Luminescent chiral organoboron 8-aminoquinolate-coordination polymers

Article abstract of DOI:10.1002/aoc.1599

We have successfully synthesized optically active organoboron aminoquinolate-based coordination polymers bearing the chiral side chain derived from L-alanine, and studied their optical behavior by UV-vis and photoluminescence spectroscopies. Higher absolute quantum yields (φ_F) of the obtained polymers, measured by integrating sphere method, were observed with electron-withdrawing substituent (φ_F = 0.80) than with electron-donating substituent (φ_F = 0.52). The circular dichroism (CD) study in the mixed solvents of CHCl₃ and DMF showed that the secondary structures of the obtained polymers were stabilized by hydrogen-bonding interaction in the side chain. From concentration dependence on the CD spectra, the chirality of the obtained polymers originated from the nature of one molecule. Copyright

Full text of DOI:10.1002/aoc.1599

Full Paper
Received: 27 June 2009
Revised: 29 October 2009
Accepted: 30 October 2009
Published online in Wiley Interscience: 23 December 2009
(www.interscience.com) DOI 10.1002/aoc.1599
Luminescent chiral organoboron
8-aminoquinolate-coordination polymers
Yuichiro Tokoro, Atsushi Nagai and Yoshiki Chujo∗
We have successfully synthesized optically active organoboron aminoquinolate-based coordination polymers bearing the
chiral side chain derived from L-alanine, and studied their optical behavior by UV–vis and photoluminescence spectroscopies.
Higher absolute quantum yields (ꢀF) of the obtained polymers, measured by integrating sphere method, were observed with
electron-withdrawing substituent (ꢀF = 0.80) than with electron-donating substituent (ꢀF = 0.52). The circular dichroism (CD)
study in the mixed solvents of CHCl3 and DMF showed that the secondary structures of the obtained polymers were stabilized
by hydrogen-bonding interaction in the side chain. From concentration dependence on the CD spectra, the chirality of the
c
obtained polymers originated from the nature of one molecule. Copyright ꢀ 2009 John Wiley & Sons, Ltd.
Keywords: boron; conjugated polymer; chirality; amino acid; photoluminescence
Introduction
and conjugation is stricter, is the construction of chiral polymers
with stable and rigid structures, such as helical structure.[8]
A particularly interesting moiety with amide group for chiral
induction is derived from amino acids.[9] The combination of
π-stacking and hydrogen-bonding interactions favors a more
rigid chiral conformation. Therefore, it seems that the chiral
amide side chain leads to safe preparation and stability of π-
conjugated organoboron coordination polymers. Herein, we wish
to report novel synthesis of chiral organoboron coordination
polymers exhibiting high fluorescence quantum yield.
Active current interests in light-emitting organoboron dyes
encompass both biological and material sciences, as well as
chemistry. Many fluorescent organoboron dyes have been used as
chemical probes,[1] photosensitizers[2] and optical sensing[3] due
to large molar extinction coefficients and two-photon absorption
cross sections, high emission quantum yields and sensitivity to
the surrounding medium.[4] Incorporation of them, including
boron 8-aminoquinolate as electroluminescent chromophores
into π-conjugated polymer main chains,[5] i.e. π-conjugated
organoboron polymers, is more attractive for applications such
as electroluminescent devices, organic field-effect transistors, Results and Discussion
photovoltaics, and so on.[6] Recently, designs of π-conjugated
Initially, the ligand N-hexanoyl-L-alanine-Nꢁ-5-iodo-8-quinolyl-
organoboron polymers can be prepared by three conceivable
approaches: (i) cross-coupling reaction between organoboron
dye having bis-iodo groups and diyne compounds;[5a,c–e] (ii)
additional coordination to π-conjugated polymer linker by
boron compound;[5b,f] and (iii) direct coordination of two
ligand-functionalizedcompoundwithdiborylatedcompounds.[5g]
The approach (iii) was unattainable until Ja¨kle and coworkers
recently succeeded in synthesis of π-conjugated organoboron
quinolate polymers through boron-induced ether cleavage.
Photoluminescence properties of these polymers can be tuned
by varying the degree of conjugation of the linker between the
quinolate groups.
