| 1. |
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| 2. |
- Marcos, Rocio, et al.
(författare)
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Bicarbonate Hydrogenation Catalyzed by Iron : How the Choice of Solvent Can Reverse the Reaction
- 2016
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Ingår i: ACS Catalysis. - : American Chemical Society (ACS). - 2155-5435. ; 6:5, s. 2923-2929
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Tidskriftsartikel (refereegranskat)abstract
- Here we report a mechanism study of the hydrogenation of bicarbonate by tetradentate phosphines iron-complexes. It is an extension of our recent study on the reverse reaction by the same type of complexes [Chem.-Eur. J. 2013, 19, 11869], with special emphasis herein on the effects of the choice of solvent. By using density functional theory we have located the most plausible mechanism and have found remarkable effects of the solvent on the reversibility of this reaction. We predict that the solvent used in experiment, MeOH, for the hydrogenation of bicarbonate to formate could be replaced to enhance the activity of the system. There is a direct correlation of the solubility of the base to favor or disfavor the hydrogenation of bicarbonate to formate.
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| 3. |
- Agrawal, Santosh, et al.
(författare)
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Readily Available Ruthenium Complex for Efficient Dynamic Kinetic Resolution of Aromatic alpha-Hydroxy Ketones
- 2014
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Ingår i: Organic Letters. - : American Chemical Society (ACS). - 1523-7060 .- 1523-7052. ; 16:8, s. 2256-2259
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Tidskriftsartikel (refereegranskat)abstract
- A ruthenium complex formed from commercially available [Ru(p-cymene)Cl-2](2) and 1,4-bis(diphenylphosphino)butane catalyzes the racemization of aromatic alpha-hydroxy ketones very efficiently at room temperature. The racemization is fully compatible with a kinetic resolution catalyzed by a lipase from Pseudomonas stutzeri. This is the first example of dynamic kinetic resolution of alpha-hydroxy ketones at ambient temperature in which the metal and enzyme catalysts work in concert in one pot at room temperature to give quantitative yields of esters of alpha-hydroxy ketones with very high enantioselectivity.
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| 4. |
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| 5. |
- Ahlstrand, David A., et al.
(författare)
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Csp(3)-H Activation without Chelation Assistance in an Iridium Pincer Complex Forming Cyclometallated Products
- 2017
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Ingår i: Chemistry - A European Journal. - : WILEY-V C H VERLAG GMBH. - 0947-6539 .- 1521-3765. ; 23:8, s. 1748-1751
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Tidskriftsartikel (refereegranskat)abstract
- Cyclometallation of 8-methylquinoline and 2-(dimethylamino)-pyridine in an iridium-based pincer complex is described. The C-H activation of 2-(dimethylamino) pyridine is not chelation assisted, which has not been described before for Csp(3)-H bonds in cyclometallation reactions. The mechanism of the cyclometallation of 2-(dimethylamino) pyridine was studied by DFT calculations and kinetic measurements.
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| 6. |
- Bartoszewicz, Agnieszka, 1983-, et al.
(författare)
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A Highly Active Bifunctional Iridium Complex with an Alcohol/Alkoxide-Tethered N-Heterocyclic Carbene for Alkylation of Amines with Alcohols
- 2012
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Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 18:45, s. 14510-14519
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Forskningsöversikt (refereegranskat)abstract
- A series of new iridium(III) complexes containing bidentate N-heterocyclic carbenes (NHC) functionalized with an alcohol or ether group (NHC?OR, R=H, Me) were prepared. The complexes catalyzed the alkylation of anilines with alcohols as latent electrophiles. In particular, biscationic IrIII complexes of the type [Cp*(NHC-OH)Ir(MeCN)]2+2[BF4-] afforded higher-order amine products with very high efficiency; up to >99?% yield using a 1:1 ratio of reactants and 12.5 mol?% of Ir, in short reaction times (216 h) and under base-free conditions. Quantitative yields were also obtained at 50?degrees C, although longer reaction times (4860 h) were needed. A large variety of aromatic amines have been alkylated with primary and secondary alcohols. The reactivity of structurally related iridium(III) complexes was also compared to obtain insights into the mechanism and into the structure of possible catalytic intermediates. The IrIII complexes were stable towards oxygen and moisture, and were characterized by NMR, HRMS, single-crystal X-ray diffraction, and elemental analyses.
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| 7. |
- Bartoszewicz, Agnieszka, et al.
(författare)
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Mechanistic Studies on the Alkylation of Amines with Alcohols Catalyzed by a Bifunctional Iridium Complex
- 2015
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Ingår i: Acs Catalysis. - : American Chemical Society (ACS). - 2155-5435. ; 5:6, s. 3704-3716
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Tidskriftsartikel (refereegranskat)abstract
- The mechanism of the N-alkylation of amines with alcohols catalyzed by an iridium complex containing an N-heterocyclic carbene (NHC) ligand with a tethered alcohol/alkoxide functionality was investigated by a combination of experimental and computational methods. The catalyst resting state is an iridium hydride species containing the amine substrate as a ligand, and decoordination of the amine, followed by coordination of the imine intermediate to the iridium center, constitute the rate-determining step (rds) of the catalytic process. The alcohol/alkoxide that is tethered to the NHC participates in every step of the catalytic cycle by accepting or releasing protons and forming hydrogen bonds with the reacting species. Thus, the iridium complex with the alcohol/alkoxide tethered to the N-heterocyclic carbene ligand acts as a bifunctional catalyst.
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| 8. |
- Bernal, Ximena E., et al.
(författare)
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Empowering Latina scientists
- 2019
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 363:6429, s. 825-826
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 9. |
- Carson, Fabian, et al.
(författare)
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Effect of the functionalisation route on a Zr-MOF with an Ir-NHC complex for catalysis
- 2015
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 51:54, s. 10864-10867
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Tidskriftsartikel (refereegranskat)abstract
- A new iridium N-heterocyclic carbene (NHC) metallolinker has been synthesised and introduced into a metal-organic framework (MOF), for the first time, via two different routes: direct synthesis and postsynthetic exchange (PSE). The two materials were compared in terms of the Ir loading and distribution using X-ray energy dispersive spectroscopy (EDS), the local Ir structure using X-ray absorption spectroscopy (XAS) and the catalytic activity. The materials showed good activity and recyclability as catalysts for the isomerisation of an allylic alcohol.
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| 10. |
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