Cross olefin metathesis for the selective functionalization, ferrocenylation, and solubilization in water of olefin-terminated dendrimers, polymers, and gold nanoparticles and for a divergent dendrimer construction

Article abstract of DOI:10.1021/ja077392v

Olefin cross metathesis was used to efficiently functionalize polyolefin dendrimers, polymers, and gold nanoparticles using the second-generation Grubbs catalyst. In these structures, the tethers were lengthened to prevent the facile cross metathesis that otherwise predominates in polyolefin dendrimers having short tethers. This synthetic strategy allows the one-step access to polyacid, polyester, and polyferrocenyl structures from polyolefins. Cross metathesis is also used to efficiently achieve an iterative divergent dendritic construction. All the cross metathesis reactions were monitored by ¹H NMR showing the chemio-, regio-, and stereoselectivity. MALDI-TOF mass spectrometry was a very useful technique to confirm the efficiency of this synthetic strategy.

Full text of DOI:10.1021/ja077392v

Published on Web 01/05/2008
Cross Olefin Metathesis for the Selective Functionalization,
Ferrocenylation, and Solubilization in Water of
Olefin-Terminated Dendrimers, Polymers, and Gold
Nanoparticles and for a Divergent Dendrimer Construction
Ca´tia Ornelas,† Denise Me´ry,† Eric Cloutet,‡ Jaime Ruiz Aranzaes,† and
Didier Astruc*,†
Institut des Sciences Mole´culaires, UMR CNRS N° 5255, UniVersite´ Bordeaux I, 351 Cours de
la Libe´ration, 33405 Talence Cedex, France, and LCPO, UMR CNRS N° 5629, UniVersite´
Bordeaux I, 33405 Talence Cedex, France
Received September 25, 2007; E-mail: d.astruc@ism.u-bordeaux1.fr
Abstract: Olefin cross metathesis was used to efficiently functionalize polyolefin dendrimers, polymers,
and gold nanoparticles using the second-generation Grubbs catalyst. In these structures, the tethers were
lengthened to prevent the facile cross metathesis that otherwise predominates in polyolefin dendrimers
having short tethers. This synthetic strategy allows the one-step access to polyacid, polyester, and
polyferrocenyl structures from polyolefins. Cross metathesis is also used to efficiently achieve an iterative
1
divergent dendritic construction. All the cross metathesis reactions were monitored by H NMR showing
the chemio-, regio-, and stereoselectivity. MALDI-TOF mass spectrometry was a very useful technique to
confirm the efficiency of this synthetic strategy.
Introduction
group applied the RCM to dendrimer chemistry and showed
that this reaction successfully allows molecular imprinting inside
Olefin metathesis1 has recently emerged as a powerful and
convenient synthetic technique in organic chemistry and polymer
science with the development of well-known catalysts that
possess high tolerance toward functional groups.1 Ring-closing
metathesis (RCM) and ring-opening metathesis polymerization
(ROMP) are possibly the most popular facets of olefin metath-
esis, because of their considerable impact on the synthesis of
biologically important cyclic compounds and polymers, respec-
tively.1
Olefin metathesis has also transformed the way chemists
design new molecular structures. Remarkable examples can be
found in transition-metal architectures such as RCM metathesis
of olefin-terminated ligands.2,3 RCM was also the synthetic
approach chosen by the Gladysz,2 van Koten4 and Newkome4
groups to construct giant ring structures. Zimmerman and his
dendrimers and its application to the fabrication of nanotubes.5
Compared with RCM and ROMP, cross metathesis (CM)
remains an underrepresented area of olefin metathesis. This has
been predominantly the result of several factors: (i) low catalyst
activity to effect a reaction without a strong enthalpic driving
force (such as ring-strain release in ROMP) or the entropic
advantage of intramolecular reactions (such as RCM); (ii) low
product selectivity for the CM product; and (iii) poor stereo-
selectivity in the newly formed olefin.1 Blechert et al. showed,
however, that the use of excess of one olefin together with that
of Schrock’s Mo catalyst1c favors the formation of the cross
product, whereas steric factors favor E stereoselectivity.6
Grubbs’ group categorized four types of olefins by reactivity
and rationalized a useful general mode that predicts the product
selectivity and stereoselectivity in CM.7b They have shown that,
when a terminal olefin is metathesized with catalyst A (second-
generation Grubbs catalyst), in the presence of another olefin
† Institut des Sciences Mole´culaires.
‡ LCPO.
(1) (a) Handbook of Metathesis; Grubbs, R. H., Ed.; Wiley-VCH: Weinheim,
Germany, 2003; Vols. 1-3. (b) Grubbs, R. H. Angew. Chem., Int. Ed. 2006,
23, 3760. (c) Schrock, R. R. Angew. Chem., Int. Ed. 2006, 23, 3748. (d)
Chauvin, Y. Angew. Chem., Int. Ed. 2006, 23, 3740. (e) Fu¨rstner, A. Angew.
Chem., Int. Ed. 2000, 39, 3012. (f) For a recent historical perspective, see:
Astruc, D. New J. Chem. 2005, 29, 42.
(4) (a) Chuchryukin, A. V.; Dijkstra, H. P.; Suijkerbuijk, B. M. J. M.; Gebbink,
R. J. M. K.; van Klink, G. P. M.; Mills, A. M.; Spek, A. L.; van Koten, G.
Angew. Chem., Int. Ed. 2003, 42, 228. (b) Wang, P.; Moorefield, C. N.;
Newkome, G. R. Angew. Chem., Int. Ed. 2005, 44, 1679.
(5) (a) Wendland, M. S.; Zimmerman, S. C. J. Am. Chem. Soc. 1999, 121,
1389. (b) Zimmerman, S. C.; Zharov, I.; Wendland, M. S.; Rakow, N. A.;
Suslick, K. S. J. Am. Chem. Soc. 2003, 125, 13504. (c) Kim, Y.; Mayer,
M. F.; Zimmerman, S. C. Angew. Chem., Int. Ed. 2003, 42, 1121. (d)
Lemcoff, N. G.; Spurlin, T. A.; Gewirth, A. A.; Zimmerman, S. C.; Beil,
J. B.; Elmer, S. L.; Vandeveer, H. G. J. Am. Chem. Soc. 2004, 126, 11420.
(e) Beil, J.; Lemcoff, N. G.; Zimmerman, S. C. J. Am. Chem. Soc. 2004,
126, 13576.
(2) (a) Martin-Alvarez, A. M.; Hampel, F.; Arif, A. M.; Gladysz, J. A.
Organometallics 1999, 18, 955. (b) Bauer, E. B.; Ruwwe, J.; Hampel, F.
A.; Szafert, S.; Gladysz, J. A. Chem. Commun. 2000, 22, 2261. (c) Horn,
C. R.; Martin-Alvarez, J. M.; Gladysz, J. A. Organometallics 2002, 21,
5386. (d) Bauer, E. B.; Hampel, F.; Gladysz, J. A. Organometallics 2003,
22, 5567. (e) Shima, T.; Bauer, E. B.; Hampel, F.; Gladysz, J. A. Dalton
Trans. 2004, 7, 1012. (f) Shima, T.; Hampel, F.; Gladysz, J. A. Angew.
Chem., Int. Ed. 2004, 43, 5537.
(3) (a) Dietrich-Bucherer, C.; Rapenne, G.; Sauvage, J.-P. Chem. Commun.
1997, 2053. (b) Weck, M.; Mohr, B.; Sauvage, J.-P.; Grubbs, R. H. J. Org.
Chem. 1999, 64, 5463. (c) Rapenne, G.; Dietrich-Bucherer, C.; Sauvage,
J.-P. J. Am. Chem. Soc. 1999, 121, 994.
(6) (a) Bru¨mmer, O.; Ru¨ckert, A.; Blechert, S. Chem.-Eur. J. 1997, 3, 441.
(b) Schuster, M.; Blechert, S. Angew. Chem., Int. Ed. 1997, 36, 2036. (c)
Connon, S. J.; Blechert, S. Angew. Chem., Int. Ed. 2003, 42, 1900.
9
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J. AM. CHEM. SOC. 2008, 130, 1495-1506
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Results and Discussion
bearing a strongly electron-withdrawing substituent, the stereo-
selectivity leads to high yields of the E functionalized cross
olefin.7
1. Functionalization of Dendrimers by Cross Metathesis.
CM was first applied to the known nonallyl core 1, C6H3{C(CH2-
CHdCH2)3}3, synthesized by the CpFe+-induced activation of
mesitylene under ambient conditions in the presence of KOH
and allyl bromide in THF,12 followed by photochemical de-
complexation.13 Our group showed that the nonallyl core 1
provides organometallic and organic cyclophanic capsules such
as 2, in the presence of catalyst A. Two of the three allyl
branches of the triallyl tripods readily undergo RCM, and the
remaining allyl branch reacts intermolecularly by CM of the
allyl termini forming the capsules (Scheme 1).9 The same
reaction in the presence of an electron-deficient olefin such as
acrylic acid or methyl acrylate avoids the formation of the
capsules. Even if the RCM is always the most favored reaction,
the third allyl branch, in the presence of catalyst A, undergoes
only stereoselective CM with the acrylate derivative (electron-
deficient olefin), affording the bifunctionalized molecules 3a
and 3b (Scheme 1).
