A convenient short cut from aromatic iodides to alkynylstannanes and their use for the straightforward preparation of polyacetylene and polymetallaacetylene polymers

Article abstract of DOI:10.1016/S0022-328X(98)01124-3

The palladium-catalyzed cross-coupling reaction (Stille coupling) of aromatic iodides Ar-I and tributyl(ethynyl)tin Bu₃SnC≡CH form the aromatic acetylides Ar-C≡CH and the side product tributyltin iodide Bu₃SnI in equimolar amount. In situ addition of lithium diisopropylamide (LDA) to this crude mixture directly affords the tributyl(ethynyl)tin aromatics Ar-C≡C-SnBu₃ in high yield. In the case of the bis(iodoaromatic) I-Ar-I (Ar = phenyl, thiophene), this straightforward transformation affords the corresponding bis[tributyl(ethynyl)tin]derivative Bu₃Sn-C≡C-Ar-C≡C-SnBu₃. In the presence of Pd this latter species can be directly reacted with a second bis(iodoaromatic) or a bis(metaliodide) unit to form acetylenic and metallaacetylenic polymers with tailored monomer units inserted in a stereoregular polymer chain.

Full text of DOI:10.1016/S0022-328X(98)01124-3

Journal of Organometallic Chemistry 578 (1999) 210–222
A convenient short cut from aromatic iodides to alkynylstannanes and
their use for the straightforward preparation of polyacetylene and
polymetallaacetylene polymers
Eleonora Antonelli, Patrizia Rosi, Claudio Lo Sterzo *, Egidio Viola
Centro CNR di Studio sui Meccanismi di Reazione, Dipartimento di Chimica, Uni6ersita ‘La Sapienza’, Box 34-Roma 62, Piazzale Aldo Moro,
5 00185 Rome, Italy
Received 19 July 1998
Abstract
The palladium-catalyzed cross-coupling reaction (Stille coupling) of aromatic iodides ArꢀI and tributyl(ethynyl)tin Bu3SnCꢁCH
form the aromatic acetylides ArꢀCꢁCH and the side product tributyltin iodide Bu3SnI in equimolar amount. In situ addition of
lithium diisopropylamide (LDA) to this crude mixture directly affords the tributyl(ethynyl)tin aromatics ArꢀCꢁCꢀSnBu3 in high
yield. In the case of the bis(iodoaromatic) IꢀArꢀI (Ar=phenyl, thiophene), this straightforward transformation affords the
corresponding bis[tributyl(ethynyl)tin]derivative Bu3SnꢀCꢁCꢀArꢀCꢁCꢀSnBu3. In the presence of Pd this latter species can be
directly reacted with a second bis(iodoaromatic) or a bis(metaliodide) unit to form acetylenic and metallaacetylenic polymers with
tailored monomer units inserted in a stereoregular polymer chain. © 1999 Elsevier Science S.A. All rights reserved.
Keywords: Stille coupling; Alkynylstannanes; Polyacetylene; Polymetallaacetylene
perethynylated compounds [6], and of linear chain
metal-containing polymers [7]. These species constitute
a variety of highly ethynylated carbon networks repre-
senting the ultimate focus of advanced materials [8].
We have recently found that in the presence of
palladium catalysts alkynylstannanes can efficiently
couple with metal iodides to form s-metal acetylides
[9], thus adding new usefulness to these intermediates.
All procedures commonly used for the preparation of
alkynylstannanes require the previous preparation and
isolation of the corresponding pure alkynes, then trans-
formation is accomplished by the use of tin amides, tin
oxides, or more often, by treatment with a base and a
tin halide [6a,7b,9a,10]. These two steps must be kept
separated being the reaction conditions under which the
alkyne is formed incompatible with reagents used for
the subsequent transformation.
1. Introduction
Alkynylstannanes are a class of functionalized alky-
nes playing an important role in numerous organic and
organometallic synthetic designs. They represent the
coupling partners that more efficiently perform the
palladium catalyzed coupling between organotin
reagents and electrophiles [1], namely the Stille reac-
tion; nowadays the most used procedure to form car-
bonꢀcarbon bond by transition metal catalysis [2].
Moreover, alkynylstannanes are used to prepare
alkynyliodonium salts, which are synthons of elec-
trophilic acetylene [3], and to label steroids with metal-
locarbonyl fragments for their use in immunoessay
FTIR tecniques [4]. More recently, material science has
also taken advantage of the use of alkynylstannanes for
the construction of aromatic polyacetylenes [5], of
With respect to the preparation of aromatic acetyle-
nes, a wide variety of efficient methods are currently
available [11], the most used rely on transition metal
* Corresponding author.
E-mail address: losterzo@uniroma1.it (C. Lo Sterzo)
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(98)01124-3

E. Antonelli et al. / Journal of Organometallic Chemistry 578 (1999) 210–222
211
catalyzed couplings of aromatic halides and polyhalides
with trimethylsilylacetylene (TMSA) or 2-methyl-3-bu-
tyn-2-ol to form the protected aromatic acetylenes, that
will be subsequently deprotected just prior to use. Al-
ternatively, the Stille coupling of aromatic halides and
tributyl(ethynyl)tin directly affords the aromatic
acetylenes. In any case, the free acetylene functionality
is a sensitive group that may become very dangerous to
handle in the case of aromatic polyacetylenes and per-
acetylenics [11,12].
Herein, we describe an efficient direct transformation
of mono- and bis-iodides into mono- and bis-alkynyl-
stannanes, based on the one-pot performance of two
steps: (1) the Stille coupling between an aromatic iodide
and tributyl(ethynyl)tin to form an aromatic acetylide,
and (2) the base promoted recombination of the trib-
utyltiniodide, generated as a side product in the first
step, with the acetylide. The basic concept of this
transformation is outlined in Scheme 1.
thienyl) were formed and directly reacted with a second
bis(iodoaromatic) or a bis(metaliodide) in the presence
of Pd to form acetilenic and metallaacetylenic polymers
(Scheme 2).
2. Results and discussion
The possibility of achieving direct formation of tin
acetylides by the one pot sequence of transformation
outlined in Scheme 1 was envisaged for the first time by
1
examining the H-NMR spectrum of the product ob-
tained upon reacting
a
mixture of 2(ethynyl)-
5[(trimethylsilyl)ethynyl]tiophene (1) and Bu3SnI with
Et2NSnMe3 [13] (Scheme 3). 1H-NMR spectrum
showed that along with the expected product
2[(trimethylsilyl)ethynyl]-5(trimethyltinethynyl)tiophene
(2) a considerable amount of 2[(trimethylsilyl)ethynyl]-
5(tributyltinethynyl)tiophene (3) was formed. Evidently,
while the diethylamino group abstracts the acetylenic
proton, reaction with Bu3SnI occurs and 3 is formed,
despite the Me3Sn functionality is favorite in the re-
placement of this proton to form 2 (Scheme 4). This
Moreover, by carrying out the same transformation
on bis(iodoaromatics) of type IꢀArꢀI (Ar=phenyl,
thienyl) the corresponding bis[tributyl(ethynyl)tin]-
derivatives Bu3SnꢀCꢂCꢀArꢀCꢂCꢀSnBu3 (Ar=phenyl,
Scheme 1.
Scheme 2.
Scheme 3.
Scheme 4.

