Synthesis and solid-state polymerization of triyne and enediyne derivatives with similar π-conjugated structures

Article abstract of DOI:10.1246/bcsj.81.1028

Three diacetylene monomer model compounds with similar π-conjugation systems, 10-phenyl-5,7,9-decatriynyl W-phenylcarbamate (1), (E)-10-phenyldec-9- en-5,7-diynyl /V-phenylcarbamate (2), and (E)-10-phenyldec-5-en-7,9-diynyl N-phenylcarbamate (3), were synthesized and their properties and solid-state polymerization were investigated. Based on the absorption spectra of the monomers, it was found that the conjugation effect of a double bond was different from that of a triple bond in solution. Monomers 1,2, and 3 gave one, two, and five crystal forms, respectively, of which 1 and one of the crystal forms of 2 (2a) could be polymerized in the solid state. The conversions after y-ray irradiation (1 MGy dose) were 53% and 20%, respectively. The longest-wavelength absorption maxima of the polymers prepared from 1 and 2a were 645 and 655 nm, respectively. The polymerizable crystals 1 and 2a were found to have layered monomer structures with spacing of 3.1-3.6 nm. Based on solid-state ¹³CNMR spectra, the polymerization sites of 1 were determined to be the 1,4- and 3,6-positions with respect to the phenyl ring, and that of 2a was determined to be the 3,6-position with respect to the phenyl ring.

Full text of DOI:10.1246/bcsj.81.1028

1028 Bull. Chem. Soc. Jpn. Vol. 81, No. 8, 1028–1037 (2008)
Ó 2008 The Chemical Society of Japan
Synthesis and Solid-State Polymerization of Triyne and Enediyne
Derivatives with Similar ꢀ-Conjugated Structures
ꢀ1
Kana Mizukoshi,1 Shuji Okada, Tatsumi Kimura,2 Satoru Shimada,2 and Hiro Matsuda2
1Department of Polymer Science and Engineering, Graduate School of Science and Engineering,
Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510
2Photonics Research Institute, National Institute of Advanced Industrial Science and Technology,
Central 5-1, 1-1-1 Higashi, Tsukuba 305-8565
Received February 15, 2008; E-mail: okadas@yz.yamagata-u.ac.jp
Three diacetylene monomer model compounds with similar ꢀ-conjugation systems, 10-phenyl-5,7,9-decatriynyl
N-phenylcarbamate (1), (E)-10-phenyldec-9-en-5,7-diynyl N-phenylcarbamate (2), and (E)-10-phenyldec-5-en-7,9-diyn-
yl N-phenylcarbamate (3), were synthesized and their properties and solid-state polymerization were investigated. Based
on the absorption spectra of the monomers, it was found that the conjugation effect of a double bond was different from
that of a triple bond in solution. Monomers 1, 2, and 3 gave one, two, and five crystal forms, respectively, of which 1 and
one of the crystal forms of 2 (2a) could be polymerized in the solid state. The conversions after ꢁ-ray irradiation (1 MGy
dose) were 53% and 20%, respectively. The longest-wavelength absorption maxima of the polymers prepared from 1 and
2a were 645 and 655 nm, respectively. The polymerizable crystals 1 and 2a were found to have layered monomer struc-
tures with spacing of 3.1–3.6 nm. Based on solid-state 13C NMR spectra, the polymerization sites of 1 were determined
to be the 1,4- and 3,6-positions with respect to the phenyl ring, and that of 2a was determined to be the 3,6-position with
respect to the phenyl ring.
Solid-state polymerization is a unique synthetic process for
polymers, with the advantages of stereoregularity in topo-
chemical synthesis, and environmental benignity, as no sol-
vents are used in the reaction. When this polymerization pro-
cess is applied to certain butadiyne derivatives, polydiacety-
lenes (PDAs) are obtained as single-crystalline polymers.1,2
These have been considered for a variety of applications due
to their ꢀ-conjugated polymer backbone structures. Color
change in PDAs originates from an order–disorder transforma-
tion of the conjugated backbone structure in solution, the mo-
lecular aggregate and crystalline states,3–7 and it has recently
been applied in bio- and chemo-sensing.8,9 Topochemical
PDA synthesis has been used to obtain molecular wires.10
Uniquely among conjugated polymers, significant third-order
nonlinear optical (NLO) properties have been reported for
PDAs;11 thus, ultrafast NLO response12 and device applica-
tions13 have been the subject of extensive investigation.
In our studies on PDAs, we have investigated ꢀ-conjugation
between the polymer backbone and the substituents,14–20 be-
cause these effects are thought to result in an extension of
effective ꢀ-conjugation, causing enhanced NLO properties.21
When oligoyne derivatives with more than three conjugated
acetylene groups were used, we obtained PDAs with acetylen-
ic substituents.19,20 However, 1,4-addition polymerization oc-
curred at the butadiyne section at the end of the conjugated
acetylenes in the presence of alkyl-type substituents, and re-
gioselective polymerization was reported only for an asymmet-
rically substituted phenyloctatetrayne derivative.22
multiple bonds. Solid-state polymerization in these compounds
was expected to proceed in the diyne moieties, because solid-
state polymerization of butenyne derivatives has not yet been
reported. Thus, by controlling the polymerization site, we
may prepare polymers with several ꢀ-conjugated systems
from monomers with similar conjugation systems, as shown
in Figure 1. In order to investigate this, we synthesized model
compounds 1–3. A phenylurethane group was introduced as a
common substituent, as this group has often been found to give
solid-state polymerizable butadiyne and oligoyne deriva-
tives.23–25 The properties of these monomers, including solid-
state polymerizability, were then investigated.
