Next Article in Journal
Solid-Phase Synthetic Route to Multiple Derivatives of a Fundamental Peptide Unit
Next Article in Special Issue
Hydrogen Generation Using a CuO/ZnO-ZrO2 Nanocatalyst for Autothermal Reforming of Methanol in a Microchannel Reactor
Previous Article in Journal
Antioxidant Activities of Various Extracts from Artemisisa selengensis Turcz (LuHao)
Previous Article in Special Issue
Recyclable Nanostructured Catalytic Systems in Modern Environmentally Friendly Organic Synthesis
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:

Extremely Efficient Catalysis of Carbon-Carbon Bond Formation Using "Click" Dendrimer-Stabilized Palladium Nanoparticles

ISM, UMR CNRS N°5255, Université Bordeaux 1, 3305 Talence Cedex, France
Author to whom correspondence should be addressed.
Molecules 2010, 15(7), 4947-4960;
Received: 24 June 2010 / Revised: 8 July 2010 / Accepted: 12 July 2010 / Published: 20 July 2010
(This article belongs to the Special Issue Nano-catalysts and Nano-technologies for Green Organic Synthesis)


This article is an account of the work carried out in the authors’ laboratory illustrating the usefulness of dendrimer design for nanoparticle palladium catalysis. The “click” synthesis of dendrimers constructed generation by generation by 1→3 C connectivity, introduces 1,2,3-triazolyl ligands insides the dendrimers at each generation. Complexation of the ligands by PdII followed by reduction to Pd0 forms dendrimer-stabilized Pd nanoparticles (PdNPs) that are extremely reactive in the catalysis of olefin hydrogenation and C-C bond coupling reactions. The stabilization can be outer-dendritic for the small zeroth-generation dendrimer or intra-dendritic for the larger first- and second-generation dendrimers. The example of the Miyaura-Suzuki reaction that can be catalyzed by down to 1 ppm of PdNPs with a “homeopathic” mechanism (the less, the better) is illustrated here, including catalysis in aqueous solvents.

1. Introduction

Catalysis by dendrimers appeared 20 years ago when Shell patented van Leeuwen’s work on the catalysis of CO/alkene polymerization. This study involved the comparison between mononuclear and star-shaped hexaphosphine-palladium catalysts. The star-shaped catalyst gave 3% fouling whereas the mono-palladium catalyst gave 50% fouling, which was already a positive dendritic effect [1,2]. Later, dendrimer catalysis was widely developed [3,4,5,6,7,8] for most known catalytic processes, the catalyst being covalently linked to the dendrimer frame [9,10,11,12,13,14,15,16,17]. Palladium catalysts are the most frequently used catalysts in synthesis [18], and this trend remains true for dendrimer catalysis [19,20]. Dendrimer catalysts indeed present the advantages of recyclability to a certain extent [21,22,23,24] and dendritic effects that can occasionally be positive [25,26,27,28,29,30,31,32,33,34,35], but experiences in our group have indicated that the concept is somewhat limited by the leaching of Pd [36,37,38,39]. Therefore, we have investigated the possibility of PdNP catalysis upon coordinating PdII to intradendritic nitrogen ligands. Triazolyl ligands have thus been introduced during dendritic construction upon “click” chemistry, followed by reduction to Pd0 atoms that agglomerate in PdNPs protected by the dendrimer frame. The concept of dendrimer-encapsulated nanoparticle catalysis had been introduced and developed since of the 90s by Crooks with polyamidoamine (PAMAM) dendrimers, and small dendrimers have also been shown to stabilize nanoparticles that are too large to fit in the dendrimer interior [40,41,42,43,44,45,46,47,48,49,50,51,52,53,54]. The catalytic reactions were carried out in organic solvents, water, supercritical CO2 (sc CO2), or fluorous/organic biphasic solvents. Besides PAMAM and poly(propyleneimine) (PPI) dendrimers that are commercially available, there has been only a few reports concerning the catalysis by dendrimer-stabilized nanoparticles, in particular with phenylazomethine dendrimers reported by the Yamamoto group [55,56,57,58].

2. Palladium Nanoparticle (PdNP) Catalysts in Carbon-Carbon Coupling Reactions

PdNP catalysis was developed by Beller et al. and Reetz et al. in 1996 [59,60], and this prolific area, including mechanistic issues in the Heck reaction, have been reviewed [61,62,63,64,65,66]. Aryl iodides and activated aryl bromides are easily coupled. Even aryl chlorides can couple, but much less selectively and in lower yields at temperatures of the order of 150 °C or higher. The source of PdNPs can be ligand free Pd complexes such as palladacycles, pincers, solid supports such as mesoporous silica, metal oxides, zeolites, hydroxyapatite, activated carbons, and organic polymers. In many examples, including polymer-stabilized PdNPs [67], it has been shown that leaching of Pd0 from the PdNPs (even temporarily and in very small amounts) into the solution provides the actual catalysts that are ligandless soluble mono- or biatomic palladium species [61,62,63,64,65,66].
Dendrimers are perfect macromolecules having a behavior related to that of polymers that have been long used for nanoparticle stabilization. The great advantage of dendrimers over polymers, however, is their perfect molecular definition and specific topology allowing molecular engineering that involves introducing a precise number of atoms into the PdNP layer after layer subsequent to the dendritic construction generation by generation [17,68,69,70].