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E. Antonelli et al. / Journal of Organometallic Chemistry 578 (1999) 210–222
Scheme 5.
Fig. 1. Organometallic structures of compounds 7 and 8.
unexpected finding then suggested the possibility of
forming tin acetylides directly by recombination of the
aromatic acetylide and the tin halide generated during
the Stille coupling of aromatic iodides and trib-
utyl(ethynyl)tin (step 2 of Scheme 1).
0°C, a stoichiometric amount of LDA was added, and
following warm up at room temperature, complete
formation of Bu3SnꢀCꢁCꢀC6H5 (6a) was ascertained by
GC-MS. Following a simple work-up, the pure product
was isolated in 83% yield. By applying the same se-
quence of transformation to the 2-iodothiophene (4b),
the 2-ethynylthiophene (5b) was first obtained, then
after cooling at −80°C, treatment with LDA afforded
the 2-(tributyltin)ethynylthiophene (6b) that was iso-
lated in 94% yield. In this case, the treatment with base
was carried out at lower temperature in order to pre-
vent a possible attack in position 5 of 2-ethynylthio-
phene. This straightforward procedure was also tested
on (h5-iodocyclopentadienyl)metallocarbonyl deriva-
tives 4c–e with the expectation of obtaining a conve-
nient access to the corresponding trialkyltinethynyl
derivatives, which are important intermediates for as-
sembling a variety of organometallic structures [4b,9e]
(Fig. 1).
Iodobenzene (4a) was chosen as model in order to
verify the feasibility of this transformation and to
search the conditions to conveniently carry out the
overall process. Since the Stille reaction can be effi-
ciently carried out under a variety of conditions, the use
of Pd(PPh3)4 as catalyst and THF as solvent resulted to
be suitable conditions either for the coupling with
tributyl(ethynyl)tin and for the subsequent use of LDA
as base to allow recombination of phenylacetylene (5a)
and Bu3SnI (Scheme 5). Transformations outlined in
Scheme 5 were conveniently monitored by GC-MS
and/or 1H-NMR. Iodobenzene (4a) and trib-
utyl(ethynyl)tin were reacted in the presence of 5 mol.%
of Pd(PPh3)4 catalyst in THF solvent. Following
overnight stirring at 70°C, a sample of the reaction
mixture analyzed by GC-MS showed only the presence
of phenylacetylene (5a) and Bu3SnI. After cooling at
We performed the Stille coupling to form compounds
5c–e using (CH3CN)2PdCl2 as catalyst and DMF sol-
vent [1e,f], which are milder conditions than those used

E. Antonelli et al. / Journal of Organometallic Chemistry 578 (1999) 210–222
213
The results obtained in the preparation of compounds
6a–e prompted us to use this one pot procedure to form
bifunctionalized tin acetylides, in view of the potential
of these compounds for the construction of highly
ethynylated materials (Scheme 2). The array of diiodo
aromatic derivatives 9a–f were then considered
(Scheme 6) in the perspective of using combination of
them and of the corresponding (bis)stannylethynyl
derivatives in the formation of polymeric materials.
All the diiodo compounds 9a–f efficiently undergo
the whole transformation outlined in Scheme 6 afford-
ing the corresponding (bis)tributyltinacetylides 11a–f in
80–90% isolated yields. As in the case of the mono-
functionalized derivatives, the progress of the two steps
1
sequence was conveniently checked by H-NMR spec-
troscopy (Fig. 2). Despite the fact that the side chains
on the aromatic rings compounds 9b–d and f, can
partially overlap with the signals of the butyl groups on
tin, a sequence of spectroscopic variations, as those
reported in Fig. 2 can be clearly depicted for all
substrates.
1
Trace (a) of Fig. 2 represents a portion of the H-
NMR spectrum of the reaction mixture before addition
of the palladium catalyst, thus before the start of the
reaction. The spectrum shows the spectroscopic pattern
of Bu3SnꢀCꢁCH characterized by four distinct multi-
plets, due to the methyl group and to the three
methylene groups, and a singlet due to the acetylenic
proton. Trace (b) is the spectrum of the reaction mix-
ture after the completion of the first step. Bu3SnꢀCꢁCH
has been totally consumed and Bu3SnI formed displays
three multiplets. The methyl and one of the three
methylene groups show distinct signals, while signals of
the other two methylenes are collapsing in a single
multiplet. Trace (c) of Fig. 2 is characteristic of the
completion of the overall process. The Bu3Sn group—
bound again to the acetylene moiety—displays the four
multiplets pattern as it was in trace (a). This sequence
was identically observed for all substrates.
Fig. 2. Portions of 1H-NMR spectra in the range 2.3–0.7 ppm for the
transformation 9a–11a. Spectra were recorded on a sample of the
reaction mixture evacuated from the solvent and redissolved in
CDCl3. Trace (a) 9a and Bu3SnꢀCꢁCH before the addition of the Pd
catalyst. Trace (b) complete formation of 10a and Bu3SnI. Trace (c)
complete formation of 11a.
on compounds 4a,b, due to the more delicate nature of
the intermediate organometallic alkynes. After this first
step, LDA was directly added to the cooled reaction
mixture, and, trialkyltinethynyl derivatives 6c–e were
then isolated in 86–90% yields.
The reactions of compounds 4c–e were monitored by
1H-NMR techniques, which provided a very clear pic-
ture of the overall transformation (vide infra Fig. 2).
Scheme 6.