Results and Discussion
Monomer Synthesis. Monomers 1, 2, and 3 were synthe-
sized according to the procedures shown in Figures 2, 3, and 4,
respectively. Compound 6 was synthesized by a coupling reac-
tion between ethynylbenzene (4) and 4-bromo-2-methyl-3-bu-
tyn-2-ol (5) in 83% yield (Figure 2). This compound was also
prepared by a coupling reaction between 2-methyl-3-butyn-2-
ol (10) and 1-bromo-2-phenylethyne (19), but in this case the
yield of 6 was 58%, which was 25% lower than that obtained
from the reaction between 4 and 5, and a considerable amount
of diphenylbutadiyne (21) was obtained as a by-product from
the self-coupling reaction of 19. In order to synthesize 1, phen-
ylbutadiyne (7) and 6-bromo-5-hexyn-1-ol (8) were coupled to
form 10-phenyl-5,7,9-decatriyn-1-ol (9) (Figure 2). We also
attempted to prepare 9 by a coupling reaction between 5,7-oc-
tadiyn-1-ol (22) and 19, but in this case the polarity of starting
material 22 was quite similar to that of the product 9, so that
Compounds 1–3, shown in Figure 1, have similar ꢀ-conju-
gation systems consisting of a benzene ring and three C–C
Published on the web August 11, 2008; doi:10.1246/bcsj.81.1028

K. Mizukoshi et al.
Bull. Chem. Soc. Jpn. Vol. 81, No. 8 (2008) 1029
Figure 1. Chemical structures of model compounds 1–3 and possible schemes for polymerization in the solid state. In this study,
the polymerization positions are counted from the phenyl-substituted end for all compounds, as indicated above.
Figure 2. Synthesis scheme of 1.
separation using conventional column chromatography was
difficult. In addition, the yield of 9 was low because the
self-coupling reaction of 19 occurred predominantly to give di-
phenylbutadiyne (21) in 62% yield. For these reasons, we
selected the synthesis scheme shown in Figure 2.
Because compound 11 was commercially available only as
an E/Z mixture, all products prepared in the following reac-
tions (Figure 3) were also E/Z mixtures. In addition to this,
5-hexyn-1-ol (23) was produced after the reaction of 13 and
8 to synthesize 14, although the mechanism by which 23
was produced from 8 was unclear. Separation of the E isomer
of 14 from the corresponding Z isomer and 23 by conventional
column chromatography was quite difficult. To overcome this
difficulty, the mixture was successively reacted with phenyl
isocyanate and, at the final stage, the E isomer of 2 was isolat-
ed by repeated recrystallization from ether.
The problem of the E/Z mixture also occurred in the synthe-
sis of 3 (Figure 4). When ring-opening reaction of 17 was car-
ried out using a strong base, an E/Z mixture of 18 was ob-
tained. In this reaction, the use of potassium amide rather than
sodium amide resulted in a better yield of 18.26 Although sub-
sequent reactions were carried out using the E/Z mixture, the
E isomer of 3 was finally isolated by repeated recrystallization
from ether, as in the case of 2.
Characterization of Monomers in Solution. All of the
monomer structures were confirmed by 1H and 13C NMR
spectroscopy and elemental analysis (see the Experimental
section and Table 1, respectively). UV spectra were used to

1030 Bull. Chem. Soc. Jpn. Vol. 81, No. 8 (2008)
Polymerization of a Triyne and Enediynes
Figure 3. Synthesis scheme of 2.
Figure 5. UV absorption spectra of (a) 1, (b) 2, and (c) 3 in
ether. The base lines of 1 and 2 are shifted by 0:6 ꢁ 10ꢂ5
and 1:2 ꢁ 10ꢂ5 cmꢂ1 L molꢂ1, respectively.
Figure 4. Synthesis scheme of 3.
Table 1. Elemental Analysis, Melting Points, Characteristic IR Peaks, and UV-Induced Color Changes of Monomers
1, 2, and 3
Elemental analysisaÞ/%
Melting
point/ꢃC
Wavenumber/cmꢂ1
Color
changebÞ
Compound
Polymorph
C
H
N
ꢂCꢄC
2213, 2190
ꢂC=O
1
2
80.68
80.54
80.19
80.58
80.37
80.69
5.31
6.12
6.03
6.05
6.10
6.05
4.08
4.03
4.02
4.10
4.06
4.10
100
115
115
106
106
80–90dÞ
1697
1697
1705
1701
1701
1697
Blue
Blue
Yellow
Yellow
Yellow
Red
cÞ
cÞ
2a
2b
3a
3b
3c
—
—
3
2214
cÞ
—
2214
a) Calculated values for 1: C, 80.92; H, 5.61; N, 4.10%. Calculated values for 2 and 3: C, 80.44; H, 6.16; N,
4.08%. b) After UV irradiation. c) Not detected. d) In this range, there is an endothermic peak followed by an
exothermic peak, corresponding to the transition from 3c to 3d.
obtain information on monomer ꢀ-conjugation systems, as
shown in Figure 5. The monomer spectra showed different
features. The order of the longest-wavelength peaks was
1 (333 nm) > 2 (328 nm) > 3 (321 nm). When we compare
the absorption peaks at wavelengths longer than 260 nm, fine
structure was observed for 1, although the " values were small.
