Efficient, high-yield route to long, functionalized p-phenylene oligomers containing perfluorinated segments, and their cyclodimerizations by zirconocene coupling

Article abstract of DOI:10.1021/ja011018s

Linear oligophenylene diynes containing 6, 9, and 12 phenylene rings were synthesized in high yields using the nucleophilic aromatic substitution (S_NAr) of perfluoroarenes by aryllithium reagents as the key carbon - carbon bond-forming reaction

Full text of DOI:10.1021/ja011018s

J. Am. Chem. Soc. 2001, 123, 10183-10190
10183
Efficient, High-Yield Route to Long, Functionalized p-Phenylene
Oligomers Containing Perfluorinated Segments, and Their
Cyclodimerizations by Zirconocene Coupling
Jonathan R. Nitschke and T. Don Tilley*
Contribution from the Center for New Directions in Organic Synthesis, Department of Chemistry,
UniVersity of California, Berkeley, Berkeley, California 94720
ReceiVed April 23, 2001
Abstract: Linear oligophenylene diynes containing 6, 9, and 12 phenylene rings were synthesized in high
yields using the nucleophilic aromatic substitution (SNAr) of perfluoroarenes by aryllithium reagents as the
key carbon-carbon bond-forming reaction. This reaction was demonstrated to proceed readily at low
temperatures with sterically hindered substrates and in the presence of base-sensitive silylalkynyl groups. Diynes
synthesized by this methodology were readily zirconocene-coupled into large dimeric macrocycles using the
zirconocene reagent Cp2Zr(py)(Me3SiCtCSiMe3).
Introduction
behavior, and stability.16-18 Finally, oligophenylene building
blocks have been employed in the synthesis of large, rigid
macrocycles,19-22 including a cyclotetraicosophenylene with a
diameter of ∼3 nm.23
Oligo(p-phenylenes) have been the subject of many recent
investigations, as well-defined models for poly(p-phenylene)1-3
and as new materials with chemically tailored properties.4,5 In
addition, oligo(p-phenylenes) have been extensively employed
as rigid-rod components in supramolecular chemistry. For
example, they can mediate excitation energy transfer between
chromophores that they hold several nanometers apart.6-9 As
linkers, oligophenylenes have also been observed to couple
electronic properties between distant metal centers, as indicated
by changes in redox potentials.10,11 Functionalized oligophe-
nylenes have found use as synthetic ionophores, which facilitate
ion migration through lipid bilayers.12-15 As monomer units
employed in copolymerizations, oligophenylenes have been used
to tailor polymeric properties such as crystallinity, fluorescence
Macrocyclizations via zirconocene-coupling methods allow
the cyclization of diynes possessing various geometries and
functional groups.24-33 This synthetic approach to macrocycles
offers many advantages over traditional methods, which typi-
cally involve high-dilution techniques, lengthy separations, and
relatively low yields.34 The zirconocene-coupling approach to
macrocycles provides very high yields of a single product and
is based on the reversibility of carbon-carbon bond formation
(16) Deimede, V.; Andrikopoulos, K. S.; Voyiatzis, G. A.; Konstanda-
kopoulou, F.; Kallitsis, J. K. Macromolecules 1999, 32, 8848-8856.
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Macromolecules 1998, 31, 5264-5271.
(19) Hensel, V.; Lutzow, K.; Jacob, J.; Gessler, K.; Saenger, W.; Schlu¨ter,
A.-D. Angew. Chem., Int. Ed. Engl. 1997, 36, 2654-2656.
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(21) Haley, M. M.; Pak, J. J.; Brand, S. C. Top. Curr. Chem. 1999, 201,
81-130.
(22) Ohkita, M.; Ando, K.; Suzuki, T.; Tsuji, T. J. Org. Chem. 2000,
65, 4385-4390.
(23) Hensel, V.; Schlu¨ter, A. D. Chem. Eur. J. 1999, 5, 421-429.
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7032.
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molecules 1996, 29, 7432-7445.
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10.1021/ja011018s CCC: $20.00 © 2001 American Chemical Society
Published on Web 09/29/2001

10184 J. Am. Chem. Soc., Vol. 123, No. 42, 2001
Nitschke and Tilley
in the coupling of silyl-substituted alkynes.28 Given the potential
of this method, and the widespread interest in macrocycles, we
have explored its application in the construction of very large
(nanometer-scaled) rings, which are difficult to obtain via
traditional coupling procedures.23,35
Scheme 1. Synthesis of Hexaphenylene Diynes 3 and 4a
Investigation of the size limitations of the zirconocene-
coupling method requires long, rigid diynes as precursors.
Previously, we have shown this macrocyclization reaction to
provide high-yielding routes to large, triangular macrocycles
via coupling of the tetraphenylene diyne Me3SiCtC(C6H4)4Ct
CSiMe327 and the isostructural 2,2′-bipyridine Me3SiCtC(C6H4)-
(C5H4N)(C5H4N)(C6H4)CtCSiMe3.24 However, obtaining sig-
nificant quantities of diynes with longer spacer groups has
proven difficult, given the inherently low solubility of oligophe-
nylenes and the low cumulative yields associated with multistep
coupling reactions. Thus, the use of zirconocene coupling in
the synthesis of nanoscaled macrocycles requires development
of large-scale, efficient synthetic routes to rigid, oligomeric
diynes.
In this contribution, we describe convergent, high-yielding
synthetic routes to long, terminally derivatized oligophenylenes.
Linear oligophenylenes containing 12 phenylene units have been
synthesized, and longer oligomers should be readily accessible
by analogous methods. The four oligophenylenes described here
are terminated by trialkylsilylalkynyl groups and are efficiently
cyclized via zirconocene coupling to dimeric products. These
macrocycles are readily demetalated to give very large, air-stable
cyclophanes.
Our synthetic strategy is based on nucleophilic aromatic
substitution of perfluorinated arenes by aryllithium nucleophiles.
Perfluoroarenes are excellent electrophiles, undergoing nucleo-
philic substitution readily under mild conditions, and many
perfluoroarene substrates exhibit very high regioselectivities.36
The ease with which fluorinated arenes undergo nucleophilic
aromatic substitution (reactions are often rapid below 0 °C)37
translates into tolerance of many functional groups. Hindered
nucleophiles also react readily, allowing the incorporation of
synthons bearing bulky, solubility-enhancing substituents.
Oligophenylenes containing perfluorinated segments have
found recent use as electron-transport materials in organic light-
emitting diodes,38,39 sensitizers for the photoactivation of water,40
and elements in the rational design of liquid crystals.41 Su-
pramolecular chemistry involving phenyl-perfluorophenyl in-
teractions is also a topic of growing interest,42-45 and molecules
containing both phenyl and perfluorophenyl groups are important
in this area. Macrocycles containing perfluorinated phenylene
segments are likewise of interest as supramolecular building
a Conditions: (a) Pd(PPh3)4/CuI, HCtCSiMe2R; (b) 2 equiv of
t-BuLi; (c) 0.5 equiv of decafluorobiphenyl.
blocks, as the macrocyclic effect can greatly enhance the
attractive interactions between electron-poor perfluoroarenes and
electron-rich arenes,42,45,46 facilitating their use in supramolecular
construction.