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E. Antonelli et al. / Journal of Organometallic Chemistry 578 (1999) 210–222
Scheme 7.
Scheme 8.
3. Formation of polymers
Compounds 9b–d and f of Scheme 6, bearing side
chains of variable length on the aromatic ring, were
prepared foreseeing that high molecular weight materi-
als would be more easily accessible if good solubility
can be assured [19a]. In addition, material properties
are strongly influenced by the presence and the size of
side chains [21]. It is important to remark that in the
preparation of compounds 9b–d, described by Yu [22]
and adopted by several other authors [23] (Scheme 7),
we experienced that a larger amount of absolutely fresh
reagents [24] must be used in order to succeed in the
formation of the expected products.
The first attempt of preparing a polymeric material
by palladium-catalyzed cross-coupling was carried out
by reacting an equivalent amount of 2,5-
bis[(tributyltin)ethynyl]thiophene (11e) and 1,4-dibu-
toxy-2,5-diiodobenzene (9b) in the presence of 5 mol.%
of Pd(PPh3)4 in THF solvent (Scheme 8). After 24 h at
80°C, a sample of the reaction mixture examined by
1H-NMR showed complete consumption of starting
materials and a new set of signals attributable to poly-
meric material was observed. After filtration on a celite
pad precipitation by methanol yielded a red powder.
The molecular weight of the polymeric material 12,
evaluated by gel permeation chromatograpy (GPC), is
2100 and corresponds to 6 repeat units (Table 2). Fig. 3
reports the 13C-NMR spectrum of the product ob-
tained; the pattern of the signals indicates the stereoreg-
ular structure of the polymer and the estimated 6-term
chain length by the ratio of signals of internal and
terminal CꢁC groups [25].
According to the general design outlined on path (a)
of Scheme 2, compounds 9a–f and 11a–f (Scheme 6)
represent two arrays of coupling partners suitable to be
combined under the Stille protocol to generate p-conju-
gated poly(arylene ethynylene) type polymers
(ꢀArꢀCꢁCꢀAr%ꢀCꢁCꢀ)n (Ar, Ar%=phenyl, thienyl).
Moreover, by the use of our recently developed Pd-cat-
alyzed procedure for metal–carbon bond formation [9]
(path (b) of Scheme 2), coupling of (bis)stannylethynyl
derivatives 9a–f with organometallic dihalides should
allow formation of polymers incorporating metals into
the conjugated backbone of type (ꢀArꢀCꢁCꢀMꢀCꢁCꢀ)n
(Ar=phenyl, M=metal). In this respect, researchers
involved in advanced materials sciences are currently
devoting a great deal of attention to these two class of
polymers in view of their remarkable properties, and
new convenient preparative methods are intensely ex-
plored [14–22]. With regard to poly(arylene ethynylene)
materials, beside the Hay oxidative coupling of terminal
alkynes [14], the palladium/copper-mediated couplings
of aryl halides and terminal alkynes are the most used
methods to obtain these polymers [15–17], while the
palladium catalyzed coupling reaction of tinalkynes and
aryl halides—the Stille reaction—has only recently re-
ceived some attention [18,19]. Conversely, preparation
of polymers containing s-bonded metals in the main
chain has essentially been developed by the following
procedures: (i) dehydroalogenation between bis-ethynyl
compounds and transition metal halides, (ii) oxidative
coupling of terminal alkyne complexes, (iii) alkynyl
ligand exchange reaction [20], and (iv) condensation of
transition metal halides with bis(trimethylstannyl) com-
plexes [28].
We then decided to extend the one pot procedure,
used to form 11e, to the preparation of the polymer
itself. 2,5-Diiodothiophene (9e) was thus reacted with

E. Antonelli et al. / Journal of Organometallic Chemistry 578 (1999) 210–222
215
All polymers remained in solution during synthesis,
but some of them (vide infra) became insoluble after
isolation. Differences in solubility are observed within
the set of the organic polymers 12–16. Polymer 12 is
more soluble in dicholoromethane than in chloroform,
polymer 13 shows a very limited solubility in common
organic solvents, while 14–16 are well-soluble in chlo-
roform, dichloromethane and THF. These solubility
differences are correlated with the length and the num-
ber of the side chains on the aromatic moieties
[21b,16f]. On the contrary, after precipitation, all the
organometallic polymers 19–21 remained insoluble. Ev-
idently, the introduction of an aryl spacer bearing two
butyloxy (20) or octyloxy (21) side chains had no effect
on solubility with respect to 19, where a simple thio-
phene unit is spacing the organometallic blocks. The
tetramer 22 is a well-soluble material obtained by our
standard procedure. It represents a low oligomer of a
polymer obtained by Hagiara by dehydrohalogenation
[20]. Although the present method yields only a four
chain unit, its formation shows that the platinum–chlo-
rine moiety may also undergo palladium-catalyzed cou-
pling with tributyltin acetylides, thus envisioning a
possible expansion of our Pd-catalyzed metal–carbon
bond formation procedure [9].
tributyl(ethynyl)tin in the presence of Pd(PPh3)4 and
LDA, according to procedure outlined in Scheme 6.
Once ascertained complete formation of 11e, by 1H-
NMR, 1,4-dibutoxy-2,5-diiodobenzene (9b) and an ad-
ditional amount of zerovalent palladium catalyst were
directly added to the same reaction mixture where 11e
had formed. Following 24 h of reflux and work up, a
product showing identical characteristics of 12 was
isolated. This result shows that not only the two steps
needed to transform the diiodide in distannylacetylyde
may be carried out one pot, but that, once the distan-
nane is formed, a second diiodide may be added di-
rectly into the same reaction mixture, thus extending
the one pot process up to the formation of the poly-
meric material (path (a) of Scheme 2). It is important to
note that while the first coupling only occurs in the
presence of Pd(PPh3)4, the second coupling, leading to
the polymer, may be efficiently carried out using either
Pd(PPh3)4 or Pd(dba)2. When Pd(dba)2 is added to
perform the second coupling, the reaction mixture con-
tains PPh3 from the catalyst of the first coupling.
Therefore, the effective catalytic specie may be the same
in the two different steps [26].
By the use of this extended one pot procedure poly-
meric materials listed in Table 1 were obtained in a
straightforward manner. As described for 12 all the
polymers were isolated and purified by precipitation
with methanol. Polymers 13–16 were obtained in good
yield as yellow, red or brownish solids and are stable in
air, while organometallic polymers 19–21, obtained by
Pd-catalyzed coupling of bis(tin)acetylydes 9e, b and c
with the diiododerivative 17 [9e] (Fig. 4) appear as dark
brown solids.
Molecular weights were estimated using GPC. Table
2 reports the weight average molecular weights (MW),
the number average molecular weights (Mn), and the
molecular weight distribution (MWD=MW/Mn) values
calculated against polystyrene standards. It is known
that, using randomly coiled polystyrene as calibration
standards, the molecular weight of rigid rod material
may be greatly overestimated. Therefore, we adopted
Fig. 3. 13C-NMR spectra of polymer 12. The multiplet marked with an asterisk is relative to the CD2Cl2 solvent.