To achieve the monofunctionalization of the dendrimers, we
have lengthened the dendritic tethers to avoid the formation of
the favored five- or six-membered rings by RCM. This was
achieved by hydrosilylation14,15 of 1 with HSi(Me)2CH2Cl
followed by Williamson reaction with p.OHC6H4O(CH2)9CHd
CH2, 4, giving the nonaolefin 6.
Since polyferrocenyl dendrimers present interesting applica-
tions in nanoelectronics because of their redox properties, we
have now synthesized an acrylate derivative that contains a
ferrocenyl group (ferrocenylmethyl acrylate, 5) to introduce it
in the dendrimer periphery by CM. This synthesis was achieved
by reaction of acryloyl chloride with ferrocenemethanol in
dichloromethane in the presence of triethylamine.16
Despite the usefulness of this property that has been applied
in organic synthesis,7 its application to functionalization of
nanostructures is still scarce.8 Liang and Fre´chet used CM to
incorporate small guest molecules into the interior of a den-
drimer bearing 22 allyl groups throughout the interior.8a Our
group recently reported the construction of organic cyclophanic
capsules by triple RCM followed by CM between allyl termini.9
Functionalization of structures such as dendrimers, polymers,
or nanoparticles is considerably more challenging than that of
mono-olefin molecules, because it requires a clean and quantita-
tive reaction to avoid the formation of mixtures among the
branch termini.10
CM in polyolefin molecules is often condemned by the
possibility of intramolecular RCM reaction or by the intermo-
lecular cross-linking. Our challenge now is to show that
polyolefin molecules can be efficiently functionalized by CM
using catalyst A.
We have reported, in a preliminary form, the monofunction-
alization of dendrimers with carboxylic acid and ester termini
by CM, using catalyst A in the presence of acrylic acid and
methyl acrylate, respectively.11 The intradendritic RCM was
avoided by lengthening the dendrimer tethers, which cancelled
the possibility to form five- or six-membered rings by RCM.
The use of catalyst A in the presence of an electron-deficient
olefin favored CM and avoided interdendritic cross-linking.
Contrary to that of 1, the metathesis reaction of 6 with CH2d
CHCO2R (R ) H, CH3, and CH2Fc, Fc ) ferrocenyl) selectively
yields the CM products 7a, 7b, and 7c, resulting from stereo-
selective terminal olefin functionalization (Scheme 1 and Figure
1). Likewise, the tethers of the known 27- and 81-allyl
dendrimers15 (G1 and G2), resulting from sequential hydrosily-
lation of 1 with HSiMe2CH2Cl and reaction with the dendron
p.HOC6H4C(allyl)3,17 were lengthened using the same synthetic
strategy, to give the new 27- and 81-olefin dendrimers 8 and
10. These dendrimers were also submitted to the metathesis
reaction in the presence of catalyst A and the acrylate deriva-
tives, efficiently yielding only the CM products (eqs 1 and 2).
After the remarkable results obtained using catalyst A in terms
of selectivity in cross metathesis of polyolefin dendrimers with
methyl acrylate, we have now generalized the reaction to other
acrylate derivatives that contain ferrocenyl groups or dendronic
bricks. We have extended this synthetic approach to efficiently
functionalize, by CM, different kinds of structures such as
dendrimers, polymers, and gold nanoparticles (AuNPs) with
acid, ester, and ferrocenyl termini. In this work, we also show
that CM can be an astute strategy to iteratively achieve divergent
dendrimer construction.
1
All the dendrimers were characterized by H, 13C, and 29Si
1
NMR spectroscopy and elemental analysis. In the H NMR
(7) (a) Chatterjee, A. K.; Morgan, J. P.; Scholl, M.; Grubbs, R. H. J. Am. Chem.
Soc. 2000, 122, 3783. (b) Chatterjee, A. K.; Choi, T.-L.; Sanders, D. P.;
Grubbs, R. H. J. Am. Chem. Soc. 2003, 125, 11360. (c) Chatterjee, A. K.
In Handbook of Metathesis; Grubbs, R. H., Ed.; Wiley-VCH: Weinheim,
Germany, 2003; Vol. 2, Chapter 2.8, pp 246-295. (d) For catalyst A, see
also: Grubbs, R. H. Acc. Chem. Res. 2001, 34, 18.
(8) (a) Liang, C. O.; Fre´chet, J. M. J. Macromolecules 2005, 38, 6276. (b)
Dutta, S.; Perring, M.; Barret, S.; Mitchell, M.; Kenis, P. J. A.; Bowden,
N. B. Langmuir 2006, 22, 2146. (c) Mathers, R. T.; Coates, G. W. Chem.
Commun. 2004, 422. (d) Samanta, D.; Faure, N.; Rondelez, F.; Sarkar, A.
Chem. Commun. 2003, 1186.
(9) Martinez, V.; Blais, J.-C.; Astruc, D. Angew. Chem., Int. Ed. 2003, 42,
4366.
spectra, we can clearly see the complete disappearance of the
terminal olefinic protons at 5.8 (multiplet) and 4.9 ppm (triplet)
and the appearance of the new internal olefinic protons at 7.0
(12) Astruc, D.; Nlate, S.; Ruiz, J. In Modern Arene Chemistry; Astruc, D.,
Ed., Wiley-VCH: Weinheim, Germany, 2002; pp 400-434.
(13) (a) Moulines, F.; Astruc, D. Angew. Chem., Int. Ed. Engl. 1988, 27, 1347.
(b) Moulines, F.; Djakovitch, L.; Boese, R.; Gloaguen, B.; Thiel, W.; Fillaut,
J.-L.; Delville, M.-H.; Astruc, D. Angew. Chem., Int. Ed. Engl. 1993, 32,
1075. (c) Fillaut, J.-L.; Linares, J.; Astruc, D. Angew. Chem., Int. Ed. Engl.
1994, 33, 2460. (d) Plault, L.; Hauseler, A.; Nlate, S.; Astruc, D.; Ruiz, J.;
Gatard, S.; Neumann, R. Angew. Chem., Int. Ed. 2004, 43, 2924.
(14) van der Made, A. W.; van Leeuwen, P. W. N. M.; de Wilde, J. C.; Brandes,
R. A. C. AdV. Mater. 1993, 5, 466.
(10) (a) Newkome, G. R.; Moorefield, C. N.; Vo¨gtle, F. Dendrons and
Dendrimers. Concepts, Synthesis and Applications; Wiley-VCH: Wein-
heim, Germany, 2001. (b) Dendrimers and Other Dendritic Polymers;
Tomalia, D., Fre´chet, J. M. J., Eds.; Wiley-VCH: New York, 2002. (c)
Dendrimers and Nanosciences; Astruc, D., Ed., C. R. Chim. 2003, 6, 709-
1208.
(15) Ruiz, J.; Lafuente, G.; Marcen, S.; Ornelas, C.; Lazare, S.; Blais, J.-C.;
Cloutet, E.; Astruc, D. J. Am. Chem. Soc. 2003, 125, 7250.
(16) Kuwabara, J.; Takeuchi, D.; Osakada, K. Organometallics 2005, 24, 2705.
(17) Sartor, V.; Fillaut, J.-L.; Djakovitch, L.; Moulines, F.; Marvaud, V.; Neveu,
F.; Blais, J.-C.; Astruc, D. J. Am. Chem. Soc. 1999, 121, 2929.
(11) Ornelas, C.; Me´ry, D.; Blais, J.-C.; Cloutet, E.; Ruiz, A. J.; Astruc, D.
Angew. Chem., Int. Ed. 2005, 44, 7399.
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Scheme 1. Bifunctionalization of the Nonallyl Core, Lenthening of the Dendrimer Tethers, and Efficient Monofunctionalization by Cross
Metathesis
(multiplet) and 5.8 ppm (doublet) (Figure 1). No other olefinic
protons are present in the 1H NMR spectra of the functionalized
dendrimers showing the absence (at the NMR accuracy) of the
intra- and interdendritic metathesis between the allyl termini
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Figure 3. SEC of the three generations of dendrimers (respectively, 9, 27,
and 81 tethers): (a) allyl dendrimers (before functionalization by cross
metathesis), (b) ester dendrimers functionalized by CM, and (c) ferrocenyl
dendrimers functionalized by CM. (Polydispersity indices between 1.00 and
1.02.)
of the three generations of polyallyl, polyester, and polyferro-
cenyl dendrimers, confirming the size progression from a
generation to the next one and including the inexistence of cross-
linking between the dendrimers in the metathesis reaction.
Figure 1. (a) 1H NMR spectrum of dendrimer 10. (b) 1H NMR spectrum
of 11a. By comparing these two 1H NMR spectra, it is possible to see that
the CM reaction is complete (at the NMR accuracy) at the dendrimer
periphery (disappearance of the allyl protons in (a) and appearance of the
olefin protons in (b)) and that only the trans isomer is obtained (complete
absence of cis protons around 6.4 ppm in (b)).