Withregardtofunctionalizationoftheorganoborondyes,boron
8-aminoquinolates are more attractive than boron 8-quinolinolate
because the former can introduce an additional functional group
by amide linkage. The organoboron dyes need stability in sev-
eral environments, such as acid, base, heat and light. To give
this stability to the boron complexes, we tested introduction of a
chiral substituent by amide linkage to stabilize the polymer main
chain coordinated boron complex; i.e. if it is possible to prepare
π-conjugated organoboron complex-connected polymers carry-
ing chiral side chain, the stability of polymer backbone will be en-
hanced by secondary interactions of not only π-stacking between
polymer backbone but also chiral stacking between polymer side
chains.[7] This strategy, in which the relationship between chirality
amide (4) was prepared from 8-aminoquinoline as starting com-
pound according to Scheme 1. The reaction of this ligand (4) with
4,4ꢁ-bis[bromo(phenyl)boryl]biphenyl, which was treated with
bis(dibromoboryl)biphenyl[10] and trimethyl(phenyl)tin by a mod-
ification of a literature procedure,[11] produced an organoboron
aminoquinolate-based monomer 6 bearing bis-iodo and amide
groups (Scheme 2). Monomer 6 was obtained as a yellow powder
in 24% yield. Tetracoordination state of the boron atom of 6 was
confirmed by the 11B-NMR spectrum in CDCl3 (δB = 7.13 ppm).
The basic structure of 6 was also identified by 1H-NMR, 13C-NMR,
IR and high-resolution mass spectroscopies. However, 1H-NMR
and 13C-NMR spectra of 6 showed the presence of many multi-
ple peaks attributable to diastereomers, which originate from the
stereogenic borons.[5g]
The Sonogashira–Hagihara coupling polymerization of 6
was conducted with 1,4-diethynyl-2,5- dioctyloxybenzene or
1,4-diethynyl-2-(perfluorooctyl)-5-(trifluoromethyl)benzene in the
∗
Correspondenceto:Yoshiki Chujo,DepartmentofPolymerChemistry,Graduate
School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510,
Japan. E-mail: chujo@chujo.synchem.kyoto-u.ac.jp
Department of Polymer Chemistry, Graduate School of Engineering, Kyoto
University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
c
Appl. Organometal. Chem. 2010, 24, 563–568
Copyright ꢀ 2009 John Wiley & Sons, Ltd.

Y. Tokoro, A. Nagai and Y. Chujo
Scheme 1. Synthesis of N-hexanoyl-L-alanine-Nꢁ-5-iodo-8-quinolylamide.
Scheme 2. Synthesis of monomer 6.
presence of Pd(PPh3)4 and CuI in the mixed solvent of tetrahydro-
furan (THF) and triethylamine (NEt3) at 40 ◦C for 48 h (Scheme 3).
The obtained polymers poly1 and poly2 were collected as orange
and yellow solids, respectively, after reprecipitation in methanol
and in hexane. Their yields were 80 and 59%, respectively. The
number-average molecular weights (Mn) and the molecular
weight distributions (Mw/Mn) of poly1 and poly2, measured by
size-exclusion chromatography (SEC) in THF, were 5300 and 2.8,
and 7900 and 3.1, respectively. The degrees of polymerization
(DPs)estimatedbyMn fromSECwere4.0and5.0(poly1andpoly2,
respectively). The structures of the polymers were characterized
spectroscopically. The 1H, 11B-NMR, 13C-NMR and IR spectra of the
polymers exhibited signals reasonably assignable to the structures
illustratedinScheme 3. Forexample, theIRspectraofthepolymers
showed the absorption peaks at around 2208 cm−1, which are
attributable to stretching of the –C C–bond in the polymer
backbone, and the characteristic peaks at c. 4.40–6.35 ppm, which
are assigned to tetracoordination state of the boron atom of
the polymers, clearly seen by 11B-NMR spectroscopy. These data
indicate that the coupling reaction proceeded effectively without
decomposition of the boron complex in the polymer main chain.
The polymers were soluble in N,N-dimethylformamide (DMF),
THF, CHCl3 and CH2Cl2, and partly soluble in toluene, while
insoluble in hexane, methanol and acetone.
UV–vis absorption spectra of monomer and the obtained
polymers were recorded in CHCl3 (1.0 × 10−5 mol l−1) as shown in
Fig. 1(a). The absorption bands of all compounds at c. 268–270 nm
could be commonly assigned to the absorption of biphenyl
unit in the polymer chain, corresponding to π –π∗ transition.
