First perphenylated carbo-oligoacetylenes: An extension of the polytriacetylene family

Article abstract of DOI:10.1002/chem.201201555

The first examples of a novel family of sp-carbon-rich n-π-conjugated oligomers/polymers, namely carbo-mers of polyacetylene, also referred to as "1,4-PTA" isomers of the classical polytriacetylenes (1,2-PTAs), are described in the perphenylated series. T

Full text of DOI:10.1002/chem.201201555

FULL PAPER
DOI: 10.1002/chem.201201555
First Perphenylated carbo-oligoacetylenes:
An Extension of the Polytriacetylene Family
Arnaud Rives,[a, b] Valꢀrie Maraval,*[a, b] Nathalie Saffon-Merceron,[c] and
Remi Chauvin*[a, b]
Abstract: The first examples of a novel
zag arrangement in the crystal state.
The third member of the family, isolat-
ed in SnCl2 matrix, proved to be stable
in the solid state and was characterized
by MALDI-TOF MS, 1H NMR,
family of sp-carbon-rich n-p-conjugat-
ed oligomers/polymers, namely carbo-
mers of polyacetylene, also referred to
as “1,4-PTA” isomers of the classical
polytriacetylenes (1,2-PTAs), are de-
scribed in the perphenylated series.
The two first representatives proved to
be stable in solution, and exhibit a zig-
CPMAS 13C NMR, and absorption
spectroscopy. An explanation for its re-
activity in solution is proposed. The
chromophoric properties in the visible
region are shown to vary significantly
and consistently along the series.
Keywords: alkynes · chromophores ·
conjugation · polymers · solid-state
structures
Introduction
and theoretical levels.[5] The PTAs, here termed as “1,2-
PTAs”, however, possess regioisomers, termed 1,4-PTA,
that, in contrast, have not been exemplified, nor even con-
sidered yet to the best of our knowledge (an explanation for
the 1,2- vs. 1,4-locants is illustrated in Figure 1). It should be
noted that alternative denominations would also be consis-
tent with respect to the OPE series (OMEs, “oligomethine-
thynylenes”), or to more classical methods for generating
names (“oligopropargylidenyls”). The backbone of 1,4-PTAs
is actually the carbo-mer of the reference PA backbone,[6]
and these “carbo-oligoacetylenes” naturally deserve atten-
tion, for their conducting properties in particular. The chem-
istry of carbo-mers hitherto focused on cyclic molecules, and
more precisely on pericyclynes[7] (carbo-mers of cycloal-
kanes)[8] and carbo-benzenes.[9] The extent of p-conjugation
of the latter make them suitable for endowment of chromo-
phoric properties, whereas their intrinsic associated sensitivi-
ty (to protonation, oxidation, reduction, polymerization, or
p-rearrangements) was assumed to be moderated by their
aromatic character.[10] A few early and recent publications,
however, show that related acyclic sp-carbon-rich di- and
tetra-alkynylbutatrienes are actually quite stable when they
are capped with aromatic or bulky silyl substituents.[11]
These reports encouraged us to undertake the synthesis of
oligomeric versions of 1,4-PTAs. The results are disclosed
herein.
