 71%; mp 198–199 ꢁC (decomp.); IR
(KBr, cmꢀ1): 2961, 1591, 1502; 1H NMR (400 MHz,
CD3CN, 233 K, syn:anti¼1:2.2): d 8.63 (s, 2H, phenylenesyn),
8.542 (t, 2H, J¼8.0 Hz, pyanti), 8.538 (t, 2H, J¼8.0 Hz, pysyn),
8.46 (d, 2H, J¼8.7 Hz, phenyleneanti), 8.12 (d, 4H, J¼8.0 Hz,
pyanti), 8.11 (d, 4H, J¼8.0 Hz, pysyn), 7.90 (d, 8H, J¼8.6 Hz,
phsyn and phanti), 7.43 (d, 2H, J¼8.7 Hz, phenyleneanti), 7.24
(s, 2H, phenylenesyn), 6.94 (d, 8H, J¼8.6 Hz, phsyn and phanti),
4.87–4.79 (m, 16H, Oxsyn and Oxanti), 3.95–3.88 (m, 2H,
Oxsyn), 3.80–3.73 (m, 2H, Oxanti), 3.58–3.50 (m, 2H, Oxsyn),
3.32–3.24 (m, 2H, Oxanti), 3.18 (br s, 24H, NCH3), 1.49–1.42
(m, 8H, CH), 0.84–0.75 (m, 24H, CH3), 0.67–0.58 (m, 24H,
CH3); MS (FAB): m/z¼1420 ((MꢀBF4)+). Anal. Calcd for
C56H70N10O4Pd2(BF4)4: C, 44.62; H, 4.68; N, 9.29. Found:
C, 44.44; H, 4.74; N, 9.61.
4.11. Synthesis of 7
A mixture of 2,6-bis[(S)-40-isopropyloxazolin-20-yl]pyri-
dine ((S,S)-L4H2) or 2,6-bis[(R)-40-isopropyloxazolin-
20-yl]pyridine ((R,R)-L4H2) (45.2 mg, 0.15 mmol) and
Pd(MeCN)4(BF4)2 (66.6 mg, 0.15 mmol) in acetonitrile
(5.0 mL) was stirred under argon at room temperature for
5 h. After evaporation of the solution, the palladium
complex ((S,S)-L4)Pd(MeCN)(BF4)2 ((S,S)-7) or ((R,R)-
L4)Pd(MeCN)(BF4)2 ((R,R)-7) was isolated as pale-yellow
crystal by recrystallization from acetonitrile and ethyl ether.
Acknowledgements
This work was financially supported in part by a Grant-
in-Aid for Scientific Research on Priority Areas from the
Ministry of Education, Culture, Sports, Science, and
Technology, Japan, Murata Scientific Foundation, and
Iketani Science Technology Foundation. Thanks are also
due to the Analytical Center, Graduate School of Engineer-
ing, Osaka University, for the use of the NMR and MS
instruments.
4.11.1. (S,S)-7. Yield 98%; mp 204–206 ꢁC (decomp.); IR
(KBr, cmꢀ1): 2964, 1641, 1608, 1578; 1H NMR
(400 MHz, CD3CN): d 8.56 (t, 1H, J¼8.04 Hz, Hpy), 8.08
(d, 2H, J¼8.04 Hz, Hpy), 5.05–4.94 (m, 4H, Hox), 4.44–
4.39 (m, 2H, Hox), 2.12–2.07 (m, 2H, Hox), 1.95 (s, 3H,
HNH), 0.98 (d, 6H, J¼6.6 Hz, HMe), 0.97 (d, 6H,
J¼6.6 Hz, HMe). Anal. Calcd for C19H26N4O2Pd(BF4)2: C,
36.66; H, 4.21; N, 9.00. Found: C, 36.49; H, 4.19; N, 9.01.
References and notes
4.11.2. (R,R)-7. Yield 95%; mp 204–206 ꢁC (decomp.); IR
(KBr, cmꢀ1): 2964, 1641, 1608, 1578; 1H NMR
(400 MHz, CD3CN): d 8.56 (t, 1H, J¼8.04 Hz, Hpy), 8.08
(d, 2H, J¼8.04 Hz, Hpy), 5.05–4.94 (m, 4H, Hox), 4.44–
4.39 (m, 2H, Hox), 2.12–2.07 (m, 2H, Hox), 1.95 (s, 3H,
HNH), 0.98 (d, 6H, J¼6.6 Hz, HMe), 0.97 (d, 6H,
J¼6.6 Hz, HMe). Anal. Calcd for C19H26N4O2Pd(BF4)2: C,
36.66; H, 4.21; N, 9.00. Found: C, 36.77; H, 4.28; N, 8.82.
1. (a) MacDiarmid, A. G.; Yang, L. S.; Huang, W. S.; Humphrey,
B. D. Synth. Met. 1987, 18, 393–398; (b) Salaneck, W. R.;
Clark, D. T.; Samuelsen, E. J. Science and Application of
Conductive Polymers; Adams Hilger: New York, NY, 1990;
(c) Ofer, D.; Crooks, R. M.; Wrighton, M. S. J. Am. Chem.
Soc. 1990, 112, 7869–7879; (d) Gustafsson, G.; Cao, Y.;
Treacy, G. M.; Klavetter, F.; Colaneri, N.; Heeger, A. J.
ꢀ
Nature 1992, 357, 477–479; (e) Jestin, I.; Frere, P.;
4.12. Synthesis of 8
Blanchard, P.; Roncali, J. Angew. Chem., Int. Ed. 1998, 37,
942–945 and references therein. See also the Nobel lectures
of Shirakawa, H.; MacDiarmid, A. G.; Heeger, A. J. Angew.
Chem., Int. Ed. 2001, 40, 2574–2611.
A mixture of L3 (17.2 mg, 0.05 mmol) and (S,S)-7 or (R,R)-7
(62.3 mg, 0.10 mmol) was stirred in acetonitrile (5 mL)
under argon at room temperature for 5 h. After evaporation
of the solution, the chiral complex (S,S)-8 or (R,R)-8 was iso-
lated by recrystallization from acetonitrile and diethyl ether.
2. (a) Ritonga, M. T. S.; Sakurai, H.; Hirao, T. Tetrahedron
Lett. 2002, 43, 9009–9013; (b) Sakurai, H.; Ritonga,
M. T. S.; Shibatani, H.; Hirao, T. J. Org. Chem. 2005, 70,
2754–2762.
4.12.1. (S,S)-8. Yield 80%; mp 198–199 ꢁC (decomp.); IR
(KBr, cmꢀ1): 2961, 1591, 1502; 1H NMR (400 MHz,
CD3CN, 233 K, syn:anti¼1:2.2): d 8.63 (s, 2H, phenylenesyn),
8.542 (t, 2H, J¼8.0 Hz, pyanti), 8.538 (t, 2H, J¼8.0 Hz, pysyn),
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