On the other hand, 2 shows relatively broad peaks, but the
largest peak was observed for 2 (" ¼ 5:79 ꢁ 104 cmꢂ1 L molꢂ1
at 313 nm). The spectral shape of 3 seems to be intermediate
between these two. It was concluded that double and triple
bonds showed different conjugation effects in solution. It is
known that conjugated polyyne compounds show absorption

K. Mizukoshi et al.
Bull. Chem. Soc. Jpn. Vol. 81, No. 8 (2008) 1031
Figure 6. Powder X-ray diffractograms of (a) 2a and (b) 2b.
spectra with fine structures27 and " values of conjugated poly-
ene compounds are larger than the corresponding polyyne
compounds in the long-wavelength region.28 Similar tendency
was also observed in the present case. We recently found that
there was a large difference in the solution absorption spectra
of diyne and diene compounds substituted by two aromatic
rings.29 This was explained as being due to the ease of rotation
of the aromatic ring in the diyne compound, which results in
less conjugation between the aromatic rings at each end. How-
ever, in the present case, the compounds have only one aro-
matic ring and the effect of aromatic ring rotation in the triyne
compound seemed to be ignored.
Figure 7. 13C NMR spectra of (a) 2 in CDCl3 and (b) 2a
and (c) 2b in the solid state using the TOSS pulse
sequence.
Table 2. 13C Peaks of Monomer 2 Observed in the Upfield
RegionaÞ
ꢃ/ppm
Assignmentb),c)
2 in CDCl3
2a
2b
19.14
24.58
27.92
22.8
27.4
32.0
19.6
24.3
28.9
a
b
c
Characterization of Monomer Crystals. Monomer 1 was
obtained as colorless needle-shaped crystals from chloroform
solution by cooling. Monomer 2 exhibited polymorphism,
which was confirmed by powder X-ray diffraction patterns
(Figure 6). Colorless needle-shaped crystals of 2a were ob-
tained from methanol solution by the cooling method, while
2b was obtained as a white powder from ether solution by slow
evaporation. Figure 7 compares the 13C NMR spectra of 2 in
deuterated chloroform solution with those of the two poly-
morphs in the solid state, and the methylene carbon chemical
shifts in the upfield region are tabulated in Table 2. The chem-
ical shifts of 2b in Table 2 are found upfield of those of 2a.
However, the peak positions of 2b and 2 in solution are simi-
lar, which indicates that the molecules are more loosely
packed in 2b than in 2a.
Polymorphism was also observed for monomer 3, although
it was much more complicated. From methanol solution, two
types of colorless needle-shaped crystals 3a and 3b and plate
crystals 3c were grown by the cooling method. Type 3c trans-
formed irreversibly to 3d in the temperature range from 80 to
90 ꢃC. When 3d was melted at 105 ꢃC and cooled to ambient
temperature, 3e was obtained. Powder X-ray diffraction pat-
terns of the five crystalline forms of 3 are shown in Figure 8.
The different diffraction patterns obtained clearly indicated
five polymorphs. Some phenylurethane-substituted butadiyne
derivatives are know to show polymorphism,30,31 and bis(3-
quinolyl)butadiyne has been found to show three types.32
a) The full spectra are shown in Figure 7. b) Referring
the 13C NMR spectrum of 5-hexyn-1-ol (SDBS Web: http://
riodb01.ibase.aist.go.jp/sdbs/ (National Institute of Advanced
Industrial Science and Technology)). c) ꢄC–CH2–CH2–
a
b
CH2–.
c
Thus, polymorphism in butadiyne derivatives is not unusual.
However, five modifications in one compound are rare.
Solid-State Polymerization. The monomer crystals were
subjected to UV irradiation to investigate polymerization.
Upon irradiation, 1 and 2a turned blue due to production of
polydiacetylene structures via regular 1,4-addition polymeriza-
tion. However, the other crystals became yellow. Figure 9
shows diffuse reflectance spectra of 1 in the visible region after
various periods of UV irradiation. After 2 min irradiation,
peaks appeared at 645 and 600 nm. These peaks became more
intense as irradiation continued up to about 20 min. Finally, the
spectral edge reached ꢅ800 nm.
Diffuse reflectance spectra of 2a and 2b after UV irradiation
are shown in Figure 10. Although 2a shows peaks at 655 and
590 nm, 2b shows only an increase in the visible region less
than ꢅ600 nm. The changes in the spectra of the five poly-
morphs of 3 were similar to those observed for 2b. Since con-
ventional polydiacetylenes generally show an absorption peak
at wavelengths shorter than 640 nm, it was thought that the ꢀ-
conjugated systems had been extended in 1 and 2a due to ꢀ-

1032 Bull. Chem. Soc. Jpn. Vol. 81, No. 8 (2008)
Polymerization of a Triyne and Enediynes
Figure 10. Diffuse reflectance spectra of 2a and 2b after
UV irradiation.
Figure 8. Powder X-ray diffractograms of (a) 3a, (b) 3b,
(c) 3c, (d) 3c heated at 77 ꢃC accompanied by newly
formed 3d, (e) 3d obtained by heating 3c at 90 ꢃC and
(f) 3e obtained by cooling after melting.