Results
The carbanion precursors 1 and 2 used in the nucleophilic
aromatic substitution reactions were synthesized from 4-bromo-
4′-iodobiphenyl47 by means of the Sonogashira reaction48
(Scheme 1). The reaction of 2 equiv of t-BuLi with these
bromoarenes at -78 °C produced solutions of the desired
aryllithium reagents. Addition of 0.5 equiv of decafluorobiphe-
nyl to these in situ-generated carbanions gave hexaphenylene
diynes 3 and 4 (Scheme 1). This reaction proceeded at an
appreciable rate at -78 °C, as evidenced by the precipitation
of a colorless solid (3 and LiF) within minutes of the start of
addition. As expected, the butyl groups of 4 make it significantly
more soluble than 3 in organic solvents.
The reaction of 1 equiv of lithiated 2 with a slight excess
(1.2 equiv) of decafluorobiphenyl gave an excellent yield (98%)
of the monosubstitution product 5 (Scheme 2). This product
precipitated out of the reaction mixture, which prevented further
conversion to the disubstituted product 4. Reaction of 2 equiv
of 5 with 1,4-dilithio-2,5-diisopropylbenzene, prepared in situ
from 1,4-diiodo-2,5-diisopropylbenzene, gave nonaphenylene
6 in 79% yield (Scheme 2).
(35) Pascal, R. A.; Barnett, L.; Qiao, X.; Ho, D. M. J. Org. Chem. 2000,
65, 7711-7717.
(36) Brooke, G. M. J. Fluorine Chem. 1997, 86, 1-76.
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(38) Winkler, B.; Meghdadi, F.; Tasch, S.; Mullner, R.; Stelzer, F. Opt.
Mater. 1998, 9, 159-162.
Monolithiation of 1,4-dibromo-2,5-diisopropylbenzene, fol-
lowed by reaction with 0.5 equiv of decafluorobiphenyl, gave
dibromoquaterphenyl 7 (Scheme 3) in 93% yield. Quaterphenyl
7 may then be dilithiated; the resulting dianion then reacted
with 2 equiv of 5 to give dodecaphenylene 8 in 95% yield
(Scheme 3).
(39) Heidenhain, S. B.; Sakamoto, Y.; Suzuki, T.; Miura, A.; Fujikawa,
H.; Mori, T.; Tokito, S.; Taga, Y. J. Am. Chem. Soc. 2000, 2000, 10240-
10241.
(40) Kitamura, T.; Wada, Y.; Yanagida, S. J. Fluorine Chem. 2000, 105,
305-311.
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1999, 2493-2494.
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304.
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Bull. Soc. Chim. Fr. 1997, 134, 955-958.
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E. B.; Grubbs, R. H. Angew. Chem., Int. Ed. 1999, 38, 2741-2745.
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Grubbs, R. H. Angew. Chem., Int. Ed. Engl. 1997, 36, 248-251.
2140-2141.
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tions: Synthetic Aspects and Catalytic Cycles; Academic Press: San Diego,
1997.

p-Phenylene Oligomers with Perfluorinated Segments
J. Am. Chem. Soc., Vol. 123, No. 42, 2001 10185
Scheme 2. Synthesis of Monosubstituted Alkyne 5 and
Nonaphenylene Diyne 6a
Scheme 3. Synthesis of Dibromoquaterphenyl 7 and
Dodecaphenylene Diyne 8a
a Conditions: (a) 2 equiv of t-BuLi; (b) 1.2 equiv of decafluorobi-
phenyl; (c) 5 is added to a solution of 0.5 equiv of 1,4- dilithio-2,5-
diisopropylbenzene, which is generated in situ from 0.5 equiv of 1,4-
diiodo-2,5-diisopropylbenene and 2 equiv of t-BuLi.
Diynes 3, 4, and 6 were cyclodimerized via zirconocene
coupling under nearly identical synthetic conditions (Scheme
4). The diynes were suspended in an aromatic solvent (benzene
for 3 and 6, mesitylene for 4), and a solution of Cp2Zr(py)-
(Me3SiCtCSiMe3) was then added in the same solvent.
Sonication of these suspensions yielded clear orange solutions,
and over 24 h at 40 °C, crystalline (9) or microcrystalline (10
and 11) product precipitated from solution.
a Conditions: (a) 1 equiv of t-BuLi; (b) 0.5 equiv of decafluorobi-
phenyl; (c) 2 equiv of t-BuLi; (d) 2 equiv of 5.
Dodecaphenylene zirconacycles 9 and 10 are soluble in
benzene, which allowed their characterization by NMR spec-
troscopy. Octadecaphenylene 11 was highly insoluble in toluene
and benzene, however, and decomposed in dichloromethane and
THF solution at room temperature, which rendered infeasible
its characterization by NMR spectroscopy. The successful
synthesis of 11 may be inferred, however, from the full
characterization of its derivative 14 (see below).
The crystal structure of 9 was determined from a crystal
formed during the course of its synthesis. Selected crystal data
are presented in Table 1, and a detailed account of the structure
determination is presented in the Supporting Information. An
ORTEP view of the structure is shown in Figure 1.
The reaction of 10 with benzoic acid in benzene solution
resulted in bleaching of the yellow color of the zirconacycle
over several hours. The material isolated from this reaction
exhibited three distinct vinyl 1H NMR resonances, which
suggests that the macrocycle had been cleaved. Reactions of 9,
10, and 11 with trifluoroacetic acid in benzene, however, rapidly
produced the desired cyclophanes 12-14 (Scheme 5). Com-
pound 12 was even less soluble than its precursor 9, and attempts
to characterize it by NMR spectroscopy and mass spectrometry
were not successful. Its characterization is therefore based solely
on elemental analysis. However, the clean demetalations of 10
and 11 to give fully characterized 13 and 14, respectively,
suggest that 9 was demetalated to give 12 in identical fashion.
Dodecaphenylene diyne 8 also reacted with Cp2Zr(py)(Me3-
SiCtCSiMe3), giving an orange solution, which subsequently
produced a yellow precipitate. This precipitate was insoluble
in benzene, toluene, THF, and dichloromethane. A suspension
of this product in benzene reacted with trifluoroacetic acid to
give a white material that was also highly insoluble. Elemental
analysis of the zirconocene-coupled product gave results
consistent with a macrocycle, but the extremely low solubilities
of the presumed zirconocycle and its demetalated derivative
precluded further characterization by NMR spectroscopy or mass
spectrometry.