216
E. Antonelli et al. / Journal of Organometallic Chemistry 578 (1999) 210–222
Table 1
dure can lead to higher order of polymerization. The
UV absorption spectra of polymers, recorded in chloro-
form, show a typical broad absorption with a maxi-
mum in the range of u=400–440 nm (Table 2). As an
example, Fig. 5 shows the UV spectra of polymer 16
and the corresponding block precursors 11d and 11f.
The consistent shift with respect of the value of the
maximum of the corresponding aromatic diacetylenic
units is a rather direct evidence of extensive electronic
conjugation, and to some extent it is a direct measure
of chain length growing [19b], although to a certain
value this effect approaches saturation [15c,17,27].
The one pot route to polyacetylene and polymetal-
laacetylene polymers here described has some resem-
blance with a one pot route to polyacetylenes previously
reported by Carpita [28] and others [16,17]. There are
however some remarkable differences between the two
the criteria used by Tour [15b,c], which has demon-
strated that the actual molecular weight of rigid rod
polymers is better estimated by decreasing of about
20% the Mn value obtained by GPC. In the case of
polymers 19–21 that are scarcely soluble in THF, the
values reported are probably related only to the frac-
tions of lower oligomers. Since the scarce solubility of
these polymers did not allow the characterization by
NMR, they were characterized only by UV and IR
spectroscopy. Two distinct bands in the region 2210–
2092 cm−1 were observed in the IR spectra of polymers
19–21. The higher frequency was assigned to the
stretching of the CꢁC spacing the cyclopentadienyl and
the thiophene moieties, the second to the CꢁC spacing
the iron and the other thiophene unit.
Polymers 12, 14–16 and 22 were fully characterized
1
1
by H- and 13C-NMR spectra, whereas only H-NMR
was recorded for 13, due to its limited solubility. As in
the case of 12 (Fig. 3) the complete carbon skeleton of
all the soluble polymers was clearly identified in the
13C-NMR spectra, including the acetylenic carbons that
are usually very difficult to detect [16f,19a]. A number
average degree of polymerization (DP) of about 5–9
repeated units was obtained for all the soluble polymers
by this method. Although these degrees of polymeriza-
tion are in the lower range of the average values
reported for polymers obtained by Pd-catalyzed cou-
pling of bis(trialkyltin) acetylides and dihalides
[18,19a,c], we believe that optimization of this proce-
Fig. 4. Organometallic structures of compounds 17 and 18.

E. Antonelli et al. / Journal of Organometallic Chemistry 578 (1999) 210–222
217
Table 2
Characteristic values of the polymers 12–22
a
b
Polymer
Yield (%)
MW
Mn
MWDc
DPd
umax (nm)e
w (CꢁC) (cm−1
)
12
13
14
15
16
19
94
72
93
86
98
82
8850
10150
6600
7950
25100
3300
2900
3650
3000
4600
10300
2700
3.0
2.7
2.2
1.7
2.4
1.2
6i
8i
5i
5i
9i
4j
437
394
404
412
443
339
2206f
2209f
2208f
2196f
2194f
2210g
2091
20
21
22
88
79
87
2000
3500
2600
1800
3000
1700
1.1
1.2
1.5
3j
4j
4j
365
356
380
2192g
2101
2204g
2105
2102h
a Weight average molecular weights.
b Number average molecular weights.
c Molecular weight distribution (MW/Mn).
d Degree of polymerization.
e UV–visible spectra recorded in CHCl3.
f Recorded in Nujol.
g Recorded in KBr.
h Recorded in CH2Cl2.
i Calculated by decreasing the Mn value by 20%.
j Calculated on the basis of the MW value [7b].
Fig. 5. UV–visible spectra in CHCl3 of 16 (—), 11d (······) and 11f (---).
reaction mixture produced cleavage of the carbinol
protecting group and formation of the polymers (24).
Although in the reported cases polymers are formed
in moderate to good yields, the phase transfer condi-
tions might be restricting conditions for more general
procedures. In that report (Scheme 9), palladium catal-
ysis coupling of a dihaloarene (20) with two equivalents
of 2-methyl-3-butyn-2-ol (21), under basic phase trans-
fer conditions, afforded the arylbisalkynol 22. Addition
of the second dihaloarene (23) and warming up of the

