Ir4 cluster-based selective catalytic hydrogenation of 1,5-cyclooctadiene

Moura, Flávia C.C.; Santos, Eduardo N. dos; Lago, Rochel M.; Vargas, Maria D.; Araújo, Maria Helena

doi:10.1016/j.molcata.2004.10.033

Cited by 23 publications

(8 citation statements)

References 69 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As expected, COD is released during the formation of 3 , and it proved to be hydrogenated on a slower timescale, first to form COE and then COA [where COE = cyclooctene and COA = cyclooctane] according to NMR analysis. The substitution of COD for pyridine in a related cyclometallated square planar palladium system has been reported49 as has the hydrogenation of COD in series of related systems 50–52…”

Section: Resultsmentioning

confidence: 96%

Catalytic Transfer of Magnetism Using a Neutral Iridium Phenoxide Complex

et al. 2015

View full text Add to dashboard Cite

A novel neutral iridium carbene complex Ir(κC,O-L)(COD) () [where COD = cyclooctadiene and L = 3-(2-methylene-4-nitrophenolate)-1-(2,4,6-trimethylphenyl) imidazolylidene] with a pendant alkoxide ligand has been prepared and characterized. It contains a strong Ir-O bond and X-ray analysis reveals a distorted square planar structure. NMR spectroscopy reveals dynamic solution state behavior commensurate with rapid seven-membered ring flipping. In CDCl solution, under hydrogen at low temperature, this complex dominates although it exists in equilibrium with a reactive iridium dihydride cyclooctadiene complex. reacts with pyridine and H to form neutral Ir(H)(κC,O-L)(py) which also exists in two conformers that differ according to the orientation of the seven-membered metallocycle and whilst its Ir-O bond remains intact, the complex undergoes both pyridine and H exchange. As a consequence, when placed under hydrogen, efficient polarization transfer catalysis (PTC) is observed via the Signal Amplification By Reversible Exchange (SABRE) approach. Due to the neutral character of this catalyst, good hyperpolarization activity is shown in a wide range of solvents for a number of substrates. These observations reflect a dramatic improvement in solvent tolerance of SABRE over that reported for the best PTC precursor IrCl(IMes)(COD). For THF, the associatedH NMR signal enhancement for the proton signal of pyridine shows an increase of 600-fold at 298 K. The level of signal enhancement can be increased further through warming or varying the magnetic field experienced by the sample at the point of catalytic magnetization transfer.

show abstract

Section: Resultsmentioning

confidence: 96%

Catalytic Transfer of Magnetism Using a Neutral Iridium Phenoxide Complex

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Thus, the catalytic sites on the metal surface at the beginning of the reaction are saturated by dienes. As hydrogen is added to the first C C double-bond, the resulting monoene (COE) is immediately displaced by a diene [52].…”

Section: Hydrogenation Reactionsmentioning

confidence: 99%

Ionic liquid layer on Pd/C catalyst: Membrane-like effect on the selectivity for multistep hydrogenation reactions

Nassor

Tristão

Santos

et al. 2012

Journal of Molecular Catalysis A: Chemical

Self Cite

View full text Add to dashboard Cite

“…In accordance with previous reports, the reaction of cyclooctene is slow compared to the formation of cyclooctene from 15. [25,26] The hydrogenation of 1 (model reaction) was also used for recycling experiments. The catalyst was reused after the reaction (three reaction cycles), employing two different methods of catalyst treatment: 1) after separation of the catalyst from the reaction mixture by filtration (recovery > 96 %), the spent catalyst was washed and air-dried before its reuse (Figure 3), or 2) the washed catalyst was oven-dried for 2 h at 300 8C (Figure 4).…”

mentioning

confidence: 99%

A Practical Approach for Ambient‐Pressure Hydrogenations Using Pd on Porous Glass

et al. 2009

View full text Add to dashboard Cite

A Pd on porous glass catalyst system was used in the liquid-phase hydrogenation of terpenoid substrates with dihydrogen at room temperature and atmospheric pressure. A multitude of substances were hydrogenated selectively with yields of 90-100 %. In all experiments, only C--C, C--N, and N--N double bonds were hydrogenated. Studies revealed that carbonyl and aromatic double bonds are inert towards catalytic reduction with dihydrogen under the conditions employed. In some cases, hydrogenation was accompanied by isomerization, so that treatment of beta-pinene, for example, afforded isomeric alpha-pinene, which was subsequently hydrogenated to pinane.

show abstract

Ir4 cluster-based selective catalytic hydrogenation of 1,5-cyclooctadiene

Cited by 23 publications

References 69 publications

Catalytic Transfer of Magnetism Using a Neutral Iridium Phenoxide Complex

Catalytic Transfer of Magnetism Using a Neutral Iridium Phenoxide Complex

Ionic liquid layer on Pd/C catalyst: Membrane-like effect on the selectivity for multistep hydrogenation reactions

A Practical Approach for Ambient‐Pressure Hydrogenations Using Pd on Porous Glass

Contact Info

Product

Resources

About