Discussion
As noted earlier, a primary goal of this research was the
synthesis of silyl-terminated oligophenylene diynes of nano-
meter dimension for use in zirconocene-coupling macrocycle
syntheses.24-33 The high-yielding macrocyclizations of quater-
phenyl diynes27 and isostructural bipyridine-containing diynes25
suggested that even longer diynes might be efficiently cyclized

10186 J. Am. Chem. Soc., Vol. 123, No. 42, 2001
Nitschke and Tilley
Scheme 4. Synthesis of Zirconocene-Coupled Dimers 9, 10,
and 11
Table 1. Crystallographic Data for Dimeric Macrocycle 9
empirical formula
formula weight
crystal system
space group
crystal color, habit
a (Å)
C124H100F16Si4Zr2
2188.91
triclinic
P1h(No. 2)
yellow, blocks
12.0173(3)
16.0939(4)
16.5390(4)
85.785(1)
71.949(1)
88.627(1)
3033.1(1)
161 ( 1
Figure 1. ORTEP diagram of macrocycle 9. Heteroatoms of the
asymmetric unit are labeled. The closest F‚‚‚F distance across the center
of the macrocycle is 2.69 Å.
b (Å)
c (Å)
Scheme 5. Demetalation of 9-11 To Give 12-14
R (deg)
â (deg)
γ (deg)
cell volume (Å3)
temp (K)
Z
1
R, Rw
goodness of fit
0.045, 0.054
1.64
via zirconocene-coupling methodology. Initial attempts to obtain
hexaphenylene diynes, based on a Suzuki-coupling strategy,49
were hindered by the insolubility of the hexaphenylene deriva-
tives. Furthermore, attempts to introduce solubility-enhancing
alkyl groups ortho to the site of coupling greatly lowered yields
of the final product. Thus, numerous chromatographic separa-
tions were required to isolate pure products, which were
therefore difficult to obtain in large quantities. Moreover,
silylalkynes did not survive the harsh, basic conditions of Suzuki
coupling, limiting the flexibility of this synthetic approach.
In contrast, nucleophilic aromatic substitutions with perfluo-
roarenes proceed under much milder conditions37 than those
typically employed for palladium-catalyzed carbon-carbon
bond-forming reactions.50 The terminal 4 and 4′ fluorine atoms
of decafluorobiphenyl and analogous compounds such as 5 are
regiospecifically substituted by aryllithium reagents.36 Sterically
encumbered aryllithiums worked well in this reaction, as
demonstrated by the high-yielding syntheses of 6, 7, and 8. The
mild reaction conditions also allow for the presence of base-
(49) Hensel, V.; Schlu¨ter, A. D. Liebigs Ann.-Recl. 1997, 303-309.
(50) Stanforth, S. P. Tetrahedron 1998, 54, 263-303.

p-Phenylene Oligomers with Perfluorinated Segments
J. Am. Chem. Soc., Vol. 123, No. 42, 2001 10187
sensitive silylalkynes, which would have been rapidly desilylated
by extremely basic aryllithium reagents at room temperature.
The higher yields obtained through this procedure also greatly
facilitated the isolation and purification of products, eliminating
the need for chromatography.
The successful syntheses of hexaphenylenes 3 and 4 (Scheme
1) demonstrates the feasibility of this method for producing
oligophenylenes. These reactions cleanly converted the two
starting materials, each containing two aromatic rings, into a
product containing six aromatic rings. To investigate the
possibility of synthesizing longer oligophenylenes by this
convergent “length-tripling” methodology, a version of this
reaction (Scheme 2) was developed in which the asymmetric
substitution product 5 was exclusively formed. The synthesis
of 5 is facilitated by the low solubility of the product in the
pentane/diethyl ether reaction mixture. Monosubstituted 5
precipitates from solution as it forms, which prevents further
conversion to disubstituted 4. This solubility effect allowed only
a slight excess of decafluorobiphenyl to be used while giving a
98% yield of 5. The possibility of asymmetric substitution lends
additional flexibility to this methodology. The synthesis of
nonaphenylene 6 from 5 and dilithiodiisopropylbenzene (Scheme
2) demonstrates the feasibility of a slightly different approach
involving a difunctional aryllithium reagent and 2 equiv of a
monofunctional fluoroarene.
The synthesis of 7 (Scheme 3) demonstrates the addition of
a bromolithioarene to a perfluoroarene, such that further
lithium-halogen exchange via SNAr steps could be carried out
in the stepwise construction of an oligoarene chain. Thus, the
reaction of dilithiated 7 with 5 gives the dodecaphenylene 8 in
95% yield. Significantly, then, an oligoarene may be synthesized
from a dilithioarene containing perfluorinated segments. Oli-
gophenylenes may therefore be synthesized in an iterative
fashion, without side reactions involving attack on internal
perfluorophenylene segments. The successful synthesis of
dodecaphenylene 8 suggests that an iterative divergent/
convergent approach similar to that described by Tour et al.51,52
may be employed for oligophenylene synthesis via the synthetic
methods described here. A notable advantage of the method
described here, however, is that molecular weight and length
are tripled (rather than doubled) with each iteration.
The macrocyclization protocol described above is effectively
identical to that employed25,26 to synthesize dimers and trimers
from bipyridine-containing diynes using Rosenthal’s Cp2Zr(py)-
(Me3SiCtCSiMe3).53 Yields are again consistently high, with
exclusive formation of a single product. The product in all cases,
however, is not the expected trimer but instead a dimer. To
close into a dimeric macrocycle, a linear diyne must bend, and
there is an energetic cost to this bending which must be
compensated for if a dimer is to be the thermodynamic product.
Entropy clearly favors the formation of dimers over trimers;
three dimers could be formed from two trimers, and trimers
also include substantial void spaces that are not present in the
more compact dimers. Inclusion of solvent molecules25 in these
cavities would further reduce the entropy. In addition to solution
thermodynamics, crystallization may also perturb dimer-trimer
equilibria by trapping out less soluble kinetic products.
The structure of macrocycle 9 provides insight into the nature
of the bending of the oligophenylene spacer groups. Figure 2
Figure 2. Angles between para carbon atoms of the hexaphenylene
chain of 9. The closest F‚‚‚F distance across the center of the macrocycle
is 2.69 Å.
provides a minimal view of the structure of 9. The solid lines
in this figure are phenyl-phenyl C-C bonds, and the dashed
lines represent vectors connecting the para carbon atoms of each
phenyl ring. The angles between these bonds and vectors, given
in Figure 2, describe the bending of the hexaphenylene chain.
Much of the bending is seen to be concentrated at one end of
this chain. This appears to facilitate packing of the two
oligophenylene chains, to give a compact, centrosymmetric
structure that excludes solvent of crystallization from the center
of the macrocycle. Attempts to obtain X-ray quality crystals of
macrocycles 10-14 did not prove successful, but mass spec-
trometry clearly showed the demetalated macrocycles 13 and
14 to be dimeric.
The failure of benzoic acid as a demetalation reagent is
noteworthy in light of this reagent’s utility in demetalating
trimeric macrocycles.25 The observation that it reacts more
slowly than trifluoroacetic acid suggests that rapidity of de-
metalation is crucial; a mono-demetalated macrocycle may be
substantially more strained than its precursor Zr2 macrocycle
and thus more prone to ring opening.
Concluding Remarks
The methodology outlined herein provides a straightforward,
high-yielding, and versatile route to oligophenylenes containing
perfluorinated segments. These oligophenylenes contain base-
sensitive silylacetylene groups, and we believe that these coupl-
ing reactions will also tolerate other functional groups as a
consequence of the very low barrier to the SNAr reaction. The
zirconocene-mediated macrocyclization of these oligophenylene
diynes was also demonstrated to proceed readily and in high
yield. The size limits for macrocycles obtained by this method
have not yet been reached, as indicated by the high synthetic
yields observed. Note that the crystallographic Zr-Zr distance
of 9 is 32.4 Å, and models suggest that the Zr-Zr distance in
11 is 44 Å. If dodecaphenylene 8 forms a zirconocene-coupled
dimeric structure analogous to 9, 10, and 11, this macrocycle
will have a Zr-Zr distance of ∼57 Å. This macrocycle would
be the second cyclotetraicosaphenylene to be synthesized,
although it would have a geometry that is quite different from
that of the hexagon reported by Hensel and Schlu¨ter.23
The oligophenylenes and macrocycles described here may
be of interest as electronic materials. The incorporation of
perfluorophenylene segments into these macrocycles allow for
their use in arene-perfluoroarene supramolecular systems,
opening the door to host-guest chemistry and molecular
recognition with nanometer-scale substrates. Investigations of
these, and other, implications of this chemistry are currently
underway.
