scholarly journals Design, scope and mechanism of highly active and selective chiral NHC–iridium catalysts for the intramolecular hydroamination of a variety of unactivated aminoalkenes

2021 ◽  
Author(s):  
Daven Foster ◽  
Pengchao Gao ◽  
Ziyun Zhang ◽  
Gellért Sipos ◽  
Alexandre N. Sobolev ◽  
...  
Keyword(s):  
Iridium Complexes ◽  
Iridium Catalysts ◽  
Highly Active

Chiral, cationic NHC–iridium complexes are introduced as catalysts for the intramolecular hydroamination reaction of unactivated aminoalkenes.

Highly active, separable and recyclable bipyridine iridium catalysts for C–H borylation reactions

2018 ◽  
Vol 8 (1) ◽  
pp. 124-127 ◽  
Author(s):  
Hind Mamlouk ◽  
Jakkrit Suriboot ◽  
Praveen Kumar Manyam ◽  
Ahmed AlYazidi ◽  
David E. Bergbreiter ◽  
...  
Keyword(s):  
Iridium Complexes ◽  
Iridium Catalysts ◽  
Mild Conditions ◽  
Highly Active

Iridium complexes generated from Ir(i) precursors and PIB oligomer functionalized bpy ligands efficiently catalyzed the reaction of arenes with bis(pinacolato)diboron under mild conditions to produce a variety of arylboronate compounds.

scholarly journals Post Synthetic Defect Engineering of UiO-66 Metal-Organic Framework with Iridium(III)-HEDTA Complex and Application in Catalysis for Water Oxydation

2019 ◽  
Author(s):  
Ferdinando Costantino ◽  
Alceo Macchioni ◽  
Giordano Gatto ◽  
Roberto Bondi ◽  
Fabio Marmottini
Keyword(s):  
Water Oxidation ◽  
Metal Organic Framework ◽  
Partial Substitution ◽  
Iridium Complexes ◽  
Defect Engineering ◽  
Cerium Ammonium Nitrate ◽  
Highly Active ◽  
Metal Organic ◽  
Heterogenous Catalyst ◽  
Sacrificial Agent

Clean production of renewable fuels is a great challenge of our scientific community. Iridium complexes have demonstrated a superior catalytic activity in the water oxidation (WO) reaction, which is a crucial step in water splitting process. Herein we have used a defective zirconium MOF with UiO-66 structure as support of a highly active Ir complex based on EDTA with formula [Ir(HEDTA)Cl]Na. The defects are induced by the partial substitution of tereftalic acid with smaller formiate groups. Anchoring of the complex occurs through a post-synthetic exchange of formiate anions, coordinated at the zirconium clusters of the MOF, with the free carboxylate group of the [Ir(HEDTA)Cl]-complex. The modified material was tested as heterogenous catalyst for the WO reaction by using Cerium Ammonium Nitrate as sacrificial agent. Although TOF and TON values are comparable to those of other iridium heterogenized catalysts, the MOF exhibits iridium leaching not limited at the first catalytic run, as usually observed, suggesting a lack of stability of the hybrid system under strong oxidative conditions.

scholarly journals Post Synthetic Defect Engineering of UiO-66 Metal–Organic Framework with An Iridium(III)-HEDTA Complex and Application in Water Oxidation Catalysis

Inorganics ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 123 ◽  
Author(s):  
Giordano Gatto ◽  
Alceo Macchioni ◽  
Roberto Bondi ◽  
Fabio Marmottini ◽  
Ferdinando Costantino
Keyword(s):  
Water Oxidation ◽  
Metal Organic Framework ◽  
Oxidation Catalysis ◽  
Partial Substitution ◽  
Iridium Complexes ◽  
Cerium Ammonium Nitrate ◽  
Highly Active ◽  
Water Oxidation Catalysis ◽  
Metal Organic ◽  
Organic Framework

Clean production of renewable fuels is a great challenge of our scientific community. Iridium complexes have demonstrated a superior catalytic activity in the water oxidation (WO) reaction, which is a crucial step in water splitting process. Herein, we have used a defective zirconium metal–organic framework (MOF) with UiO-66 structure as support of a highly active Ir complex based on EDTA with the formula [Ir(HEDTA)Cl]Na. The defects are induced by the partial substitution of terephthalic acid with smaller formate groups. Anchoring of the complex occurs through a post-synthetic exchange of formate anions, coordinated at the zirconium clusters of the MOF, with the free carboxylate group of the [Ir(HEDTA)Cl]− complex. The modified material was tested as a heterogeneous catalyst for the WO reaction by using cerium ammonium nitrate (CAN) as the sacrificial agent. Although turnover frequency (TOF) and turnover number (TON) values are comparable to those of other iridium heterogenized catalysts, the MOF exhibits iridium leaching not limited at the first catalytic run, as usually observed, suggesting a lack of stability of the hybrid system under strong oxidative conditions.