With the aim of tuning the electronic or optical properties
of organic materials, the design and synthesis of conjugated
oligomers and polymers are currently based on the decora-
tion of standard hydrocarbon backbones, such as oligophe-
nylenes (OPs), oligophenylenevinylenes (OPVs), oligophe-
nyleneethynylenes (OPEs), and others, providing a tradeoff
between stability and p-conjugation efficiency.[1] In most of
these materials, however, the stabilizing aromatic phenylene
units tend to act as p-insulating motifs. Nonaromatic back-
bones have thus also been considered by reference to polya-
cetylene (PA).[2] Beside the poly(diacetylene)s (PDAs),[3] the
family of nonaromatic conjugated oligomers has been ex-
tended to the even more carbon-rich poly(triacetylene)s
(PTAs), first exemplified in 1994 (Figure 1).[4] Since then,
many examples of PTA oligomers have been considered for
their physicochemical properties, at both the experimental
[a] Dr. A. Rives, Dr. V. Maraval, Prof. R. Chauvin
CNRS
LCC (Laboratoire de Chimie de Coordination)
205, route de Narbonne
31077 Toulouse (France)
Fax : (+33)5-61-55-30-03
E-mail: vmaraval@lcc-toulouse.fr
chauvin@lcc-toulouse.fr
[b] Dr. A. Rives, Dr. V. Maraval, Prof. R. Chauvin
Universitꢀ de Toulouse, UPS, INPT, LCC
31077 Toulouse (France)
Results and Discussion
[c] Dr. N. Saffon-Merceron
Universitꢀ de Toulouse
UPS, Institut de Chimie de Toulouse, ICT-FR 2599
118, route de Narbonne, 31062 Toulouse (France)
Although, to the best of our knowledge, phenylated 1,2-
PTAs are not known, the first 1,4-PTA oligomers were tar-
geted in the perphenylated series; the synthesis of related
hexaoxy[6]pericyclynes and carbo-benzenes is indeed easier
in their aryl-substituted versions.[8b,d,9] On the other hand, in
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/chem.201201555. It includes synthetic
procedures and characterization data for all new compounds, as well
as details of the crystal-structure determination of 6.
Chem. Eur. J. 2012, 00, 0 – 0
ꢁ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
1
&
ÞÞ
These are not the final page numbers!

in dichloromethane (CH2Cl2) at
low temperature. The resulting
pink-red solution was then
treated with aqueous NaOH to
give the conjugated bis-buta-
triene 6, which was isolated in
95% yield after chromatogra-
phy.
1H NMR spectroscopy in
CDCl3 solution showed that 6
occurs as a mixture of its three
diastereoisomers (cis-cis, cis-
trans, and trans-trans). Whereas
the kinetic barrier of the binary
cis/trans stereoconversion of 1
could
be
determined
by
¼
1H NMR spectroscopy (DG
AHCTUNGTRENNUNG
(298 K)=22 kcalmolꢀ1),[11d] sim-
ilar attempts for the ternary cis-
cis/cis-trans/trans-trans stereo-
conversion of 6 were not con-
clusive due to the overlap of
the aromatic 1H signals of the
Figure 1. Examples of conjugated polymers with all-carbon nonaromatic backbones and almost homogeneous
constitutions. A specificity of the 1,4-PTA backbone is that it possesses a single type of apolar resonance form,
just as the reference polyacetylene does. Because the lateral substituents (or H atoms) at the sp2-C atoms are
not in vicinal positions, the formal polymerization of triacetylene relies on a sequential 1,4-CH-addition proc-
ess rather than the 1,2-CH-addition process for the classical PTAs, here termed 1,2-PTAs (the direct triacety-
ꢀ
lene polymerization scheme without C H bond cleavage also generates 1,2-PTAs through the less representa- eight nonequivalent phenyl
tive resonance form b involving [5]cumulenic motifs).
groups (instead of two for 1.
the challenging 1,4-PTA chain, the butatriene motifs are in-
trinsically more sensitive than the butyne motifs. Although
terminal substitution of the external butatriene motifs by
aryl groups should be more stabilizing (and possibly inter-
esting for other purposes), the longest linearly conjugated
fragments targeted here are terminated with alkynyl ends.
Because alkynylbutatrienes have been shown to be stabi-
lized by bulky aryl or trialkylsilyl substituents, tri(isopropyl)-
silyl (TIPS) end caps were retained. The smallest represen-
tative is the known diphenyl-bis-[tri(isopropyl)silylethynyl]-
butatriene (1), which was pre-
Scheme 1. Preparation and molecular view of the X-ray crystal structure
of the known diphenylated 1,4-PTA monomer 1.[11d]
pared by reductive coupling of
the
gem-dihaloenyne
2
(Scheme 1).[11d] The 1,4-PTA
monomer 1 proved to be stable
both in solution and in the solid
state, and was found to crystal-
lize in its trans configuration.