Experimental Section
(51) Schumm, J. S.; Pearson, D. L.; Tour, J. M. Angew. Chem., Int. Ed.
Engl. 1994, 33, 1360-1363.
General Information. All reactions involving air-sensitive com-
pounds were carried out under nitrogen or argon using standard Schlenk
techniques and dry, oxygen-free solvents. Pentane, diethyl ether,
benzene, and tetrahydrofuran were distilled under nitrogen from sodium
(52) Pearson, D. L.; Schumm, J. S.; Tour, J. M. Macromolecules 1994,
27, 2348-2350.
(53) Rosenthal, U.; Ohff, A.; Baumann, W.; Tillack, A.; Gorls, H.;
Burlakov, V. V.; Shur, V. B. Z. Anorg. Allg. Chem. 1995, 621, 77-83.

10188 J. Am. Chem. Soc., Vol. 123, No. 42, 2001
Nitschke and Tilley
benzophenone ketyl. Toluene, toluene-d8, and benzene-d6 were distilled
under nitrogen from Na/K. Dichloromethane-d2 was vacuum transferred
from CaH2. Respectively, n-BuLi and t-BuLi were used as a 1.6 M
solution in hexanes and a 1.7 M solution in pentane. Literature methods
were followed to prepare 4-bromo-4′-iodobiphenyl.47
solution. This solution was allowed to stir at -78 °C for 30 min.
Decafluorobiphenyl (1.50 g, 4.49 mmol) was loaded into a 50-mL
Schlenk flask, which was then purged with dry nitrogen for 30 min.
Addition of dry toluene (40 mL) gave a clear solution with stirring.
This solution was then added dropwise by cannula to the first flask at
-78 °C. Cloudiness was observed in the reaction flask when the
addition was nearly complete. On completion of addition, the Teflon
stopper of the reaction flask was sealed, and the reaction was allowed
to warm slowly to room temperature over 6 h, as the dry ice evaporated
from the cold bath. The reaction mixture, thick with white precipitate,
was then washed with water (2 × 100 mL) in a separatory funnel and
the white, finely divided product was isolated on a medium frit. The
product was then washed with water (2 × 25 mL) and diethyl ether (2
× 25 mL) and dried under dynamic vacuum. The yield of white
microcrystalline product was 2.26 g, 63%: 1H NMR (500 MHz,
benzene-d6) δ 0.30 (s, 9 H, Si(CH3)3), 7.20 (d, J ) 8 Hz, 2 H,
phenylene), 7.24 (d, J ) 8 Hz, 2 H, phenylene), 7.29 (d, J ) 8 Hz, 2
H, phenylene), 7.57 (d, J ) 8 Hz, 2 H, phenylene); 19F NMR (470.6
MHz, benzene-d6) δ -78.9 (m, 4 F), -75.2 (m, 4 F); EI-MS m/z 794
(M+), 779 (M+ - Me); λmax (CH2Cl2) 306 nm. Anal. Calcd for C46H34F8-
Si2: C, 69.50; H, 4.31. Found: C, 69.52; H, 4.24.
1
All NMR spectra were recorded at room temperature. H and 13C
chemical shifts were referenced to the residual proton or carbon
resonance of the deuterated solvent. 19F chemical shifts were referenced
to R,R,R-trifluorotoluene (0 ppm) in a sealed capillary. All mass spectra
and combustion analyses were obtained at the Micro-Mass Facility of
the University of California, Berkeley.
4-Bromo-4′-(trimethylsilyl)alkynylbiphenyl (1). 4-Bromo-4′-io-
dobiphenyl (10.4 g, 29.0 mmol), Pd(PPh3)4 (0.168 g, 0.145 mmol), and
CuI (0.0552 g, 0.290 mmol) were loaded into a 500-mL Schlenk flask
with a Teflon stopper in the drybox, and dry benzene (250 mL) was
added on the Schlenk line. Stirring this suspension resulted in bleaching
of the yellow color of the Pd(PPh3)4 within minutes as it dissolved.
Diisopropylamine (50 mL) and then trimethylsilylacetylene (4.10 mL,
29.0 mmol) were added via syringe, and the Teflon stopcock was sealed.
The reaction solution warmed notably, and a large amount of diiso-
propylammonium iodide was deposited as the color changed from
colorless to pale yellow. After 1 h, the reaction solution was again
colorless and no longer warm to the touch. The volatile materials were
removed after another 2 h under dynamic vacuum, and the reaction
mixture was suspended in pentane (500 mL). This pentane suspension
was filtered through a plug of silica (50 mL), and the pentane was
then removed under dynamic vacuum. The crude product was recrystal-
lized from 95% ethanol. The yield of white needles was 6.80 g, 71%:
1H NMR (500 MHz, benzene-d6) δ 0.27 (s, 9 H, Si(CH3)3), 6.86 (d, J
) 6.5 Hz, 2 H, phenylene), 7.01 (d, J ) 6.5 Hz, 2 H, phenylene), 7.25
(d, J ) 6.5 Hz, 2 H, phenylene), 7.49 (d, J ) 6.5 Hz, 2 H, phenylene);