3. Highly Efficient “Click”-Dendrimer-Encapsulated and Stabilized Pd Nanoparticle Pre-Catalysts

PAMAM and PIP dendrimers had not been specially designed for catalysis. Therefore, appropriate dendrimer design was necessary with a view to improved nanoparticle catalysis performance. We had reported arene-cored star [71] and dendrimer synthesis [72,73,74,75] by CpFe+-induced arene activation [76] involving nona-allylation of mesitylene following photolysis with visible light [77]. Generation growth with 1→3 connectivity [78,79] was carried out in a divergent way using selective hydrosilylation with HSiMe2CH2Cl, followed by nucleophilic substitution by a phenolate triallyl dendron producing dendrimers terminated by 3n+2 allyl branches (n = 0–7). [73,74,75] Variation of divergent growth included cross metathesis with acrylate functionalized dendron at the focal point [80] or “click” chemistry between a propargyl modified dendron at the focal point and dendritic cores terminated by azido groups [81]. The 1,2,3-triazolyl dendrimers obtained by “click” chemistry were ideal ligands for PdII [82] and AuIII [83].
When these click dendrimers were terminated by 1,2,3-triazolyl ligands connected to ferrocenyl (Fc) groups, the Fc groups were used as redox sensors for the recognition and titration of PdII ions. This electrochemical recognition was straightforward using cyclic voltammetry, because all the peripheral redox Fc groups appeared equivalent in a single wave that is both chemically and electrochemically reversible [84,85]. Various transition metal cations and oxo-anions (including ATP2-) could be sensed with selectivity, as monitored by the shift of the redox potential of the Fc wave. This titration technique was simple and useful to in order to determine the number of PdII cations encapsulated in the “click” dendrimers of various generations (Figure 1). [86]
Figure 1. Cyclic voltammetry: recognition of both oxo-anions and transition-metal cationic acetonitrile complexes by a second-generation “click” ferrocenyl dendrimer.
Figure 1. Cyclic voltammetry: recognition of both oxo-anions and transition-metal cationic acetonitrile complexes by a second-generation “click” ferrocenyl dendrimer.
Molecules 15 04947 g001
There are various known modes of coordination of PdII with triazole ligands, and the monohapto mode X-ray mode was confirmed by X-ray crystal structure determination [87]. Reduction of the G1 (27 Fc) and G2 (81 Fc) dendritic-PdII complexes using NaBH4 or methanol provided PdNPs for which the sizes, determined by TEM, corresponded to the theoretical number of Pd atoms according to the one-to-one stoichiometry determined by electrochemical titration of the PdII precursors. This result was indicative of intra-dendritic PdNP formation and encapsulation. On the other hand, the PdNPs formed from the G0 dendrimer (9 Fc) were large. This small dendrimer cannot encapsulate NPs, but stabilization is still occurring by locating dendrimer around the PdNPs (Figure 2).
Figure 2. Pd nanoparticle surrounded and stabilized by several small G0 nonaferrocenyl dendrimers.
Figure 2. Pd nanoparticle surrounded and stabilized by several small G0 nonaferrocenyl dendrimers.
Molecules 15 04947 g002
The fact that these G0-PdNPS were large confirmed that the size was independent on the dendrimer size when the latter is too small. Thus the smallest PdNPs were those formed from the G1 dendrimer containing 27 Fc groups 36 triazolyl rings and encapsulating PdNPs that contained 36 Pd atoms (Scheme 1).
Scheme 1. Synthesis of “click”-ferrocenyl dendrimer-encapsulated PdNPs.
Scheme 1. Synthesis of “click”-ferrocenyl dendrimer-encapsulated PdNPs.
Molecules 15 04947 g003
Selective hydrogenation of dienes to monoenes was readily achieved under ambient conditions for small dienes [88], but large steroidal dienes failed to react, in accord with their lack of ability to reach the PdNP surface. The rates (TOFs) and TONs of hydrogenation were all the larger as the PdNPs were smaller, as expected from previous results with polymer-stabilized PdNPs [67] according to a mechanism that involves mechanistic steps of the hydrogenation on the PdNP surface [88].

4. “Homeopathic” Catalysis of Miyaura-Suzuki C-C Coupling by “Click” Dendrimer-Stabilized PdNPs under Ambient Conditions