218
E. Antonelli et al. / Journal of Organometallic Chemistry 578 (1999) 210–222
Scheme 9.
uses. Moreover, being deprotection of acetylene groups
the rate limiting factor, the second part of the reactions
must be run at high temperature (110–130°C) and
needs long reaction times (48–72 h), conditions that
might be detrimental for the intermediate free diacetyle-
nes. Finally, owing to the more complicate reaction
media, isolation of the final product is more laborious.
5. Experimental
5.1. General procedures
Elemental analyses were performed by the Servizio
Microanalisi of the Area della Ricerca di Roma (CNR,
Montelibretti). IR spectra were recorded on a Nicolet
FT 510 instrument in the solvent subtraction mode,
using a 0.1 mm CsI cell or polyethylene disk. UV
spectra were recorded on a Varian Cary 1 spectropho-
tometer. 1H-NMR, 13C-NMR and 31P-NMR spectra
were recorded on a Bruker AC300P spectrometer at
300, 75 and 121 MHz, respectively. The 1H-NMR
chemical shifts (ppm) are relative to Me4Si, assigning
4. Concluding remarks
With the present work we have disclosed an efficient
one pot process allowing direct transformation of aro-
matic iodides and diiodides into the corresponding
trialkyltinacetylides and bistrialkyltinacetylides. These
products may be either isolated and used for a variety
of synthetic purposes or reacted in situ with a proper
coupling partner in an extended one pot procedure to
form polyacetylene or polymetallaacetylene polymers.
There are distinct advantages of our straightforward
transformation. No isolation of the free alkyne interme-
diate is necessary. This is a particularly remarkable
point, considering the fact that free alkynes are delicate
materials which often present uncontrolled reactivity,
troublesome preparation, and hazardous handling
[11,12], thus discouraging their use. In addition new,
expensive or hazardous tin reagents are not required to
transform the intermediate free alkyne into tinacetylide,
since the side product generated during the first step of
the transformation is reutilized. In this respect, authors
using the (trimethyltin)ethynyl/halide condensation pro-
cedure clearly alert users about the hazardous handling
of trimethyltinchloride [29], the most toxic tin reagent
[30], whereas tributyltin halides have a very low toxicity
and are easier to handle. Finally, the poly(arylene
ethynylene) materials prepared by this new and conve-
nient synthetic route show an high degree of stereoregu-
larity, and in most cases of processability, which are
important prerequisites for applications in electronic
and optical devices. The same procedure was also
shown to be very promising for obtaining organometal-
lic polymers. These materials will probably improve
their chemical properties by elongation of the side
chains on the aromatic moieties.
1
the residual H impurity signal in the solvent at 7.24
ppm (CDCl3) and 5.30 ppm (CD2Cl2). The 13C-NMR
chemical shifts are calibrated to the 13C triplet of
CDCl3 at 77.00 ppm and to the 13C multiplet of CD2Cl2
at 54.20 ppm. The31P-NMR chemical shifts are relative
to 85% H3PO4. GC-MS analyses were performed on a
HP5890 GC (OV1 capillary column, 12 m×0.2 mm)
coupled with a HP5970 MSD and on a Fisons Instru-
ments VG-Platform Benchtop LC-MS (positive ion
electrospray mass spectra, ESP+) spectrometer. Molec-
ular weights were determined (relative to polystyrene
standard) on a Perkin-Elmer gel permeation chro-
matograpy (GPC) equipped with a set of PL-gel
columns and a UV detector. CHCl3 (HPLC grade;
Aldrich) was the eluent (flow rate: 1 ml min−1).
Solvents, including those used for NMR and chro-
matograpy, and liquids were thoroughly degassed be-
fore use. Chromatographic separations were performed
with 70–230 mesh silica gel (Merck).
All manipulations were carried out with Schlenk-type
equipment under an atmosphere of argon on a dual
manifold/argon vacuum system. All solvents were dried
(sodium–potassium alloy for tetrahydrofuran (THF),
CaH2 for N,N-dimethylformamide (DMF) and P2O5
for CH2Cl2) and argon-saturated prior to use. The
compounds:
(h5-C5H4I)Fe(CO)2CH3
[6a],
(h5-
C5H4I)Re(CO)3 [6a], (h5-C5H4I)W(CO)3CH3 [6a],
(CH3CN)2PdCl2 [14], (PPh3)4Pd [15], trans-[PtCl2{n-
C4H9)3P}2] [31] were prepared by known methods. 3-
Hexadecylthiophene [32] was prepared from 3-bromo-

E. Antonelli et al. / Journal of Organometallic Chemistry 578 (1999) 210–222
219
thiophene and hexadecylmagnesiumbromide in the
presence of Ni(dppp)2Cl2 following a reported proce-
dure [33]. In our hands 1,4-diiodo-2,5-bis(butyl-
oxy)benzene [22], 1,4-diiodo-2,5-bis(octyloxy)benzene