13C{1H} NMR (125 MHz, benzene-d6) δ 0.4 (Si(CH3)3), 95.8 (alkynyl),
106.1 (alkynyl), 122.6 (phenylene), 123.3 (phenylene), 127.4 (phe-
nylene), 129.2 (phenylene), 132.4 (phenylene), 133.1 (phenylene), 139.6
(phenylene), 140.5 (phenylene); EI-MS m/z 330 (Br doublet, M+), 315
(Br doublet, M+ - Me). Anal. Calcd for C17H17BrSi: C, 62.00; H,
5.20. Found: C, 62.00; H, 5.18.
4-Bromo-4′-(butyldimethylsilyl)alkynylbiphenyl (2). 4-Bromo-4′-
iodobiphenyl (10.0 g, 27.9 mmol), Pd(PPh3)4 (0.322 g, 0.279 mmol),
and CuI (0.106 g, 0.557 mmol) were loaded into a 500-mL Schlenk
flask with a Teflon stopper in the drybox, and dry benzene (250 mL)
was added on the Schlenk line. Stirring caused rapid bleaching of the
yellow color of Pd(PPh3)4 as it dissolved. Diisopropylamine (50 mL)
and then butyldimethylsilylacetylene (3.91 g, 27.9 mmol) were added
via syringe, and the Teflon stopcock was sealed. The reaction solution
warmed notably and turned pale yellow, and diisopropylammonium
iodide precipitated. After stirring for 1 h, the reaction solution was
again colorless and no longer warm to the touch. The volatile materials
were removed after another 2 h under dynamic vacuum, and the reaction
mixture was suspended in pentane (500 mL). This pentane suspension
was filtered through a plug of silica (50 mL), and the pentane was
removed under dynamic vacuum. The yield of white microcrystals was
9.76 g, 94%: 1H NMR (500 MHz, benzene-d6) δ 0.29 (s, 6 H, SiMe2-
Bu), 0.74 (t, J ) 8.5 Hz, 2 H, SiMe2CH2CH2CH2CH3), 0.92 (t, J ) 7
Hz, 3 H, SiMe2CH2CH2CH2CH3), 1.39 (q, J ) 7 Hz, 2 H, SiMe2-
CH2CH2CH2CH3), 1.51 (m, 2 H, SiMe2CH2CH2CH2CH3), 6.86 (d, J
) 6.5 Hz, 2 H, phenylene), 7.01 (d, J ) 6.5 Hz, 2 H, phenylene), 7.25
(d, J ) 6.5 Hz, 2 H, phenylene), 7.50 (d, J ) 6.5 Hz, 2 H, phenylene);
13C{1H} NMR (125 MHz, benzene-d6) δ -1.1 (SiMe2Bu), 14.4
(SiMe2Bu), 16.6 (SiMe2Bu), 26.9 (SiMe2Bu), 27.1 (SiMe2Bu), 95.3
(alkynyl), 106.5 (alkynyl), 122.6 (phenylene), 123.4 (phenylene), 127.4
(phenylene), 129.2 (phenylene), 132.4 (phenylene), 133.1 (phenylene),
139.6 (phenylene), 140.5 (phenylene); GC-MS m/z 372 (Br doublet,
M+), 357 (Br doublet, M+ - Me). Anal. Calcd for C20H23BrSi: C,
64.68; H, 6.24. Found: C, 64.60; H, 6.35.
Hexaphenylene Diyne 4. Alkyne 2 (3.11 g, 9.43 mmol) was loaded
into a 500-mL Schlenk flask with a Teflon stopper in the drybox and
then dissolved in dry hexanes (100 mL) on the Schlenk line. Dry diethyl
ether (50 mL) was added to this solution, and it was chilled to -85 °C
in a liquid nitrogen/methanol bath, giving a white suspension. tert-
Butyllithium (7.6 mL, 12.9 mmol) was then added dropwise with a
syringe, which did not change the appearance of the reaction mixture.
The reaction mixture was allowed to warm to -60 °C to give a clear,
light amber solution. Decafluorobiphenyl (1.00 g, 2.99 mmol) was
loaded into a 100-mL Schlenk flask, which was then purged with dry
nitrogen for 30 min. Dry hexanes (40 mL) were then added, and this
mixture was stirred until a colorless solution was obtained. This solution
was added to the first flask dropwise by cannula, at -80 °C. Cloudiness
was observed in the reaction flask once the addition was nearly
complete. On completion of addition, the Teflon stopper of the reaction
flask was sealed, and the reaction was allowed to warm slowly to room
temperature over 3 h. The reaction mixture, containing white precipitate,
was then diluted with dichloromethane (500 mL). Insoluble salts were
first removed by filtering the suspension through filter paper and then
the product solution was passed through a plug of silica (50 mL).
Solvents were then removed under dynamic vacuum, and the product
was washed with hexanes (250 mL). The yield of white microcrystalline
product was 2.03 g, 78%: 1H NMR (500 MHz, benzene-d6) δ 0.32 (s,
6 H, SiMe2Bu), 0.76 (t, J ) 8.5 Hz, 2 H, SiMe2CH2CH2CH2CH3), 0.94
(t, J ) 7 Hz, 3 H, SiMe2CH2CH2CH2CH3), 1.41 (q, J ) 7.5 Hz, 2 H,
SiMe2CH2CH2CH2CH3), 1.53 (m, 2 H, SiMe2CH2CH2CH2CH3), 7.21
(d, J ) 8 Hz, 2 H, phenylene), 7.24 (d, J ) 8 Hz, 2 H, phenylene),
7.29 (d, J ) 6.5 Hz, 2 H, phenylene), 7.58 (d, J ) 6.5 Hz, 2 H,
phenylene); 13C{1H} NMR (125 MHz, benzene-d6, not all resonances
observed due to poor solubility) δ -1.1 (SiMe2Bu), 14.4 (SiMe2Bu),
16.6 (SiMe2Bu), 26.9 (SiMe2Bu), 27.1 (SiMe2Bu), 127.7 (phenylene),
127.8 (phenylene), 128.9 (phenylene), 131.2 (phenylene), 133.2 (phe-
nylene), 140.6 (phenylene); 19F NMR (470.6 MHz, benzene-d6) δ -78.9
(m, 4 F), -75.2 (m, 4 F); FAB-MS m/z 878 (M+), 821 (M+ - Bu);
λmax (CH2Cl2) 306 nm. Anal. Calcd for C52H46F8Si2: C, 71.05; H, 5.27.
Found: C, 71.14; H, 5.21.
Alkyne 5. Alkyne 2 (9.29 g, 25.0 mmol) was loaded into a 1-L
Schlenk flask with a Teflon stopper and then dissolved in dry pentane
(250 mL). Dry diethyl ether (100 mL) was added to this solution, and
it was chilled to -78 °C in a dry ice/acetone bath, giving a white
suspension. tert-Butyllithium (30.9 mL, 52.5 mmol) was then added
dropwise with a syringe. The reaction mixture was allowed to warm
to the point where all solids redissolved, giving a clear yellow solution,
and then cooled once more to -78 °C. Decafluorobiphenyl (10.0 g,
30.0 mmol) was loaded into a 250-mL Schlenk flask, which was then
purged with dry nitrogen for 30 min. Dry pentane (125 mL) was added,
and stirring was continued until a clear solution was obtained. This
solution was added dropwise by cannula to the first flask, at -78 °C.