Whereas hydrogenation catalysis proceeds at the PdNP surface, as shown above, and therefore depends on the PdNP size, the catalysis of Miyaura-Suzuki C-C coupling [89] between PhI and PhB(OH)2 was carried out at room temperature and does not depend on the PdNP size and whether its stabilization is intra- or interdendritic. This shows that the dendrimer is not involved in the rate-limiting step of the reaction. The dendrimer-stabilized PdNPs work identically, whatever their size, and the TONs increase upon decreasing the amount of catalyst from 1% down to 1 ppm or upon dilution of the reaction solution. Thus, the efficiency of the catalyst is remarkable in homeopathic amounts (54% yield at 25 °C with 1 ppm equivalent of Pd atom, i.e., TON = 540,000) and a quantitative yield is not even reached (75% yield) with 1% equivalent Pd atom. [90] The “homeopathic” catalysis was already observed for the Heck reaction at 150°C and was rationalized by de Vries on the basis of a leaching mechanism involving detachment of Pd atoms from the PdNP subsequent to oxidative addition of the organic halide PhI on the PdNP surface [64,66]. This mechanism is established for high temperature reactions due to decomposition of the Pd catalyst to naked PdNPs, but it is less expected for a room-temperature reaction. The ease of the room-temperature reaction must be due, however, to the lack of ligation onto the dendrimer-stabilized PdNPs that therefore can easily undergo oxidative addition of PhI at their surface, which provokes the leaching of Pd atoms. These isolated Pd atoms are apparently extraordinarily reactive in solution, because their do not bear ligands other than the very weakly coordinating solvent molecules. The limit in their efficiency lies in that they are trapped by their mother NP if the solution is moderately concentrated. This inhibiting trapping mechanism is all the less efficient as the catalyst is more diluted in the solution, therefore it is not efficient under extremely diluted solutions whereas it strongly inhibits catalysis at relatively high concentrations. It is likely that this concept can be extended to other PdNP-catalyzed C-C bond formation reactions (Scheme 2).
Scheme 2. Leaching mechanism in the “homeopathic” catalysis of Suzuki C-C coupling at ambient temperature between PhI and PhB(OH)2 by “click” ferrocenyl dendrimer-stabilized PdNPs [64].
Scheme 2. Leaching mechanism in the “homeopathic” catalysis of Suzuki C-C coupling at ambient temperature between PhI and PhB(OH)2 by “click” ferrocenyl dendrimer-stabilized PdNPs [64].
Molecules 15 04947 g004
Analogous click-dendrimer-stabilized PdNP with other termini including sulfonate providing solubility in water were also active in aqueous media for hydogenation and Suzuki coupling reaction with high TOF and TON numbers [91], as were also related “click”-polymer-stabilized PdNPs [92].
The G1-dendrimer-encapsulated PdNPs can be extracted by hexanethiol to yield a PdNP-cored hexanethiol star that also catalyze the Suzuki reaction under ambient conditions between phenylboronic acid and iodobenzene, but not bromobenzene, contrary to the G1-dendrimer-encapsulated PdNPs. PdNP-cored decanethiolate species were formerly found to be air and water stable and to be good catalysts for the latter Suzuki reaction. Thus, the thiolate ligands are not a poison for this catalysis, but the PdNP are not as free in the presence of the alkylthiolate ligands as in the dendrimer-stabilized PdNPs that are extremely active catalysts (Scheme 3) [93].
Scheme 3. Extraction of “click”-dendrimer-encapsulated PdNPs from the dendrimer with hexathiol leading to hexanethiolate-PdNPs.
Scheme 3. Extraction of “click”-dendrimer-encapsulated PdNPs from the dendrimer with hexathiol leading to hexanethiolate-PdNPs.
Molecules 15 04947 g005

5. Conclusions and Prospects

Homogeneous PdNP catalysis is of interest, because the efficiencies and rates are, in many cases, considerably higher than those obtained with molecular catalysts for olefin hydrogenation and Miyaura-Suzuki reactions. The most difficult C-C coupling reactions involving non-activated aryl chlorides require very reactive molecular catalysts, however, although all catalysts decompose at high temperature to PdNPs that are also active in Heck coupling of aryl chlorides. The seminal work by Crooks’ group, [43,44,45] among others, had elegantly demonstrated multiple opportunities of PAMAM-dendrimer-encapsulated nanoparticle catalysis. PPI [94,95,96,97,98,99] of phenylazomethine [55,56,57,58] dendrimers have also offered related possibilities. Our contribution focused on the design of very active “click”-dendrimer-encapsulated and “click”-dendrimer-stabilized PdNP catalysts showing the key role of the intradendritic triazole ligands in these nanoreactors that worked in organic as well as aqueous solvents. This approach provided very active PdNP catalysts for C-C coupling reactions under ambient conditions and led to information concerning the leaching mechanism occurring in PdNP catalysis. Recent work has indicated that related leaching mechanisms may occur in other dendrimer-Pd-catalyzed reactions [100].


Financial support from the Institut Universitaire de France (IUF), the Ministère de la Recherche et de la Technologie (MRT), the Centre National de la Recherche Scientifique (CNRS), the Université Bordeaux 1, and the Agence Nationale de la Recherche (ANR) is gratefully acknowledged.