[23] and 1,4-diiodo-2,5-bis(hexadecyloxy)benzene [22]
were successfully prepared only by using a fourfold
excess of freshly received I2, HIO3, H2SO4 and
CH3COOH [24]. Other chemicals were purchased from
Aldrich or Strem and used as received unless otherwise
specified.
with 50 ml of hexane. The phases were separated, and
the organic layer was washed with water (3×50 ml)
and dried over sodium sulfate. Filtration and removal
of the solvent under reduced pressure provided 1.11 g
(90%) of product as a yellow liquid, which was spectro-
scopically pure. Attempts of obtaining an analytically
pure sample by chromatographic separation caused
partial removal of tributyltin groups.
In some cases the reaction was interrupted at the
formation of the intermediate bisacetylene, and the
product was isolated after treatment with an aqueous
saturated solution of KF and chromatographic separa-
tion [9d,e] (silica gel/hexanes).
5.2. Preparation of 2,5-diiodo-3-hexadecylthiophene
(9f)
1
Finely powdered I2 (5.205 g, 20 mmol) was added to
a stirred solution of 3-hexadecylthiophene (6.368 g, 20
mmol) in CH2Cl2 (40 ml) and the resulting mixture was
heated to reflux. A solution of HNO3 (1.7 ml) in H2O
(1.7 ml) was added dropwise with such a rate to main-
tain a gentle refluxing. After a further 3 h of reflux, the
flask was cooled and the organic layer was separated,
washed with H2O (2×50 ml), a saturated solution of
Na2S2O3 (50 ml), and dried over anhydrous Na2SO4.
The dried solution was evaporated to a crude product,
which was purified by column chromatography (SiO2)
using hexane as eluant. The product (9.37 g; 81%) was
isolated as tan solid.
5.3.1.1. 10a. H-NMR (CDCl3): l 3.14 (s, 2H, ꢁCH),
7.42 (s, 2H, ArꢀH).
MS (EI) m/e 126 (M+). Spectroscopic data are con-
sistent with literature reports [34].
5.3.1.2. 11a. IR (neat): 2925 (s), 2854 (s), 2135 (m), 1494
(m), 1461 (m), 1377 (m), 1258 (m), 600 (m), 510 (m)
cm−1
.
1H-NMR (CDCl3): l 0.89 (t, 18H, J=6.76 Hz), 1.03
(m, 12H), 1.33 (m, 12H), 1.55 (m, 12H)
(SnCH2CH2CH2CH3), 7.32 (s, 4H, ArꢀH).
13C-NMR (CDCl3): l 10.62, 13.14, 26.42, 28.36
(SnCH2CH2CH2CH3), 122.94, 131.08 (Ar), 94.66,
109.22 (ꢀCꢁCꢀ). Spectroscopic data are consistent with
literature reports [5].
IR (CH2Cl2): 3054 (s), 2987 (m), 2928 (m), 2855 (w),
2306 (w), 1422 (m), 1266 (s), 897 (m), 747 (s) cm−1
.
1H-NMR (CDCl3): l 0.85 (t, 3H, J=6.6 Hz, ꢀCH3),
1.23 (m, 28H, ꢀCH2ꢀ)14, 2.48 (t, 2H, J=7.6 Hz,
ꢀCH2ꢀthiop), 6.86 (s, 1H, Hꢀthiop). 13C-NMR
(CDCl3): l 14.18 (ꢀCH3), 22.73, 29.15, 29.41, 29.74,
29.98, 31.96, (ꢀCH2ꢀ)15, 75.81 (ꢀSꢀC(I)ꢂ), 137.80
(ꢀC(H)ꢂ), 149.56 (ꢀC(C16)ꢂ).
5.3.2. 1,4-Bis(ethynyl)-2,5-di(butyloxy)benzene (10b)
and 1,4-bis[(tributyltin)ethynyl]-2,5-di(butyloxy)benzene
(11b)
1
5.3.2.1. 10b. H-NMR (CDCl3): l 0.94 (t, 6H, J=7.41
Anal. Calc. for C20H34I2S: C, 42.87; H, 6,12. Found:
C, 42.56; H, 6.06.
Hz, ꢀCH3), 1.53 (m, 4H, ꢀCH2ꢀ), 1.76 (m, 4H, ꢀCH2ꢀ),
3.95 (t, 4H, J=6.51 Hz, ꢀOCH2ꢀ), 3.31(s, 2H, ꢁCH),
6.93, (s, 2H, ArꢀH).
5.3. General preparation of bis(ethynyl) deri6ati6es
(10a–f) and Bis[(tributyltin)ethynyl] deri6ati6es (11a–f)
13C-NMR (CDCl3): l 13.83 (ꢀCH3), 19.12, 31.16,
(ꢀCH2ꢀ)2, 69.24, (ꢀOCH2ꢀ), 79.75, 117.60, 153.88 (Ar),
82.37, 113.14 (ꢀCꢁCꢀ). Spectroscopic data are consis-
tent with literature reports [35].
5.3.1. 1,4-Bis(ethynyl)benzene (10a) and 1,4-bis[(tri-
butyltin)ethynyl]benzene (11a)
The procedure for the preparation of 1,4-bi-
s(ethynyl)benzene (10a) and 1,4-bis[(tributyltin)eth-
ynyl]benzene (11a) is representative. To a solution of
0.069 g (0.059 mmol) of Pd(PPh3)4 and 0.049 g of (1.49
mmol) of 1,4-diiodobenzene in 15 ml of THF, 0.86 ml
(2.98 mmol) of tributyl(ethynyl)tin were added. Follow-
ing overnight stirring 50°C, GC-MS analysis indicated
complete consumption of reactants. After cooling at
0°C, 1.49 ml (2.98 mmol) of a solution of LDA (2.0 M
sol. in THF/heptane/ethylbenzene) was added, and the
mixture was allowed to warm at room temperature.
Water (10 ml) was added to the reaction mixture, which
was then by transferred to a separatory funnel along
5.3.2.2. 11b. IR (CH2Cl2): 2925 (s), 2854 (s), 2132 (m),
1464 (m), 1377 (m), 1073 (m), 602 (w), 510 (w) cm−1
.
1H-NMR (CDCl3): l 0.89 (t, 18H, J=7.17 Hz), 1.03
(m, 12H), 1.34 (m, 12H), 1.58 (m, 12H)
(SnCH2CH2CH2CH3), 0.94 (t, 6H, J=6.96 Hz, ꢀCH3),
1.53 (m, 4H, ꢀCH2ꢀ), 1.74 (m, 4H, ꢀCH2ꢀ), 3.95 (t, 4H,
J=6.51 Hz, ꢀOCH2ꢀ), 6.85 (s, 2H, ArꢀH).
13C-NMR (CDCl3): l 11.15, 13.65, 26.95, 28.77
(SnCH2CH2CH2CH3), 13.88 (ꢀCH3), 19.21 (ꢀCH2ꢀ),
31.39 (ꢀCH2ꢀ), 69.04 (ꢀOCH2ꢀ), 114.08, 117.46, 153.74
(Ar), 99.09, 105.84 (ꢀCꢁCꢀ).
MS (ESP+) m/e 887 (M+K)+.