The monomer 6 showed the weak absorption band at 415 nm
originating from the aminoquinoline ligand unit. In contrast
to 6, the absorption bands of both polymers (poly1, 461 nm,
poly2, 446 nm) were red-shifted and significantly broadened
to bathochomic side, and new bands of poly1 and poly2
appeared at 352 and 382 nm, respectively, attributable to
p-phenylene–ethynylene units. The molar absorption coefficients
(ε) of aminoquinoline moieties in the polymers (poly1: ε =
0.38 × 105
M
−1 cm−1, poly2: ε = 0.55 × 105
M
−1 cm−1) were
higher than that in monomer (6: ε = 0.12 × 105
M
−1 cm−1). These
results indicate that π-conjugation lengths of the polymers were
extended along the polymer backbone. Further, the absorption
band of poly1 was bathochromically shifted in comparison with
that of poly2, while the ε of poly2 was higher than that of poly1.
These bathochromic shifts should be caused by the electronic
structures of comonomers, i.e. donor–acceptor relation.[5d,12]
Figure 1(b) illustrates the emission bands of 6, poly1, and poly2 in
CHCl3 (1.0 × 10−5 mol l−1). The emission of poly2 was green color
at 509 nm (excited at 446 nm), while it was almost identical to that
c
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Copyright ꢀ 2009 John Wiley & Sons, Ltd.
Appl. Organometal. Chem. 2010, 24, 563–568

Chiral organoboron 8-aminoquinolate-coordination polymers
Scheme 3. Cross-coupling reaction of monomer 6 with diyne compounds.
Figure 1. (a) UV–vis spectra of 6, poly1 and poly2 in CHCl3(1.0 × 10−5 mol l−1), and (b) normalized emission spectra of 6, poly1 and poly2 in CHCl3
(1.0 × 10−5 mol l−1).
at 516 nm of 6 (excited at 415 nm). In contrast, the emission band
of poly1 was red-shifted to the bathochromic side as compared
with those of 6 and poly2 due to the highly electron-donating
nature of the comonomer. Higher absolute quantum yields (ꢀF),
measured by integrating sphere method, were observed with
electron-withdrawing substituent (poly2: ꢀF = 0.80) than that
with electron-donating substituent (poly1: ꢀF = 0.52),[12a] and 6
having bis-iodo groups on the aminoquinoline ligand displayed a
lower ꢀF of 0.24 due to the internal heavy-atom effect.[13] These
observations suggest that the substituents in the comonomers
should be responsible for the intensity of fluorescence of the
obtained polymers.
structures in the main chain are derived from chirality of amino
acid moiety in the side chain, although it is difficult to completely
control regulated higher-order structures such as helixes due to
the contamination of the diastereomeric conformations in the
polymers. The CD signals of the polymers gradually decreased by
increasingtheDMFcontent,suggestingstabilizationbyhydrogen-
bonding interaction. In contrast, the specific rotations ([α]25
)
D
of the polymers in CDCl3 and DMF were almost unchanged
(poly1, −267◦ in CHCl3 and −213◦ in DMF; and poly2, −264◦
in CHCl3 and −279◦ in DMF). However, [α]25 of monomer
D
6 in CHCl3 ([α]25 = −294◦) was higher than that in DMF
D
([α]25 = −192◦). These findings mean that the secondary
D
To confirm the secondary structures of the obtained polymers
stabilized by hydrogen-bonding interaction, which is stimulated
in polar solvents such as DMF, we carried out CD and UV–vis
spectroscopic studies of poly1 and poly2 in the mixed solvent
of CHCl3 –DMF as depicted in Fig. 2(a, b). In CHCl3, the CD and
UV–vis maxima of poly1 were observed at 268, 352 and 461 nm,
respectively, attributable to bisphenyl, p-phenylene-ethynylene
and aminoquinoline units, respectively. Similarly, poly2 also
showed signals at 272 nm and at around 446 nm, at which
both p-phenylene–ethynylene and aminoquinoline units were
overlapped. These data indicate that the ordered secondary
structures of the obtained polymers were stabilized by stronger
hydrogen-bondinginteractionthanthatofthemonomer.Next,the
concentration dependence on the secondary structure of poly1
was carried out in CHCl3 (Fig. 3). Increasing the concentration
leads to both bathochromic shifts and decrease in the CD effect,
and the CD signal of poly1 almost completely disappeared at
1.0 × 10−3 mol l−1. The observed concentration dependence
clearly shows that the observed Cotton effects are not due
to supramoleuclar aggregation but due to the nature of one
macromolecule. Figure 2(c, d) illustrates the emission spectra of
the polymers in the mixed solvent of CHCl3 –DMF. Similarly to CD
c
Appl. Organometal. Chem. 2010, 24, 563–568
Copyright ꢀ 2009 John Wiley & Sons, Ltd.