  1. Kleij, R.A.; van Leeuwen, P.W.N.M.; van der Made, A.W. Catalyst compositions and polymerization process, hexakisphosphines and hexahalo compounds. EP0456317 1991. [Chem. Abstr. 1992, 116, 129870]. [Google Scholar]
  2. Oosterom, G.E.; Reek, J.N.H.; Kamer, P.C.J.; van Leeuwen, P.W.N.M. Transition Metal Catalysis Using Functionalized Dendrimers. Angew. Chem. Int. Ed. 2001, 40, 1828–1849. [Google Scholar] [CrossRef]
  3. Brunner, H.; Fürst, J.; Ziegler, J. Enantioselektive katalyse: LXXXI. Optisch aktive zweischalenphosphine. J. Organomet. Chem. 1993, 454, 87–94. [Google Scholar]
  4. Knapen, J.W.J.; van der Made, A.W.; de Wilde, J.C.; van Leeuwen, P.W.N.M.; Wijkens, P.; Grove, D.M.; van Koten, G. Homogeneous catalysts based on silane dendrimers functionalized with arylnickel(II) complexes. Nature 1994, 372, 659–663. [Google Scholar]
  5. Miedaner, A.; Curtis, C.J.; Barkley, R.M.; DuBois, D.L. Electrochemical Reduction of CO2 Catalyzed by Small Organophosphine Dendrimers Containing Palladium. Inorg. Chem. 1994, 33, 5482–5490. [Google Scholar] [CrossRef]
  6. Lee, J.-J.; Ford, W.T.; Moore, J.A.; Li, Y. Reactivity of Organic Anions Promoted by a Quaternary Ammonium Ion Dendrimer. Macromolecules 1994, 27, 4632–4634. [Google Scholar] [CrossRef]
  7. Brunner, H. Dendrizymes: Expanded ligands for enantioselective catalysis. J. Organomet. Chem. 1995, 500, 39–46. [Google Scholar]
  8. Ardoin, N.; Astruc, D. The Molecular Trees: From Syntheses towards Applications. Bull. Soc. Chim. Fr. 1995, 132, 875–909. [Google Scholar]
  9. Astruc, D.; Chardac, F. Dendritic Catalysts and Dendrimers in Catalysis. Chem. Rev. 2001, 101, 2991–3031. [Google Scholar] [CrossRef]
  10. van Heerbeek, R.; Kamer, P.C.J.; van Leeuwen, P.W.N.M.; Reek, J.N.H. Dendrimers as Support for Recoverable Catalysts and Reagents. Chem. Rev. 2002, 102, 3717–3756. [Google Scholar] [CrossRef]
  11. Gade, L. Dendrimer Catalysis; Springer: Heidelberg, Germany, 2006. [Google Scholar]
  12. Helms, B.; Fréchet, J.M.J. The Dendrimer Effect in Homogeneous Catalysis. Adv. Synth. Catal. 2006, 348, 1125–1148. [Google Scholar] [CrossRef]
  13. Méry, D; Astruc, D. Dendritic catalysis: Major concepts and recent progress. Coord. Chem. Rev. 2006, 250, 1965–1979. [Google Scholar] [CrossRef]
  14. Hwang, S.-H.; Shreiner, C.D.; Moorefield, C.N.; Newkome, C.N. Recent progress and applications for metallodendrimers. New J. Chem. 2007, 31, 1192–1217. [Google Scholar] [CrossRef]
  15. de Jesús, E.; Flores, J.C. Dendrimers: Solutions For Catalyst Separation and Recycling–A Review. Ind. Eng. Chem. Res. 2008, 47, 7968–7981. [Google Scholar] [CrossRef]
  16. Martinez-Olid, F.; Benito, J.M.; Flores, J.C.; de Jesus, E. Polymetallic Carbosilane Dendrimers Containing N,N'-Iminopyridine Chelating Ligands: Applications in Catalysis. Isr. J. Chem. 2009, 49, 99–108. [Google Scholar] [CrossRef]
  17. Astruc, D.; Boisselier, E.; Ornelas, C. Dendrimers Designed for Functions: From Physical, Photophysical, and Supramolecular Properties to Applications in Sensing, Catalysis, Molecular Electronics, Photonics, and Nanomedicine. Chem. Rev. 2010, 110, 1857–1959. [Google Scholar] [CrossRef]
  18. Tsuji, J. Modern Palladium Catalysis. Palladium Reagents and Catalysts: New Perspectives for the 21rst Century; Wiley: Chichester, UK, 2004. [Google Scholar]
  19. Andrés, R.; de Jesus, E.; Flores, J.C. Catalysts based on palladium dendrimers. New J. Chem. 2007, 31, 1161–1191. [Google Scholar] [CrossRef]
  20. Astruc, D. Palladium Catalysis Using Dendrimers: Molecular Catalysts versus Nanoparticles. Tetrahedron Asymmetry 2010, in press. [Google Scholar]
  21. Reetz, M.-T.; Lohmer, G.; Schwickardi, R. Systhesis and Catalytic Activity of Dendritic Diphosphane Metal Complexes. Angew. Chem. Int. Ed. Engl. 1997, 36, 1526–1529. [Google Scholar] [CrossRef]
  22. Dijskstra, H.P.; Kruihof, C.A.; Ronde, N.; van de Coevering, R.; Ramon, D.J.; Vogt, D.; van Klink, G.M.P.; van Koten, G. Shape-Persistent Nanosize Organometallic Complexes: Synthesis and Application in a Nanofiltration Membrane Reactor. J. Org. Chem. 2003, 68, 675–685. [Google Scholar]
  23. Dijskstra, H.P.; Ronde, N.; Ramon, D.J.; van Klink, G.M.P.; Vogt, D.; van Koten, G. Application of a Homogeneous Dodecakis(NCN-PdII) Catalyst in a Nanofiltration Membrane Reactor under Continuous Reaction Conditions. Adv. Synth. Catal. 2003, 345, 364–369. [Google Scholar] [CrossRef]