220
E. Antonelli et al. / Journal of Organometallic Chemistry 578 (1999) 210–222
5.3.3. 1,4-Bis(ethynyl)-2,5-di(octyloxy)benzene (10c)
and 1,4-bis[(tributyltin)ethynyl]-2,5-di(octyloxy)benzene
(11c)
(ꢀOCH2ꢀ), 114.06, 117.50, 153.74 (Ar), 99.00, 105.86
(ꢀCꢀCꢀ).
MS (ESP+) m/e 1185 (M+H)+.
1
5.3.3.1. 10c. H-NMR (CDCl3): l 0.86 (t, 6H, J=6.81
5.3.5. 2,5-Bis[(ethynyl)thiophene (10e) and 2,5-bis[(tri-
butyltin)ethynyl]thiophene (11e)
Hz, ꢀCH3), 1.28 (m, 12H, ꢀCH2ꢀ)3, 1.45 (m, 8H,
ꢀCH2ꢀ)2, 1.77 (m, 4H, ꢀCH2ꢀ), 3.94 (t, 4H, J=6.59 Hz,
ꢀOCH2ꢀ), 3.31(s, 2H, ꢁCH), 6.93, (s, 2H, ArꢀH).
13C-NMR (CDCl3): l 14.08 (ꢀCH3), 22.64 (ꢀCH2ꢀ),
25.96 (ꢀCH2ꢀ), 29.26 (ꢀCH2ꢀ)2, 31.83 (ꢀCH2ꢀ)2, 69.81
(ꢀOCH2ꢀ), 79.63, 117.60, 153.78 (Ar), 82.37, 113.13
(ꢀCꢁCꢀ). Spectroscopic data are consistent with litera-
ture reports [16d].
5.3.5.1. 10e. 1H-NMR (CDCl3): 3.33 (s, 2H, ꢁCH),
7.09, (s, 2H, thiopꢀH).
13C-NMR (CDCl3): l 76.33, 81.81 (ꢀCꢁCꢀ), 121.87,
131.62 (thiop).
MS (EI) m/e 132 (M+). Spectroscopic data are con-
sistent with literature reports [11a].
5.3.3.2. 11c. IR (CH2Cl2): 2925 (s), 2854 (s), 2130 (m),
1496 (m), 1466 (m), 1377 (m), 1221 (m), 604 (w), 504
5.3.5.2. 11e. IR (neat): 2925 (s), 2854 (s), 2122 (s), 1464
(w) cm−1
.
(s), 1377 (s), 1165 (s), 1074 (s), 802 (m), 687 (s), 599
1H-NMR (CDCl3): l 0.89 (t, 18H, J=7.41 Hz), 1.03
(m, 12H), 1.35 (m, 12H), 1.59 (m, 12H)
(SnCH2CH2CH2CH3), 0.86 (t, 6H, J=6.88 Hz, ꢀCH3),
1.28 (m, 12H, ꢀCH2ꢀ)3, 1.45 (m, 8H, ꢀCH2ꢀ)2, 1.76 (m,
4H, ꢀCH2ꢀ), 3.91 (t, 4H, J=6.66 Hz, ꢀOCH2ꢀ), 6.85 (s,
2H, ArꢀH).
(m), 504 (m) cm−1
.
1H-NMR (CDCl3): l 0.88 (t, 18H, J=7.20 Hz), 1.03
(m, 12H), 1.32 (m, 12H), 1.54 (t, 12H, J=7.20 Hz)
(SnCH2CH2CH2CH3), 6.94 (s, 2H, thiopꢀH).
13C-NMR (CDCl3): l 11.24, 13.64, 26.95, 28.83
(SnCH2CH2CH2CH3), 124.47, 131.26 (thiop), 99.54,
101.81 (ꢀCꢁCꢀ). Spectroscopic data are consistent with
literature reports [9c].
13C-NMR (CDCl3): l 11.17, 13.65, 26.72, 28.85
(SnCH2CH2CH2CH3), 14.04 (ꢀCH3), 22.66 (ꢀCH2ꢀ),
25.98 (ꢀCH2ꢀ), 29.30 (ꢀCH2ꢀ)2, 31.87 (ꢀCH2ꢀ)2, 69.41
(ꢀOCH2ꢀ), 114.11, 117.52, 153.74 (Ar), 99.07, 105.88
(ꢀCꢀCꢀ).
5.3.6. 2,5-Bis[(ethynyl)-3-(hexadecyl)thiophene (10f)
and 2,5-bis[(tributyltin)ethynyl]-3-(hexadecyl)thiophene
(11f)
MS (ESP+) m/e 967 (M+Li)+.
5.3.4. 1,4-Bis(ethynyl)-2,5-di(hexadecyloxy)benzene
(10d) and 1,4-bis[(tributyltin)ethynyl]-2,5-di(hexadecyl-
oxy)benzene (11d)
5.3.6.1. 10f. IR (neat): 3311 (s), 2924 (s), 2854 (s), 2104
(m), 1640 (m), 1466 (m), 1377 (m), 659 (m) cm−1
.
1H-NMR (CDCl3): 0.88 (t, 3H, J=6.44 Hz, ꢀCH3),
1.26 (m, 26H, (ꢀCH2ꢀ)13), 1.58 (m, 2H, ꢀCH2ꢀ), 2.64 (t,
2H, J=7.63 Hz, thiopꢀCH2ꢀ), 3.30 (s, 1H, ꢁCH), 3.42
(s, 1H, ꢁCH), 7.00, (s, 1H, thiopꢀH).
1
5.3.4.1. 10d. H-NMR (CDCl3): l 0.86 (t, 6H, J=6.67
Hz, ꢀCH3), 1.23 (m, 52H, ꢀCH2ꢀ)13, 1.78 (m, 4H,
ꢀCH2ꢀ), 3.94 (t, 4H, J=6.66 Hz, ꢀOCH2ꢀ), 3.31(s, 2H,
ꢁCH), 6.92, (s, 2H, ArꢀH).
13C-NMR (CDCl3): l 14.15 (ꢀCH3), 22.75, 29.19,
29.41, 29.74, 30.04, 30.34, 31.98, (ꢀCH2ꢀ)15, 76.01,
76.69, 81.67, 83.93 (ꢀCꢁCꢀ), (ꢀCꢁCꢀ), 118.89, 122.04,
133.71, 148.65 (thiop).
13C-NMR (CDCl3): l 14.13 (ꢀCH3), 22.69 (ꢀCH2ꢀ),
29.35 (ꢀCH2ꢀ), 29.69 (ꢀCH2ꢀ)11, 31.92 (ꢀCH2ꢀ), 69.60
(ꢀOCH2ꢀ), 79.75, 117.62, 153.91 (Ar), 82.39, 113.15
(ꢀCꢀCꢀ).
MS (ESP+) m/e 380 (M+Na)+.
MS (ESP+) m/e 692 (M+Na)+. Spectroscopic data
are consistent with literature reports [16c].
5.3.6.2. 11f. IR (neat): 2925 (s), 2854 (s), 2135 (m), 1494
(m), 1461 (m), 1377 (m), 1258 (m), 600 (m), 510 (m)
5.3.4.2. 11d. IR (CH2Cl2): 2925 (s), 2854 (s), 2132 (m),
cm−1
.
1496 (m), 1466 (m), 1377 (m), 1221 (m), 602 (w), 510
1H-NMR (CDCl3): 0.90 (t, 18H, J=7.15 Hz), 1.03
(m, 12H), 1.31 (m, 12H), 1.56 (m, 12H)
(SnCH2CH2CH2CH3), 0.89 (t, 3H, J=7.16 Hz, ꢀCH3),
1.23 (m, 26H, (ꢀCH2ꢀ)13), 1.57 (m, 2H, ꢀCH2ꢀ), 2.59 (t,
2H, J=7.78 Hz, thiopꢀCH2ꢀ), 6.86, (s, 1H, thiopꢀH).
13C-NMR (CDCl3): l 11.20, 13.63, 26.93, 28.88
(SnCH2CH2CH2CH3), 14.08 (ꢀCH3), 22.67, 29.34,
29.67, 31.93 (ꢀCH2ꢀ)15, 98.91, 101.03, 101.67, 102.31
(ꢀCꢁCꢀ), (ꢀCꢁCꢀ), 119.88, 122.67, 132.45, 147.10
(thiop).
(w) cm−1
.
1H-NMR (CDCl3): l 0.89 (t, 18H, J=7.26 Hz), 1.03
(m, 12H), 1.32 (m, 12H), 1.57 (m, 12H)
(SnCH2CH2CH2CH3), 0.86 (t, 6H, J=6.82 Hz, ꢀCH3),
1.23 (m, 52H, (ꢀCH2ꢀ)13), 1.76 (m, 4H, ꢀCH2ꢀ), 3.91 (t,
4H, J=6.51 Hz, ꢀOCH2ꢀ), 6.85 (s, 2H, ArꢀH).
13C-NMR (CDCl3): l 11.18, 13.68, 27.03, 28.87
(SnCH2CH2CH2CH3), 14.12 (ꢀCH3), 22.69 (ꢀCH2ꢀ),
29.36 (ꢀCH2ꢀ), 29.70 (ꢀCH2ꢀ)11, 31.92 (ꢀCH2ꢀ), 69.40