Figure 11. Solid-state 13C NMR spectra (TOSS) of (a) 1,
(b) 1 after ꢁ-ray irradiation (1 MGy), and (c) the isolated
polymer, obtained as the part of the ꢁ-irradiated sample
insoluble in ethyl acetate. Peaks A and B in spectrum
(b) are assigned as the sp-carbon in the polydiacetylene
backbone and the methylene carbon attached to the poly-
mer backbone, respectively. Peaks C, D, and E in spec-
trum (c) correspond to the sp2-carbon in the polydiacety-
lene backbone, sp-carbons in the side chains and the
sp3-carbon attached to the acetylenic moiety, respectively.
Figure 9. Variation in diffuse reflectance spectra of 1 with
UV irradiation time.
conjugation between the polymer backbone and the substitu-
ents. Although polymerization of styryl-substituted butadiyne
has been reported for 1,6-diphenylocta-1,7-dien-3,5-diyne de-
rivatives in the liquid-crystalline state,33 this is the first exam-
ple, to our knowledge, of polymerization of styryl-substituted
butadiyne in the crystalline state to give polydiacetylene.
Changes in absorption similar to those observed for 2b and
3a–3e have often been observed for compounds with irregular
polymerization or oligomerization, irrespective of conver-
sion.34,35
In the polymerization of monomer 1 by UV irradiation, the
conversion was determined to be about 40% based on the de-
crease in the absorbance of the ꢂCꢄC band in the IR spectra.
Since UV cannot usually penetrate samples completely due
to absorption and scattering, the samples were then subjected
to ꢁ-ray irradiation (1 MGy). In this case, the conversions ob-
tained by gravimetric analysis were 53%, 20%, and 0% for 1,
2a, and 2b, respectively. Similarly to 2b, not all of the poly-
morphs of 3 yielded polymers, which were defined as solid
portions insoluble in monomer-soluble ethyl acetate.
In order to confirm the polymer structures, solid-state
13C NMR spectra were measured for the polymers obtained
from 1 and 2a (Figures 11 and 12, respectively). In both fig-
ures, the upper spectra (a) are of the monomers, and the spectra
in the middle (b) are of the samples after 1 MGy ꢁ-ray irradi-
ation. The ꢁ-irradiated samples were then washed with ethyl
acetate to remove the remaining monomer, and the spectra
of the resulting polymers are shown in (c). Despite the poly-
merization reaction, the signals assigned to the phenyl groups
and methylenes away from the polymerization site did not
show significant changes. However, a prominent difference
between spectra (a) and (b) in both cases is the appearance
of new peaks at around 103 ppm (indicated as peak A) and
around 37 ppm (peak B) in spectra (b). Peaks A and B appear

K. Mizukoshi et al.
Bull. Chem. Soc. Jpn. Vol. 81, No. 8 (2008) 1033
Table 3. 2ꢅ of the X-ray Diffraction Peaks Assigned to the
Progression Related to the Interlayer Spacing d
Order of diffraction
1
2aaÞ
3cbÞ
3dcÞ
1
2
3
4
5
6
7
2.78
5.56
2.38
4.88
7.34
9.78
12.24
14.74
17.20eÞ 23.04
3.22
6.46
9.80
13.08
16.36
19.70
3.60
7.28
8.40
11.28
10.94
14.06
18.30
22.00
25.74
dÞ
—
16.96
19.88
a) The diffractogram is shown in Figure 6a. b) The diffracto-
gram is shown in Figure 8c. c) The diffractogram is shown in
Figure 8e. d) The peak was too weak. e) Peaks were observed
up to the fifteenth diffraction.
the translation direction is about 45ꢃ.2 To create polymerizable
stacks in the crystalline form for molecules like 1–3, layered
structures are often essential. Typical examples are amphi-
philic butadiyne derivatives in Langmuir–Blodgett films42,43
and other crystalline butadiyne derivatives with methylene
chains.44 Table 3 summarizes 2ꢅ of the X-ray diffraction
peaks, which correspond to the progression related to the inter-
layer spacing d. The polymerizable crystal 2a shows an X-ray
diffraction pattern with progression, corresponding to a layered
structure (Figure 6a) with interlayer spacing (d) of 3.61 nm.
The polymerizable crystal 1 showed a similar diffraction pat-
tern to 2a, with a d value of 3.14 nm. In contrast, 2b did not
show a clear diffraction pattern corresponding to a layered
structure (Figure 6b). Similarly, 3a, 3b, and 3e do not have
layered structures (Figures 8a, 8b, and 8f, respectively), and
they do not undergo polymerization. Layered crystal structures
were observed for 3c and 3d (Figures 8c and 8e, respectively);
however, the d values are 2.71 and 2.42 nm, respectively,
which are smaller than those of 1 and 2a. Figure 13 shows mo-
lecular orientation models for 1 in the layered structure, and
similar molecular arrangements were also considered for 2
and 3. In this figure, d is the interlayer spacing, L is the length
of the molecular long axis, is the molecular tilting angle,
which is defined as the angle between the layered plane and
the long axis of the molecule, and ꢄ is one of the packing pa-
rameters for solid-state polymerization of butadiyne moieties
mentioned above. Since compounds 1–3 have a kink in the
molecular structures, ꢄ can be varied as shown in Figure 13,
in which model A is for the smallest ꢄ and model B is for
the largest ꢄ. From the optimized molecular structures ob-
tained by a semiempirical calculation, and ꢄ were roughly
estimated (Table 4). Angle becomes large in the following
order: 2a < 1 < 3c < 3d. If the molecular arrangement like
model B were realized for 3c and 3d to give ꢄ of about 45ꢃ,
they could be polymerized. Actually, however, 3c and 3d do
not polymerize, and their monomer alignments in crystals
deviate from polymerizable conditions.