  24. Astruc, D.; Heuze, K.; Gatard, S.; Méry, D.; Nlate, S.; Plault, L. Metallodendritic Catalysis for Redox and Carbon-Carbon Bond Formation Reactions: A Step towards Green Chemistry. Advan. Syn. Catal. 2005, 347, 329–338. [Google Scholar] [CrossRef]
  25. Brienbauer, R.; Jacobsen, E.N. Cooperative Asymmetric Catalysis with Dendrimeric [Co(salen)] Complexes. Angew. Chem. Int. Ed. 2000, 39, 3604–3607. [Google Scholar] [CrossRef]
  26. Francavilla, C.; Drake, M.D.; Bright, F.V.; Detty, M.R. Dendrimeric Organochalcogen Catalysts for the Activation of Hydrogen Peroxide: Improved Catalytic Activity through Statistical Effects and Cooperativity in Successive Generations. J. Am. Chem. Soc. 2001, 123, 57–67. [Google Scholar] [CrossRef]
  27. Dahan, A.; Portnoy, M. Dendritic effect in polymer-supported catalysis of the intramolecular Pauson–Khand reaction. Chem. Commun. 2002, 2700–2701. [Google Scholar] [CrossRef]
  28. Gatard, S.; Nlate, S.; Cloutet, E.; Bravic, G.; Blais, J.C.; Astruc, D. Dendritic Stars by Ring-Opening-Metathesis Polymerization from Ruthenium-Carbene Initiators. Angew. Chem. Int. Ed. 2003, 42, 452–456. [Google Scholar] [CrossRef]
  29. Dahan, A.; Portnoy, M. Remarkable Dendritic Effect in the Polymer-Supported Catalysis of the Heck Arylation of Olefins. Org. Lett. 2003, 5, 1197–2000. [Google Scholar] [CrossRef]
  30. Gatard, S.; Kahlal, S.; Méry, D.; Nlate, S.; Cloutet, E.; Saillard, J.-Y.; Astruc, D. Synthesis, Chemistry, DFT Calculations, and ROMP Activity of Monomeric Benzylidene Complexes Containing a Chelating Diphosphine and of Four Generations of Metallodendritic Analogues. Positive and Negative Dendritic Effects and Formation of Dendritic Ruthenium−Polynorbornene Stars. Organometallics 2004, 23, 1313–1324. [Google Scholar]
  31. Fujihara, T.; Obora, Y.; Tokunaga, M.; Sato, H. Dendrimer N-heterocyclic carbene complexes with rhodium(I) at the core. Chem. Commun. 2005, 4526–4528. [Google Scholar]
  32. Xang, X.; Xu, H.; Dong, Z.; Wang, Y.; Liu, J. Highly Efficient Dendrimer-Based Mimic of Glutathione Peroxidase. J. Am. Chem. Soc. 2004, 126, 10556–10557. [Google Scholar] [CrossRef]
  33. Delors, E.; Darbre, T.; Reymond, J.L. A Strong Positive Dendritic Effect in a Peptide Dendrimer-Catalyzed Ester Hydrolysis Reaction. J. Am. Chem. Soc. 2004, 126, 15642–15643. [Google Scholar]
  34. Ouali, A.; Laurent, R.; Caminade, A.M.; Majoral, J.P.; Taillefer, M. Enhanced Catalytic Properties of Copper in O- and N-Arylation and Vinylation Reactions, Using Phosphorus Dendrimers as Ligands. J. Am. Chem. Soc. 2006, 128, 15990–15991. [Google Scholar] [CrossRef]
  35. Fujihara, T.; Yoshida, S.; Ohta, H.; Tsuji, Y. Triarylphosphanes with Dendritically Arranged Tetraethylene Glycol Moieties at the Periphery: An Efficient Ligand for the Palladium-Catalyzed Suzuki-Miyaura Coupling Reaction. Angew. Chem. Int. Ed. 2008, 47, 8310–8313. [Google Scholar] [CrossRef]
  36. Heuzé, K.; Méry, D.; Gauss, D.; Astruc, D. Copper-free, recoverable dendritic Pd catalysts for the Sonogashira reaction. Chem. Commun. 2003, 2274–2275. [Google Scholar]
  37. Heuzé, K.; Méry, D.; Gauss, D.; Blais, J.-C.; Astruc, D. Copper-Free Monomeric and Dendritic Palladium Catalysts for the Sonogashira Reaction: Substituent Effects, Synthetic Applications, and the Recovery and Re-Use of the Catalysts. Chem. Eur. J. 2004, 10, 3936–3944. [Google Scholar] [CrossRef]
  38. Astruc, D.; Blais, J.-C.; Daniel, M.-C.; Gatard, S.; Nlate, S.; Ruiz, J. C. R. Nano-scale Metallodendritic Complexes in Electron-Transfer Processes and Catalysis. Chimie 2003, 6, 1117–1127. [Google Scholar] [CrossRef]
  39. Lemo, J.; Heuzé, K.; Astruc, D. Efficient Dendritic Diphosphino Pd(II) Catalysts for the Suzuki Reaction of Choroarenes. Org. Letters 2005, 7, 2253–2256. [Google Scholar] [CrossRef]
  40. Zhao, M.; Sun, L.; Crooks, R.M. Preparation of Cu Nanoclusters within Dendrimer Templates. J. Am. Chem. Soc. 1998, 120, 4877–4878. [Google Scholar] [CrossRef]
  41. Balogh, L.; Tomalia, D.A. Poly(Amidoamine) Dendrimer-Templated Nanocomposites. 1. Synthesis of Zerovalent Copper Nanoclusters. J. Am. Chem. Soc. 1998, 120, 7355–7356. [Google Scholar] [CrossRef]
  42. Esumi, K.; Suzuki, A.; Aihara, N.; Usu, K. Torigoe, Preparation of Gold Colloids with UV Irradiation Using Dendrimers as Stabilizer K. Langmuir 1998, 14, 3157–3159. [Google Scholar]
  43. Crooks, R.M.; Zhao, M.; Sun, L.; Chechik, V.; Yeung, L.K. Dendrimer-Encapsulated Metal Nanoparticles: Synthesis, Characterization, and Applications to Catalysis. Acc. Chem. Res. 2001, 34, 181–190. [Google Scholar]