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Y. Tokoro, A. Nagai and Y. Chujo
Figure 2. CD and UV-vis spectra of (a) poly1 and (b) poly2 in CHCl3 and CHCl3 –DMF mixtures (1.0 × 10−5 mol l−1), and emission spectra of (c) poly1
and (d) poly2 in CHCl3 and CHCl3 –DMF mixtures (1.0 × 10−5 mol l−1).
charge separated state,[14] and the ꢀF of poly1 (ꢀF = 0.15) was
also smaller than that of poly2 (ꢀF = 0.52) in DMF.
Conclusions
We have successfully synthesized optically active organoboron
aminoquinolate-based coordination polymers bearing the chiral
side chain derived from L-alanine, and studied their optical
behavior by UV–vis and photoluminescence spectroscopies. The
dependence of the photoluminescence property on the solvent’s
polarity suggested the existence of intramolecular charge transfer.
The CD study in the mixed solvents of CHCl3 and DMF showed
that the secondary structures of the obtained polymers were
Figure 3. Concentration dependence in CHCl3 of CD spectrum of poly1.
stabilized by hydrogen-bonding interaction in the side chain. The
concentration dependence on the CD spectra demonstrated that
the regulated higher-order structures of the obtained polymers
are macromolecular in nature.
effects of the polymers in the mixed solvents, the emission spectra
of the polymers also gradually decreased together with shifting
to bathochromic side by increasing the DMF content, ruling
out the possibility of effect on hydrogen-bonding interaction
in the polymers. In other words, the red-shift and decrease of
intensity in emission spectra mean that the excited state after
intramolecularchargetransfer(CT)isstabilizedinthepolarsolvent.
Further, the intensity of poly1 with the electron-donating group
greatly decreased in comparison with that of poly2 having a
electron-withdrawing group due to higher stabilization of the
Experimental
General Procedures
1H (400 MHz), 13C (100 MHz), and 11B (128 MHz)-NMR spectra were
recorded on a Jeol JNM-EX400 spectrometer. 1H- and 13C-NMR
spectra used tetramethylsilane (TMS) as an internal standard,
11B-NMR spectra were referenced externally to BF3OEt2 (sealed
c
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Copyright ꢀ 2009 John Wiley & Sons, Ltd.
Appl. Organometal. Chem. 2010, 24, 563–568

Chiral organoboron 8-aminoquinolate-coordination polymers
capillary) in CDCl3. The number-average molecular weights (Mn)
and molecular weight distribution [weight-average molecular
weight/number-average molecular weight (Mw/Mn)] values of all
polymers were estimated by size-exclusion chromatography (SEC)
with a TOSOH G3000HXI system equipped with three consecutive
polystyrene gel columns (TOSOH gels: α-4000, α-3000 and α-2500)
and a UV detector at 40 ◦C. The system was operated at a flow rate
of 1.0 ml min−1, with tetrahydrofuran as an eluent. Polystyrene
standards were employed for calibration. UV–vis spectra were
recorded on a Shimadzu UV-3600 spectrophotometer. Fluores-
cence emission spectra were recorded on a Horiba Jobin Yvon
Fluoromax-4 spectrofluorometer. FT-IR spectra were obtained us-
ing a Perkin-Elmer 1600 infrared spectrometer. Elemental analysis
was performed at the Microanalytical Center of Kyoto University.
calcd for C17H20IN3O3: C, 46.27; H, 4.57; N, 9.52. Found: C, 46.25; H,
4.64; N, 9.44.