The second 1,4-PTA repre-
sentative was then targeted
from two known precursors,
namely diether 3 (as a meso/dl
mixture)[8d] and TIPS-protected
ynone 4a.[11d] Addition of the
Scheme 2. Synthesis of tetraphenylated 1,4-PTA dimer 6.
dilithium salt of triyne 3 to two
equivalents of 4a gave pentayne 5a in 51% yield after chro-
matography (Scheme 2). It must be stressed that 5a and all
related phenylcarbinoxy-skipped oligoynes described below
were obtained as mixtures of stereoisomers, which were not
resolved before further treatment. The diol mixture 5a was
thus submitted to acidic reductive treatment with SnCl2/HCl
See Figure S1 in the Supporting Information). This 1,4-PTA
dimer proved, however, to be stable, both in solution and in
the solid state. Green-iridescent black crystals deposited
from a CHCl3/CH3CN solution were analyzed by X-ray dif-
fraction, and were found to correspond to the all-trans con-
figuration of 6 (Figure 2).[12] The measured bond lengths and
&
2
&
www.chemeurj.org
ꢁ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 0000, 00, 0 – 0
ÝÝ
These are not the final page numbers!

Perphenylated Carbo-oligoacetylenes
FULL PAPER
Scheme 4. Preparation of hexaphenylated 1,4-PTA trimer 11.
Figure 2. Molecular view of the all-trans isomer of the 1,4-PTA dimer
6.[12]
however, the medium became brown and the expected tris-
butatriene 11 could be neither isolated nor even detected by
1H NMR spectroscopy. Assuming that the blue product was
the 1,4-PTA trimer 11, the reaction mixture was carefully fil-
tered at low temperature (ꢀ258C) to give the dark-blue
solid, which turned out to be stable in the “dry” state at
room temperature, but readily decomposed upon partial re-
dissolution. MALDI-TOF MS analysis of the solid showed a
molecular peak at m/z 1016.52, corresponding to that of the
trimeric 1,4-PTA structure 11.
angles are similar to those measured in the previously re-
ported monomer 1 (see Table S1 in the Supporting Informa-
tion). The relative extension of the linear n-p-conjugation
upon going from 1 (7 bonds) to 6 (13 bonds) thus has negli-
gible effects on both the stability and the geometry.
The third member of the perphenylated-silyl-capped 1,4-
PTA series was envisaged through the same strategy, from
triyne 3 and TMS-protected ynone 4b (Scheme 3). TMS-
Further characterization of 11 was hampered by its poor
solubility and stability in classi-
cal organic solvents. Indeed,
light-colored blue solutions
could be obtained in tetrahy-
drofuran (THF), CH2Cl2 or
CHCl3, but rapidly turned
green,
then
brown.
The
1H NMR spectrum of a saturat-
ed, but low concentration, solu-
tion of 11 in CDCl3 was, howev-
er, recorded at ꢀ308C, and it
confirmed the absence of the
OCH3 signals of the precursor
10. Revealing the presence of
several stereoisomers (at least
Scheme 3. Synthesis of TIPS-capped heptayndiol 9 from triyne-diether 3.
three among six possible), mul-
capped pentayne 5b was thus obtained in 73% yield, then
methylated to the tetraether 7, and finally desilylated to
generate bis-terminal pentayne 8 in 95% overall yield. Ad-
dition of the dilithium salt of 8 to two equivalents of ynone
4a afforded the TIPS-capped heptayne 9 in 79% yield
(Scheme 3). Diol 9 was finally converted into diether 10 in
90% yield by the same procedure previously used for the di-
methylation of 5b to 7 (deprotonation followed by reaction
with iodomethane in the presence of DMSO).
Since first attempts at reductive elimination from diol 9
with the SnCl2/HCl system did not give clear evidence of
the formation of the 1,4-PTA target 11, efforts focused on
the diether substrate 10. It was observed that treatment of
10 with SnCl2/HCl in CH2Cl2 solution at ꢀ788C induced the
appearance of a blue color of the solution containing a
dark-blue solid suspension when the temperature reached
ꢀ308C (Scheme 4). Upon warming to room temperature,
tiplets were observed around d=8.0 ppm for the ortho-1H
nuclei of the phenyl substituents, and around d=7.5 ppm for
their meta and para congeners; the TIPS signals merged into
a broad singlet at d=1.21 ppm. Due to insufficient concen-
tration, attempts at recording 13C{1H} spectra in CDCl3 solu-
tion failed to bring out the quaternary 13C signals of 11.