Cross metathesis thus proved to be an efficient strategy to
cleanly synthesize polyacid, polyester, and polyferrocenyl
dendrimers in one step from polyolefin dendrimers with high
chemio-, regio-, and stereoselectivity. The polyferrocenyl den-
drimers 7c, 9c, and 11c present a single, fully reversible redox
wave in cyclic voltammetry at 610 mV vs FeCp2* (Cp* ) η5-
C5Me5), for all the equivalent (but distant) ferrocenyl groups
whose potentials are similar, the electrostatic factor being
apparently very weak (Chart 1).18 These dendrimers present
potential applications in molecular electronics because of their
nanosize and high redox stability.18
The polycarboxylic acid dendrimers give water- or methanol-
soluble sodium carboxylate salts upon contact with aqueous
NaOH or NaOH in methanol. Water-soluble dendrimers are used
for applications such as molecular micelles, cation binding,
and vector to drug delivery.19 The polycarboxylic acid den-
drimers are also very useful for their reactions with various
amines, a further functionalization procedure. For instance,
reaction of the new amine dendron N{(CH2)4Fc}3 (Fc )
ferrocenyl), 12, with 11a gives the supramolecular 243-
ferrocenyl dendrimer 13 (eq 3) showing a single wave in cyclic
voltammetry (SI).18
Figure 2. MALDI-TOF mass spectra of 7b.
(otherwise, a singlet would appear at 5.5 ppm). The new
functionalized dendrimers only contain the trans isomers,
because otherwise the cis conformation would present the
olefinic protons at 6.4 and 6.0 ppm. These NMR data (for NMR
spectra, see the Supporting Information, SI, pp 36-37) show
that the functionalization of the dendrimers by CM is chemio-,
regio-, and stereoselective.
Up to 81 ammonium carboxylate linkages might form, which
is shown by the change of solubility from 11a that is insoluble
in methylene chloride (but soluble in acetone) to 13 that becomes
soluble in methylene chloride. Moreover, the 1H and 13C NMR
signals of the methylene groups attached to the carboxylate and
amine groups, respectively, are strongly shifted in 13 compared
to the precursors 11a and 12 (the NCH2 signal of 12 at
In addition, the MALDI-TOF mass spectra of 7a, 7b, 7c, 9a,
and 9b show the corresponding molecular peaks (Figure 2 and
SI, pp 44-48), which confirms the efficiency of the function-
alization strategy. In particular, in Figure 2, the MALDI-TOF
mass spectrum of 7b shows the corresponding molecular peak
at 4037.2 (calcd for C234H372Si9O36Na: 4037.3), and in SI Figure
4 (SI, p 44), the mass spectrum of 9b shows the molecular peak
13 813.1 (calcd for C801H1272Si36O117Na: 13 808.9). Overall, the
mass and NMR spectra of the cross metathesis products show
that the conversions are larger than 95%.
(18) (a) Fillaut, J.-L.; Linares, J.; Astruc, D. Angew. Chem., Int. Ed. 1994, 33,
240. (b) Vale´rio, C.; Fillaut, J.-L.; Ruiz, J.; Guittard, J.; Blais, J.-C.; Astruc,
D. J. Am. Chem. Soc. 1997, 119, 2588. (c) For a comprehensive review on
ferrocene dendrimers and their electrochemistry, see for instance: Casado,
C. M.; Moran, M.; Alonso, B.; Garcia, B.; Gonzales, J.; Losada, J. Coord.
Chem. ReV. 1999, 185/186, 53. (d) Daniel, M.-C.; Ruiz, J.; Nlate, S.;
Blais, J.-C.; Astruc, D. J. Am. Chem. Soc. 2003, 125, 2617. (e) Daniel,
M.-C.; Sakamoto, A.; Ruiz, J.; Astruc, D.; Nishihara, H. Chem. Lett. 2006,
38.
(19) (a) Newkome, G. R. Pure Appl. Chem. 1988, 70, 2337. (b) Newkome, G.
R.; Moorefield, C. N.; Baker, G. R.; Saunders, M. J.; Grossman, S. H.
Angew. Chem., Int. Ed. Engl. 1991, 30, 1178. (c) Gopidas, K. R.; Leheny,
A. R.; Caminati, G.; Turro, N. J.; Tomalia, D. A. J. Am. Chem. Soc.
1991, 113, 7335. (d) Jansen, J. F. G. A.; de Brabander-van den Berg, E.
M. M.; Meijer, E. W. Science 1994, 1226. (e) Balzani, V.; Ceroni, P.;
Gestermann, S.; Gorka, M.; Kauffmann, C.; Vo¨gtle, F. Tetrahedron 2002,
58, 629.
The dendrimers were also characterized by size exclusion
chromatography (SEC). The size exclusion chromatograms
shown in Figure 3 with Gaussian-type distributions indicate
monodispersities (polydispersity indices between 1.00 and 1.02)
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Chart 1. Ferrocenyl Dendrimers 7c, 9c, and 11c, Obtained Directly by Cross Metathesis from the Polyolefin Dendrimers 6, 8, and 10
2.4 ppm is shifted downfield to 2.7 ppm, and the olefin proton
of 11a at 7.0 ppm is shifted upfield at 6.8 ppm in c) (SI, p 34).
2. Dendritic Construction by Cross Metathesis. CM
can now be used as an efficient synthetic strategy for
iterative divergent dendritic construction. This could in-
deed be achieved by functionalizing the focal point of the
phenolic dendron (14) with the acrylate function (15)
(eq 4).
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This dendron was used as an electron-deficient olefin in CM
reaction with dendrimer 6, using catalyst A. This reaction
quantitatively yielded a 27-chloromethyl dendrimer, 16, that is
suitable to continue the dendritic construction. Reaction of
Scheme 2. Iteractive Divergent Dendritic Construction by Selective Cross Metathesis
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Scheme 3. Functionalization of Polymers by Olefin Cross
Metathesis
characterization of dendrimer 16 by mass spectrometry, showing
its molecular peak at 8729.77 (calcd for C450H759O36Si36Cl27-
Na: 8736.90) in the MALDI-TOF spectrum (SI, p 50). The 1H
NMR of the series clearly shows the signals of the protons
corresponding to the expected double bonds (see the NMR
spectra in the SI, pp 38-40). Correct elemental analysis obtained
for the new series of dendrimers confirms the efficiency and
purity of the products obtained. In conclusion, the functional-
ization of dendrons with the acrylate function opens a wide range
of possibilities to achieve convergent or divergent dendritic
construction by selective cross metathesis.
3. Functionalization of Polymers by Cross Metathesis. The
functionalization of polymers is often limited by steric problems,
and polymer chemists resort to dramatic reaction conditions or
high stoichiometries to achieve functionalization. We now show
that cross metathesis can be a useful strategy to easily achieve
the functionalization of polyolefin polymers. Classic radical
polymerization of chloromethyl styrene using AIBN as an
initiator yielded the chloromethyl styrene polymer (19). Further
reaction with p.hydroxyphenyl undecene-1-yl ether 4, in the
presence of K2CO3 and NaI in DMF at 80 °C for 48 h, yielded
a styrenic polymer with long olefinic tethers (20). This polymer
was submitted to cross metathesis, using catalyst A, with methyl
acrylate and ferrocenylmethyl acrylate (5), affording the cor-
responding ester and ferrocenyl polymers (21b and 21c,
respectively) (Scheme 3).
dendrimer 16 with p.HOC6H4O(CH2)9CHdCH2 (4) yielded the
dendrimer 17 that contains 27 long allyl tethers. CM of the
dendrimer 17 with dendron 15 successfully afforded the
dendrimer 18 that contains 81 chloromethyl termini (Scheme
2).
We show here two complete iterations (lengthening of
dendrimer tethers and CM) in the synthesis of a new dendrimer
series. The success of this strategy is evidenced by the
The functionalization of polymer 20 by CM was achieved
using only 2 equiv per branch of reactant and 5% of catalyst,
which is a remarkable feature in polymer chemistry. The
Scheme 4. Functionalization of AuNPs by Olefin Cross Metathesis
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million (δ, ppm) with reference to Me4Si (TMS). Elemental analyses
were performed by the Center of Microanalyses of the CNRS at Lyon-
Villeurbanne, France. MALDI mass spectra were recorded with a
PerSeptive Biosystems Voyager Elite time-of-flight mass spectrometer.
General Procedure for the Metathesis Reactions. The polyolefin,
dry CH2Cl2, the acrylate derivative (2 equiv per branch), and catalyst
A (5% equivalent per branch) were successively introduced into a
Schlenk flask under an inert atmosphere. The solution was stirred at
40 °C for 18 h. After the solvent was removed under vacuum, the
product was washed with methanol and precipitated with dichlo-
romethane/methanol in the case of polyester or polyferrocenyl or with
THF/methanol in the case of the polycarboxylic acid dendrimers.
Synthesis of 3a. The product 3a was synthesized from the nonallyl
derivative 1 (0.050 g, 0.10 mmol), acrylic acid (0.130 g, 1.80 mmol),
and catalyst A (0.040 g, 0.047 mmol), following the general procedure
for the metathesis reactions, and it was obtained as a white solid in
76% yield (0.042 g).
polydispersity of the polymers (1.33, obtained by SEC) did not
change after CM, indicating the absence of cross-linking
between the olefinic termini during the metathesis reaction (for
the NMR spectra, see the SI, pp 41-42). The ferrocenyl polymer
21c presents a single, fully reversible redox wave at 610 mV
in cyclic voltammetry, for all the equivalent (but distant)
ferrocenyl groups whose potentials are almost identical.18
4. Functionalization of AuNPs by Cross Metathesis.
AuNPs are finding a rapidly increasing number of important
applications in nanoscience, such as catalysts and optoelectronic
sensors including biosensors and vectors.20 Thus, cross metath-
esis can be a useful strategy to efficiently functionalize AuNPs.