Alanine-Nꢁ-5-iodo-8-aminoquinolylamide (3)
N-(tert-Butoxycarbonyl)-L-alanine-Nꢁ-5-iodo-8-quinolylamide
(5.00 g, 11.3 mmol) was treated with TFA (17 ml) in CHCl3 (17 ml)
for 32 h. An aliquot of 10% aqueous ammonia was added to
the resulting mixture, followed by extraction with diethyl ether,
drying over MgSO4, and removal of the solvent to give a brown
solid in 77.3% yield (2.98 g, 8.73 mmol). 1H-NMR (CDCl3): δ = 1.52
(d, J = 7.48 Hz, 3H, -CH3), 1.87 (s, 2H, -NH2), 3.78 (q, J = 6.96 Hz,
-CH →), 7.53 (dd, J = 4.28 and 8.44 Hz), 8.07 (d, J = 8.32 Hz,
1H, Ar–H), 8.36 (dd, J = 8.56 and 1.48 Hz, 1H, Ar–H), 8.60 (d,
J = 8.32 Hz, 1H, Ar–H), 8.83 (dd, J = 4.16 and 1.48 Hz, 1H, Ar–H),
11.43 (s, 1H, -NH–CO–CH→) ppm. 13C-NMR (CDCl3): δ = 174.61
(<C O), 149.06 (Ar), 140.59 (Ar), 139.66 (Ar), 138.18 (Ar), 135.37
(Ar), 129.66 (Ar), 123.03 (Ar), 117.75 (Ar), 89.43 (Ar–I), 52.04
(-CH→), 21.77 (-CH3) ppm. HRMS: m/z, calcd for C12H12IN3O:
341.0025; found: 341.0030 [M]+. Anal. calcd for C12H12IN3O3: C,
42.25; H, 3.55; N, 12.32. Found: C, 42.53; H, 3.71; N, 12.11.
Preparation of the Compounds
1,4-Diethynyl-2,5-dioctyloxybenzene,[15] 4,4ꢁ-bis(dibromoboryl)
biphenyl[16] and 1.4-diethynyl-2-perfluorooctyl-5-trifluoromethyl-
benzene[17] were prepared according to the literature. Tetrahy-
drofuran (THF) and triethylamine (Et3N) were purified using a
two-column solid-state purification system (Glasscontour System,
Joerg Meyer, Irvine, CA, USA). Other reagents were commercially
available and used as received.
N-Hexanoyl-L-alanine-Nꢁ-5-iodo-8-quinolylamide (4)
Alanine-Nꢁ-5-iodo-8-aminoquinolylamide (2.73 g, 8.00 mmol)
and triethylamine (1.17 ml, 8.40 mmol) were dissolved in
dichloromethane (36 ml), followed by addition of hexanoyl chlo-
ride(1.17 ml, 8.40 mmol). Theresulting mixturewasstirredatroom
temperature for 24 h. The mixture was transferred to a separating
funnel and washed with aqueous NaHCO3. The organic layer was
dried over MgSO4. Filtration and evaporation of the solvent gave
a pale brown solid in 85.5% yield (3.01 g, 6.84 mmol). 1H-NMR
(CDCl3): δ = 0.88 (t, J = 6.8 Hz, 3H, -CH2 –CH3), 1.33 (m, 4H,
-CH2-), 1.56 (d, J = 7.1 Hz, 3H, <CH–CH3), 1.68 (m, 2H, -CH2-),
2.28 (t, J = 7.6 Hz, 2H), 4.86 (m, 1H, -CH →), 6.24 (d, J = 7.1 Hz,
1H, -NH–CO–CH2-), 7.54 (dd, J = 8.6, 4.1 Hz, 1H, Ar–H), 8.07 (d,
J = 8.3 Hz, 1H, Ar–H), 8.36 (d, J = 8.6 Hz, 1H, Ar–H), 8.48 (d,
J = 8.3 Hz, 1H, Ar–H), 8.78 (d, J = 4.1 Hz, 1H, Ar–H), 10.20 (s,
1H, -NH–CO–CH→) ppm. 13C-NMR (CDCl3): δ = 173.97 (<C O),
170.91 (<C O), 149.06 (Ar), 140.73 (Ar), 139.02 (Ar), 138.08 (Ar),
134.91 (Ar), 129.60 (Ar), 123.29 (Ar), 118.00 (Ar), 89.92 (Ar–I), 49.77
(-CH→), 36.65, 31.42, 25.34, 22.39, 18.92, 18.82, 13.93 ppm. IR(KBr):
ν = 3280, 3059, 2927, 2865, 1698, 1652, 1540, 1474, 1380, 1357,
1315, 1250, 1211, 1151, 1103, 1076, 1036, 961, 934, 908, 837, 785,
724, 694 cm−1. HRMS:m/z, calcdforC18H22IN3O2:439.0757;found:
439.0760 [M]+. Anal. calcd for C18H22IN3O2: C, 49.21; H, 5.05; N,
9.57. Found: C, 49.38; H, 5.06; N, 9.52.
5-Iodo-8-aminoquinoline (1)
A 0.1 M HCl (900 ml) aliquot was added to a solution of
8-aminoquinoline (13.0 g, 90.0 mmol), NaClO2 (4.08 g, 45.0 mmol),
and NaI (13.5 g, 90.0 mmol) in methanol, and the mixture was
stirred at room temperature for 4 h. The precipitate was collected,
and rinsed with aqueous Na2S2O3 and water to afford 5-iodo-8-
aminoquinoline in 68% yield (16.6 g, 61.4 mmol). 1H-NMR (CDCl3):
δ = 5.07 (s, 2H, -NH2), 6.72 (d, J = 8.0 Hz, 1H, quinoline ring, H7),
7.45 (dd, J = 8.6, 4.1 Hz, 1H, H3), 7.82 (d, J = 8.0 Hz, 1H, H6), 8.27
(d, J = 8.6 Hz, 1H, H4), 8.71 (d, J = 4.1 Hz, 1H, H2) ppm. 13C-NMR
(DMSO-d6): δ = 147.60, 146.43, 139.19, 138.23, 138.11, 129.45,
123.43, 110.41, 77.85 (Ar–I). Anal. calcd for C9H7IN2: C, 40.03; H,
2.61; N, 10.37. Found: C, 40.14; H, 2.62; N, 10.35.
N-(tert-Butoxycarbonyl)-L-alanine-Nꢁ-5-iodo-8-quinolylamide (2)
N-(tert-Butoxycarbonyl)-L-alanine (3.41 g, 18.0 mmol) was dis-
solved in THF (90 ml), and triethylamine (2.50 ml, 18.0 mmol)
and ethyl chlorocarbonate (1.72 ml, 18.0 mmol) were added to the
mixture at 0 ◦C. After the mixture had been stirred at 0 ◦C for 1 h,
5-iodo-8-aminoquinoline was added. The reaction was continued
at 0 ◦C for 1 h, and then stirred at room temperature for 11 h. The
resulting mixture was filtered, and the filtrate was concentrated
under vacuum. The crude product was purified by silica gel col-
umn chromatography eluted with hexane–ethyl acetate to give
Monomer (6)
Trimethyl(phenyl)tin (4.78 ml, 26.3 mmol) was added to a solution
of 4,4ꢁ-bis(dibromoboryl)biphenyl (6.49 g, 13.2 mmol) in toluene
(263 ml) and the mixture was stirring for 14 h. All volatile
components were removed under a high vacuum, and the
crude product was washed with hexane. This product (1.17 g), N-
hexanoyl-L-alanine-Nꢁ-5-iodo-8-quinolylamide(2.11 g, 4.80 mmol)
and triethylamine (0.67 mll, 4.8 mmol) were dissolved in toluene
(38 ml). After the reaction mixture had refluxed for 12 h,
the solvent was removed by rotary evaporation. The residue
was treated with water, followed by extraction with ethyl
acetate, drying over MgSO4 and removal of the solvent under
vacuum. The crude products were purified by silica gel (neutral)
column chromatography eluted with hexane–ethyl acetate.