Figure 12. Solid-state 13C NMR spectra (TOSS) of (a) 2a,
(b) 2a after ꢁ-ray irradiation (1 MGy) and (3) the isolated
polymer, obtained as the part of the ꢁ-irradiated sample
insoluble in ethyl acetate. Peaks A and B in spectrum
(b) are assigned as the sp-carbon in the polydiacetylene
backbone and the methylene carbon attached to the poly-
mer backbone, respectively.
even in spectra (c), indicating that they are due to the poly-
mers. As it has been confirmed that the sp-carbon in the poly-
diacetylene backbone generally appears in the range from 100
to 110 ppm,19,20,36–39 peak A can be assigned as the acetylenic
carbon in the polymer backbone. In addition, peak B, in the
aliphatic carbon region, corresponds to a newly formed sp3-
carbon next to the polymer backbone.19,20,40,41 Based on this
information, it was concluded that polymerization proceeds
at the 3,6-position with respect to the phenyl ring in both 1
and 2a, as shown in Figure 1. In contrast, in the spectrum of
the polymer obtained from 1 after extraction of the monomers,
there is a peak around 22 ppm (indicated by E in Figure 11c).
Monomers 1 and 2a also show a peak at around 22 ppm and
these peaks are assigned as sp3-carbons directly attached to
the acetylenic moiety. Thus, polymer 1 contains the same type
of carbon. As this means that polymerization took place with-
out loss of the aliphatic carbons next to the acetylene moieties,
it was concluded that 1 also undergoes polymerization at the
1,4-position with respect to the phenyl ring. 1,4-Addition poly-
merization of 2a was concluded not to have taken place be-
cause no peak around 22 ppm was observed in the spectrum af-
ter removal of the monomer (Figure 12c). Referring to the data
of a polymer from triyne,19 peak C at 112 ppm and peaks D in
the range from 80 to 105 ppm of polymer 1 (Figure 11c) can
be assigned as the olefinic carbon in the polymer backbone
and the acetylenic carbons in the side chain, respectively.
Among the eight crystal forms investigated in this study,
only 1 and 2a showed solid-state polymerizability. Criteria
for polymerizability in butadiyne derivatives have been crys-
tallographically established: the distance between adjacent
monomers along the translation direction must be about
0.5 nm, and the angle (ꢄ) between the butadiyne moiety and
Conclusion
We prepared phenyl-substituted triyne 1 and two types of
enediynes 2 and 3 as model compounds with similar ꢀ-conju-
gated systems. The shapes of the absorption spectra of the
monomers were quite different, and the conjugation effects
of double and triple bonds were found to be different in the so-

1034 Bull. Chem. Soc. Jpn. Vol. 81, No. 8 (2008)
Polymerization of a Triyne and Enediynes
φ
φ
Model A
d
ψ
ψ
Model B
L
Figure 13. Molecular orientation models for 1 in the layered structure. Red and blue thick lines indicate phenylhexatriynyl group
and methylene chain with phenylurethane group, respectively, and the corresponding molecular models are displayed beside
these lines.
13C NMR measurements, CP/MAS, dipolar dephasing and TOSS
(total suppression of spinning sidebands) pulse sequences were
used to assign peaks. The methylene carbon of adamantane at
29.5 ppm was used as an external standard. Powder X-ray diffrac-
Table 4. Interlayer Spacing d, Molecular Length L, and
Estimated Angles and ꢄ
Crystal
daÞ/nm
LbÞ/nm
cÞ/ꢃ
ꢄdÞ/ꢃ
tion patterns were recorded on a Rigaku RINT-Ultima III diffrac-
tometer using a Cu Kꢆ source. Elemental analysis was performed
using a Perkin-Elmer 2400II analyzer.
1
3.14
3.61
2.71
2.42
2.66
2.64
2.64
2.64
54
47
59
63
19–53
28–58
16–46
12–42
2a
3c
3d
Preparation of Compounds. 2-Methyl-6-phenyl-3,5-hexa-
diyn-2-ol (6):
To a mixture of copper(I) chloride (0.30 mg,
a) Obtained from X-ray diffraction experiments (see Table 3).
b) Calculated using PM3 in MOPAC 2002 (ver. 2.5.0). c)
¼ cosꢂ1ðd=2LÞ. d) Left and right numbers correspond to
the angles for models A and B in Figure 13, respectively.