  44. Niu, Y.; Crooks, R.M. Dendrimer-encapsulated metal nanoparticles and their applications to catalysis. C. R. Chimie 2003, 8, 1049–1059. [Google Scholar]
  45. Scott, R.W.J.; Wilson, O.M.; Crooks, R.M. Synthesis, Characterization, and Applications of Dendrimer-Encapsulated Nanoparticles. J. Phys. Chem. B 2005, 109, 692–704. [Google Scholar]
  46. Zhao, M.; Crooks, R.M. Homogeneous Hydrogenation Catalysis with Monodisperse, Dendrimer-Encapsulated Pd and Pt Nanoparticles. Angew. Chem. Int. Ed. 1999, 38, 364–366. [Google Scholar] [CrossRef]
  47. Yeung, L.K.; Crooks, R.M. Heck Heterocoupling within a Dendritic Nanoreactor. Nano Lett. 2001, 1, 14–17. [Google Scholar] [CrossRef]
  48. Yeung, L.K.; Lee, C.T.; Johnston, K.P.; Crooks, R.M. Catalysis in supercritical CO2 using dendrimer-encapsulated palladium nanoparticles. Chem. Commun. 2001, 2290. [Google Scholar]
  49. Scott, R.W.J.; Wilson, O.M.; Crooks, R.M. Titania-Supported Au and Pd Composites Synthesized from Dendrimer-Encapsulated Metal Nanoparticle Precursors. Chem. Mater. 2004, 16, 5682–5688. [Google Scholar]
  50. Scottt, R.W.J.; Datye, A.K.; Crooks, R.M. Bimetallic Palladium−Platinum Dendrimer-Encapsulated Catalysts. J. Am. Chem. Soc. 2003, 125, 3708–3709. [Google Scholar] [CrossRef]
  51. Wilson, O.M.; Scott, R.W.J.; Garcia-Martinez, J.C.; Crooks, R.M. Synthesis, Characterization, and Structure-Selective Extraction of 1−3-nm Diameter AuAg Dendrimer-Encapsulated Bimetallic Nanoparticles. J. Am. Chem. Soc. 2005, 127, 1015–1024. [Google Scholar]
  52. Scott, R.W.J.; Sivadiranarayana, C.; Wilson, O.M.; Yan, Z.; Goodman, D.W.; Crooks, R.M. Titania-Supported PdAu Bimetallic Catalysts Prepared from Dendrimer-Encapsulated Nanoparticle Precursors. J. Am. Chem. Soc. 2005, 127, 1380–1381. [Google Scholar]
  53. Garcia-Martinez, J.C.; Lezutekong, R.; Crooks, R.M. Dendrimer-Encapsulated Pd Nanoparticles as Aqueous, Room-Temperature Catalysts for the Stille Reaction. J. Am. Chem. Soc. 2005, 127, 5097–5098. [Google Scholar] [CrossRef]
  54. Feng, Z.V.; Lyon, J.L.; Croley, J.S.; Crooks, R.M.; Vanden Bout, D.A.; Stevenson, K.J. Synthesis and Catalytic Evaluation of Dendrimer-Encapsulated Cu Nanoparticles. An Undergraduate Experiment Exploring Catalytic Nanomaterials. J. Chem. Ed. 2009, 86, 368–372. [Google Scholar]
  55. Yamamoto, K.; Higushi, M.; Shiki, S.; Tsuruta, M.; Chiba, H. Stepwise radial complexation of imine groups in phenylazomethine dendrimers. Nature 2002, 415, 509–511. [Google Scholar] [CrossRef]
  56. Higushi, M.; Shiki, S.; Ariga, S.; Yamamoto, K. First Synthesis of Phenylazomethine Dendrimer Ligands and Structural Studies. J. Am. Chem. Soc. 2001, 123, 4414–4420. [Google Scholar]
  57. Satoh, N.; Nakashima, T.; Kamikura, K.; Yamamoto, K. Quantum size effect in TiO2 nanoparticles prepared by finely controlled metal assembly on dendrimer templates. Nature Nanotechnol. 2008, 2, 106–111. [Google Scholar]
  58. Nakamura, I.; Yamanoi, Y.; Yonezawa, T.; Imaoka, T.; Yamamoto, K.; Nishihara, H. Nanocage catalysts—rhodium nanoclusters encapsulated with dendrimers as accessible and stable catalysts for olefin and nitroarene hydrogenations. Chem. Commun. 2008, 5716–5718. [Google Scholar]
  59. Beller, M.; Lohmer, G.; Kühlein, K.; Reisinger, C.P.; Herrmann, W.A. First palladium-catalyzed Heck reactions with efficient colloidal catalyst systems. J. Organomet. Chem. 1996, 520, 257. [Google Scholar]
  60. Reetz, M.T.; Lohmer, G. Propylene carbonate stabilized nanostructured palladium clusters as catalysts in Heck reactions. Chem. Commun. 1996, 1921–1922. [Google Scholar] [CrossRef]
  61. Biffis, A.; Zecca, M.; Basato, M. Palladium metal catalysts in Heck C-C coupling reactions. J. Mol. Catal. A Chem. 2001, 173, 249–260. [Google Scholar] [CrossRef]
  62. Astruc, D.; Lu, F.; Ruiz, J. Nanoparticles as Recyclable Catalysts: The Fast-growing Frontier between Homogeneous and Heterogeneous Catalysts. Angew. Chem. Int. Ed. 2005, 44, 7852–7872. [Google Scholar] [CrossRef]
  63. Phan, N.T.S.; van der Sluis, M.; Jones, C.J. On the Nature of the Active Species in Palladium Catalyzed Mizoroki-Heck and Suzuki-Miyaura Couplings - Homogeneous or Heterogeneous Catalysis, A Critical Review. Adv. Syn. Catal. 2006, 348, 609–679. [Google Scholar] [CrossRef]
  64. de Vries, G.J. A unifying mechanism for all high-temperature Heck reactions. The role of palladium colloids and anionic species. Dalton. Trans. 2006, 421–429. [Google Scholar] [CrossRef]