1
a brown solid in 73% yield (5.81 g, 13.2 mmol). H-NMR (CDCl3):
δ = 1.49 (m, 12H, -CH3), 4.51 (m, 1H, -CH →), 5.19 (m, 1H), 7.53
(dd, J = 8.6, 4.0 Hz, 1H, Ar–H), 8.07 (d, J = 8.3 Hz, 1H, Ar–H), 8.36
(d, J = 8.6 Hz, 1H, Ar–H), 8.53 (d, J = 8.3 Hz, 1H, Ar–H), 8.77 (d,
J = 4.0 Hz, 1H, Ar–H), 10.36 (s, 1H, -NH–CO–CH→) ppm. 13C-
NMR (CDCl3): δ = 171.37 (-NH–CO–CH→), 155.34 (-NH–CO–O-),
148.83 (Ar), 140.59 (Ar), 139.11 (Ar), 138.09 (Ar), 135.02 (Ar), 129.54
(Ar), 123.15 (Ar), 117.88 (Ar), 89.68 (Ar–I), 80.23 [-O–C(CH3)3],
51.33(-CH →),28.33[-O–C(CH3)3],18.55(<CH–CH3) ppm.IR(KBr):
ν = 3320, 2972, 2929, 1695, 1506, 1368, 1315, 1248, 1160, 1101,
1061, 1028, 942, 912, 861, 832, 784, 750, 704, 639 cm−1. HRMS:
m/z, calcd for C17H20IN3O3: 441.0549; found: 441.0548 [M]+. Anal.
c
Appl. Organometal. Chem. 2010, 24, 563–568
Copyright ꢀ 2009 John Wiley & Sons, Ltd.
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Y. Tokoro, A. Nagai and Y. Chujo
Recrystallization from hexane–dichloromethane gave a yellow References
solid in 24% yield (0.70 g, 0.58 mmol). 1H-NMR (CDCl3): δ = 0.53
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7.27 (6H, Ar–H), 7.37 (4H, Ar–H), 7.52 (8H, Ar–H), 7.70 (2H, Ar–H),
8.26 (2H, Ar–H), 8.53 (4H, Ar–H), 8.72 (2H, Ar–H) ppm. 11B-NMR
(CDCl3): δ = 7.13 ppm. 13C-NMR (CDCl3): δ = 177.00 (<C O),
171.11 (<C O), 143.50 (Ar), 143.39 (Ar), 142.34 (Ar), 142.24 (Ar),
141.95 (Ar), 140.88 (Ar), 140.73 (Ar), 140.14 (Ar), 140.07 (Ar), 139.84
(Ar), 138.18 (Ar), 134.69 (Ar), 134.59 (Ar), 134.29 (Ar), 132.74 (Ar),
132.57 (Ar), 132.29 (Ar), 129.60 (Ar), 128.07 (Ar), 127.65 (Ar), 127.50
(Ar), 126.71 (Ar), 126.58 (Ar), 126.46 (Ar), 123.99 (Ar), 123.93 (Ar),
120.76 (Ar), 120.63 (Ar), 83.48 (Ar–I), 50.31 (-CH→), 36.50, 31.28,
25.32, 22.40, 18.75, 13.96. IR(KBr): ν = 3418, 3331, 3070, 3045,
3006, 2954, 2926, 2855, 1645, 1578, 1575, 1504, 1462, 1393, 1307,
1276, 1192, 1145, 1114, 1070, 1022, 1003, 962, 882, 840, 818, 782,
738, 706, 666, 642 cm−1. HRMS: m/z, calcd for C60H60B2I2N6O4:
1204.2952; found: 1204.2997 [M]+. Anal. calcd for C60H60B2I2N6O4:
C, 59.82; H, 5.02; N, 6.98. Found: C, 59.50; H, 4.88; N, 6.99.
´
Å. Johansson,L. Strandberg,T. Ny,J.Am.Chem.Soc. 1994,116,7801;
´
d) C.-W. Wan, A. Burghart, J. Chen, F. Bergstro¨m, L. B.-Å. Johanson,
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Poly1
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H. Otaka, Y. Chujo, Macromolecules 2008, 41, 737; c) Y. Nagata,
Y. Chujo, Macromolecules 2007, 40, 6; d) Y. Nagata, Y. Chujo,
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Y. Nagata, Y. Chujo, J. Am. Chem. Soc. 2008, 130, 15276; f) A. Nagai,
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Wiley-VCH: Weinheim, 2000; b) G. Hughes, M. H. Bryce, J. Mater.
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Polymers, 2nd edn, Marcel Dekker: New York, 1997.