3 mmol), isopropylamine (150 mL), and ethanol (90 mL), ethynyl-
benzene (4) (10.2 g, 100 mmol) was added under a nitrogen atmo-
sphere, and 25.0 g (80 mmol) of 4-bromo-2-methyl-3-butyn-2-ol45
(5) was then added dropwise for 6 h. When the color of the reaction
mixture became deep green, hydroxylamine hydrochloride was
added until the color changed to yellow. After addition of 5 was
completed, the reaction mixture was further stirred for 18 h. The
solvent was removed under reduced pressure and water was added
to the residue for extraction with ether. The ether layer was collect-
ed and dried over anhydrous magnesium sulfate. After filtration to
remove the solid portion, the solvent in the filtrate was evaporated
and the residue was purified by column chromatography (silica gel,
chloroform) to give 12.2 g (83%) of 6 as yellow solid: ꢃH
(400 MHz, CDCl3): 1.58 (6H, s), 1.99 (1H, br s), 7.28–7.39 (3H,
m), 7.48 (2H, d, J ¼ 7:7 Hz); ꢃC (100 MHz, CDCl3): 31.07,
65.70, 67.01, 73.11, 78.75, 86.66, 121.49, 128.38, 129.20, 132.47.
Phenylbutadiyne (7): Alcohol 6 (6.00 g, 33 mmol) was dis-
solved in benzene (60 mL) and 1.45 g of powdered potassium hy-
droxide was added. The mixture was refluxed for 1 h and filtered.
The solvent of the filtrate was removed under reduced pressure,
and the residue was purified by column chromatography (silica
gel, chloroform) to give 2.90 g (71%) of 7 as a brown viscous
oil: ꢃH (400 MHz, CDCl3): 2.47 (1H, s), 7.29–7.41 (3H, m),
7.51 (2H, d, J ¼ 7:5 Hz); ꢃC (100 MHz, CDCl3): 68.08, 71.27,
73.46, 75.32, 121.05, 128.52, 129.60, 132.84.
lution state. Although monomer 1 gave polymerizable crystals,
monomer 2 gave two types of crystal, one polymerizable (2a)
and the other not polymerizable (2b). Monomer 3 was found to
give five polymorphs 3a–3e that could not be polymerized. X-
ray powder diffraction measurements showed that the crystals
of the polymerizable monomers 1 and 2a had layered struc-
tures with spacings in the range 3.1–3.6 nm. The polymer ab-
sorption maxima of 1 and 2a were observed at around 650 nm.
The conversions of 1 and 2a after 1-MGy ꢁ-ray irradiation
were 53% and 20%, respectively. It was found that polymer-
ization of 1 occurred at both the 1,4- and 3,6-positions with re-
spect to the phenyl ring, while that of 2a proceeded only at the
3,6-position. This result indicates that the solid-state polymer-
ization site within conjugated multiple bonds can be controlled
by the introduction of a double bond next to the polymerizable
butadiyne moieties when appropriate monomer arrangements
for solid-state polymerization are obtained in crystals.
Experimental
Apparatus. Melting points were measured using a Yanaco
MP-500P micro-melting-point apparatus and are uncorrected. Dif-
ferential thermal analysis was performed using an SII TG/DTA
220 analyzer. UV–visible spectra were measured using a Jasco
V-570 spectrophotometer, which was equipped with an integration
sphere (Jasco ILN-472) for diffuse reflectance spectrum measure-
ment. IR spectra were recorded on a Horiba FT-210 spectrometer.
NMR spectra were obtained using Jeol EX-270 and ECX-400
spectrometers for solution-state spectra and an ECX-400 spec-
trometer for solid-state spectra. For solution-state measurements,
tetramethylsilane was used as an internal standard. In solid-state
10-Phenyl-5,7,9-decatriynyl N-Phenylcarbamate (1): To a
mixture of copper(I) chloride (100 mg), isopropylamine (36 mL),
and ethanol (20 mL), 7 (2.90 g, 23 mmol) was added under a nitro-
gen atmosphere. 6-Bromo-5-hexyn-1-ol (8) (3.54 g, 20 mmol) was
then added dropwise for 90 min. When the color of the reaction
mixture became deep green, hydroxylamine hydrochloride was
added until the color turned to yellow. After addition of 8 was
completed, the reaction mixture was further stirred for 17 h, and
the solvent was removed under reduced pressure. Water was add-
ed to the residue for extraction with ether. The ether layer was col-
lected and dried over anhydrous magnesium sulfate. After filtra-

K. Mizukoshi et al.
Bull. Chem. Soc. Jpn. Vol. 81, No. 8 (2008) 1035
tion, the solvent in the filtrate was evaporated to give 4.44 g of
brown viscous oil. This residue was found to contain 8 and 10-
phenyl-5,7,9-decatriyn-1-ol (9), which were difficult to separate
by column chromatography because of their similar polarities.
Thus, the mixture was used in the subsequent reaction.
the mixture was extracted with ether. The ether layer was collect-
ed, washed twice with dilute hydrochloric acid, and dried over
anhydrous magnesium sulfate. After filtration, the solvent was
evaporated to give brown viscous oil. This residue contained the
E and Z isomers of 10-phenyldec-9-en-5,7-diyn-1-ol (14), with
5-hexyn-1-ol as a by-product. These three compounds were diffi-
cult to separate by column chromatography, and thus the mixture
was used for subsequent reactions.