Nevertheless, recording the CP-MAS 13C{1H} spectrum of
the dry solid allowed complete assignment of all the 13C
nuclei of 11, which unambiguously confirmed the 1,4-PTA-
type structure (Figure 3).
119Sn NMR spectroscopy of the blue solid, however, re-
vealed the presence of 1H/13C NMR-silent SnCl2 in the
sample (the obtained chemical shift was identical to that of
a pure SnCl2 sample, and no other 119Sn signal was observed,
showing that no significant interaction occurs between 11
and surrounding SnCl2 molecules: see Figure S2 in the Sup-
porting Information). The blue powder was thus submitted
Chem. Eur. J. 2012, 00, 0 – 0
ꢁ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
&
3
&
ÞÞ
These are not the final page numbers!

V. Maraval, R. Chauvin et al.
Figure 3. CP-MAS 13C{1H} NMR spectrum of 11 in the solid state.
to elemental analysis, which indicated that the mixture was
actually composed of a 10% molar ratio of 11, correspond-
ing to a 11/SnCl2 ratio of 38:62 by weight. The yield of the
reductive elimination process from 10 to 11, isolated as a
mixture with SnCl2, was thus estimated to be 48%
(Scheme 4; 10 equiv of SnCl2 was used). However, all at-
tempts to separate 11 from the SnCl2 matrix (by chromatog-
raphy or any method requiring dissolution) failed because
of the instability of the tris-butatriene in solution. This also
prevented selective crystallization of 11 (all the deposited
single crystals submitted to XRD analysis to date turned out
to be SnCl2 crystals).
These results indicate that perphenylated 1,4-PTAs are
less stable than 1,2-PTA congeners, which were described to
be stable and soluble, even for quite large oligomers.[13]
Whereas all the known 1,2-PTAs are described as yellow
solids irrespective of their length, the three 1,4-PTAs 1, 6,
and 11 are dark solids, giving yellow, pink, and blue solu-
tions, respectively (Figure 4). The corresponding UV/Vis
spectra present systematic bathochromic shifts of ca. 100 nm
along the series 1!6!11, reflecting the parallel increase of
the extent of conjugation from monomer 1 to trimer 11
(Figure 4).
Figure 4. Absorption spectra of the monomeric, dimeric, and trimeric 1,4-
PTAs 1, 6, and 11 in CHCl3 solution, respectively (bottom), and corre-
sponding photographs of diluted solutions in CH2Cl2 (top). The spectrum
of 11 was recorded at 08C after rapid preparation of a diluted solution of
undetermined concentration.
maximum intensity after nearly one hour, then began to de-
crease, and disappeared after two days. Although the struc-
ture of products could not be determined (the 1H NMR
spectrum of the degradation material was not characteris-
tic), the monitoring suggests that the evolution of 11 pro-
ceeds quite selectively through an intermediate of shorter
maximal p-conjugation extent (419 vs. 655 nm for 11),
roughly corresponding to that of dialkynyldiphenylbuta-
trienes such as 1 (453 nm). By comparison to 6, the sensitivi-
ty of 11 might thus be attributed to the possibility of intra-
molecular reactions between facing external butatriene units
in some cisoid-folded conformations of stereoisomers of 11
Whereas the extinction coef-
ficients of 1 and 6 were calcu-
lated to be quasi-identical (ca.
50000 Lmolꢀ1 cmꢀ1), that of 11
could not be determined be-
cause of its instability in solu-
tion. When the degradation of
11 was monitored at room tem-
perature (Figure 5), it was ob-
served that the initial most in-
tense band at 655 nm almost
disappeared after 22 min and
was replaced by an intense
band at 419 nm, while the ini-
tially blue solution turned pro-
gressively to green, then yellow,
and finally to pale-brown.
Continuing to monitor the
solution, it was observed that
Figure 5. UV/Vis monitoring of the decomposition of the 1,4-PTA trimer 11 in CHCl3 solution at room tem-
the band at 419 nm reached a perature. The time intervals are provided between the successive spectra (min) versus the initial time t0.