A typical procedure is shown as follows: triethylamine (0.70 ml)
was added to a solution of 6 (0.170 g, 0.14 mmol), 1,4-diethynyl-
2,5-dioctyloxybenzene (0.053 g, 0.140 mmol), Pd(PPh3)4 (8.10 mg,
7.00 µmol), CuI (2.60 mg, 14.0 µmol) in THF (1.40 ml) at room
temperature. After the mixture had been stirred at 40 ◦C for 48 h, a
smallamountofCHCl3 wasaddedandpouredintoalargeexcessof
methanol to precipitate the polymer. The polymer was purified by
repeated precipitations from a small amount of CHCl3 into a large
excess of methanol and hexane respectively to give a red solid
1
in 80.7% yield (0.15 g, 0.11 mmol). Mn = 5319. H-NMR (CDCl3):
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J. Mater. Chem. 2006, 16, 728.
δ = 0.55 (6H, -CH2 –CH3), 0.70 (1H), 0.86 (9H), 1.23(20H, -CH2-),
1.37 (6H), 1.53 (8H, -CH2-), 1.94 (4H, -CH2-), 2.02 (4H, -CO–CH2-),
4.12 (4H), 4.74 (2H, -CH →), 6.22 (2H, -NH–CO–CH2-), 7.11 (2H,
Ar–H), 7.29 (6H, Ar–H), 7.42 (4H, Ar–H), 7.55 (8H, Ar–H), 7.68 (2H,
Ar–H), 8.02 (2H, Ar–H), 8.58 (2H, Ar–H), 9.05 (2H, Ar–H), 9.07 (2H,
Ar–H) ppm. 11B-NMR (CDCl3): δ = 4.40 ppm. 13C-NMR (CDCl3):
δ = 177.08 (<C O), 171.17 (<C O), 153.70 (Ar), 141.29 (Ar),
140.72 (Ar), 137.59 (Ar), 135.48 (Ar), 134.65 (Ar), 134.32 (Ar), 132.85
(Ar), 132.69 (Ar), 132.39 (Ar), 128.12 (Ar), 127.64 (Ar), 127.50 (Ar),
126,74 (Ar), 126.60 (Ar), 126.49 (Ar), 123.11 (Ar), 119.00 (Ar), 115.7
(Ar), 113.49 (Ar), 112.67 (Ar), 92.03 (Ar), 90.91 (Ar), 69.35 (-OCH2-),
50.47 (-CH→), 36.69, 36.62, 31.74, 31.46, 31.31, 29.57, 29.40, 29.26,
26.02, 25.36, 22.60, 22.43, 22.37, 22.30, 19.01, 18.82, 14.07, 13.96,
13.83 ppm. IR(KBr): ν = 3418, 2926, 2854, 2208 (-C C-), 1645,
1574, 1498, 1395, 1309, 1270, 1197, 1192, 1143, 1034, 1003, 860,
848, 820, 783, 738, 705 cm−1. Anal. calcd for C86H96B2N6O6: C,
77.58; H, 7.27; N, 6.31. Found: C, 76.22; H, 7.03; N, 6.21.
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S. Kappaum, S. Rentenberger, A. Pogantsch, E. Zojer, K. Mereiter,
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Poly2
1
Yield = 59.1% (0.11 g, 0.07 mmol). Mn = 7880. H-NMR (CDCl3):
δ = 0.55 (6H, -CH2 –CH3), 0.71 (1H), 0.87 (5H), 1.22 (8H, -CH2-),
1.52 (4H, -CH2-), 2.03 (4H, -CO–CH2-), 4.75 (2H, -CH →), 6.19 (2H,
-NH–CO–CH2-), 7.29 (4H, Ar–H), 7.41 (6H, Ar–H), 7.54 (8H, Ar–H),
7.71 (1H, Ar–H), 7.79 (1H, Ar–H), 8.01 (1H, Ar–H), 8.12 (3H, Ar–H),
8.61 (2H, Ar–H), 8.79 (1H, Ar–H), 8.85 (1H, Ar–H), 8.94 (2H, Ar–H)
ppm. 11B-NMR (CDCl3): δ = 6.35 ppm. IR (KBr): ν = 3419, 3071,
3007,2955,2926,2862,2205(-C C-),1652,1574,1499,1475,1447,
1396, 1310, 1252, 1240 (C–F), 1201 (C–F), 1144 (C–F), 1035, 1003,
882, 849, 820, 783, 711, 706 cm−1. Anal. calcdforC79H62B2N6O4F20
C, 60.79; H, 4.00; N, 5.38. Found: C, 59.40; H, 4.07; N, 5.16.
:
c
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Appl. Organometal. Chem. 2010, 24, 563–568