E. Antonelli et al. / Journal of Organometallic Chemistry 578 (1999) 210–222
221
5.4. General preparation of polymers
13C-NMR (CDCl3): l 14.13 (ꢀCH3), 22.72 (ꢀCH2ꢀ),
26.05 (ꢀCH2ꢀ), 29.40 (ꢀCH2ꢀ), 29.74 (ꢀCH2ꢀ)10, 31.95,
69.63, (C16H33ꢀthioph and C16H33O2ꢀAr), 113.68,
116.44, 153.52 (Ar), 120.39, 123.34, 132.83, 147.76
(thioph), 88.58, 90.80 (ꢀCꢁCꢀ).
The typical polymerization procedure was as follows:
the diiodo monomer (1 mmol) and zero valent palla-
dium (2 mol.% equivalent) were directly added to the
flask where the distannyl monomer (1 mmol) had just
formed according to the one pot procedure described as
above. The mixture was then refluxed for 24 h and after
cooling, was filtered on a glass frit over a celite pad in
order to remove the metallic palladium. The filtrate was
then concentrate to a minimum volume, and precipi-
tated with methanol. The precipitate was collected by
filtration, washed with methanol repeatedly, and dried
under vacuum.
5.4.6. Poly{2,5-bis[(p5-(ethynyl)cyclopentadienyl)-
irondicarbonyl]thiophene-2,5-bis(ethynyl)thiophene} (19)
IR (KBr): 2210.5, 2091.9, 2041.5, 1997.7 cm−1
.
5.4.7. Poly{2,5-bis[(p5-(ethynyl)cyclopentadienyl)-
irondicarbonyl]thiophene-1,4-[2,5-di(butyloxy)benzene]}
(20)
IR (KBr): 2192.0, 2101.1, 2038.8, 1994.5 cm−1
.
5.4.1. Poly{[1,4-bis (ethynyl)-2,5-di(butyloxy)-
benzene]-1,4-thiophene} (12)
5.4.8. Poly{2,5-bis[(p5-(ethynyl)cyclopentadienyl)-
irondicarbonyl]thiophene-1,4-[2,5-di(octyloxy)benzene]}
(21)
1H-NMR (CD2Cl2): l 0.98 (m, 6H, ꢀCH3), 1.54 (m,
4H, ꢀCH2ꢀ), 1.81 (m, 4H, ꢀCH2ꢀ), 4.00 (m, 4H,
ꢀOCH2ꢀ), 6.96 (s, 2H, thiopꢀH), 7.13, (s, 2H, ArꢀH).
13C-NMR (CD2Cl2): l 14.46 (ꢀCH3), 20.08, 32.05,
(ꢀCH2ꢀ)2, 70.10, (ꢀOCH2ꢀ), 114.31, 117.05, 154.38
(Ar), 125.66, 132.81 (thioph), 88.45, 91.92 (ꢀCꢁCꢀ).
IR (KBr): 2204.4, 2104.8, 2040.1, 1995.7 cm−1
.
5.4.9. Poly{2,5-bis[(ethynyl) benzene]-trans-
(bistributylphosphine)platinum} (22)
IR (CH2Cl2): 2959 (s), 2102 (m), 1498 (m), 1436 (m),
1262 (s), 1094 (s), 1019 (s), 904 (w) 801 (s) 367 (w)
5.4.2. Poly{[1,4-bis (ethynyl)-2,5-di(butyloxy)benzene]-
1,4-benzene} (13)
cm−1
.
1H-NMR (CDCl3): l 0.89 (br, 72H), 1.42–1.53 (br,
96H), 2.11 (br, 48H), 1.56 (m, (P(CH2CH2CH2CH3)3),
7.08 (s, 12H, Ar).
1H-NMR (CDCl3): l 0.99 (m, 6H, ꢀCH3), 1.57 (m,
4H, ꢀCH2ꢀ), 1.80 (m, 4H, ꢀCH2ꢀ), 4.00 (m, 4H,
ꢀOCH2ꢀ), 7.00 (s, 2H, ArꢀH), 7.48, (s, 4H, ArꢀH).
13C-NMR (CDCl3):
l
13.60, 23.95, 26.19
(P(CH2CH2CH2CH3)3), 109.44 (ꢀCꢁCꢀ), 127.61, 130.09
5.4.3. Poly{[1,4-bis (ethynyl)-2,5-di(octyloxy)-
benzene]-1,4-benzene} (14)
(Ar).
31P-NMR (CDCl3): l 0.85 (JPꢀPt=2302 Hz), 3.54
(JPꢀPt=2363 Hz).
1H-NMR (CDCl3): l 0.86 (m, 6H, ꢀCH3), 1.26 (m,
20H, ꢀCH2ꢀ)4, 1.54 (m, 4H, ꢀCH2ꢀ), 1.81 (m, 4H,
ꢀCH2ꢀ), 3.99 (m, 4H, ꢀOCH2ꢀ), 6.97, (s, 2H, ArꢀH),
7.47, (br, 4H, ArꢀH).
6. Supplementary material
13C-NMR (CDCl3): l 13.94 (ꢀCH3), 22.86 (ꢀCH2ꢀ),
26.09 (ꢀCH2ꢀ), 27.11 (ꢀCH2ꢀ), 29.42 (ꢀCH2ꢀ)2, 31.99
(ꢀCH2ꢀ), 69.60 (ꢀOCH2ꢀ), 114.96, 117.24, 153.59 (Ar),
123.26, 131.37 (Ar), 88.47, 93.74 (ꢀCꢁCꢀ).
NMR spectra for all new compounds are available
on request from the corresponding author.
5.4.4. Poly{[1,4-bis (ethynyl)-2,5-di(hexadecyloxy)-
benzene]-1,4-thiophene} (15)
Acknowledgements
1H-NMR (CDCl3): l 0.85 (br, 6H, ꢀCH3), 1.23 (br,
52H, (ꢀCH2ꢀ)13), 1.79 (br, 4H, ꢀCH2ꢀ), 3.97 (br, 4H,
ꢀOCH2ꢀ), 6.95 (s, 2H, thiopꢀH), 7.12, (s, 2H, ArꢀH).
13C-NMR (CDCl3): l 14.15 (ꢀCH3), 22.73 (ꢀCH2ꢀ),
26.05 (ꢀCH2ꢀ), 29.76 (ꢀCH2ꢀ)11, 31.97, (ꢀCH2ꢀ), 70.03,
(ꢀOCH2ꢀ), 113.71, 116.34, 153.61 (Ar), 124.92, 131.70
(thioph), 88.00, 91.01 (ꢀCꢁCꢀ).
This work was partially supported by the Consiglio
Nazionale delle Ricerche (C.N.R. Roma) within the
Progetto Finalizzato C.N.R. ‘Materiali Speciali per
Tecnologie Avanzate II’, contract n. 97.00946.PF34.
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