Alkene-terminated AuNPs (22) were synthesized from 11-
undecenethiol using the Brust method.21 These polyolefin
AuNPs were submitted to cross metathesis, using catalyst A,
with methyl acrylate and ferrocenylmethyl acrylate (5), affording
the corresponding ester and ferrocenyl AuNPs (Scheme 4). The
1H NMR (CD3COCD3, 300 MHz), δppm
: 7.19 (m, 3H, CHd
CHCOOH), 7.16 (s, 3H, CHAr), 5.87 (d, 3H, CHdCHCOOH), 5.80
(m, 6H, CHdCH), 2.86 (m, 12H, CH2CHdCH), 2.33 (m, 6H, CH2-
CHdCH). 13C NMR (CH3COCH3, 75 MHz), δppm: 168.1 (CdO), 149.1
(CHdCHCOOH), 129.9 (CH2CHdCHCH2), 119.2 (CHCOOH), 39.9
1
success of the metathesis reaction was confirmed by H NMR
that clearly shows the disappearance of the olefinic protons of
22 at 5.78 and 4.98 ppm and the appearance of the protons of
the new internal double bond at 6.97 and 5.80 ppm (for the
NMR spectra, see the SI, p 43).
and 37.1 (CH2CH). IR (KBr), νCdO
:
1711 cm-1. Anal. Calcd for
C33H36O6: C, 74.98; H, 6.86. Found: C, 74.59; H, 6.61.
Synthesis of 3b. The product 3b was synthesized from 1 (0.050 g,
0.10 mmol), methyl acrylate (0.155 g, 1.80 mmol), and catalyst A (0.040
g, 0.047 mmol), following the general procedure for the metathesis
reactions, and it was obtained as a white solid in 99% yield (0.059 g).
1H NMR (CDCl3, 300 MHz), δppm: 7.25 (m, 3H, CHdCHCOOCH3),
7.08 (s, 3H, CHAr), 5.79 (d, 3H, CHCOOCH3), 5.68 (m, 6H, CHd
CH), 3.76 (s, 9H, COOCH3), 2.71 (m, 12H, CH2CHdCH), 2.46 (m,
6H, CH2CHdCH). 13C NMR (CDCl3, 75.00 MHz), δppm: 167.2 (Cd
O),148.8(CHdCHCOOH),130.2(CH2CHdCHCH2),119.1(CHCOOH),
50.98 (COOCH3), 39.7 and 36.7 (CH2CH). IR (KBr), νCdO: 1732 cm-1
Anal. Calcd for C36H42O6: C, 75.76; H, 7.42. Found: C, 75.71; H,
7.39.
Synthesis of 7a. The nonacarboxylic acid dendrimer 7a was
synthesized from 6 (0.100 g, 0.029 mmol), acrylic acid (0.037 g, 0.52
mmol), and catalyst A (0.011 g, 0.013 mmol), following the general
procedure for the metathesis reactions, and it was obtained as a white
waxy product in 95% yield (0.107 g).
The AuNPs were characterized by TEM before and after
metathesis reaction to study the influence of the CM in the size
of the AuNPs. It was found that the AuNPs 22 (before CM)
have a diameter of 2.1 ( 0.3 nm, and the AuNPs 23b (after
CM) have a diameter of 2.2 ( 0.3 nm (SI, pp 50-51). There
is no significant difference between the AuNPs before and after
CM, thus the Grubbs catalyst only acts at the AuNPs periphery
and does not change the metallic core of the AuNPs.
Characterization of the purple product 23c by cyclic volta-
mmetry confirmed the presence of the ferrocenyl groups in the
molecule presenting a reversible redox wave at 610 mV vs.
FeCp2* (Cp* ) η5-C5Me5).
Conclusion
The disclosure of this remarkable quantitative chemio-, regio-,
and stereoselective cross olefin metathesis between different
nanostructures and acrylate derivatives, using the catalyst A,
provides a unique way to functionalize polyolefin dendrimers,
polymers, and AuNPs. This synthetic approach allows an easy
access to useful polycarboxylic acid and polyferrocenyl den-
drimers in large scales from simple polymethyl benzenes in a
few steps.14 Finally, CM is a new astute and efficient strategy
to iteratively achieve divergent dendritic construction.
1H NMR (CD3COCD3, 300 MHz), δppm: 7.01 (s, 3H, CH arom.
core), 6.95 (m, 9H, HCdCHCOOH), 6.81 (d, 36H, CH arom.), 5.82
(d, 9H, HCdCHCOOH), 3.82 (t, 18H, OCH2), 3.41 (s, 18H, SiCH2O),
2.18 (m, 36H, CH2CHdCH), 1.69 (m, 36H, OCH2CH2 and CH2CH2-
CH2Si), 1.27 (m, 108H, (CH2)6), 1.14 (s, 18H, CH2CH2CH2Si), 0.54
(s, 18H, CH2CH2CH2Si), 0.051 (s, 54H, Si(CH3)2). 13C NMR (CD3-
COCD3, 75 MHz), δppm: 168.0 (CdO), 154.7 and 151.9 (arom. OCq),
149.8 (CHdCHCOOH), 145.6 (arom. Cq, core), 122.0 (CHdCHCOOH),
121.1 (arom. CH, core), 114.3 and 113.8 (arom. CH), 67.6 (OCH2-
(CH2)8), 59.9 (SiCH2O), 43.2 (CH2CH2CH2Si), 42.0 (benzylic Cq), 33.8
(CH2HCdCH), 29.4 and 26.0 ((CH2)6), 17.8 (CH2CH2CH2Si), 14.6
(CH2CH2CH2Si), -4.5 (SiMe2). 29Si NMR (CD3COCD3, 59.62 MHz),
Experimental Section
General Data. Products 1,12 2,9 and 1418c were prepared according
to the literature. Ferrocenylmethyl acrylate was synthesized by improv-
ing the reported method16 (see the synthesis of 5, SI, p 6). Acryloyl
chloride was obtained from acrylic acid and lauroyl chloride at 100 °C
for 18 h and recovered with a trap-to-trap vacuum system. Methylene
chloride (CH2Cl2) was distilled from calcium hydride just before use.
All other chemicals were used as received. All manipulations were
carried out using Schlenk techniques or in a nitrogen-filled Vacuum
Atmosphere drylab. NMR spectra were recorded at 25 °C with a Bruker
AC 300 spectrometer. All chemical shifts are reported in parts per
δ
ppm: 0.30 (SiCH2O). IR (KBr), νCdO: 1711 cm-1. MS (MALDI-TOF,
m/z): Calcd for C225H354Si9O36: 3 888.03; found: 3 886.97 (M-H).
Anal. Calcd for C225H354Si9O36: C, 69.51; H, 9.18. Found: C, 69.39;
H, 8.97.
Synthesis of 7b. The nonaester dendrimer 7b was synthesized from
6 (0.100 g, 0.029 mmol), methyl acrylate (0.045 g, 0.52 mmol), and
catalyst A (0.011 g, 0.013 mmol), following the general procedure for
the metathesis reactions, and it was obtained as a white waxy product
in 99% yield (0.116 g).
1H NMR (CDCl3, 300 MHz), δppm: 7.03 (s, 3H, CH arom. core),
6.94 (m, 9H, HCdCHCOOCH3), 6.80 (d, 36H, CH arom.), 5.81 (m,
9H, HCdCHCOOCH3), 3.81 (t, 18H, OCH2), 3.71 (s, 18H, COOCH3),
3.39 (s, 18H, SiCH2O), 2.01 (m, 36H, CH2CHdCH), 1.71 (m, 36H,
(20) Daniel, M.-C.; Astruc, D. Chem. ReV. 2004, 101, 293.
(21) (a) Brust, M.; Walker, M.; Bethell, D.; Schiffrin, D.; Whyman, R. J. J.
Chem. Soc., Chem. Commun. 1994, 801. (b) Brust, M.; Fink, J.; Bethell,
D.; Schiffrin, D. J.; Kiely, C. J. J. Chem. Soc., Chem. Commun. 1995,
1655.
9
J. AM. CHEM. SOC. VOL. 130, NO. 4, 2008 1503

A R T I C L E S
Ornelas et al.
OCH2CH2 and CH2CH2CH2Si), 1.29 (m, 108H, (CH2)6), 1.14 (s, 18H,
CH2CH2CH2Si), 0.60 (s, 18H, CH2CH2CH2Si), 0.061 (s, 54H, Si(CH3)2).
13C NMR (CDCl3, 75 MHz), δppm: 167.1 (CdO), 154.5 and 151.6
(arom. OCq), 148.7 (CHdCHCOOCH3), 145.6 (arom. Cq, core), 122.1
(CHdCHCOOCH3), 121.1 (arom. CH, core), 114.3 and 113.8 (arom.
