From soluble to supported iridium metal nanoparticles: Active and recyclable catalysts for hydrogenation reactions

Current Organic Chemistry

Volumn 17, Issue 4, 2013, Pages 348-363

  Scholten, Jackson D ^a  

^a FEDERAL UNIVERSITY OF RIO GRANDE DO SUL   (Brazil)

Author keywords

Catalysis; Hydrogenation; Iridium; Nanoparticles

Indexed keywords

IONIC LIQUIDS; IRIDIUM; METAL NANOPARTICLES; NANOCATALYSTS;

ACTIVE CATALYST; DIFFERENT SUBSTRATES; HYDROGENATION REACTIONS; NANO-CATALYST; REACTION MEDIA; RECYCLABLE CATALYST; ]+ CATALYST;

HYDROGENATION;

EID: 84877775091     PISSN: 13852728     EISSN: None     Source Type: Journal    
DOI: 10.2174/1385272811317040005     Document Type: Review

References (105)

1. Noyori, R. Asymmetric catalysis: Science and opportunities (Nobel Lecture). Angew. Chem. Int. Ed., 2002, 41, 2008-2022.
2. Chauvin, Y. Olefin metathesis: The early days (Nobel Lecture). Angew. Chem. Int. Ed., 2006, 45, 3740-3765.
3. Thomas, A.; Driess, M. Bridging the materials gap in catalysis: Entrapment of molecular catalysts in functional supports and beyond. Angew. Chem. Int. Ed., 2009, 48, 1890-1892.
4. Lindner, E.; Schneller, T.; Auer, F.; Mayer, H. A. Chemistry in interphases - A new approach to organometallic syntheses and catalysis. Angew. Chem. Int. Ed., 1999, 38, 2154-2174.
5. Herrmann, W. A.; Cornils, B. Organometallic homogeneous catalysis - Quo vadis? Angew. Chem. Int. Ed., 1997, 36, 1048-1067.
6. Schmid, G. Large clusters and colloids - Metals in the embryonic state. Chem. Rev., 1992, 92, 1709-1727.
7. Belyakova, O. A.; Slovokhotov, Y. L. Structures of large transition metal clusters. Russ. Chem. Bul., 2003, 52, 2299-2327.
8. Bell, A. T. The impact of nanoscience on heterogeneous catalysis. Science, 2003, 299, 1688-1691.
9. Astruc, D.; Lu, F.; Aranzaes, J. R. Nanoparticles as recyclable catalysts: The frontier between homogeneous and heterogeneous catalysis. Angew. Chem. Int. Ed., 2005, 44, 7852-7872.
10. Finke, R. G. in Transition-Metal Nanoclusters (D. V. Feldheim and C. A. Foss Jr.), Marcel Dekker: New York, 2002.
11. Gelesky, M. A.; Umpierre, A. P.; Machado, G.; Correia, R. R. B.; Magno, W. C.; Morais, J.; Ebeling, G.; Dupont, J. Laser-induced fragmentation of transition metal nanoparticles in ionic liquids. J. Am. Chem. Soc., 2005, 127, 4588-4589.
12. Schulz, J.; Roucoux, A.; Patin, H. Unprecedented efficient hydrogenation of arenes in biphasic liquid-liquid catalysis by re-usable aqueous colloidal suspensions of rhodium. Chem. Commun., 1999, 535-536.
13. Stowell, C. A.; Korgel, B. A. Iridium nanocrystal synthesis and surface coating-dependent catalytic activity. Nano Lett., 2005, 5, 1203-1207.
14. Roucoux, A.; Schulz, J.; Patin, H. Arene hydrogenation with a stabilised aqueous rhodium(0) suspension: A major effect of the surfactant counteranion. Adv. Synth. Catal., 2003, 345, 222-229.
15. Iablokov, V.; Beaumont, S. K.; Alayoglu, S.; Pushkarev, V. V.; Specht, C.; Gao, J. H.; Alivisatos, A. P.; Kruse, N.; Somorjai, G. A. Size-controlled model Co nanoparticle catalysts for CO2 hydrogenation: Synthesis, characterization, and catalytic reactions. Nano Lett., 2012, 12, 3091-3096.
16. Aiken, J. D.; Lin, Y.; Finke, R. G. A perspective on nanocluster catalysis: Polyoxoanion and (n-C4H9)N+ stabilized Ir(0)~300 nanocluster 'soluble heterogeneous catalysts'. J. Mol. Catal. A: Chem., 1996, 114, 29-51.