&
4
&
www.chemeurj.org
ꢁ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 0000, 00, 0 – 0
ÝÝ
These are not the final page numbers!

Perphenylated Carbo-oligoacetylenes
FULL PAPER
Acknowledgements
In addition to the Ministꢃre de l’Enseignement Supꢀrieur de la Recher-
che et de la Technologie and the Paul Sabatier University, thanks are due
to the Centre National de la Recherche Scientifique and to the ANR
program (ANR-11-BS07-016-01) for post-doctoral fellowships to A.R.
[1] For a comparative review, see: a) D. Ayuk Mbi Egbe, B. Carbonnier,
E. Birckner, U.-W. Grummt, Progr. Polym. Sci. 2009, 34, 1023–1067.
For early references, see for example: b) Z. J. Donhauser, B. A.
Mantooth, K. F. Kelly, L. A. Bumm, J. D. Monnell, J. J. Stapleton,
D. W. Price, Jr., A. M. Rawlett, D. L. Allara, J. M. Tour, P. S. Weiss,
Science 2001, 292, 2303–2307; c) D. W. Price, Jr., J. M. Tour, Tetrahe-
dron 2003, 59, 3131–3156; d) F.-R. F. Fan, R. Y. Lai, J. Cornil, Y.
Karzazi, J.-L. Brꢀdas, L. Cai, L. Cheng, Y. Yao, D. W. Price, Jr.,
S. M. Dirk, J. M. Tour, A. J. Bard, J. Am. Chem. Soc. 2004, 126,
2568–2573.
[2] For recent reviews on PAs, see: a) A. J. Heeger, Chem. Soc. Rev.
2010, 39, 2354–2371; b) Y. W. Park, Chem. Soc. Rev. 2010, 39, 2428–
2438.
[3] For recent review on PDAs, see: X. Sun, T. Chen, S. Huang, L. Li,
H. Peng, Chem. Soc. Rev. 2010, 39, 4244–4257.
Scheme 5. Putative intramolecular process triggered at the benzylic
carbon vertices and allowed by the specific stereochemical/conformation-
al features of 11 compared to 6, accounting for the higher stability of the
latter. The dotted line encompasses a dialkynyldiphenylbutatriene motif,
the maximum absorption of which should occur in the range 400–450 nm.
featuring
a
cis-configured central butatriene unit
(Scheme 5). Such a transformation might also be facilitated
by traces of SnCl2 in solution. The use of other reductants
has been attempted,[14] but although SnCl2 alone (in the ab-
sence of HCl) proved to be less efficient, the strongly acidic
KI/H2SO4 system produced black polymeric materials. The
classical SnCl2/HCl system thus appears to act in a manner
that is a trade-off between acidity and reductive efficiency
for 10.
[4] M. Schreiber, J. Anthony, F. Diederich, M. E. Spahr, R. Nesper, M.
Hubrich, F. Bommeli, L. Degiorgi, P. Wachter, P. Kaatz, C. Bos-
shard, P. Gꢄnter, M. Colussi, U. W. Suter, C. Boudon, J.-P. Gissel-
brecht, M. Gross, Adv. Mater. 1994, 6, 786–790.
[5] a) J. F. Nierengarten, D. Guillon, B. Heinrich, J. F. Nicoud, Chem.
Commun. 1997, 1233–1234; b) J. Xiao, M. Yang, J. W. Lauher, F. W.
Fowler, Angew. Chem. 2000, 112, 2216–2219; Angew. Chem. Int. Ed.
2000, 39, 2132–2135; c) F. Diederich, Chem. Commun. 2001, 219–
227 and references therein; d) A. P. H. J. Schenning, J.-D. Arndt, M.
Ito, A. Stoddart, M. Schreiber, P. Siemsen, R. E. Martin, C. Boudon,
J.-P. Gisselbrecht, M. Gross, V. Gramlich, F. Diederich, Helv. Chim.
Acta 2001, 84, 296–334; e) N. F. Utesch, F. Diederich, C. Boudon, J.-
P. Gisselbrecht, M. Gross, Helv. Chim. Acta 2004, 87, 698–718;
f) J. F. Nierengarten, Helv. Chim. Acta 2004, 87, 1357–1367.