CH), 67.6 (OCH2(CH2)8), 59.9 (SiCH2O), 50.3 (COOCH3), 43.2 (CH2-
CH2CH2Si), 42.0 (benzylic Cq), 33.5 (CH2HCdCH), 29.4 and 26.0
((CH2)6), 17.8 (CH2CH2CH2Si), 14.6 (CH2CH2CH2Si), -4.5 (SiMe2).
29Si NMR (CDCl3, 59.62 MHz), δppm: 0.30 (SiCH2O). IR (KBr), νCd
O: 1732 cm-1. MS (MALDI-TOF, m/z): Calcd for C234H372Si9O36Na:
4037.27; found: 4037.20 (MNa). Anal. Calcd for C234H372Si9O36: C,
70.01; H, 9.34. Found: C, 69.78; H, 9.24.
Synthesis of 7c. The nonaferrocenyl dendrimer 7c was synthesized
from 6 (0.100 g, 0.029 mmol), 5 (0.140 g, 0.52 mmol), and catalyst A
(0.011 g, 0.013 mmol), following the general procedure for the
metathesis reactions, and it was obtained as a yellow waxy product in
98% yield (0.161 g).
1H NMR (CDCl3, 300 MHz), δppm: 7.03 (s, 3H, CH arom. core),
6.96 (m, 9H, HCdCHCOOCH2Fc), 6.80 (d, 36H, CH arom.), 5.81 (d,
9H, HCdCHCOOCH2Fc), 4.96 (s, 18H, CH2Fc), 4.29 and 4.17 (d, 81H,
CH of Fc), 3.85 (t, 18H, OCH2), 3.46 (s, 18H, SiCH2O), 2.20 (m, 36H,
CH2CHdCH), 1.71 (m, 36H, OCH2CH2 and CH2CH2CH2Si), 1.29 (m,
108H, (CH2)6), 1.15 (s, 18H, CH2CH2CH2Si), 0.59 (s, 18H, CH2-
CH2CH2Si), 0.09 (s, 54H, Si(CH3)2). 13C NMR (CDCl3, 75 MHz),
324H, (CH2)6), 1.19 (s, 72H, CH2CH2CH2Si), 0.56 (s, 72H, CH2-
CH2CH2Si), 0.030 (s, 216H, Si(CH3)2). 13C NMR (CDCl3, 75 MHz),
δppm: 167.1 (CdO), 159.0 (inner arom. OCq), 155.7 and 153.0 (outer
arom. Cq), 149.7 (CHdCHCOOCH3), 127.2 and 113.4 (arom. CH of
the dendron), 120.8 (CHdCHCOOCH3), 115.5 and 114.8 (arom. CH),
68.6 (OCH2(CH2)8), 60.9 (outer SiCH2O), 60.2 (inner SiCH2O), 51.3
(COOCH3), 43.0 (CH2CH2CH2Si), 42.0 (benzylic Cq), 32.2 (CH2HCd
CH), 29.4 and 26.0 ((CH2)6), 17.6 (CH2CH2CH2Si), 14.6 (CH2CH2CH2-
Si), -4.5 (SiMe2). 29Si NMR (CDCl3, 59.62 MHz), δppm: 0.46 and
0.29 (inner and outer SiCH2O). IR (KBr), νCdO
:
1732 cm-1. MS
(MALDI-TOF, m/z): Calcd for C801H1272O117Si36Na: 13 808.9; found:
13 813.1 (MNa). Anal. Calcd for C801H1272O117Si36: C, 68.73; H, 9.16.
Found: C, 68.72; H, 9.23.
Synthesis of 9c. The 27-ferrocenyl dendrimer 9c was synthesized
from 8 (0.050 g, 0.0041 mmol), 5 (0.060 g, 0.221 mmol), and catalyst
A (0.005 g, 0.0055 mmol), following the general procedure for the
metathesis reactions, and it was obtained as a yellow waxy product in
96% yield (0.074 g).
1H NMR (CDCl3, 300 MHz), δppm: 7.12 (d, 18H, arom.), 6.96 (m,
27H, HCdCHCOOCH2Fc), 6.79 (d, 126H, arom.), 5.81 (d, 27H, HCd
CHCOOCH2Fc), 4.94 (s, 54H, CH2Fc), 4.28 and 4.16 (d, 243H, CH
of Fc), 3.84 (t, 54H, OCH2CH2), 3.46 (s, 72H, SiCH2O), 2.17 (m, 54H,
CH2CHdCH), 1.69 (d, 126H, OCH2CH2 and CH2CH2CH2Si), 1.28 (d,
324H, (CH2)6), 1.18 (s, 72H, CH2CH2CH2Si), 0.55 (s, 72H, CH2-
CH2CH2Si), 0.078 and 0.018 (s, 216H, Si(CH3)2). 13C NMR (CDCl3,
75 MHz), δppm: 166.4 (CdO), 158.9 (inner arom. OCq), 155.6 and
153.0 (outer arom. OCq), 149.7 (CHdCHCOOCH2Fc), 127.2 and 113.4
(arom. CH of the dendron), 121.0 (CHdCHCOOCH2Fc), 115.2 and
114.7 (arom. CH), 81.5 (Cq of Fc), 69.6 (OCH2(CH2)8), 68.6 (CH of
Fc), 62.5 (CH2Fc), 60.8 (outer SiCH2O), 60.2 (inner SiCH2O), 43.9
(CH2CH2CH2Si), 42.0 (benzylic Cq), 32.2 (CH2HCdCH), 29.4 and 26.0
((CH2)6), 17.6 (CH2CH2CH2Si), 14.6 (CH2CH2CH2Si), -4.6 (SiMe2).
29Si NMR (CDCl3, 59.62 MHz), δppm: 0.46 and 0.29 (inner and outer
δppm
: 166.4 (CdO), 155.7 and 153.0 (arom. OCq), 149.7 (CHd
CHCOOCH2Fc), 145.8 (arom. Cq, core), 121.2 (arom. CH, core), 121.1
(CHdCHCOOCH2Fc), 115.3 and 114.7 (arom. CH), 81.7 (Cq of Fc),
69.6 (OCH2(CH2)8), 68.5 (CH of Fc), 62.5 (CH2Fc), 60.9 (SiCH2O),
43.9 (CH2CH2CH2Si), 42.0 (benzylic Cq), 32.1 (CH2HCdCH), 29.4
and 26.0 ((CH2)6), 17.8 (CH2CH2CH2Si), 14.6 (CH2CH2CH2Si), -4.5
(SiMe2). 29Si NMR (CDCl3, 59.62 MHz), δppm: 0.30 (SiCH2O). IR
(KBr), νCdO: 1732 cm-1. MS (MALDI-TOF, m/z): Calcd for C324H444
-
Si9O36Fe9: 5670.48; found: 5670.85. Anal. Calcd for C324H444Si9O36-
Fe9: C, 68.63; H, 7.89. Found: C, 68.30; H, 8.41.
SiCH2O). IR (KBr), νCdO: 1732 cm-1. Anal. Calcd for C1071H1488
-
Si36O117Fe27: C, 68.59; H, 8.00. Found: C, 68.21; H, 7.97.
Synthesis of 9a. The 27-carboxylic acid dendrimer 9a was synthe-
sized from 8 (0.086 g, 0.00701 mmol), acrylic acid (0.027 g, 0.379
mmol), and catalyst A (0.008 g, 0.0095 mmol), following the general
procedure for the metathesis reactions, and it was obtained as a colorless
waxy product in 56% yield (0.0525 g).
Synthesis of 11a. The 81-carboxylic acid dendrimer 11a was
synthesized from 10 (0.080 g, 0.00209 mmol), acrylic acid (0.024 g,
0.340 mmol), and catalyst A (0.014 g, 0.0169 mmol), following the
general procedure for the metathesis reactions, and it was obtained as
a colorless waxy product in 72% yield (0.063 g).
1H NMR (CD3COCD3, 300 MHz), δppm: 7.21 (d, 18H, arom.), 6.95
(m, 27H, HCdCHCOOH), 6.82 (s, 126H, arom.), 5.82 (d, 27H, HCd
CHCOOH), 3.86 (t, 54H, OCH2CH2), 3.50 (s, 18H, inner SiCH2O),
3.44 (s, 54H, outer SiCH2O), 2.19 (t, 54H, CH2HCdCH2), 1.72 (d,
126H, OCH2CH2 and CH2CH2CH2Si), 1.33 (m, 324H, (CH2)6), 1.20
(s, 72H, CH2CH2CH2Si), 0.60 (s, 72H, CH2CH2CH2Si), 0.044 (s, 216H,
Si(CH3)2). 13C NMR (CD3COCD3, 75.0 MHz), δppm: 168.0 (CdO),
159.0 (inner arom. OCq), 156.6 and 154.1 (outer arom. Cq), 150.4 (CHd
CHCOOH), 128.1 and 113.4 (arom. CH of the dendron), 122.2 (CHd
CHCOOH), 116.0 and 115.6 (arom. CH), 69.0 (OCH2(CH2)8), 61.4
(outer SiCH2O), 60.2 (inner SiCH2O), 43.5 (CH2CH2CH2Si), 42.4
(benzylic Cq), 32.8 (CH2HCdCH), 30.2 and 26.5 ((CH2)6), 17.8
(CH2CH2CH2Si), 14.6 (CH2CH2CH2Si), -4.5 (SiMe2). 29Si NMR (CD3-
COCD3, 59.62 MHz), δppm: 0.48 and 0.29 (inner and outer SiCH2O).