17. Aiken, J. D.; Finke, R. G. Polyoxoanion- and tetrabutylammonium-stabilized Rh(0)n nanoclusters: Unprecedented nanocluster catalytic lifetime in solution. J. Am. Chem. Soc., 1999, 121, 8803-8810.
18. Widegren, J. A.; Aiken, J. D.; Ozkar, S.; Finke, R. G. Additional investigations of a new kinetic method to follow transition-metal nanocluster formation, including the discovery of heterolytic hydrogen activation in nanocluster nucleation reactions. Chem. Mater., 2001, 13, 312-324.
19. Pan, C.; Pelzer, K.; Philippot, K.; Chaudret, B.; Dassenoy, F.; Lecante, P.; Casanove, M. J. Ligand-stabilized ruthenium nanoparticles: Synthesis, organization, and dynamics. J. Am. Chem. Soc., 2001, 123, 7584-7593.
20. Pellegatta, J. L.; Blandy, C.; Colliere, V.; Choukroun, R.; Chaudret, B.; Cheng, P.; Philippot, K. Catalytic investigation of rhodium nanoparticles in hydrogenation of benzene and phenylacetylene. J. Mol. Catal. A: Chem., 2002, 178, 55-61.
21. Dupont, J.; Fonseca, G. S.; Umpierre, A. P.; Fichtner, P. F. P.; Teixeira, S. R. Transition-metal nanoparticles in imidazolium ionic liquids: Recycable catalysts for biphasic hydrogenation reactions. J. Am. Chem. Soc., 2002, 124, 4228-4229.
22. Ryu, H. J.; Sanchez, L.; Keul, H. A.; Raj, A.; Bockstaller, M. R. Imidazolium-based ionic liquids as efficient shape-regulating solvents for the synthesis of gold nanorods. Angew. Chem. Int. Ed., 2008, 47, 7639-7643.
23. Hu, Y.; Yu, Y. Y.; Hou, Z. S.; Li, H.; Zhao, X. G.; Feng, B. Biphasic hydrogenation of olefins by functionalized ionic liquid-stabilized palladium nanoparticles. Adv. Synth. Catal., 2008, 350, 2077-2085.
24. Tsuda, T.; Seino, S.; Kuwabata, S. Gold nanoparticles prepared with a roomtemperature ionic liquid-radiation irradiation method. Chem. Commun., 2009, 6792-6794.
25. Brettholle, M.; Hofft, O.; Klarhofer, L.; Mathes, S.; Maus-Friedrichs, W.; El Abedin, S. Z.; Krischok, S.; Janek, J.; Endres, F. Plasma electrochemistry in ionic liquids: Deposition of copper nanoparticles. Phys. Chem. Chem. Phys., 2010, 12, 1750-1755.
26. Leger, B.; Denicourt-Nowicki, A.; Olivier-Bourbigou, H.; Roucoux, A. Imidazolium-functionalized bipyridine derivatives: A promising family of ligands for catalytical Rh(0) colloids. Tetrahedron Lett., 2009, 50, 6531-6533.
27. Wang, Y.; Yang, H. Oleic acid as the capping agent in the synthesis of noble metal nanoparticles in imidazolium-based ionic liquids. Chem. Commun., 2006, 2545-2547.
28. Zhao, D. B.; Fei, Z. F.; Ang, W. H.; Dyson, P. J. A strategy for the synthesis of transition-metal nanoparticles and their transfer between liquid phases. Small, 2006, 2, 879-883.
29. Yang, X.; Yan, N.; Fei, Z. F.; Crespo-Quesada, R. M.; Laurenczy, G.; Kiwi-Minsker, L.; Kou, Y.; Li, Y. D.; Dyson, P. J. Biphasic hydrogenation over PVP stabilized Rh nanoparticles in hydroxyl functionalized ionic liquids. Inorg. Chem., 2008, 47, 7444-7446.
30. Antonetti, C.; Oubenali, M.; Galletti, A. M. R.; Serp, P.; Vannucci, G. Novel microwave synthesis of ruthenium nanoparticles supported on carbon nanotubes active in the selective hydrogenation of p-chloronitrobenzene to pchloroaniline. Appl. Catal. A: Gen., 2012, 421, 99-107.
31. Chinthaginjala, J. K.; Villa, A.; Su, D. S.; Mojet, B. L.; Lefferts, L. Nitrite reduction over Pd supported CNFs: Metal particle size effect on selectivity. Catal. Today, 2012, 183, 119-123.