A thin precipitate formed on addition, which thickened as the addition
progressed. On completion of addition, the Teflon stopper of the reaction
Hexaphenylene Diyne 3. Alkyne 1 (3.11 g, 9.43 mmol) was loaded
into a 500-mL Schlenk flask with a Teflon stopper in the drybox and
then dissolved in dry toluene (175 mL) on the Schlenk line. Dry diethyl
ether (50 mL) was added to this solution, which was then chilled to
-78 °C in a dry ice/acetone bath. tert-Butyllithium (11.4 mL, 19.3
mmol) was then added dropwise with a syringe, to give a clear yellow

p-Phenylene Oligomers with Perfluorinated Segments
J. Am. Chem. Soc., Vol. 123, No. 42, 2001 10189
flask was sealed, and the reaction was allowed to warm slowly to room
temperature over 6 h as the dry ice evaporated. The reaction mixture,
containing white precipitate, was washed with water (3 × 250 mL) in
a separatory funnel. The organic phase was reduced in volume by one-
third under dynamic vacuum, and the solid product was isolated on a
medium frit. The product was then washed with water (3 × 50 mL)
and pentane (3 × 25 mL). The yield of white microcrystalline product
was 14.8 g, 98%: 1H NMR (500 MHz, benzene-d6) δ 0.31 (s, 6 H,
SiMe2Bu), 0.76 (t, J ) 8.5 Hz, 2 H, SiMe2CH2CH2CH2CH3), 0.94 (t,
J ) 7 Hz, 3 H, SiMe2CH2CH2CH2CH3), 1.41 (q, J ) 7.5 Hz, 2 H,
SiMe2CH2CH2CH2CH3), 1.53 (m, 2 H, SiMe2CH2CH2CH2CH3), 7.20
(m, 4 H, phenylene), 7.27 (d, J ) 8 Hz, 2 H, phenylene), 7.57 (d, J )
8 Hz, 2 H, phenylene); 13C{1H} NMR (125 MHz, dichloromethane-d2,
not all resonances observed) δ -1.7 (SiMe2Bu), 14.0 (SiMe2Bu), 16.2
(SiMe2Bu), 26.4 (SiMe2Bu), 26.7 (SiMe2Bu), 95.3 (alkynyl), 105.25
(alkynyl), 123.2 (phenylene), 127.4 (phenylene), 127.4 (phenylene),
127.6 (phenylene), 131.0 (phenylene), 132.8 (phenylene), 140.3 (phe-
nylene), 141.87 (phenylene); 19F NMR (470.6 MHz, benzene-d6) δ
-96.9 (m, 2 F), -86.4 (m, 1 F), -78.8 (m, 2 F), -75.3 (m, 2 F),
(iPr), 23.9 (iPr), 31.6 (iPr), 33.3 (iPr),123.2 (phenylene), 123.4 (phe-
nylene), 125.1 (phenylene), 127.7 (phenylene), 129.1 (phenylene), 131.5
(phenylene), 144.1 (fluorophenylene), 146.0 (fluorophenylene), 146.3
(phenylene), 148.1 (phenylene); 19F NMR (470.6 MHz, benzene-d6) δ
-75.3 (m, 4 F), -74.3 (m, 2 F), -74.1 (m, 2 F); FAB-MS m/z 776
(M+), 761 (M+ - Me). Anal. Calcd for C57H32Br2F8: C, 55.69; H,
4.15. Found: C, 55.50; H, 4.16.
Dodecaphenylene Diyne 8. Into a 500-mL Schlenk flask was loaded
7 (1.00 g, 1.29 mmol), and the flask was fitted with a 125-mL pressure-
equalizing addition funnel. The flask and funnel were then purged with
nitrogen for 30 min, and dry toluene (200 mL) was added, giving a
clear, colorless solution. Dry diethyl ether (50 mL) was added, and the
solution was cooled to -78 °C in a dry ice/acetone bath. tert-
Butyllithium (1.59 mL, 2.71 mmol) was added dropwise via syringe,
causing a pale yellow color to develop. This solution was stirred at
-78 °C for 10 min. Alkyne 5 (1.56 g, 2.58 mmol) in toluene (100
mL) was then transferred by cannula into the addition funnel. Addition
was carried out rapidly (∼3 drops/s) at -78 °C. A white precipitate
developed in the reaction flask as the addition progressed, which became
very thick within 15 min. On completion of addition, the reaction flask
was sealed, and the reaction was allowed to warm slowly to room
temperature over 6 h as the dry ice evaporated. The precipitate
redissolved during this time, with only a slight haze remaining at room
temperature. The reaction mixture was then filtered through a plug of
silica (30 mL). Solvents were removed under dynamic vacuum. The
slightly yellow product was suspended in methanol (250 mL), stirred
vigorously for 12 h, and isolated on a fine frit. The yield of white
microcrystalline product was 2.19 g, 95%: 1H NMR (500 MHz,
dichloromethane-d2) δ 0.24 (s, 6 H, SiMe2Bu), 0.73 (t, J ) 7.5 Hz, 2
H, SiMe2CH2CH2CH2CH3), 0.94 (t, J ) 7.5 Hz, 3 H, SiMe2CH2CH2-
CH2CH3), 1.26 (br d, 12 H, CH(CH3)2), 1.44 (m, 4 H, SiMe2-
CH2CH2CH2CH3), 2.86 (m, 2 H, CH(CH3)2), 7.40 (br s, 2 H,
diisopropylphenylene) 7.58 (d, J ) 8.5 Hz, 2 H, phenylene), 7.66 (m,
4 H, phenylene), 7.81 (d, J ) 8.5 Hz, 2 H, phenylene); 13C{1H} NMR
(125 MHz, dichloromethane-d2, not all resonances observed) δ -1.7
(SiMe2Bu), 14.0 (SiMe2Bu), 16.2 (SiMe2Bu), 24.12 (CH(CH3)2), 26.4
(SiMe2Bu), 26.7 (SiMe2Bu), 31.2 (CH(CH3)2), 95.2 (alkynyl), 105.3
(alkynyl), 107.0 (phenylene-F), 122.6 (phenylene-F), 123.2 (phenylene),
126.6 (phenylene), 127.4 (phenylene), 127.7 (phenylene), 128.6 (phe-
nylene), 131.0 (phenylene), 132.8 (phenylene), 140.4 (phenylene), 141.8
(phenylene), 143.6 (phenylene-F), 145.6 (phenylene-F), 146.4 (phe-
nylene); 19F NMR (470.6 MHz, dichloromethane-d2) δ -80.5 (m, 2
F), -77.1 (m, 4 F), -76.4 (m, 1 F), -76.3 (m, 1 F), -76.1 (m, 3 F),
-76.0 (m, 1 F); FAB-MS m/z 1791 (M+), 1736 (M+ - Bu); λmax (CH2-
Cl2) 298 nm. Anal. Calcd for C100H78F24Si2: C, 67.03; H, 4.39. Found:
C, 66.93; H, 4.41.
-75.1 (m, 2 F); EI-MS m/z 606 (M+), 591 (M+ - Me), 578 (M+
-
Bu). Anal. Calcd for C52H46F8Si2: C, 63.36; H, 3.82. Found: C, 63.14;
H, 3.75.
Nonaphenylene Diyne 6. Into a 500-mL Schlenk flask was loaded
1,4-diiodo-2,5-diisopropylbenzene (0.162 g, 0.393 mmol). This flask
was then purged with nitrogen for 30 min, and dry toluene (100 mL)
was added to give a clear solution. Dry diethyl ether (50 mL) was then
added, and the solution was cooled to -78 °C in a dry ice/acetone
bath. tert-Butyllithium (0.99 mL, 1.69 mmol) was added dropwise via
syringe, giving an orange, slightly cloudy solution. This solution was
stirred at -78 °C for 30 min. Alkyne 5 (0.500 g, 0.842 mmol) in toluene
(75 mL) was then added dropwise by cannula at -78 °C, which
produced a precipitate. On completion of addition, the reaction flask
was sealed, and the reaction was allowed to warm slowly to room
temperature over 6 h as the dry ice evaporated. The reaction mixture,
containing white precipitate, was then washed with water (3 × 100
mL) in a separatory funnel. The organic phase was separated and
reduced in volume by one-third under dynamic vacuum, and the solid
product was isolated on a medium frit. The product was then washed
with water (3 × 50 mL) and pentane (3 × 25 mL). The yield of white
microcrystalline product was 0.412 g, 79%: 1H NMR (500 MHz,
dichloromethane-d2) δ 0.24 (s, 6 H, SiMe2Bu), 0.73 (t, J ) 8.5 Hz, 2
H, SiMe2CH2CH2CH2CH3), 0.93 (t, J ) 7 Hz, 3 H, SiMe2CH2CH2-
CH2CH3), 1.25 (d, J ) 6.5 Hz, 6 H, isopropyl), 1.43 (m, 4 H, SiMe2-
CH2CH2CH2CH3), 2.84 (m, J ) 6.5 Hz, 1 H, isopropyl), 7.38 (s, 1 H,
central phenylene), 7.58 (d, J ) 8 Hz, 2 H, phenylene), 7.66 (m, 4 H,
phenylene), 7.82 (d, J ) 8 Hz, 2 H, phenylene); 19F NMR (470.6 MHz,
benzene-d6) δ -78.8 (m, 2 F), -75.0 (m, 4 F), -74.2 (m, 2 F); FAB-
MS m/z 1334 (M+), 1279 (M+ - Bu); λmax (CH2Cl2) 300 nm. Anal.