  65. Astruc, D. Palladium Nanoparticles as Efficient Green Homogeneous and Heterogeneous Carbon-Carbon Coupling Pre-catalysts: A Unifying View. Inorg. Chem. 2007, 46, 1884–1894. [Google Scholar] [CrossRef]
  66. Djakovitch, L.; Köhler, K.; de Vries, J.G. The Role of Nanoparticles as Catalysts for Carbon-Carbon Coupling Reactions. In Nanoparticles and Catalysis; Astruc, D., Ed.; Wiley-VCH: Weinheim, Germany, 2007; Volume Chapter 10, pp. 303–348. [Google Scholar]
  67. He, J.-H.; Ichinose, I.; Kunitake, T.; Nakao, A.; Shiraishi, Y.; Toshima, N. Facile Fabrication of Ag−Pd Bimetallic Nanoparticles in Ultrathin TiO2-Gel Films: Nanoparticle Morphology and Catalytic Activity. J. Am. Chem. Soc. 2003, 125, 11034. [Google Scholar] [CrossRef]
  68. Newkome, G.R.; Moorefield, C.N.; Vögtle, F. Dendrimers and Dendrons. Concepts, Syntheses, Applications; Wiley-VCH: Weinheim, Germany, 2001. [Google Scholar]
  69. Tomalia, D.A.; Fréchet, J.M.J. Dendrimers and Other Dendritic Polymers; Wiley: Amsterdam, The Netherlands, 2001. [Google Scholar]
  70. Astruc, D. Dendrimers and Nanosciences. C. R. Chimie 2003, 6, 709–1208. [Google Scholar] [CrossRef]
  71. Moulines, F.; Astruc, D. Tentacled Iron Sandwiches. Angew. Chem. Int. Ed. Engl. 1988, 27, 1347–1349. [Google Scholar] [CrossRef]
  72. Moulines, F.; Djakovitch, L.; Boese, R.; Gloaguen, B.; Thiel, W.; Fillaut, J.-L.; Delville, M.-H.; Astruc, D. Organometallic Molecular Trees as Multi-Electron and Proton Reservoirs: CpFe+ Induced Nona-Allylation of Mesitylene and Phase-Transfer Catalyzed Synthesis of a Redox Active Nona-Iron Complex. Angew. Chem. Int. Ed. Engl. 1993, 32, 1075–1077. [Google Scholar] [CrossRef]
  73. Sartor, V.; Djakovitch, L.; Fillaut, J.-L.; Moulines, F.; Neveu, F.; Marvaud, V; Guittard, J.; Blais, J.-C.; Astruc, D. Organoiron Routes to a New Dendron for Fast Dendritic Syntheses Using Divergent and Convergent Methods. J. Am. Chem. Soc. 1999, 121, 2929–2930. [Google Scholar]
  74. Ruiz, J.; Lafuente, G.; Marcen, S.; Ornelas, C.; Lazare, S.; Cloutet, E.; Blais, J.-C.; Astruc, D. Construction of Giant Dendrimers Using a Tripodal Buiding Block. J. Am. Chem. Soc. 2003, 125, 7250–7257. [Google Scholar]
  75. Astruc, D.; Ruiz, J. Organoiron-mediated dendrimer syntheses with 1→3 connectivity and applications. Tetrahedron Report N° 903. Tetrahedron 2010, 66, 1769–1785. [Google Scholar] [CrossRef]
  76. Astruc, D. Organo-iron complexes of aromatic compounds. Applications in synthesis. Tetrahedron Report n° 157. Tetrahedron 1983, 39, 4027–4095. [Google Scholar] [CrossRef]
  77. Catheline, D.; Astruc, D. The Use of Ferrocene in Organometallic Synthesis: a two Step Preparation of Cyclopentadienyliron Acetonitrile and Phosphine Cations via Photolysis of Cyclopentadienyliron Tricarbonyl or Arene Cations. J. Organometal. Chem. 1984, 272, 417–426. [Google Scholar] [CrossRef]
  78. Newkome, G.R.; Yao, Z.; Baker, G.R.; Gupta, V.K. Micelles. Part 1. Cascade molecules: A new approach to micelles. A [27]-arborol. J. Org. Chem. 1985, 50, 2003–2004. [Google Scholar] [CrossRef]
  79. Newkome, G.R.; Shreiner, C. The Syntheses of Dendrimers with 1→3 Connectivity. Chem. Rev. 2010, 110. in press. [Google Scholar]
  80. Ornelas, C.; Méry, D.; Cloutet, E.; Ruiz, J.; Astruc, D. 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. J. Am. Chem. Soc. 2008, 130, 1495–1506. [Google Scholar]
  81. Ornelas, C.; Ruiz, J.; Cloutet, E.; Alves, S.; Astruc, D. Click Assembly of 1,2,3-Triazole-Linked Dendrimers Including Ferrocenyl Dendrimers that Sense Both Oxo-anions and Metal Cations. Angew. Chem. Int. Ed. 2007, 46, 872–877. [Google Scholar] [CrossRef]
  82. Ornelas, C.; Salmon, L.; Ruiz, J.; Astruc, D. "Click" Dendrimers: Synthesis, Redox Sensing of Pd(OAc)2, and Remarkable Catalytic Hydrogenation Activity of Precise Pd Nanoparticles Stabilized by 1,2,3-Triazole-Containing Dendrimers. Chem. Eur. J. 2008, 14, 50–64. [Google Scholar] [CrossRef]
  83. Boisselier, E.; Diallo, A. K.; Salmon, L.; Ornelas, C.; Ruiz, J.; Astruc, D. Encapsulation and Stabilization of Gold Nanoparticles with “Click” Polyethyleneglycol Dendrimers. J. Am. Chem. Soc. 2010, 132, 2729–2742. [Google Scholar]
  84. Daniel, M.-C.; Ruiz, J.; Blais, J.-C.; Daro, N.; Astruc, D. Synthesis of Five Generations of Redox Stable Pentamethylamidoferrocenyl Dendrimers and Compared Use of Amidoferrocenyl- and Pentamethylamidoferrocenyl Dendrimers As Electrochemical Exoreceptors for the Selective Recognition of H2PO4-, HSO4- and Adenosyl-5’-Triphosphate (ATP) Anions. Stereoelectronic and Hydrophobic Roles of the Cp Permethylation. Chem. Eur. J. 2003, 9, 4371–4379. [Google Scholar] [CrossRef]