32. Ismail, A. A.; Hakki, A.; Bahnemann, D. W. Mesostructure Au/TiO2 nanocomposites for highly efficient catalytic reduction of p-nitrophenol. J. Mol. Catal. A: Chem., 2012, 358, 145-151.
33. Pelisson, C. H.; Vono, L. L. R.; Hubert, C.; Denicourt-Nowicki, A.; Rossi, L. M.; Roucoux, A. Moving from surfactant-stabilized aqueous rhodium(0) colloidal suspension to heterogeneous magnetite-supported rhodium nanocatalysts: Synthesis, characterization and catalytic performance in hydrogenation reactions. Catal. Today, 2012, 183, 124-129.
34. Castillejos, E.; Gallegos-Suarez, E.; Bachiller-Baeza, B.; Bacsa, R.; Serp, P.; Guerrero-Ruiz, A.; Rodriguez-Ramos, I. Deposition of gold nanoparticles on ZnO and their catalytic activity for hydrogenation applications. Catal. Commun., 2012, 22, 79-82.
35. Shen, C.; Wang, Y. J.; Xu, J. H.; Wang, K.; Luo, G. S. Size control and catalytic activity of highly dispersed Pd nanoparticles supported on porous glass beads. Langmuir, 2012, 28, 7519-7527.
36. Chun, Y. S.; Shin, J. Y.; Song, C. E.; Lee, S. G. Palladium nanoparticles supported onto ionic carbon nanotubes as robust recyclable catalysts in an ionic liquid. Chem. Commun., 2008, 942-944.
37. Fonseca, G. S.; Umpierre, A. P.; Fichtner, P. F. P.; Teixeira, S. R.; Dupont, J. The use of imidazolium ionic liquids for the formation and stabilization of Ir0 and Rh0 nanoparticles: Efficient catalysts for the hydrogenation of arenes. Chem. Eur. J., 2003, 9, 3263-3269.
38. Kundu, S.; Liang, H. Shape-selective formation and characterization of catalytically active iridium nanoparticles. J. Colloid Interface Sci., 2011, 354, 597-606.
39. Lin, Y.; Finke, R. G. Novel polyoxoanion- and Bu4N+-stabilized, isolable, and redissolvable, 20-30-Angstrom Ir~300-900 nanoclusters: The kinetically controlled synthesis, characterization, and mechanism of formation of organic solvent-soluble, reproducible size, and reproducible catalytic activity metal nanoclusters. J. Am. Chem. Soc., 1994, 116, 8335-8353.
40. Lin, Y.; Finke, R. G. A more general approach to distinguishing homogeneous from heterogeneous catalysis: Discovery of polyoxoanionand Bu4N+-stabilized, isolable and redissolvable, high-reactivity Ir~190-450 nanocluster catalysts. Inorg. Chem., 1994, 33, 4891-4910.
41. Hornstein, B. J.; Finke, R. G. Transition-metal nanocluster catalysts: Scaledup synthesis, characterization, storage conditions, stability, and catalytic activity before and after storage of polyoxoanion- and tetrabutylammoniumstabilized Ir(0) nanoclusters. Chem. Mater., 2003, 15, 899-909.
42. Ott, L. S.; Finke, R. G. Transition-metal nanocluster stabilization for catalysis: A critical review of ranking methods and putative stabilizers. Coord. Chem. Rev., 2007, 251, 1075-1100.
43. Watzky, M. A.; Finke, R. G. Transition metal nanocluster formation kinetic and mechanistic studies. A new mechanism when hydrogen is the reductant: Slow, continuous nucleation and fast autocatalytic surface growth. J. Am. Chem. Soc., 1997, 119, 10382-10400.
44. Watzky, M. A.; Finke, R. G. Nanocluster size-control and magic number investigations, experimental tests of the living-metal polymer concept and of mechanism-based size-control predictions leading to the syntheses of iridium(0) nanoclusters centering about four sequential magic numbers. Chem. Mater., 1997, 9, 3083-3095.