1H NMR (CD3COCD3, 300 MHz), δppm: 7.21 (d, 72H, arom.), 6.95
(m, 81H, HCdCHCOOH), 6.82 (s, 396H, arom.), 5.87 (d, 81H, HCd
CHCOOH), 3.86 (t, 162H, OCH2CH2), 3.49 (s, 234H, SiCH2O), 2.22
(m, 162H, CH2HCdCH2), 1.70 (d, 396H, OCH2CH2 and CH2CH2CH2-
Si), 1.33 (m, 972H, (CH2)6), 1.20 (s, 234H, CH2CH2CH2Si), 0.59 (s,
234H, CH2CH2CH2Si), 0.13 and 0.070 (s, 702H, Si(CH3)2). 13C NMR
(CD3COCD3, 75.0 MHz), δppm: 168.0 (CdO), 159.0 (inner arom. OCq),
156.6 and 154.1 (outer arom. Cq), 150.4 (CHdCHCOOH), 128.1 and
113.1 (arom. CH of the dendron), 122.2 (CHdCHCOOH), 116.0 and
115.6 (arom. CH), 69.0 (OCH2(CH2)8), 61.4 (outer SiCH2O), 43.5 (CH2-
CH2CH2Si), 42.4 (benzylic Cq), 32.8 (CH2HCdCH), 30.2 and 26.5
((CH2)6), 17.8 (CH2CH2CH2Si), 14.6 (CH2CH2CH2Si), -4.3 (SiMe2).
29Si NMR (CD3COCD3, 59.62 MHz), δppm: 0.49 (inner SiCH2O), 0.29
IR (KBr), νCdO
C
:
1711 cm-1. MS (MALDI-TOF, m/z): calcd for
774H1218O117Si36Na: 13 430.2; found: 13 434.2. Anal. Calcd for
(outer SiCH2O). IR (KBr), νCdO
2421H3810O360Si117: C, 69.29; H, 9.15. Found: C, 69.47; H, 9.11.
Synthesis of 11b. The 81-ester dendrimer 11b was synthesized from
:
1711 cm-1. Anal. Calcd for
C
C774H1218O117Si36: C, 69.34; H, 9.16. Found: C, 69.07; H, 8.90.
Synthesis of 9b. The 27-ester dendrimer 9b was synthesized from
10 (0.052 g, 0.00130 mmol), methyl acrylate (0.018 g, 0.211 mmol),
and catalyst A (0.009 g, 0.0105 mmol), following the general procedure
for the metathesis reactions, and it was obtained as a colorless waxy
product in 92% yield (0.052 g).
1H NMR (CDCl3, 300 MHz), δppm: 7.19 (d, 72H, arom.), 6.95 (m,
81H, HCdCHCOOCH3), 6.79 (d, 396H, arom.), 5.80 (d, 81H, HCd
CHCOOCH3), 3.84 (t, 162H, OCH2CH2), 3.71 (s, 243H, COOCH3),
3.50 (s, 54H, inner SiCH2O), 3.44 (s, 162H, outer SiCH2O), 2.19 (t,
162H, CH2HCdCH), 1.71 (d, 396H, OCH2CH2 and CH2CH2CH2Si),
1.30 (d, 972H, (CH2)6), 1.19 (s, 234H, CH2CH2CH2Si), 0.56 (s, 234H,
8 (0.051 g, 0.00418 mmol), methyl acrylate (0.019 g, 0.221 mmol),
and catalyst A (0.005 g, 0.0056 mmol), following the general procedure
for the metathesis reactions, and it was obtained as a colorless waxy
product in 99% yield (0.0575 g).
1H NMR (CDCl3, 300 MHz), δppm: 7.19 (d, 18H, arom.), 6.95 (m,
27H, HCdCHCOOCH3), 6.79 (d, 126H, arom.), 5.80 (d, 27H, HCd
CHCOOCH3), 3.84 (t, 54H, OCH2CH2), 3.71 (s, 81H, COOCH3), 3.50
(s, 18H, inner SiCH2O), 3.44 (s, 54H, outer SiCH2O), 2.19 (t, 54H,
CH2HCdCH), 1.71 (d, 126H, OCH2CH2 and CH2CH2CH2Si), 1.30 (d,
9
1504 J. AM. CHEM. SOC. VOL. 130, NO. 4, 2008

Cross Olefin Metathesis
A R T I C L E S
CH2CH2CH2Si), 0.030 (s, 702H, Si(CH3)2). 13C NMR (CDCl3, 75 MHz),
1.62 (s, 6H, CH2CH2CH2Si), 1.09 (s, 6H, CH2CH2CH2Si), 0.58 (s, 6H,
CH2CH2CH2Si), 0.051 (s, 18H, Si(CH3)2). 13C NMR (CDCl3, 75 MHz),
δppm: 166.5 (CdO), 159.0 (inner arom. OCq), 155.7 and 153.0 (outer
arom. Cq), 149.9 (CHdCHCOOCH3), 129.0 and 112.4 (arom. CH of
the dendron), 120.8 (CHdCHCOOCH3), 115.2 and 114.8 (arom. CH),
68.6 (OCH2(CH2)8), 60.9 (outer SiCH2O), 60.2 (inner SiCH2O), 51.3
(COOCH3), 44.0 (CH2CH2CH2Si), 43.0 (benzylic Cq), 32.5 (CH2HCd
CH), 29.5 and 26.0 ((CH2)6), 17.1 (CH2CH2CH2Si), 14.9 (CH2CH2CH2-
Si), -4.8 (SiMe2). 29Si NMR (CDCl3, 59.62 MHz), δppm: 0.50 (inner
SiCH2O), 0.29 (outer SiCH2O). IR (KBr), νCdO: 1732 cm-1. Anal. Calcd
for C3002H3972O360Si117: C, 69.72; H, 9.29. Found: C, 69.73; H, 9.94.
Synthesis of 11c. The 81-ferrocenyl dendrimer 11c was synthesized
from 10 (0.050 g, 0.00130 mmol), 5 (0.057 g, 0.212 mmol), and catalyst
A (0.004 g, 0.00527 mmol), following the general procedure for the
metathesis reactions, and it was obtained as a yellow waxy product in
94% yield (0.071 g).
1H NMR (CDCl3, 300 MHz), δppm: 7.11 (d, 72H, arom.), 6.96 (m,
81H, HCdCHCOOCH2Fc), 6.79 (d, 396H, arom.), 5.80 (d, 81H, HCd
CHCOOCH2Fc), 4.94 (s, 162H, CH2Fc), 4.27 and 4.15 (d, 729H, CH
of Fc), 3.84 (t, 162H, OCH2CH2), 3.48 (s, 72H, SiCH2O), 2.16 (m,
162H, CH2CHdCH), 1.70 (d, 396H, OCH2CH2 and CH2CH2CH2Si),
1.25 (m, 972H, (CH2)6), 1.18 (s, 234H, CH2CH2CH2Si), 0.54 (s, 72H,
CH2CH2CH2Si), 0.067 (s, 702H, Si(CH3)2). 13C NMR (CDCl3, 75 MHz),
δppm: 164.4 (CdO), 148.1 (OCAr), 144.9 (arom. Cq), 132.2 (CH2d
CH), 128.0 (CH2dCH), 127.2 and 120.7 (unsubstituted arene C of the
dendron), 43.4 (CH2CH2CH2Si), 41.7 (benzylic Cq), 30.3 (CH2Cl), 17.4
(CH2CH2CH2Si), 14.3 (CH2CH2CH2Si), -4.55 (SiMe2). IR (KBr), νCd
O: 1732 cm-1. Anal. Calcd for C28H49O2Si3Cl3: C, 55.29; H, 8.12.
Found: C, 55.68; H, 8.03.
Synthesis of 16. The 27-Cl dendrimer 16 was synthesized from 6
(0.050 g, 0.0145 mmol), dendron 15 (0.159 g, 0.261 mmol), and catalyst
A (0.006 g, 0.0065 mmol), following the general procedure for the
metathesis reactions, and it was obtained as a colorless waxy product
in 95% yield (0.120 g).
1H NMR (CDCl3, 300 MHz), δppm: 7.29 and 7.06 (2d, 36H, arom.