  85. Astruc, D.; Ornelas, C.; Ruiz, J. Ferrocenyl-terminated Dendrimers: Design for Applications in Molecular Electronics, Molecular Recognition and Catalysis. J. Inorg. Organomet. Polym. Mater. 2008, 18, 4–17. [Google Scholar] [CrossRef]
  86. Astruc, D.; Ornelas, C.; Ruiz, J. Metallocenyl Dendrimers and their Applications in Molecular Electronics, Sensing and Catalysis. Acc. Chem. Res. 2008, 41, 841–856. [Google Scholar] [CrossRef]
  87. Badèche, S.; Daran, J.-C.; Ruiz, J.; Astruc, D. Synthesis and Coordination Chemistry of Ferrocenyl-1,2,3-triazolyl Ligands. Inorg. Chem. 2008, 47, 4903–4908. [Google Scholar] [CrossRef]
  88. Ornelas, C.; Salmon, L.; Ruiz, J.; Astruc, D. Catalytically Efficient Palladium Nanoparticles Stabilized by Click Ferrocenyl Dendrimers. Chem. Commun. 2007, 4946–4948. [Google Scholar]
  89. Suzuki, A. The Susuki Reaction with Arylboron Compounds in Arene Chemistry. In Modern Arene Chemistry; Astruc, D., Ed.; Wiley-VCH: Weinheim, Germany, 2002; pp. 53–106. [Google Scholar]
  90. Diallo, A.K.; Ornelas, C.; Salmon, L.; Ruiz, J.; Astruc, D. Catalytically Efficient Palladium Nanoparticles Stabilized by Click Ferrocenyl Dendrimers. Angew. Chem. Int. Ed. Engl. 2007, 46, 8644–8648. [Google Scholar] [CrossRef]
  91. Ornelas, C.; Ruiz, J.; Salmon, L.; Astruc, D. Sulfonated “Click” Dendrimer-Stabilized Palladium Nanoparticles as Highly Efficient Catalysts for Olefin Hydrogenation and Suzuki Coupling Reactions Under Ambient Conditions in Aqueous Media. Adv. Syn. Catal. 2008, 350, 837–845. [Google Scholar] [CrossRef]
  92. Ornelas, C.; Diallo, A.K.; Ruiz, J.; Astruc, D. “Click” polymer-supported palladium nanoparticles as highly efficient catalysts for olefin hydrogenation and Suzuki coupling reaction under ambient conditions. Adv. Synth. Catal. 2009, 351, 2147–2154. [Google Scholar]
  93. Lu, F.; Ruiz, J.; Astruc, D. Palladium-dodecanethiolate nanoparticles as stable and recyclable catalysts for the Suzuki-Miyaura reaction of aryl halides under ambient conditions. Tetrahedron Lett. 2004, 9443–9445. [Google Scholar]
  94. Oee, M.; Murata, M.; Mizugaki, T.; Ebitani, K.; Kaneda, K. Dendritic Nanoreactors Encapsulating Pd Particles for Substrate-Specific Hydrogenation of Olefins. Nano Lett. 2002, 2, 999. [Google Scholar] [CrossRef]
  95. Mizugaki, T.; Muratra, M.; Fukubayashi, S.; Mitsudome, T.; Jitsujkawa, K.; Kaneda, K. PAMAM dendron-stabilised palladium nanoparticles: Effect of generation and peripheral groups on particle size and hydrogenation activity. Chem. Commun. 2008, 241–243. [Google Scholar]
  96. Lemo, J.; Heuzé, K.; Astruc, D. Synthesis and Catalytic Activity of DAB-dendrimer Encapsulated Pd Nanoparticles for the Suzuki Coupling Reaction. Inorg. Chim. Acta 2006, 359, 4909–4911. [Google Scholar] [CrossRef]
  97. Chung, Y.; Rhree, H.K. Partial hydrogenation of 1,3-cyclooctadiene using dendrimer-encapsulated Pd–Rh bimetallic nanoparticles. J. Mol. Cat. A 2003, 206, 291–294. [Google Scholar] [CrossRef]
  98. Narayanan, R.; El-Sayed, M.A. Effect of Colloidal Catalysis on the Nanoparticle Size Distribution: Dendrimer−Pd vs PVP−Pd Nanoparticles Catalyzing the Suzuki Coupling Reaction. J. Phys. Chem. B 2004, 108, 8572–8577. [Google Scholar] [CrossRef]
  99. Rahim, E.H.; Kamounah, F.S.; Frederiksen, J.; Christensen, J.B. Heck Reactions Catalyzed by PAMAM-Dendrimer Encapsulated Pd(0) Nanoparticles. Nano Lett. 2001, 1, 499–502. [Google Scholar] [CrossRef]
  100. Bernechea, M.; de Jesus, E.; Lopez-Mardomingo, C.; Terreros, P. Dendrimer-Encapsulated Pd Nanoparticles versus Palladium Acetate as Catalytic Precursors in the Stille Reaction in Water. Inorg. Chem. 2009, 48, 4491–4496. [Google Scholar] [CrossRef]
  • Sample Availability: Not Available.

Share and Cite

MDPI and ACS Style

Astruc, D.; Ornelas, C.; Diallo, A.K.; Ruiz, J. Extremely Efficient Catalysis of Carbon-Carbon Bond Formation Using "Click" Dendrimer-Stabilized Palladium Nanoparticles. Molecules 2010, 15, 4947-4960.

AMA Style

Astruc D, Ornelas C, Diallo AK, Ruiz J. Extremely Efficient Catalysis of Carbon-Carbon Bond Formation Using "Click" Dendrimer-Stabilized Palladium Nanoparticles. Molecules. 2010; 15(7):4947-4960.

Chicago/Turabian Style

Astruc, Didier, Cátia Ornelas, Abdou K. Diallo, and Jaime Ruiz. 2010. "Extremely Efficient Catalysis of Carbon-Carbon Bond Formation Using "Click" Dendrimer-Stabilized Palladium Nanoparticles" Molecules 15, no. 7: 4947-4960.

Article Metrics

Back to TopTop