Temperature-Controlled Bidirectional Enantioselectivity in Asymmetric Hydrogenation Reactions Utilizing Stereodynamic Iridium Complexes

Synthesis ◽  
2017 ◽  
Vol 49 (15) ◽  
pp. 3485-3494 ◽  
Author(s):  
Max Siebert ◽  
Golo Storch ◽  
Frank Rominger ◽  
Oliver Trapp
Keyword(s):  
Elevated Temperatures ◽  
Asymmetric Hydrogenation ◽  
Iridium Complexes ◽  
Chirality Transfer ◽  
Iridium Catalysts ◽  
Thermal Equilibration ◽  
Hydrogenation Reactions ◽  
Temperature Controlled ◽  
First Time ◽  
Solid State Structures

Stereochemically flexible 2,2(-bis(diphenylphosphino)biphenyl (BIPHEP) ligands were modified with chiral α-substituted carboxylic acid auxiliaries in the 3- and 3′-position. The resulting central-to-axial chirality transfer to the stereochemically flexible chiral axis of the BIPHEP­ core was investigated as well as complexation of these diastereomeric ligands to iridium(I). Solid-state structures of both ligand diastereomers and a diastereomerically pure iridium(I) BIPHEP complex were obtained. Thermal equilibration of the resulting iridium(I) complexes was studied to investigate the stereodynamic properties of the BIPHEP ligands. The iridium(I) complexes without and after pre-catalysis warming in solution — which induces a shift of the diastereomeric ratio — were applied for asymmetric hydrogenation of a prochiral α-substituted acrylic acid, resulting in temperature-controlled bidirectional enantioselectivity of iridium catalysts for the first time. In both cases, enantioenriched (R)-naproxen as well as (S)-naproxen — after re-equilibration of the catalyst at elevated temperatures — was obtained by using the same catalyst.

scholarly journals Formation of Enamines via Catalytic Dehydrogenation by Pincer-Iridium Complexes

2019 ◽  
Author(s):  
Xiawei Zhang ◽  
Santanu Malakar ◽  
Karsten Krogh-Jespersen ◽  
Faraj Hasanayn ◽  
Alan Goldman
Keyword(s):  
Isotope Effects ◽  
Oxidative Addition ◽  
Kinetic Isotope Effects ◽  
Catalytic Dehydrogenation ◽  
Iridium Complexes ◽  
Tertiary Amines ◽  
Iridium Catalysts ◽  
Kinetic Isotope ◽  
Dehydrogenation Mechanism

Efficient pincer-ligated iridium catalysts are reported for the dehydrogenation of simple tertiary amines to give enamines, and for the dehydrogenation of β-functionalized amines to give the corresponding 1,2-difunctionalized olefins. Experimentally determined kinetic isotope effects in conjunction with DFT-based analysis support a dehydrogenation mechanism involving initial pre-equilibrium oxidative addition of the amine α C-H bond followed by rate-determining elimination of the β-C-H bond.<br>

scholarly journals Cationic NHC‐Phosphine Iridium Complexes: Highly Active Catalysts for Base‐Free Hydrogenation of Ketones

2020 ◽  
Vol 26 (58) ◽  
pp. 13311-13316
Author(s):  
Xu Quan ◽  
Sutthichat Kerdphon ◽  
Bram B. C. Peters ◽  
Janjira Rujirawanich ◽  
Suppachai Krajangsri ◽  
...  
Keyword(s):  
Iridium Complexes ◽  
Highly Active

scholarly journals Highly active nano-sized iridium catalysts: synthesis and operando spectroscopy in a proton exchange membrane electrolyzer

2018 ◽  
Vol 9 (14) ◽  
pp. 3570-3579 ◽  
Author(s):  
P. Lettenmeier ◽  
J. Majchel ◽  
L. Wang ◽  
V. A. Saveleva ◽  
S. Zafeiratos ◽  
...  
Keyword(s):  
High Purity ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Operando Spectroscopy ◽  
Iridium Catalysts ◽  
Highly Active ◽  
Ultra High Purity ◽  
Exchange Membrane

Ultra-high purity nano-sized iridium enclosed in a monolayer of IrIII/IrIV oxides/hydroxides leads to an enhancement in OER activity.

ChemInform Abstract: Cyclometalated Iridium Complexes as Highly Active Catalysts for the Hydrogenation of Imines.

ChemInform ◽  
2014 ◽  
Vol 45 (24) ◽  
pp. no-no
Author(s):  
Weijun Tang ◽  
Chunho Lau ◽  
Xiaofeng Wu ◽  
Jianliang Xiao
Keyword(s):  
Iridium Complexes ◽  
Highly Active
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