45. Hornstein, B. J.; Finke, R. G. Transition-metal nanocluster kinetic and mechanistic studies emphasizing nanocluster agglomeration: Demonstration of a kinetic method that allows monitoring of all three phases of nanocluster formation and aging. Chem. Mater., 2004, 16, 139-150.
46. Besson, C.; Finney, E. E.; Finke, R. G. Nanocluster nucleation, growth, and then agglomeration kinetic and mechanistic studies: A more general, fourstep mechanism involving double autocatalysis. Chem. Mater., 2005, 17, 4925-4938.
47. Aiken, J. D.; Finke, R. G. A review of modern transition-metal nanoclusters: Their synthesis, characterization, and applications in catalysis. J. Mol. Catal. A: Chem., 1999, 145, 1-44.
48. Mevellec, V.; Roucoux, A.; Ramirez, E.; Philippot, K.; Chaudret, B. Surfactant-stabilized aqueous iridium(0) colloidal suspension: An efficient reusable catalyst for hydrogenation of arenes in biphasic media. Adv. Synth. Catal., 2004, 346, 72-76.
49. Dupont, J.; Scholten, J. D. On the structural and surface properties of transition-metal nanoparticles in ionic liquids. Chem. Soc. Rev., 2010, 39, 1780-1804.
50. Scholten, J. D.; Leal, B. C.; Dupont, J. Transition metal nanoparticle catalysis in ionic liquids. ACS Catal., 2012, 2, 184-200.
51. Migowski, P.; Dupont, J. Catalytic applications of metal nanoparticles in imidazolium ionic liquids. Chem. Eur. J., 2007, 13, 32-39.
52. Silveira, E. T.; Umpierre, A. P.; Rossi, L. M.; Machado, G.; Morais, J.; Soares, G. V.; Baumvol, I. L. R.; Teixeira, S. R.; Fichtner, P. F. P.; Dupont, J. The partial hydrogenation of benzene to cyclohexene by nanoscale ruthenium catalysts in imidazolium ionic liquids. Chem. Eur. J., 2004, 10, 3734-3740.
53. Scheeren, C. W.; Machado, G.; Dupont, J.; Fichtner, P. F. P.; Texeira, S. R. Nanoscale Pt(0) particles prepared in imidazolium room temperature ionic liquids: Synthesis from an organometallic precursor, characterization, and catalytic properties in hydrogenation reactions. Inorg. Chem., 2003, 42, 4738-4742.
54. Machado, G.; Scholten, J. D.; De Vargas, T.; Teixeira, S. R.; Ronchi, L. H.; Dupont, J. Structural aspects of transition-metal nanoparticles in imidazolium ionic liquids. Int. J. Nanotechnol., 2007, 4, 541-563.
55. Dupont, J.; De Souza, R. F.; Suarez, P. A. Z. Ionic liquid (molten salt) phase organometallic catalysis. Chem. Rev., 2002, 102, 3667-3691.
56. Fei, Z. F.; Geldbach, T. J.; Zhao, D. B.; Dyson, P. J. From dysfunction to bisfunction: On the design and applications of functionalised ionic liquids. Chem. Eur. J., 2006, 12, 2123-2130.
57. Wasserscheid, P.; Welton, T. Ionic Liquids in Synthesis, Wiley-VCH: Weinheim, 2003.
58. Tsuzuki, S.; Tokuda, H.; Hayamizu, K.; Watanabe, M. Magnitude and directionality of interaction in ion pairs of ionic liquids: Relationship with ionic conductivity. J. Phys. Chem. B, 2005, 109, 16474-16481.
59. Dupont, J.; Suarez, P. A. Z. Physico-chemical processes in imidazolium ionic liquids. Phys. Chem. Chem. Phys., 2006, 8, 2441-2452.
60. Hardacre, C.; Holbrey, J. D.; Mcmath, S. E. J.; Bowron, D. T.; Soper, A. K. Structure of molten 1,3-dimethylimidazolium chloride using neutron diffraction. J. Chem. Phys., 2003, 118, 273-278.