The above mixture (5.0 g) and phenyl isocyanate (2.7 g,
23 mmol) were placed in 50 mL of toluene under a nitrogen atmo-
sphere. To this, two drops of dibutyltin dilaurate were added, and
the mixture was stirred for 3.5 h at ambient temperature. The
solvent was then evaporated. At this stage, separation of the
compounds by column chromatography was still difficult. After
repeated recrystallization from ether, only the E isomer of 2
(2.5 g, 21% from 13) was obtained: ꢃH (270 MHz, CDCl3): 1.68
(2H, tt, J ¼ 6:8, 6.8 Hz), 1.82 (2H, tt, J ¼ 6:8, 6.8 Hz), 2.43
(2H, t, J ¼ 6:8 Hz), 4.21 (2H, t, J ¼ 6:8 Hz), 6.16 (1H, d, J ¼
16:4 Hz), 6.58 (1H, br s), 7.06 (1H, d, J ¼ 16:4 Hz), 7.07 (1H,
tt, J ¼ 6:2, 1.4 Hz), 7.27–7.43 (9H, m); ꢃC (67.5 MHz, CDCl3):
19.14, 24.58, 27.92, 64.49, 65.84, 74.73, 76.41, 84.53, 106.83,
118.70, 123.44, 126.39, 128.80, 129.09, 129.14, 135.88, 137.94,
144.22, 153.67.
2-(1-Propynyl)tetrahydropyran (17):26,45 To a 0.5 mol Lꢂ1
tetrahydrofuran (THF) solution of 1-propynylmagnesium bromide
(240 mL), 2-chlorotetrahydropyran (16)45,46 (11.2 g, 93 mmol) was
added dropwise over a few minutes at ꢂ15 ꢃC. After addition was
completed, the cooling bath was removed and the reaction mixture
was stirred for 14 h. To this, saturated ammonium chloride solu-
tion was added, and the mixture was extracted with ether. The
ether layer was dried over anhydrous magnesium sulfate and
filtered, following which the solvent was evaporated to give
9.2 g (80%) of 17 as a pale yellow oil: ꢃH (400 MHz, CDCl3):
1.45–2.00 (6H, m), 1.86 (3H, d, J ¼ 2:3 Hz), 3.50 (1H, m), 3.98
(1H, m), 4.19 (1H, ddd, J ¼ 8:3, 2.4, 2.4 Hz).
The mixture of 8 and 9 (4.40 g) and phenyl isocyanate (3.00 g,
26 mmol) were dissolved in 100 mL of toluene under a nitrogen
atmosphere. To this solution, two drops of dibutyltin dilaurate
were added, and the mixture was stirred for 1 h at ambient temper-
ature. The solvent was then evaporated and the residue was puri-
fied by column chromatography (silica gel, chloroform). After
recrystallization from hexane–chloroform mixed solvent, 2.40 g
(36% from 7) of 1 was obtained as colorless solid: ꢃH (400
MHz, CDCl3): 1.69 (2H, tt, J ¼ 7:7, 7.1 Hz), 1.81 (2H, tt, J ¼
7:7, 6.2 Hz), 2.42 (2H, t, J ¼ 7:1 Hz), 4.20 (2H, t, J ¼ 6:2 Hz),
6.60 (1H, br s), 7.07 (1H, tt, J ¼ 7:2, 1.4 Hz), 7.28–7.41 (7H,
m), 7.50 (2H, dtt, J ¼ 7:0, 2.3, 1.3 Hz); ꢃC (100 MHz, CDCl3):
19.23, 24.51, 28.02, 59.83, 64.42, 66.16, 67.09, 74.49, 75.59,
81.69, 118.63, 120.99, 123.41, 128.41, 129.01, 129.50, 132.91,
137.78, 153.50.
2-Methyl-6-phenylhex-5-en-3-yn-2-ol (12):
1-Bromo-2-
phenylethene (11) (E:Z = 1:0.16, 26.8 g, 146 mmol), tetrakis(tri-
phenylphosphine)palladium(0) (441 mg), and triphenylphosphine
(220 mg) were mixed and stirred for a few minutes at ambient
temperature under a nitrogen atmosphere.45 To this mixture, piper-
idine (100 mL), 2-methyl-3-butyn-1-ol (10) (14.8 g, 176 mmol),
and copper(I) bromide (220 mg) were added, and the mixture
was stirred for 30 min. Finally, lithium bromide (700 mg) was add-
ed, and the mixture was further stirred for 90 min. After removal
of the volatile portion of the reaction mixture under reduced pres-
sure, water was added to the residue and the mixture was extracted
with ether. The collected ether layer was washed twice with
2 mol Lꢂ1 hydrochloric acid solution and dried over anhydrous
magnesium sulfate. The solid portion was removed by filtration,
and the solvent in the filtrate was removed under reduced pressure.
The residue was then purified by column chromatography (silica
gel, chloroform) to give 18.7 g (68%) of 12 (containing less than
10% Z isomer) as brown viscous oil. NMR spectral data for the E
isomer are as follows: ꢃH (270 MHz, CDCl3): 1.58 (6H, s), 2.06
(1H, br s), 6.16 (1H, d, J ¼ 16:3 Hz), 6.93 (1H, d, J ¼ 16:3 Hz),
7.24–7.41 (5H, m); ꢃC (100 MHz, CDCl3): 31.36, 65.64, 81.32,
96.03, 107.66, 126.30, 128.68, 128.78, 136.26, 141.49.
1-Phenylbut-1-en-3-yne (13): To a solution of 12 (7.3 g,
38 mmol) in toluene (100 mL), powdered potassium hydroxide
(2.0 g) was added, and the mixture was heated at 80 ꢃC for 1 h.
