Highly Active Iridium Catalysts for Alkane Dehydrogenation. Synthesis and Properties of Iridium Bis(phosphine) Pincer Complexes Based on Ferrocene and Ruthenocene

2006 ◽  
Vol 25 (22) ◽  
pp. 5466-5476 ◽  
Author(s):  
Sergey A. Kuklin ◽  
Alexey M. Sheloumov ◽  
Fedor M. Dolgushin ◽  
Mariam G. Ezernitskaya ◽  
Alexander S. Peregudov ◽  
...  
Keyword(s):  
Pincer Complexes ◽  
Iridium Catalysts ◽  
Alkane Dehydrogenation ◽  
Highly Active

Rational Design and Synthesis of Highly Active Pincer-Iridium Catalysts for Alkane Dehydrogenation

2009 ◽  
Vol 28 (18) ◽  
pp. 5432-5444 ◽  
Author(s):  
Sabuj Kundu ◽  
Yuriy Choliy ◽  
Gao Zhuo ◽  
Ritu Ahuja ◽  
Thomas J. Emge ◽  
...  
Keyword(s):  
Rational Design ◽  
Iridium Catalysts ◽  
Alkane Dehydrogenation ◽  
Design And Synthesis ◽  
Highly Active

scholarly journals H/D Exchange Under Mild Conditions in Arenes and Unactivated Alkanes with C6D6 and D2O Using Rigid, Electron-rich Iridium PCP Pincer Complexes

2020 ◽  
Author(s):  
Joel D. Smith ◽  
George Durrant ◽  
Daniel Ess ◽  
Warren Piers
Keyword(s):  
Hydrogen Isotope ◽  
Isotope Exchange ◽  
Room Temperature ◽  
Pincer Complexes ◽  
Synthesis And Characterization ◽  
Hydrogen Isotope Exchange ◽  
Mild Conditions ◽  
Highly Active ◽  
Pcp Pincer

<div>The synthesis and characterization of an iridium polyhydride complex (Ir-H4)</div><div>supported by an electron-rich PCP framework is described. This complex readily loses molecular</div><div>hydrogen allowing for rapid room temperature hydrogen isotope exchange (HIE) at the hydridic</div><div>positions and the α-C-H site of the ligand with deuterated solvents such as benzene-d6, toluene-d8</div><div>and THF-d8. The removal of 1-2 equivalents of molecular H2 forms unsaturated iridium carbene</div><div>trihydride (Ir-H3) or monohydride (Ir-H) compounds that are able to create further unsaturation</div><div>by reversibly transferring a hydride to the ligand carbene carbon. These species are highly active</div><div>hydrogen isotope exchange (HIE) catalysts using C6D6 or D2O as deuterium sources for the</div><div>deuteration of a variety of substrates. By modifying conditions to influence the Ir-Hn speciation,</div><div>deuteration levels can range from near exhaustive to selective only for sterically accessible sites.</div><div>Preparative level deuterations of select substrates were performed allowing for procurement of</div><div>>95% deuterated compounds in excellent isolated yields; the catalyst can be regenerated by</div><div>treatment of residues with H2 and is still active for further reactions.</div>

Acceptorless Alkane Dehydrogenation Catalyzed by Iridium CCC-Pincer Complexes

2014 ◽  
Vol 33 (2) ◽  
pp. 457-464 ◽  
Author(s):  
Anthony R. Chianese ◽  
Myles J. Drance ◽  
Kelsey H. Jensen ◽  
Samuel P. McCollom ◽  
Nevin Yusufova ◽  
...  
Keyword(s):  
Pincer Complexes ◽  
Alkane Dehydrogenation

Continuous-Flow Alkane Dehydrogenation by Supported Pincer-Ligated Iridium Catalysts at Elevated Temperatures

ACS Catalysis ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 7828-7841 ◽  
Author(s):  
Boris Sheludko ◽  
Molly T. Cunningham ◽  
Alan S. Goldman ◽  
Fuat E. Celik
Keyword(s):  
Continuous Flow ◽  
Elevated Temperatures ◽  
Iridium Catalysts ◽  
Alkane Dehydrogenation

Kinetics and selectivity of methane oxidation on an IrO2(110) film

2021 ◽  
Author(s):  
Christopher J Lee ◽  
Saumye Vashishtha ◽  
Mohammed Shariff ◽  
Fangrong Zou ◽  
Junjie Shi ◽  
...  
Keyword(s):  
Low Temperature ◽  
Methane Oxidation ◽  
High Stability ◽  
Product Formation ◽  
Product Selectivity ◽  
Alkane Dehydrogenation ◽  
Highly Active ◽  
Temperature Programmed ◽  
Temperature Programmed Reaction Spectroscopy ◽  
Temperature Programmed Reaction

Abstract Undercoordinated, bridging O-atoms (Obr) are highly active as H-acceptors in alkane dehydrogenation on IrO2(110) surfaces but transform to HObr groups that are inactive toward hydrocarbons. The low C-H activity and high stability of the HObr groups cause the kinetics and product selectivity during CH4 oxidation on IrO2(110) to depend sensitively on the availability of Obr atoms prior to the onset of product desorption. From temperature programmed reaction spectroscopy (TPRS) and kinetic simulations, we identified two Obr-coverage regimes that distinguish the kinetics and product formation during CH4 oxidation on IrO2(110). Under excess Obr conditions, when the initial Obr coverage is greater than that needed to oxidize all the CH4 to CO2 and HObr groups, complete CH4 oxidation is dominant and produces CO2 in a single TPRS peak between 450 and 500 K. However, under Obr-limited conditions, nearly all the initial Obr atoms are deactivated by conversion to HObr or abstracted after only a fraction of the initially adsorbed CH4 oxidizes to CO2 and CO below 500 K. Thereafter, some of the excess CHx groups abstract H and desorb as CH4 above ~500 K while the remainder oxidize to CO2 and CO at a rate that is controlled by the rate at which Obr atoms are regenerated from HObr during the formation of CH4 and H2O products. We also show that chemisorbed O-atoms (“on-top O”) on IrO2(110) enhance CO2 production below 500 K by efficiently abstracting H from Obr atoms and thereby increasing the coverage of Obr atoms available to completely oxidize CHx groups at low temperature. Our results provide new insights for understanding factors which govern the kinetics and selectivity during CH4 oxidation on IrO2(110) surfaces.

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.

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.

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