79. Nishida Y, Chaudhari C, Imatome H, Sato K, Nagaoka K (2018) Selective hydrogenation of
nitriles to secondary imines over Rh-PVP catalyst under mild conditions. Chem Lett
47:938–940
80. Gao L, Kojima K, Nagashima H (2015) Transition metal nanoparticles stabilized by ammonium salts of hyperbranched polystyrene: effect of metals on catalysis of the biphasic hydrogenation of alkenes and arenes. Tetrahedron 71:6414–6423
81. Ghosh S, Jagirdar BR (2017) Synthesis of mesoporous iridium nanosponge: a highly active,
thermally stable and efficient olefin hydrogenation catalyst. Dalton Trans 46:11431–11439
82. Özkar S, Finke RG (2005) 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 127:4800–4808
83. Bayram E, Zahmakıran M, Özkar S, Finke RG (2010) 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 26:12455–12464
84. Alley WM, Hamdemir IK, Wang Q, Frenkel AI, Li L, Yang JC, Menard LD, Nuzzo RG,
Ozkar S, Johnson KA, Finke RG (2010) Iridium Ziegler-type hydrogenation catalysts made
from [(1,5-COD)Ir(μ-O2C8H15)]2 and AlEt3: spectroscopic and kinetic evidence for the Irn
species present and for nanoparticles as the fastest catalyst. Inorg Chem 49:8131–8147
85. Widegren JA, Finke RG (2003) A review of the problem of distinguishing true homogeneous
catalysis from soluble or other metal-particle heterogeneous catalysis under reducing conditions. J Mol Cat A Chem 198:317–341
86. Hamdemir IK, Özkar S, Yih K-H, Mondloch JE, Finke RG (2012) Hydrocarbon-soluble,
isolable Ziegler-type Ir(0)n nanoparticle catalysts made from [(1,5-COD)Ir(μ-O2C8H15)]2
and 2–5 equivalents of AlEt3: their high catalytic activity, long lifetime, and AlEt3-dependent,
exceptional, 200
C thermal stability. ACS Catal 2:632–641
87. Hamdemir IK, Özkar S, Finke RG (2013) Exceptionally thermally stable, hydrocarbon soluble
Ziegler-type Ir(0)n nanoparticle catalysts made from [Ir(1,5-COD)(m-O2C8H15)]2 plus
AlEt3: tests of key hypotheses for their unusual stabilization. J Mol Cat A-Chem 378:333–343
88. Ott LS, Finke RG (2008) Supersensitivity of transition-metal nanoparticle formation to initial
precursor concentration and reaction temperature*: understanding its origins. J Nanosci
Nanotechnol 8:1551–1556
89. Laxson WW, Finke RG (2014) Nucleation is second order: an apparent kinetically effective
nucleus of two for Ir(0)n nanoparticle formation from [(1,5-COD)IrIÁP2W15Nb3O62]8À plus
hydrogen. J Am Chem Soc 136:17601–17615
90. Özkar S, Finke RG (2017) Nanoparticle nucleation is Termolecular in metal and involves
hydrogen: evidence for a kinetically effective nucleus of three {Ir3H2xÁP2W15Nb3O62}6À in
Ir(0)n nanoparticle formation from [(1,5-COD)IrIÁP2W15Nb3O62]8À plus hydrogen. J Am
Chem Soc 139:5444–5457
91. Ji Y-G, Wei K, Liu T, Wu L, Zhang W-H (2017) “Naked” iridium(IV) oxide nanoparticles as
expedient and robust catalysts for hydrogenation of nitrogen heterocycles: remarkable vicinal
substitution effect and recyclability. Adv Synth Catal 359:933–940
92. Albani D, Li Q, Vilé G, Mitchell S, Almora-Barrios N, Witte PT, López N, Pérez-Ramírez J
(2017) Interfacial acidity in ligand-modified ruthenium nanoparticles boosts the hydrogenation
of levulinic acid to gamma-valerolactone. Green Chem 19:2361–2370
93. Machado BF, Gomes HT, Serp P, Kalck P, Faria JL (2010) Liquid-phase hydrogenation of
unsaturated aldehydes: enhancing selectivity of multiwalled carbon nanotube-supported catalysts by thermal activation. ChemCatChem 2:190–197
94. Rueping M, Koenigs RM, Borrmann R, Zoller J, Weirich TE, Mayer J (2011) Size-selective,
stabilizer-free, hydrogenolytic synthesis of iridium nanoparticles supported on carbon
nanotubes. Chem Mater 23:2008–2010
95. Du X, Liu Y, Wang J, Cao Y, Fan K (2013) Catalytic conversion of biomass-derived levulinic
acid into γ-valerolactone using iridium nanoparticles supported on carbon nanotubes. Cuihua
Xuebao 34:993–1001