[6] a) R. Chauvin, Tetrahedron Lett. 1995, 36, 397–400; b) V. Maraval,
R. Chauvin, Chem. Rev. 2006, 106, 5317–5343.
Conclusion
The first examples of the 1,4-PTA family have been descri-
bed in the perphenylated series up to the oligomeric order
three. By comparison to 1,2-PTAs, which are stabilized by
the noncumulenic representative resonance form
a
(Figure 1), the poor stability of the 1,4-PTA trimer 11 in sol-
ution can be primarily attributed to two features: i) the
unique resonance form involving a [3]cumulenic motif
(Figure 1), and ii) the occurrence of cis-configured dialkynyl-
butatrienes motifs, which are both kinetically and thermody-
namically allowed (in 1,2-PTAs, the cis configuration of the
olefinic bonds is thermodynamically disfavored by steric fac-
tors). Nevertheless, the reactivity of 11 might also be due to
the benzylic nature of the sp2-vertices (Scheme 5), and steric
stabilization of these centers could be envisioned by replace-
ment of the phenyl substituents with hindered aryl groups,
such as mesityl or 2,6-diisopropylphenyl groups, or even To-
kitohꢂs “Tbt” groups.[15] The sensitivity of 11 is also possibly
related to its poor solubility,
[7] L. T. Scott, G. J. DeCicco, J. L. Hyunn, G. Reinhardt, J. Am. Chem.
Soc. 1985, 107, 6546–6555.
[8] a) L. Maurette, C. Tedeschi, E. Sermot, M. Soleilhavoup, F. Hussein,
B. Donnadieu, R. Chauvin, Tetrahedron 2004, 60, 10077–10098;
b) C. Saccavini, C. Tedeschi, L. Maurette, C. Sui-Seng, C. Zou, M.
Soleilhavoup, L. Vendier, R. Chauvin, Chem. Eur. J. 2007, 13, 4895–
4913; c) C. Saccavini, C. Tedeschi, C. Lepetit, L. Yahi, C. Pistre, V.
Maraval, R. Chauvin, Phosphorus Sulfur Silicon Relat. Elem. 2009,
184, 1573–1585; d) L. Leroyer, C. Zou, V. Maraval, R. Chauvin, C.
R. Chimie 2009, 12, 412–419.
[9] a) Y. Kuwatani, N. Watanabe, I. Ueda, Tetrahedron Lett. 1995, 36,
119–122; b) R. Suzuki, H. Tsukude, N. Watanabe, Y. Kuwatani, I.
Ueda, Tetrahedron 1998, 54, 2477–2496; c) C. Saccavini, C. Sui-
Seng, L. Maurette, C. Lepetit, S. Soula, C. Zou, B. Donnadieu, R.
Chauvin, Chem. Eur. J. 2007, 13, 4914–4931; d) C. Zou, C. Duhay-
on, V. Maraval, R. Chauvin, Angew. Chem. 2007, 119, 4415–4419;
Angew. Chem. Int. Ed. 2007, 46, 4337–4341; e) R. Chauvin, C. Lepe-
tit, V. Maraval, L. Leroyer, Pure Appl. Chem. 2010, 82, 769–800;
f) L. Leroyer, C. Lepetit, A. Rives, V. Maraval, N. Saffon-Merceron,
D. Kandaskalov, D. Kieffer, R. Chauvin, Chem. Eur. J. 2012, 18,
3226–3240.
[10] a) C. Godard, C. Lepetit, R. Chauvin, Chem. Commun. 2000, 1833–
1834; b) R. Chauvin, C. Lepetit in Acetylene Chemistry. Chemistry,
Biology and Material Sciences, (Eds.: F. Diederich, P. J. Stang, R. R.
Tykwinski), Wiley, Weinheim, 2005, Chap. 1, pp. 1–50; c) C. Zou, C.