Calcd for C76H62F16Si2: C, 68.35; H, 4.68. Found: C, 68.40; H, 4.60.
Dimeric Macrocycles 9-11. These macrocycles were synthesized
through very similar procedures; differences are noted below. Diyne 3
(0.100 g, 0.126 mmol), 4 (0.100 g, 0.114 mmol), or 6 (0.100 g, 0.0749
mmol) was loaded into a Teflon-stoppered 100-mL Schlenk flask and
suspended in dry benzene (50 mL, used with 3 and 6) or dry mesitylene
(50 mL, used with 4) in a glovebox. A solution of Cp2Zr(py)(Me3-
SiCtCSiMe3) (0.0593 g, 0.126 mmol (for 3); 0.0536 g, 0.114 mmol
(for 4); 0.0353 g, 0.0749 mmol (for 6)) in the same solvent was then
added with a pipet, and the flask was sealed and brought out of the
glovebox. The reaction mixture was sonicated to render it a homoge-
neous light brown solution (5-20 min) and placed in a 40 °C water
bath for 48 h. During this time, the product deposited as yellow
microcrystals (10 and 11) or macroscopic crystals (9) on the walls of
the flask. The solvent was removed by cannula filtration, and the product
was dried under dynamic vacuum. Yields were as follows: 9, 0.110 g,
86%; 10, 0.114 g, 91%; 11, 0.099 g, 85%. Macrocycle 9 (from diyne
3): 1H NMR (500 MHz, benzene-d6) δ 0.03 (s, 9 H, Si(CH3)3), 6.22
(s, 5 H, Cp) 6.68 (d, J ) 8 Hz, 2 H, phenylene), 7.04 (d, J ) 8 Hz, 2
H, phenylene), 7.23 (d, J ) 8 Hz, 2 H, phenylene), 7.32 (d, obscured
by 13C satellite of solvent, 2 H, phenylene); 19F NMR (470.6 MHz,
benzene-d6) δ -78.9 (m, 4 F), -75.2 (m, 4 F). Anal. Calcd for
Dibromoquaterphenyl 7. Into a 500-mL Schlenk flask was loaded
1,4-dibromo-2,5-diisopropylbenzene (10.0 g, 31.2 mmol), toluene (200
mL), and diethyl ether (50 mL), and the resulting solution was cooled
to -78 °C in a dry ice/acetone bath. tert-Butyllithium (18.4 mL, 31.2
mmol) was then added dropwise via syringe. The reaction solution first
turned pale yellow and then colorless. This solution was stirred at -78
°C for 10 min. Decafluorobiphenyl (4.97 g, 14.9 mmol) in toluene (50
mL) was then added dropwise by cannula at -78 °C. On completion
of the addition, the reaction flask was sealed, and the reaction was
allowed to warm slowly to room temperature over 6 h as the dry ice
evaporated. The reaction mixture developed a brown color, while
remaining free of precipitate over this time. The reaction mixture was
stripped of solvents under dynamic vacuum. Hexanes (500 mL) were
added, and the resulting tan suspension was filtered through a plug of
silica (20 mL). The solvents were removed under dynamic vacuum.
The slightly yellow product was then suspended in methanol (250 mL),
stirred vigorously for 12 h, and isolated on a fine frit. The yield of
white microcrystalline product was 10.7 g, 93%: 1H NMR (500 MHz,
benzene-d6) δ 0.87 (d, J ) 7 Hz, 6 H, CH(CH3)2), 1.05 (d, J ) 7 Hz,
6 H, CH(CH3)2), 2.57 (m, J ) 7 Hz, 1 H, CH(CH3)2), 3.34 (m, J ) 7
Hz, 1 H, CH(CH3)2), 7.03 (s, 1 H, phenyl), 7.67 (s, 1 H, phenyl); 13C-
{1H} NMR (125 MHz, benzene-d6, not all resonances observed) δ 23.0
C
112H88F16Si4Zr2‚C6H6: C, 67.14; H, 4.49. Found: C, 67.40; H, 4.66.
Macrocycle 10 (from diyne 4): 1H NMR (500 MHz, benzene-d6) δ
0.08 (s, 6 H, Si(CH3)2Bu), 0.34 (t, J ) 8.5 Hz, 2 H, Si(CH3)2CH2CH2-
CH2CH3), 0.96 (t, J ) 7 Hz, 3 H, Si(CH3)2CH2CH2CH2CH3), 1.37 (m,

10190 J. Am. Chem. Soc., Vol. 123, No. 42, 2001
Nitschke and Tilley
4 H, Si(CH3)2CH2CH2CH2CH3), 6.25 (s, 5 H, cyclopentadienyl) 6.70
(d, J ) 8 Hz, 2 H, phenylene), 7.04 (d, J ) 8 Hz, 2 H, phenylene),
7.23 (d, J ) 8 Hz, 2 H, phenylene), 7.32 (d, J ) 8 Hz, 2 H, phenylene);
13C{1H} NMR (125 MHz, benzene-d6) δ 1.8 (SiMe2Bu), 14.5 (SiMe2Bu),
18.6 (SiMe2Bu), 21.7 (SiMe2Bu), 27.4 (SiMe2Bu), 112.0 (cyclopenta-
dienyl), 123.6 (phenylene), 125.85 (phenylene), 126.1 (phenylene),
127.7 (phenylene), 131.1 (phenylene), 131.4 (phenylene), 137.5 (phe-
nylene), 138.0 (phenylene), 143.2 (phenylene), 146.0 (phenylene), 149.9
(phenylene), 203.1 (Zr-C); 19F NMR (470.6 MHz, benzene-d6) δ -79.6
(m, 4 F), -75.3 (m, 4 F). Anal. Calcd for C124H112F16Si4Zr2‚2 C9H12:
C, 69.86; H, 5.61. Found: C, 69.6; H, 5.34. Macrocycle 11 (from diyne
6): Attempts at characterization by NMR spectroscopy were unsuc-
cessful due to low solubility. Anal. Calcd for C124H112F16Si4Zr2‚5
C6H6: C, 69.23; H, 5.00. Found: C, 69.16; H, 5.00.