61. Fonseca, G. S.; Machado, G.; Teixeira, S. R.; Fecher, G. H.; Morais, J.; Alves, M. C. M.; Dupont, J. Synthesis and characterization of catalytic iridium nanoparticles in imidazolium ionic liquids. J. Colloid Interface Sci., 2006, 301, 193-204.
62. Ott, L. S.; Cline, M. L.; Deetlefs, M.; Seddon, K. R.; Finke, R. G. Nanoclusters in ionic liquids: Evidence for N-heterocyclic carbene formation from imidazolium-based ionic liquids detected by 2H NMR. J. Am. Chem. Soc., 2005, 127, 5758-5759.
63. Scholten, J. D.; Ebeling, G.; Dupont, J. On the involvement of NHC carbenes in catalytic reactions by iridium complexes, nanoparticle and bulk metal dispersed in imidazolium ionic liquids. Dalton Trans., 2007, 5554-5560.
64. Ott, L. S.; Campbell, S.; Seddon, K. R.; Finke, R. G. Evidence that imidazolium-based ionic ligands can be metal(0)/nanocluster catalyst poisons in at least the test case of iridium(0)-catalyzed acetone hydrogenation. Inorg. Chem., 2007, 46, 10335-10344.
65. Fonseca, G. S.; Domingos, J. B.; Nome, F.; Dupont, J. On the kinetics of iridium nanoparticles formation in ionic liquids and olefin hydrogenation. J. Mol. Catal. A: Chem., 2006, 248, 10-16.
66. Migowski, P.; Zanchet, D.; Machado, G.; Gelesky, M. A.; Teixeira, S. R.; Dupont, J. Nanostructures in ionic liquids: Correlation of iridium nanoparticles' size and shape with imidazolium salts' structural organization and catalytic properties. Phys. Chem. Chem. Phys., 2010, 12, 6826-6833.
67. Fonseca, G. S.; Silveira, E. T.; Gelesky, M. A.; Dupont, J. Competitive hydrogenation of alkyl-substituted arenes by transition-metal nanoparticles: Correlation with the alkyl-steric effect. Adv. Synth. Catal., 2005, 347, 847-853.
68. Fonseca, G. S.; Scholten, J. D.; Dupont, J. Iridium nanoparticles prepared in ionic liquids: An efficient catalytic system for the hydrogenation of ketones. Synlett, 2004, 1525-1528.
69. Scariot, M.; Silva, D. O.; Scholten, J. D.; Machado, G.; Teixeira, S. R.; Novak, M. A.; Ebeling, G.; Dupont, J. Cobalt nanocubes in ionic liquids: Synthesis and properties. Angew. Chem. Int. Ed., 2008, 47, 9075-9078.
70. Silva, D. O.; Scholten, J. D.; Gelesky, M. A.; Teixeira, S. R.; Dos Santos, A. C. B.; Souza-Aguiar, E. F.; Dupont, J. Catalytic gas-to-liquid processing using cobalt nanoparticles dispersed in imidazolium ionic liquids. ChemSusChem, 2008, 1, 291-294.
71. Redel, E.; Thomann, R.; Janiak, C. Use of ionic liquids (ILs) for the IL-anion size-dependent formation of Cr, Mo and W nanoparticles from metal carbonyl M(CO)6 precursors. Chem. Commun., 2008, 1789-1791.
72. Kramer, J.; Redel, E.; Thomann, R.; Janiak, C. Use of ionic liquids for the synthesis of iron, ruthenium, and osmium nanoparticles from their metal carbonyl precursors. Organometallics, 2008, 27, 1976-1978.
73. Redel, E.; Kramer, J.; Thomann, R.; Janiak, C. Synthesis of Co, Rh and Ir nanoparticles from metal carbonyls in ionic liquids and their use as biphasic liquid-liquid hydrogenation nanocatalysts for cyclohexene. J. Organomet. Chem., 2009, 694, 1069-1075.
74. Vollmer, C.; Janiak, C. Naked metal nanoparticles from metal carbonyls in ionic liquids: Easy synthesis and stabilization. Coord. Chem. Rev., 2011, 255, 2039-2057.