Iridium Nanoparticles for Hydrogenation Reactions
451
nitriles to secondary imines over Rh-PVP catalyst under mild conditions. Chem Lett
47:938–940
80. Gao L, Kojima K, Nagashima H (2015) Transition metal nanoparticles stabilized by ammonium salts of hyperbranched polystyrene: effect of metals on catalysis of the biphasic hydrogenation of alkenes and arenes. Tetrahedron 71:6414–6423
81. Ghosh S, Jagirdar BR (2017) Synthesis of mesoporous iridium nanosponge: a highly active,
thermally stable and efficient olefin hydrogenation catalyst. Dalton Trans 46:11431–11439
82. Özkar S, Finke RG (2005) 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 127:4800–4808
83. Bayram E, Zahmakıran M, Özkar S, Finke RG (2010) 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 26:12455–12464
84. Alley WM, Hamdemir IK, Wang Q, Frenkel AI, Li L, Yang JC, Menard LD, Nuzzo RG,
Ozkar S, Johnson KA, Finke RG (2010) Iridium Ziegler-type hydrogenation catalysts made
from [(1,5-COD)Ir(μ-O2C8H15)]2 and AlEt3: spectroscopic and kinetic evidence for the Irn
species present and for nanoparticles as the fastest catalyst. Inorg Chem 49:8131–8147
85. Widegren JA, Finke RG (2003) A review of the problem of distinguishing true homogeneous
catalysis from soluble or other metal-particle heterogeneous catalysis under reducing conditions. J Mol Cat A Chem 198:317–341
86. Hamdemir IK, Özkar S, Yih K-H, Mondloch JE, Finke RG (2012) Hydrocarbon-soluble,
isolable Ziegler-type Ir(0)n nanoparticle catalysts made from [(1,5-COD)Ir(μ-O2C8H15)]2
and 2–5 equivalents of AlEt3: their high catalytic activity, long lifetime, and AlEt3-dependent,
exceptional, 200
C thermal stability. ACS Catal 2:632–641
87. Hamdemir IK, Özkar S, Finke RG (2013) Exceptionally thermally stable, hydrocarbon soluble
Ziegler-type Ir(0)n nanoparticle catalysts made from [Ir(1,5-COD)(m-O2C8H15)]2 plus
AlEt3: tests of key hypotheses for their unusual stabilization. J Mol Cat A-Chem 378:333–343
88. Ott LS, Finke RG (2008) Supersensitivity of transition-metal nanoparticle formation to initial
precursor concentration and reaction temperature*: understanding its origins. J Nanosci
Nanotechnol 8:1551–1556
89. Laxson WW, Finke RG (2014) Nucleation is second order: an apparent kinetically effective
nucleus of two for Ir(0)n nanoparticle formation from [(1,5-COD)IrIÁP2W15Nb3O62]8À plus
hydrogen. J Am Chem Soc 136:17601–17615
90. Özkar S, Finke RG (2017) Nanoparticle nucleation is Termolecular in metal and involves
hydrogen: evidence for a kinetically effective nucleus of three {Ir3H2xÁP2W15Nb3O62}6À in
Ir(0)n nanoparticle formation from [(1,5-COD)IrIÁP2W15Nb3O62]8À plus hydrogen. J Am
Chem Soc 139:5444–5457
91. Ji Y-G, Wei K, Liu T, Wu L, Zhang W-H (2017) “Naked” iridium(IV) oxide nanoparticles as
expedient and robust catalysts for hydrogenation of nitrogen heterocycles: remarkable vicinal
substitution effect and recyclability. Adv Synth Catal 359:933–940
92. Albani D, Li Q, Vilé G, Mitchell S, Almora-Barrios N, Witte PT, López N, Pérez-Ramírez J
(2017) Interfacial acidity in ligand-modified ruthenium nanoparticles boosts the hydrogenation
of levulinic acid to gamma-valerolactone. Green Chem 19:2361–2370
93. Machado BF, Gomes HT, Serp P, Kalck P, Faria JL (2010) Liquid-phase hydrogenation of
unsaturated aldehydes: enhancing selectivity of multiwalled carbon nanotube-supported catalysts by thermal activation. ChemCatChem 2:190–197
94. Rueping M, Koenigs RM, Borrmann R, Zoller J, Weirich TE, Mayer J (2011) Size-selective,
stabilizer-free, hydrogenolytic synthesis of iridium nanoparticles supported on carbon
nanotubes. Chem Mater 23:2008–2010
95. Du X, Liu Y, Wang J, Cao Y, Fan K (2013) Catalytic conversion of biomass-derived levulinic
acid into γ-valerolactone using iridium nanoparticles supported on carbon nanotubes. Cuihua
Xuebao 34:993–1001
Iridium Nanoparticles for Hydrogenation Reactions
451