The reaction mixture was filtered and solvent in the filtrate was
removed under reduced pressure. The residue was purified by col-
umn chromatography (silica gel, hexane–ethyl acetate (4:1)) to
give 4.5 g (90%) of 13 as pale orange liquid: ꢃH (270 MHz,
CDCl3): 3.05 (1H, d, J ¼ 2:4 Hz), 6.13 (1H, dd, J ¼ 16:3, 2.4
Hz), 7.05 (1H, d, J ¼ 16:3 Hz), 7.27–7.45 (5H, m); ꢃC (67.5
MHz, CDCl3): 79.23, 84.12, 107.05, 126.43, 128.37, 128.84,
135.95, 143.25.
Oct-5-en-7-yn-1-ol (18):26,45 Dried ammonia gas was intro-
duced to a four-necked flask cooled to ꢂ78 ꢃC, and about
400 mL of liquid ammonia was collected. A piece of iron(III) ni-
trate was added, and 19.6 g (500 mmol) of potassium in small
pieces was added over 6 h. After addition of potassium was com-
pleted, the cooling bath was removed to allow completion of the
reaction of potassium with ammonia under reflux conditions.
The cooling bath was then reattached, and 17 (13.0 g, 105 mmol)
was added dropwise for 30 min. The reaction mixture was stirred
for 20 min, and then for a further 10 h after removal of the cooling
bath. During this period, most of the ammonia was vaporized. Wa-
ter was added to the residue and the mixture was extracted with
ether. The collected ether layer was dried over anhydrous magne-
sium sulfate, the drying agent was removed by filtration, and the
solvent was removed under reduced pressure. The residue was pu-
rified by column chromatography (silica gel, chloroform) to give
11.0 g (84%) of 18 (E:Z = 1:0.57) as pale yellow oil. NMR spec-
tral data for the E isomer are as follows: ꢃH (400 MHz, CDCl3):
1.43–1.66 (4H, m), 1.77 (1H, br s), 2.16 (2H, ddt, J ¼ 7:0, 1.3,
7.2 Hz), 2.79 (1H, d, J ¼ 2:3 Hz), 3.64 (2H, t, J ¼ 7:0 Hz), 5.47
(1H, ddt, J ¼ 15:9, 2.3, 1.3 Hz), 6.24 (1H, dt, J ¼ 15:9, 7.0 Hz);
ꢃC (100 MHz, CDCl3): 24.58, 31.81, 32.53, 62.17, 75.73, 81.34,
108.71, 146.20.
(E)-10-Phenyldec-9-en-5,7-diynyl N-Phenylcarbamate (2):
To a mixture of copper(I) chloride (300 mg), isopropylamine
(94 mL), and ethanol (100 mL), 13 (4.5 g, 35 mmol) was added un-
der a nitrogen atmosphere, followed by 8 (7.4 g, 42 mmol), which
was added dropwise for 1 h. When the color of the reaction mix-
ture changed to deep green, hydroxylamine hydrochloride was
added until the color turned to yellow. After addition of 8 was
completed, the reaction mixture was further stirred for 17 h, and
the solvent was evaporated. Water was added to the residue and
10-Phenyldec-5-en-7,9-diyn-1-ol (20): To a mixture of cop-
per(I) chloride (440 mg), isopropylamine (137 mL), and ethanol
(100 mL), 18 (11.0 g, 89 mmol) was added under a nitrogen atmo-
sphere; then, 1-bromo-2-phenylethyne (19) (16.1 g, 89 mmol) was

1036 Bull. Chem. Soc. Jpn. Vol. 81, No. 8 (2008)
Polymerization of a Triyne and Enediynes
added dropwise for 4.5 h. When the color of the reaction mixture
changed to deep green, hydroxylamine hydrochloride was added
until the color turned to yellow. After addition of 19 was complet-
ed, the reaction mixture was further stirred for 17 h, and the sol-
vent was removed under reduced pressure. Water was added to
the residue and the mixture was extracted with ether. The ether
layer was collected and dried over anhydrous magnesium sulfate.
The solvent was then evaporated and the residue was purified by
column chromatography (silica gel, chloroform) to give 12.5 g
(63%) of 20 (E:Z = 1:0.54) as yellow viscous oil. NMR spectral
data for the E isomer are as follows: ꢃH (400 MHz, CDCl3): 1.33–
1.80 (5H, m), 2.20 (2H, ddt, J ¼ 7:3, 1.6, 7.2 Hz), 3.65 (2H, t, J ¼
6:1 Hz), 5.60 (1H, dt, J ¼ 16:0, 1.6 Hz), 6.35 (1H, dt, J ¼ 16:0,
7.3 Hz), 7.28–7.38 (3H, m), 7.45–7.50 (2H, m); ꢃC (100 MHz,
CDCl3): 24.62, 31.94, 32.93, 62.38, 72.50, 74.02, 80.52, 80.71,
108.83, 121.84, 128.33, 128.94, 132.32, 148.43.
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into glass tubes that were then evacuated and sealed. Conversions
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ethyl acetate, in which all monomers were soluble.
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The authors wish to thank Prof. Akihiko Kanazawa and
his laboratory members for their cooperation with the powder
X-ray diffraction measurements. This study was supported
by a Grant-in-Aid for Scientific Research on Priority Areas
(No. 446) from the Ministry of Education, Culture, Sports,
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