X-ray Crystal Structure of 9. From the crystals formed during the
course of reaction, a yellow blocky crystal of dimensions 0.18 × 0.32
× 0.15 mm was selected. Data from this crystal were collected on a
Siemens SMART diffractometer with a CCD detector at 161 K using
Mo KR radiation. Frames corresponding to an arbitrary hemisphere of
data were taken using ω scans of 0.3° counted for 30 s. Of the 13 710
reflections collected, 9672 were unique, and of these, 6418 were
observed with I > 3σ(I). All non-hydrogen atoms were refined
anisotropically (739 parameters total); hydrogen atoms were included
at calculated positions but not refined. Details are included in the
Supporting Information.
Demetalated Macrocycles 12-14. Identical procedures were fol-
lowed, except where noted. Zirconacycle 9 (0.0500 g, 0.0246 mmol),
10 (0.0500 g, 0.0227 mmol), or 11 (0.0500 g, 0.0161 mmol) was loaded
into a Teflon-stoppered 100-mL Schlenk flask in a glovebox. On the
Schlenk line, dry benzene (50 mL) was added, and the mixture was
sonicated for 20 min to give a homogeneous, finely divided suspension.
Trifluoroacetic acid (19 µL, 0.25 mmol (for 9); 17 µL, 0.23 mmol (for
10); 12 µL, 0.16 mmol (for 11)) was then added via syringe with rapid
stirring, which caused the suspensions to bleach colorless within
minutes. After stirring for 1 h, the solvent and excess trifluoroacetic
acid were removed under dynamic vacuum. Highly insoluble macro-
cycle 12 (from zirconacycle 9) was suspended in dry benzene (50 mL),
sonicated for 30 min, and then isolated by filtration on a fine frit.
Macrocycles 13 and 14 were dissolved in dry dichloromethane (100
mL) and passed through a plug of silica (3 mL) in a glovebox. The
dichloromethane was then removed under dynamic vacuum, and the
product was washed with dry diethyl ether (2 × 10 mL) and isolated
on a fine frit. Yields were as follows: 12, 0.037 g, 95%; 13, 0.040 g,
92%; 14, 0.040 g, 92%. Macrocycle 12 (from zirconacycle 9): Attempts
at characterization by NMR spectroscopy and mass spectrometry were
unsuccessful due to low solubility. Anal. Calcd for C92H72F16Si4: C,
69.33; H, 4.55. Found: C, 69.10; H, 4.44. Macrocycle 13 (from
zirconacycle 10): 1H NMR (500 MHz, benzene-d6) δ 0.18 (s, 6 H,
Si(CH3)2Bu), 0.67 (t, J ) 8.5 Hz, 2 H, Si(CH3)2CH2CH2CH2CH3), 0.94
(t, J ) 7 Hz, 3 H, Si(CH3)2CH2CH2CH2CH3), 1.38 (m, 4 H, Si(CH3)2-
CH2CH2CH2CH3), 6.90 (s, 1 H, vinyl) 6.98 (d, J ) 8 Hz, 2 H,
phenylene), 7.06 (d, J ) 8 Hz, 2 H, phenylene), 7.19 (d, J ) 8 Hz, 2
H, phenylene), 7.28 (d, J ) 8 Hz, 2 H, phenylene); 13C{1H} NMR
(125 MHz, benzene-d6, not all resonances observed) δ -0.7 (SiMe2-
Bu), 14.4 (SiMe2Bu), 17.2 (SiMe2Bu), 27.1 (SiMe2Bu), 27.4 (SiMe2Bu),
126.7 (phenylene), 128.0 (phenylene), 128.9 (phenylene), 131.1 (phe-
nylene), 131.5 (phenylene), 139.0 (phenylene), 142.4 (phenylene), 142.8
(phenylene), 160.7 (phenylene); 19F NMR (470.6 MHz, benzene-d6) δ
-79.4 (m, 4 F), -75.2 (m, 4 F); FAB-MS m/z 1761.8 (M+), 1705.7
(M+ - Bu). Anal. Calcd for C104H96F16Si4: C, 70.88; H, 5.49. Found:
C, 70.59; H, 5.35. Macrocycle 14 (from zirconacycle 11): 1H NMR
(500 MHz, dichloromethane-d2) δ -0.02 (s, 6 H, SiMe2Bu), 0.54 (t, J
) 8.5 Hz, 2 H, SiMe2CH2CH2CH2CH3), 0.85 (t, J ) 7 Hz, 3 H, SiMe2-
CH2CH2CH2CH3), 1.15 (d, J ) 6.5 Hz, 6 H, isopropyl), 1.31 (m, 4 H,
SiMe2CH2CH2CH2CH3), 2.77 (m, J ) 6.5 Hz, 1 H, isopropyl), 6.47 (s,
1 H, vinyl), 6.99 (d,), 7.30 (m, 3 H, phenylene), 7.52 (d, J ) 8 Hz, 2
H, phenylene), 7.56 (d, J ) 8 Hz, 2 H, phenylene); 19F NMR (470.6
MHz, benzene-d6) δ -80.0 (m, 2 F), -76.5 (m, 4 F), -75.6 (m, 2 F);
FAB-MS m/z 2674 (M+), 2618 (M+ - Bu). Anal. Calcd for C76H62F16-
Si2: C, 68.25; H, 4.82. Found: C, 68.32; H, 4.92.
Reaction of 8 with Cp2Zr(py)(Me3SiCtCSiMe3). Dodecaphe-
nylene diyne 8 (0.100 g, 0.056 mmol) was loaded into a Teflon-
stoppered 100-mL Schlenk flask and suspended in dry toluene (50 mL).
A solution of Cp2Zr(py)(Me3SiCtCSiMe3) (0.026 g, 0.056 mmol) in
toluene (10 mL) was then added with a pipet, and the flask was sealed
and brought out of the glovebox. The reaction mixture was sonicated
to render it a homogeneous light brown solution (5 min) and placed in
a 40 °C water bath for 48 h. During this time, yellow product
precipitated from solution. The solvent was removed by cannula
filtration and the product dried under dynamic vacuum. The yield of
product was 0.101 g, 84%, if it is a zirconocene-coupled macrocycle
with three molecules of toluene. Attempts at characterization by NMR
spectroscopy were unsuccessful due to low solubility. Anal. Calcd for
C220H176F48Si4Zr2‚3 C7H8: C, 67.27; H, 4.68. Found: C, 67.39; H, 4.49.
Dry benzene (50 mL) was added to the product of this reaction (0.050
g), and the mixture was sonicated for 20 min to obtain a homogeneous
finely divided suspension. Trifluoroacetic acid (12 µL, 0.16 mmol) was
then added via syringe with rapid stirring, which caused the suspension
to bleach colorless within minutes. After stirring for 1 h, the solvent
and excess trifluoroacetic acid were removed under dynamic vacuum.
The product was washed with benzene (2 × 10 mL) and dichlo-
romethane (2 × 10 mL) and dried under dynamic vacuum. Attempts
at characterization by NMR spectroscopy and mass spectrometry were
again unsuccessful due to low solubility.
Acknowledgment is made to the National Science Founda-
tion for their generous support of this work. The Center for
New Directions in Organic Synthesis is supported by Bristol-
Myers Squibb as Sponsoring Member. We also thank Dr. Sam
Johnson for technical assistance.
Supporting Information Available: Tables of crystal data,
structure solution and refinement, atomic coordinates, bond
lengths and angles, and anisotropic thermal parameters for 9.
This material is available free of charge via the Internet at
http://pubs.acs.org.
JA011018S