Application of transition metals in hydroformylation annual survey covering the year 2001

Ungváry, Ferenc

doi:10.1016/s0010-8545(02)00051-6

Cited by 32 publications

(6 citation statements)

References 160 publications

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“…It is broadly used in organic chemistry for hydrogenation, hydroformulation, hydroboration, hydrosilylation, cycloadditions [8,9] and oxidation reactions for catalytic converters in automobiles. It remains a metal of high interest due to its unique properties for the scientific community [10,11] during the past decades. Binary intermetallic alloys that contain a transition metal display interesting electronic, structural, optical and thermal properties.…”

Section: Introductionmentioning

confidence: 99%

Ab initio study of structural, electronic, and thermal properties of Ir_{1-x}Rh_{x} alloys

Ahmed¹,

Zafar²,

Shakil³

et al. 2015

Condens. Matter Phys.

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The structural, electronic, mechanical and thermal properties of Ir 1−x Rh x alloys were studied systematically using ab initio density functional theory at different concentrations (x = 0.00, 0.25, 0.50, 0.75, 1.00). A Special Quasirandom Structure method was used to make alloys having FCC structure with four atoms per unit cell. The ground state properties such as lattice constant and bulk modulus were calculated to find the equilibrium atomic position for stable alloys. The calculated ground state properties are in good agreement with the experimental and previously presented other theoretical data. The electronic band structure and density of states were calculated to study the electronic properties for these alloys at different concentrations. The electronic properties substantiate the metallic behavior of alloys. The first principle density functional perturbation theory as implemented in quasiharmonic approximation was used for the calculation of thermal properties. We have calculated the thermal properties such as Debye temperatures, vibration energy, entropy, constant-volume specific heat and internal energy. The ab initio linear-response method was used to calculate phonon densities of states.

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Section: Introductionmentioning

confidence: 99%

Ab initio study of structural, electronic, and thermal properties of Ir_{1-x}Rh_{x} alloys

Ahmed¹,

Zafar²,

Shakil³

et al. 2015

Condens. Matter Phys.

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“…Since the discovery of rhodium in 1803 there was little interest in the applications of the element until its critical role in catalysis was discovered. − Indeed, rhodium exhibits extraordinary and often unique catalytic properties compared to most other metals, particularly in hydrogenation, carbonylation, hydroformylation, and oxidation reactions. About 80% of the worldwide annual production of rhodium (corresponding to 22 tons in 2009), is used in the fabrication of three-way catalytic converters in automobiles, catalyzing both reduction and oxidation reactions, and hence, rhodium is and will continue to be one of the rarest and the most costly metals.…”

Section: Introductionmentioning

confidence: 99%

Advances in the Rational Design of Rhodium Nanoparticle Catalysts: Control via Manipulation of the Nanoparticle Core and Stabilizer

2012

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This review describes some of the fascinating advances in the field of rhodium nanoparticle (NP) catalysis that have emerged in recent years. The examples described are categorized according to the research approach applied, involving either direct engineering of the NP core (size/shape control) or manipulating the NP via a stabilizer and/or solvent. Consequently, both surface-immobilized heterogeneous Rh NP and solvent dispersed Rh NP catalysts are included. The interplay between relevant parameters and the catalytic properties of Rh NPs are discussed, with a focus on design, function, and mechanisms. Rh NP-based multifunctional systems are also described. The approaches used to probe Rh NP catalysts at a molecular level and possible future research trends are highlighted.

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“…Hydroformylation is one of the largest-scale homogeneous catalytic industrial processes involving dihydrogen as a reactant. − As proposed by Wilkinson and co-workers for RhH(CO)(PPh 3 ) 3 in the late 1960s, the accepted mechanism for hydroformylation using metal phosphine homogeneous catalysts involves an acyl dihydride species as the final intermediate before aldehyde formation. − While relatively few hydroformylation studies employ iridium complexes as active catalysts, − such systems can be of value as stable models for reaction intermediates, and one example has permitted characterization of the putative acyl dihydride species in the form of IrH 2 (COEt)(CO)(dppe) (dppe = 1,2-bis(diphenylphosphino)ethane) . One measure of success in hydroformylation catalysis is the ratio of linear-to-branched (l/b) aldehyde products, and both Casey and van Leeuwen have shown that the use of large natural bite angle bidentate ligands in the catalysts yield higher l/b product ratios, − as well as more active catalysts, ,, than those containing chelating ligands with smaller natural bite angles.…”

Section: Introductionmentioning

confidence: 99%

A Model Iridium Hydroformylation System with the Large Bite Angle Ligand Xantphos: Reactivity with Parahydrogen and Implications for Hydroformylation Catalysis

et al. 2006

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Iridium complexes containing the large bite angle bisphosphine ligand xantphos have been synthesized and their reactivity studied. Several of these complexes are the first reported Ir(xantphos) systems to be characterized by X-ray diffraction. Variable-temperature NMR spectroscopic studies of IrI(CO)2(xantphos) (1-I) and Ir(COEt)(CO)2(xantphos) (8) show two separate dynamic processes in which the phosphorus donors and the backbone methyl groups of the xantphos ligand are exchanged. The addition of parahydrogen (p-H2) to 1-I leads to the formation of two dihydride isomers including one in which both hydride ligands are trans to the phosphorus donors, suggestive of an Ir(I) xantphos intermediate with the ligand chelated in a trans-spanning fashion (2b). The bromide and chloride Ir(I) analogues (1-Br and 1-Cl) also form this isomer upon reaction with parahydrogen, with 1-Cl yielding only this dihydride species. The trihydride complex IrH3(CO)(xantphos) (7) has been prepared, and its exchange with free hydrogen at elevated temperature is confirmed by reaction with p-H2. The hydride complexes IrH(CO)2(xantphos) (6) and IrH3(CO)(xantphos) (7), as well as the propionyl complex 8, are modest catalysts for the hydroformylation of 1-hexene and styrene under mild conditions. The addition of p-H2 to 8 permits direct observation of the propionyl dihydride species IrH2(COEt)(CO)(xantphos) (9) under both thermal and photolytic conditions, as well as unusual but weak polarization of the aldehydic proton of the propanal product that forms upon reductive elimination from 9.

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Application of transition metals in hydroformylation annual survey covering the year 2001

Cited by 32 publications

References 160 publications

Ab initio study of structural, electronic, and thermal properties of Ir_{1-x}Rh_{x} alloys

Ab initio study of structural, electronic, and thermal properties of Ir_{1-x}Rh_{x} alloys

Advances in the Rational Design of Rhodium Nanoparticle Catalysts: Control via Manipulation of the Nanoparticle Core and Stabilizer

A Model Iridium Hydroformylation System with the Large Bite Angle Ligand Xantphos: Reactivity with Parahydrogen and Implications for Hydroformylation Catalysis

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