75. Vollmer, C.; Redel, E.; Abu-Shandi, K.; Thomann, R.; Manyar, H.; Hardacre, C.; Janiak, C. Microwave irradiation for the facile synthesis of transition-metal nanoparticles (NPs) in ionic liquids (ILs) from metal carbonyl precursors and Ru-, Rh-, and Ir-NP/IL dispersions as biphasic liquid-liquid hydrogenation nanocatalysts for cyclohexene. Chem. Eur. J., 2010, 16, 3849-3858.
76. Ozkar, S.; Finke, R. G. Iridium(0) nanocluster, acid-assisted catalysis of neat acetone hydrogenation at room temperature: Exceptional activity, catalyst lifetime, and selectivity at complete conversion. J. Am. Chem. Soc., 2005, 127, 4800-4808.
77. Bayram, E.; Zahmakiran, M.; Ozkar, S.; Finke, R. G. In situ formed weakly ligated/labile ligand iridium(0) nanoparticles and aggregates as catalysts for the complete hydrogenation of neat benzene at room temperature and mild pressures. Langmuir, 2010, 26, 12455-12464.
78. Hayek, K.; Goller, H.; Penner, S.; Rupprechter, G.; Zimmermann, C. Regular alumina-supported nanoparticles of iridium, rhodium and platinum under hydrogen reduction: Structure, morphology and activity in the neopentane conversion. Catal. Lett., 2004, 92, 1-9.
79. Gupta, G.; Stowell, C. A.; Patel, M. N.; Gao, X. X.; Yacaman, M. J.; Korgel, B. A.; Johnston, K. P. Infusion of presynthesized iridium nanocrystals into mesoporous silica for high catalyst activity. Chem. Mater., 2006, 18, 6239-6249.
80. Park, I. S.; Kwon, M. S.; Kang, K. Y.; Lee, J. S.; Park, J. Rhodium and iridium nanoparticles entrapped in aluminum oxyhydroxide nanofibers: Catalysts for hydrogenations of arenes and ketones at room temperature with hydrogen balloon. Adv. Synth. Catal., 2007, 349, 2039-2047.
81. Jiang, H. Y.; Yang, C. F.; Li, C.; Fu, H. Y.; Chen, H.; Li, R. X.; Li, X. J. Heterogeneous enantioselective hydrogenation of aromatic ketones catalyzed by cinchona- and phosphine-modified iridium catalysts. Angew. Chem. Int. Ed., 2008, 47, 9240-9244.
82. Jiang, H. Y.; Sun, B.; Zheng, X. X.; Chen, H. Heterogeneous selective hydrogenation of trans-4-phenyl-3-butene-2-one to allylic alcohol over modified Ir/SiO2 catalyst. Appl. Catal. A: Gen., 2012, 421, 86-90.
83. Yang, C. F.; Jiang, H. Y.; Feng, J.; Fu, H. Y.; Li, R. X.; Chen, H.; Li, X. J. Asymmetric hydrogenation of acetophenone catalyzed by cinchonidine stabilized Ir/SiO2. J. Mol. Catal. A: Chem., 2009, 300, 98-102.
84. Jesus, Y. M. L.; Vicente, A.; Lafaye, G.; Marecot, P.; Williams, C. T. Synthesis and characterization of dendrimer-derived supported iridium catalysts. J. Phys. Chem. C, 2008, 112, 13837-13845.
85. Fan, G. Y.; Zhang, L.; Fu, H. Y.; Yuan, M. L.; Li, R. X.; Chen, H.; Li, X. J. Hydrous zirconia supported iridium nanoparticles: An excellent catalyst for the hydrogenation of haloaromatic nitro compounds. Catal. Commun., 2010, 11, 451-455.
86. Rueping, M.; Koenigs, R. M.; Borrmann, R.; Zoller, J.; Weirich, T. E.; Mayer, J. Size-selective, stabilizer-free, hydrogenolytic synthesis of iridium nanoparticles supported on carbon nanotubes. Chem. Mater., 2011, 23, 2008-2010.
87. Colindres, S. C.; Garcia, J. R. V.; Antonio, J. A. T.; Chavez, C. A. Preparation of platinum-iridium nanoparticles on titania nanotubes by MOCVD and their catalytic evaluation. J. Alloys Compd., 2009, 483, 406-409.
88. Jacinto, M. J.; Silva, F. P.; Kiyohara, P. K.; Landers, R.; Rossi, L. M. Catalyst recovery and recycling facilitated by magnetic separation: Iridium and other metal nanoparticles. ChemCatChem, 2012, 4, 698-703.