CH), 7.14 (m, 9H, HCdCHCOO), 6.80 (d, 36H, arom.), 6.01 (d, 9H,
HCdCHCOO), 3.86 (t, 18H, OCH2CH2), 3.45 (s, 9H, SiCH2O), 2.73
(s, 54H, CH2Cl), 2.28 (t, 18H, CH2HCdCH), 1.87 (d, 72H, OCH2CH2
and CH2CH2CH2Si), 1.33 (d, 108H, (CH2)6), 1.10 (s, 54H, CH2CH2-
CH2Si), 0.59 (s, 54H, CH2CH2CH2Si), 0.078 and 0.034 (s, 216H, Si-
(CH3)2). 13C NMR (CDCl3, 75 MHz), δppm: 165.0 (CdO), 155.7 and
152.9 (arom. Cq), 151.7 (CHdCHCOO), 148.3 (OCAr), 145.8 and 144.6
(arom. Cq), 127.2 and 120.8 (unsubstituted arene C of the dendron),
119.8 (CHdCHCOO), 115.1 and 114.7 (arom. CH), 68.6 (OCH2-
(CH2)8), 60.8 (SiCH2O), 43.4 (CH2CH2CH2Si), 41.8 (benzylic Cq), 32.4
(CH2HCdCH), 30.4 (CH2Cl), 29.4 and 26.0 ((CH2)6), 17.4 (CH2CH2-
CH2Si), 14.4 (CH2CH2CH2Si), -4.54 (SiMe2). 29Si NMR (CDCl3, 59.62
δppm: 166.5 (CdO), 159.0 (inner arom. OCq), 155.6 and 152.9 (outer
arom. OCq), 149.8 (CHdCHCOOCH2Fc), 127.1 and 113.3 (arom. CH
of the dendron), 121.0 (CHdCHCOOCH2Fc), 115.1 and 114.7 (arom.
CH), 81.5 (Cq of Fc), 69.6 (OCH2(CH2)8), 68.6 (CH of Fc), 62.5 (CH2-
Fc), 60.8 (outer SiCH2O), 60.2 (inner SiCH2O), 42.9 (CH2CH2CH2Si),
42.0 (benzylic Cq), 32.2 (CH2HCdCH), 29.4 and 26.0 ((CH2)6), 17.6
(CH2CH2CH2Si), 14.5 (CH2CH2CH2Si), -4.6 (SiMe2). 29Si NMR
(CDCl3, 59.62 MHz), δppm: 0.46 and 0.29 (inner and outer SiCH2O).
IR (KBr), νCdO: 1732 cm-1. Anal. Calcd for C3312H4620Si117O360Fe81:
C, 68.58; H, 8.03; found: C, 68.03; H, 7.81.
Synthesis of 13. An acetone solution of 11a (0.038 g, 0.052 mmol)
was added to another acetone solution of 12 (0.027 g, 6.43 × 10-4
mmol), formation of a precipitate was observed, and the solvent was
removed under vacuum.
1H NMR (CDCl3, 300 MHz), δppm: 7.12 (d, 72H, arom.), 6.78 (m,
477H, arom. and HCdCHCOO), 5.87 (d, 81H, HCdCHCOO-), 4.08
and 4.04 (d, 2 187H, Cp), 3.83 (t, 162H, OCH2CH2), 3.52 and 3.49 (s,
234H, inner and outer SiCH2O), 2.63 (t, 486H, NH2CH2), 2.34 (t, 486H,
FcCH2), 2.17 (m, 162H, CH2HCdCH2), 1.71 (d, 396H, OCH2CH2 and
CH2CH2CH2Si), 1.52 (m, 972H, NH2CH2(CH2)2), 1.28 (d, 972H,
(CH2)6), 1.11 (s, 234H, CH2CH2CH2Si), 0.54 (s, 234H, CH2CH2CH2-
Si), 0.073 and 0.0093 (s, 702H, Si(CH3)2). 13C NMR (CDCl3, 75 MHz),
MHz), δppm: 0.46 and 0.29 (inner and outer SiCH2O). IR (KBr), νCdO
:
1732 cm-1. MS (MALDI-TOF, m/z): Calcd for C450H759O36Si36Cl27-
Na: 8736.90; found: 8729.77. Anal. Calcd for C450H759O36Si36Cl27:
C, 62.02; H, 8.78. Found: C, 61.89; H, 8.65.
Synthesis of 17. The 27-Cl dendrimer 16 (0.100 g, 0.0115 mmol),
p.hydroxyphenyl undecene-1-yl ether 4 (0.162 g, 0.620 mmol), and
K2CO3 (0.435 g, 3.11 mmol) were introduced into a Schlenk flask,
and 30 mL of dry DMF was added. The reaction mixture was stirred
at 80 °C for 48 h. DMF was removed under vacuum, the residue was
dissolved in dichloromethane and filtered to remove K2CO3, and the
solvent was removed under vacuum. The residue was dissolved in CH2-
Cl2 and precipitated with methanol. Dendrimer 17 was obtained as a
colorless waxy product in 82% yield (0.145 g).
1H NMR (CDCl3, 300 MHz), δppm: 7.29 and 6.99 (2d, arom. CH),
7.11 (m, HCdCHCOO), 6.79 (d, arom.), 6.01 (d, HCdCHCOO), 5.80
(m, HCdCH2), 4.95 (m, HCdCH2), 3.84 (t, OCH2CH2), 3.44 (s,
SiCH2O), 2.04 (m, CH2HCdCH), 1.71 (d, OCH2CH2 and CH2CH2-
CH2Si), 1.30 (d, (CH2)6), 1.11 (s, CH2CH2CH2Si), 0.57 (s, CH2CH2CH2-
δppm: 169.7 (CdO), 158.0 (inner arom. OCq), 155.7 and 153.0 (outer
Si), 0.070 and 0.024 (s, Si(CH3)2). 13C NMR (CDCl3, 75 MHz), δppm
:
arom. Cq), 151.2 (CHdCHCOO-), 128.1 and 113.0 (unsubstituted arene
C of the dendron), 122.0 (CHdCHCOO-), 115.2 and 114.7 (arom.
CH), 88.8 (Cq of Cp), 69.0 (OCH2(CH2)8), 68.3 and 67.1 (Cp), 60.9
(outer SiCH2O), 52.8 (NH2CH2), 43.5 (CH2CH2CH2Si), 42.4 (benzylic
Cq), 32.1 (CH2HCdCH), 30.9 (CH2CH2NH2), 29.4 and 28.1 (CH2)6,
28.9 (FcCH2CH2), 26.1 (FcCH2), 15.4 (CH2CH2CH2Si), 12.1 (CH2-
CH2CH2Si), -4.14 (SiMe2). 29Si NMR (CDCl3, 59.62 MHz), δppm: 0.23
(SiCH2O). Anal. Calcd for C5823H7941O360Si117Fe243N81: C, 68.75; H,
7.87. Found: C, 67.98; H, 7.27.
Synthesis of 15. Freshly prepared acryloyl chloride (0.095 g, 1.05
mmol, dissolved in 20 mL of dichloromethane) was added to a
dichloromethane (20 mL) solution of dendron 14 (0.300 g, 0.52 mmol)
and dry triethylamine (3 mL) at 0 °C. The reaction mixture was stirred
at room temperature for 24 h under a nitrogen atmosphere. The mixture
was washed twice with an aqueous solution of K2CO3, dried with
sodium sulfate, and filtered, and the solvent was removed under
vacuum. The crude product was submitted to silica gel flash chroma-
tography using CH2Cl2 as eluent, which provided 0.304 g (96%) of
dendron 15 as a colorless oil.
165.1 (CdO), 155.6 and 152.9 (arom. Cq), 151.7 (CHdCHCOO), 148.3
(OCAr), 145.7 and 144.5 (arom. Cq), 139.1 (HCdCH2), 127.2 and 120.8
(unsubstituted arene C of the dendron), 119.8 (CHdCHCOO), 115.2
and 114.6 (arom. CH), 114.4 (HCdCH2), 68.4 (OCH2(CH2)8), 60.8
(SiCH2O), 43.3 (CH2CH2CH2Si), 41.8 (benzylic Cq), 33.8 (CH2HCd
CH2), 29.4 and 26.0 ((CH2)6), 17.4 (CH2CH2CH2Si), 14.3 (CH2CH2CH2-
Si), -4.54 (SiMe2). 29Si NMR (CDCl3, 59.62 MHz), δppm: 0.46 and
0.29 (inner and outer SiCH2O). IR (KBr), νCdO: 1732 cm-1. Anal. Calcd
for C909H1434O90Si36: C, 73.70; H, 9.76. Found: C, 73.24; H, 9.57.
Synthesis of 18. The 81-Cl dendrimer 18 was synthesized from 17
(0.070 g, 0.00473 mmol), dendron 15 (0.155 g, 0.255 mmol), and
catalyst A (0.006 g, 0.0065 mmol), following the general procedure
for the metathesis reactions, and it was obtained as a colorless waxy
product in 85% yield (0.126 g).
1H NMR (CDCl3, 300 MHz), δppm: 7.26 and 7.05 (2d, arom. CH),
7.15 (m, HCdCHCOO), 6.79 (d, arom.), 6.01 (d, HCdCHCOO), 3.83
(t, OCH2CH2), 3.44 (s, SiCH2O), 2.72 (s, CH2Cl), 2.27 (t, CH2HCd
CH), 1.96 (d, OCH2CH2), 1.67 (t, CH2CH2CH2Si), 1.32 (d, (CH2)6),
1.09 (s, CH2CH2CH2Si), 0.59 (s, CH2CH2CH2Si), 0.069 and 0.052 (s,
Si(CH3)2). 13C NMR (CDCl3, 75 MHz), δppm: 165.0 (CdO), 155.6 and
152.9 (arom. Cq), 151.6 (CHdCHCOO), 148.3 (OCAr), 144.6 (arom.