Lepetit, Y. Coppel, R. Chauvin, Pure Appl. Chem. 2006, 78, 791–
811; d) C. Lepetit, C. Zou, R. Chauvin, J. Org. Chem. 2006, 71,
6317–6324; e) A. Soncini, P. W. Fowler, C. Lepetit, R. Chauvin,
Phys. Chem. Chem. Phys. 2008, 10, 957–964.
preventing its separation from
the SnCl2 matrix. The next chal-
lenge is therefore the synthesis
of diversely substituted 1,4-PTA
oligomers, and, in particular,
the likely highly soluble TIPS-
protected total carbo-mer of
oligoacetylenes, for which C2
units are also inserted into the
Scheme 6. The
challenging
ꢀ
C H bonds (Scheme 6). Func-
soluble 1,4-PTA targets: TIPS-
protected total carbo-mers of
oligo-acetylenes.
tional 1,4-PTA oligomers are
the ultimate targets.[16]
Chem. Eur. J. 2012, 00, 0 – 0
ꢁ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
&
5
&
ÞÞ
These are not the final page numbers!

V. Maraval, R. Chauvin et al.
[11] a) J.-D. van Loon, P. Seiler, F. Diederich, Angew. Chem. 1993, 105,
1235–1238; Angew. Chem. Int. Ed. Engl. 1993, 32, 1187–1189; b) A.
Auffrant, F. Diederich, C. Boudon, J.-P. Gisselbrecht, M. Gross,
Helv. Chim. Acta 2004, 87, 3085–3105; c) A. Auffrant, B. Jaun, P. D.
Jarowski, K. N. Houk, F. Diederich, Chem. Eur. J. 2004, 10, 2906–
2911; d) V. Maraval, L. Leroyer, A. Harano, C. Barthes, A. Saquet,
C. Duhayon, T. Shinmyozu, R. Chauvin, Chem. Eur. J. 2011, 17,
5086–5100.
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
[13] R. E. Martin, T. Mꢆder, F. Diederich, Angew. Chem. 1999, 111, 834–
838; Angew. Chem. Int. Ed. 1999, 38, 817–821.
[14] L. Leroyer, V. Maraval, R. Chauvin, Chem. Rev. 2012, 112, 1310–
1343.
[15] a) N. Tokitoh, Pure Appl. Chem. 1999, 71, 495–502; b) T. Sasamori,
N. Tokitoh, Dalton Trans. 2008, 1395–1408.
[16] A. Rives, I. Baglai, V. Malytskyi, V. Maraval, N. Saffon-Merceron,
Z. Voitenko, R. Chauvin, Chem. Commun. 2012, 48, 8763–8765.
[12] Crystal data and structure refinement for 6: R=0.06. Ellipsoids are
¯
set at 50% probability. Space group: P1. Selected bond lengths in
ꢀ
ꢀ
ꢀ
ꢀ
ꢅ: Si1 C1 1.840(2), C1 C2 1.207(3), C2 C3 1.432(3), C3 C4
ꢀ
ꢀ
ꢀ
1.351(3), C4 C5 1.237(3), C5 C6 1.354(3), C6 C7 1.418(3); Selected
bond angles in degrees: C2-C1-Si1 172.3(2), C1-C2-C3 176.9(2), C2-
C3-C4 116.73(19), C3-C4-C5 179.3(2), C4-C5-C6 179.5(2), C5-C6-C7
117.88(19). CCDC-878530 contains the supplementary crystallo-
Received: May 4, 2012
Revised: July 23, 2012
Published online: && &&, 2012
&
6
&
www.chemeurj.org
ꢁ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 0000, 00, 0 – 0
ÝÝ
These are not the final page numbers!

Perphenylated Carbo-oligoacetylenes
FULL PAPER
Polyacetylenes
A. Rives, V. Maraval,*
N. Saffon-Merceron,
R. Chauvin* ................... &&&& — &&&&
First Perphenylated carbo-oligoacety-
lenes: An Extension of the Polytriace-
tylene Family
Colorful chain carbo-mers of polyace-
tylenes are isomers of the well-known
polytriacetylenes (PTAs). The three
first representatives are shown to
exhibit continuously but markedly
varying chromophoric properties (see
figure).
Chem. Eur. J. 2012, 00, 0 – 0
ꢁ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
&
7
&
ÞÞ
These are not the final page numbers!