89. Locatelli, F.; Didillon, B.; Uzio, D.; Niccolai, G.; Candy, J. P.; Basset, J. M. Preparation and characterization of small silica-supported iridium particles from iridium trisacetylacetonate precursor. J. Catal., 2000, 193, 154-160.
90. Locatelli, F.; Candy, J. P.; Didillon, B.; Niccolai, G. P.; Uzio, D.; Basset, J. M. Hydrogenolysis of cyclohexane over Ir/SiO2 catalyst: A mechanistic study of carbon-carbon bond cleavage on metallic surfaces. J. Am. Chem. Soc., 2001, 123, 1658-1663.
91. Triantafillou, N. D.; Smith, M. L.; Hepp, M. A.; Dybowski, C. R.; Gates, B. C. Deuterium absorbed on MgO-supported iridium clusters: Characterization by infrared and deuterium NMR spectroscopies. Langmuir, 1994, 10, 1793-1795.
92. Gates, B. C. Supported Metal Clusters: Synthesis, structure, and catalysis. Chem. Rev., 1995, 95, 511-522.
93. Argo, A. M.; Goellner, J. F.; Phillips, B. L.; Panjabi, G. A.; Gates, B. C. Reactivity of site-isolated metal clusters: Propylidyne on Al2O3-supported Ir4. J. Am. Chem. Soc., 2001, 123, 2275-2283.
94. Argo, A. M.; Odzak, J. F.; Lai, F. S.; Gates, B. C. Observation of ligand effects during alkene hydrogenation catalysed by supported metal clusters. Nature, 2002, 415, 623-626.
95. Argo, A. M.; Gates, B. C. Propene hydrogenation catalyzed by Al2O3 supported Ir4 clusters: Inhibition by dehydrogenated propene derivatives on Ir4. Langmuir, 2002, 18, 2152-2157.
96. Argo, A. M.; Odzak, J. F.; Gates, B. C. Role of cluster size in catalysis: Spectroscopic investigation of Al2O3 supported Ir4 and Ir6 during ethene hydrogenation. J. Am. Chem. Soc., 2003, 125, 7107-7115.
97. Li, F.; Gates, B. C. Size-dependent catalytic activity of zeolite-supported iridium clusters. J. Phys. Chem. C, 2007, 111, 262-267.
98. Uzun, A.; Dixon, D. A.; Gates, B. C. Prototype supported metal cluster catalysts: Ir4 and Ir6. ChemCatChem, 2011, 3, 95-107.
99. Aydin, C.; Lu, J.; Shirai, M.; Browning, N. D.; Gates, B. C. Ir6 clusters compartmentalized in the supercages of zeolite NaY: Direct imaging of a catalyst with aberration-corrected scanning transmission electron microscopy. ACS Catal., 2011, 1, 1613-1620.
100. Aydin, C.; Lu, J.; Browning, N. D.; Gates, B. C. A smart catalyst: Sinterresistant supported iridium clusters visualized with electron microscopy. Angew. Chem. Int. Ed., 2012, 51, 5929-5934.
101. Cho, S. J.; Lee, J.; Lee, Y. S.; Kim, D. P. Characterization of iridium catalyst for decomposition of hydrazine hydrate for hydrogen generation. Catal. Lett., 2006, 109, 181-187.
102. Guidotti, M.; Dal Santo, V.; Gallo, A.; Gianotti, E.; Peli, G.; Psaro, R.; Sordelli, L. Catalytic dehydrogenation of propane over cluster-derived Ir- Sn/SiO2 catalysts. Catal. Lett., 2006, 112, 89-95.
103. Rodriguez-Gattorno, G.; Aleman-Vazquez, L. O.; Angeles-Franco, X.; Cano-Dominguez, J. L.; Villagomez-Ibarra, R. Cyclohexane ring opening on alumina-supported Rh and Ir nanoparticles. Energy Fuels, 2007, 21, 1122-1126.
104. Nassreddine, S.; Massin, L.; Aouine, M.; Geantet, C.; Piccolo, L. Thiotolerant Ir/SiO2-Al2O3 bifunctional catalysts: Effect of metal-acid site balance on tetralin hydroconversion. J. Catal., 2011, 278, 253-265.
105. Nassreddine, S.; Casu, S.; Zotin, J. L.; Geantet, C.; Piccolo, L. Thiotolerant Ir/SiO2-Al2O3 bifunctional catalysts: Effect of support acidity on tetralin hydroconversion. Catal. Sci. Technol., 2011, 1, 408-412.