1H NMR (CDCl3, 300 MHz), δppm: 7.30 and 7.07 (2d, 4H, arom.
CH), 6.61, 6.31 and 5.96 (m, 3H, CH2dCH), 2.72 (s, 6H, CH2Cl),
9
J. AM. CHEM. SOC. VOL. 130, NO. 4, 2008 1505

A R T I C L E S
Ornelas et al.
Cq), 127.1 and 122.2 (unsubstituted arene C of the dendron), 120.7
(CHdCHCOO), 115.1 and 114.6 (arom. CH), 68.5 (OCH2(CH2)8), 60.8
(SiCH2O), 43.8 (CH2CH2CH2Si), 41.7 (benzylic Cq), 32.4 (CH2HCd
CH), 30.3 (CH2Cl), 29.6 and 27.9 ((CH2)6), 17.4 (CH2CH2CH2Si), 14.4
(CH2CH2CH2Si), -4.54 (SiMe2). 29Si NMR (CDCl3, 59.62 MHz),
red color turned to purple, and the reaction mixture was vigorously
stirred for 3 h. The organic phase was separated from the aqueous phase,
its volume was reduced to 3 mL, and 100 mL of ethanol was added.
The resulting purple precipitate was dissolved in dichloromethane and
precipitated again with methanol. The polyolefin AuNP was obtained
as dark purple powder.
1H NMR (CDCl3, 300 MHz), δppm: 5.78 (m, HCdCH2), 4.98 (m,
HCdCH2), 2.50 (m, SCH2), 2.03 (m, CH2HCdCH2), 1.29 (m, (CH2)7).
13C NMR (CDCl3, 75 MHz), δppm: 140.2 (HCdCH2), 114.1 (HCd
CH2), 33.8 (CH2HCdCH2), 29.4 and 26.0 (CH2)6. Elemental analysis:
Au, 74.00; S, 4.40. Nanoparticle size obtained by TEM: 2.1 ( 0.3 nm
(∼285 Au atoms and 103 ligands per nanoparticle; MW of polyolefin
AuNP = 75 389).
δ
ppm: 0.46 and 0.29 (inner and outer SiCH2O). IR (KBr), νCdO: 1732
cm-1. Anal. Calcd for C1611H2949O144Si117Cl81: C, 62.86; H, 9.66.
Found: C, 62.34; H, 9.52.
Synthesis of 21b. The polyester polymer 21b was synthesized from
20 (0.100 g, 0.263 mmol of monomer), methyl acrylate (0.045 g, 0.527
mmol), and catalyst A (0.011 g, 0.0132 mmol), following the general
procedure for the metathesis reactions, and it was obtained as a white
waxy product in 92% yield (0.107 g).
1H NMR (CDCl3, 300 MHz), δppm: 7.12-6.65 (m, arom. and HCd
CHCOOCH3), 5.80 (d, HCdCHCOOCH3), 3.85 (s, OCH2CH2), 3.70
(s, COOCH3), 2.17 (s, CH2HCdCH), 1.71 (s, OCH2CH2 and CH2 of
Synthesis of 23b. The polyester AuNP was synthesized from 22
(0.036 g, 0.00048 mmol AuNP, 0.049 mmol olefin termini), methyl
acrylate (0.008 g, 0.099 mmol), and catalyst A (0.003 g, 0.0025 mmol),
following the general procedure for the metathesis reactions, and it
was obtained as a dark violet powder in 74% yield (0.029 g).
1H NMR (CDCl3, 300 MHz), δppm: 6.97 (m, HCdCHCOOCH3),
5.80 (d, HCdCHCOOCH3), 3.72 (s, COOCH3), 2.47 (m, SCH2), 2.18
polymer chain), 1.28 (m, (CH2)7). 13C NMR (CDCl3, 75 MHz), δppm
:
166.5 (CdO), 154.2 and 152.3 (arom. OCq), 150.1 (CHdCHCOOCH3),
141.0 and 140.8 (arom. Cq), 127.7 and 127.2 (arom. CH of styrenic
ring), 121.2 (CHdCHCOOCH3), 115.7 and 115.0 (arom. CH), 69.3
(benzylic CH2), 68.8 (OCH2(CH2)8), 51.7 (COOCH3), 43.2 and 41.0
(CH and CH2 of polymer chain), 32.6 (CH2HCdCH), 29.7 and 26.0
(CH2)6. IR (KBr), νCdO: 1732 cm-1. Anal. Calcd for C28H36O4: C,
77.03; H, 8.31. Found: C, 76.15; H, 8.12. Polydispersity obtained by
SEC: 1.33.
(s, CH2HCdCH), 1.28 (m, (CH2)7). 13C NMR (CDCl3, 75 MHz), δppm
:
166.2 (CdO), 150.1 (CHdCHCOOCH3), 121.1 (CHdCHCOOCH3),
51.8 (COOCH3), 32.4 (CH2HCdCH), 29.8 and 26.0 (CH2)6. IR (KBr),
ν
CdO: 1732 cm-1. Nanoparticle size obtained by TEM: 2.2 ( 0.3 nm
Synthesis of 23c. The polyferrocenyl AuNP was synthesized from
Synthesis of 21c. The polyferrocenyl polymer 21c was synthesized
from 20 (0.100 g, 0.263 mmol of monomer), 5 (0.142 g, 0.527 mmol),
and catalyst A (0.011 g, 0.0132 mmol), following the general procedure
for the metathesis reactions, and it was obtained as a white waxy product
in 61% yield (0.106 g).
1H NMR (CDCl3, 300 MHz), δppm: 7.12-6.65 (m, arom. and HCd
CHCOOCH2Fc), 5.80 (d, HCdCHCOOCH2Fc), 4.94 (s, CH2Fc), 4.28
and 4.16 (d, CH of Fc), 3.87 (s, OCH2CH2), 2.17 (m, CH2HCdCH),
1.74 (s, OCH2CH2 and CH2 of polymer chain), 1.30 (m, (CH2)7). 13C
NMR (CDCl3, 75 MHz), δppm: 166.4 (CdO), 154.2 and 152.3 (arom.
OCq), 149.9 (CHdCHCOOCH2Fc), 141.2 and 140.9 (arom. Cq), 127.8
and 127.5 (arom. CH of styrenic ring), 121.0 (CHdCHCOOCH2Fc),
115.6 and 115.1 (arom. CH), 81.4 (Cq of Fc), 69.2 (benzylic CH2),
68.7 (OCH2(CH2)8), 68.7 (CH of Fc), 62.5 (CH2Fc), 32.2 (CH2HCd
CH), 29.7 and 26.0 (CH2)6. IR (KBr), νCdO: 1732 cm-1. Anal. Calcd
for C40H46O6Fe: C, 76.94; H, 8.19. Found: C, 76.25; H, 8.02.
Polydispersity obtained by SEC: 1.33.
22 (0.036 g, 0.00048 mmol AuNP, 0.049 mmol olefin termini), 5 (0.028
g, 0.099 mmol), and catalyst A (0.003 g, 0.0025 mmol), following the
general procedure for the metathesis reactions, and it was obtained as
a dark violet powder in 78% yield (0.038 g).
1H NMR (CDCl3, 300 MHz), δppm: 6.97 (m, HCdCHCOO), 5.80
(d, HCdCHCOO), 4.94 (s, CH2Fc), 4.28 and 4.16 (d, CH of Fc), 2.47
(m, SCH2), 2.18 (s, CH2HCdCH), 1.28 (m, (CH2)7). 13C NMR (CDCl3,
75 MHz), δppm: 166.2 (CdO), 150.1 (CHdCHCOO), 121.1 (CHd
CHCOO), 81.3 (Cq of Fc), 68.9 (CH of Fc), 62.3 (CH2Fc), 32.4 (CH2-
HCdCH), 29.8 and 26.0 (CH2)6. IR (KBr), νCdO: 1732 cm-1
.
Acknowledgment. We are grateful to Dr. Lionel Salmon
(LCC Toulouse) for TEM measurements and discussions,
Fundac¸a˜o para a Cieˆncia e a Tecnologia, Portugal (Ph.D. grant
to C.O.), MRT (Ph.D. grant to D.M.), the Institut Universitaire
de France (D.A.), the CNRS, and the Universite´ Bordeaux I
for financial support.
Synthesis of 22. A colorless solution of N(n-C8H17)4Br (0.262 g,
0.480 mmol) in 10 mL of toluene was added to a yellow water solution
(10 mL) of HAuCl4 (0.046 g, 0.137 mmol). The mixture was stirred
under positive nitrogen pressure, and separation between the red organic
phase (top) and colorless aqueous phase (bottom) resulted. A toluene
(10 mL) solution of thiol HS(CH2)9HCdCH2 (0.026 g, 0.137 mmol)
was added to the organic phase. Then, NaBH4 (0.057 g, 1.52 mmol) in
10 mL of water was slowly added to the stirred reaction mixture. The
Supporting Information Available: Detailed synthetic pro-
cedures including those for 4, 5, 6, 8, 10, 19, and 20, NMR
and MALDI-TOF spectra, and TEM images and data. This
material is available free of charge via the Internet at
http://pubs.acs.org.
JA077392V
9
1506 J. AM. CHEM. SOC. VOL. 130, NO. 4, 2008