Tunable iridium catalyst designs with bidentate N-heterocyclic carbene ligands for SABRE hyperpolarization of sterically hindered substrates

2020 ◽  
Vol 56 (98) ◽  
pp. 15466-15469
Author(s):  
Pierce Pham ◽  
Christian Hilty
Keyword(s):  
Exchange Rate ◽  
Sensitivity Enhancement ◽  
Carbene Ligands ◽  
Iridium Catalysts ◽  
Iridium Catalyst ◽  
Sterically Hindered ◽  
Nmr Sensitivity

A series of iridium catalysts provides NMR sensitivity enhancement using para-hydrogen. The substrate exchange rate can be tuned for optimal polarization by the choice of an aryl and a nucleophilic moiety in the catalyst.

Up to 100% Improvement in Dynamic Nuclear Polarization Solid-State NMR Sensitivity Enhancement of Polymers by Removing Oxygen

2015 ◽  
Vol 36 (15) ◽  
pp. 1416-1421 ◽  
Author(s):  
Dao Le ◽  
Fabio Ziarelli ◽  
Trang N. T. Phan ◽  
Giulia Mollica ◽  
Pierre Thureau ◽  
...  
Keyword(s):  
Solid State ◽  
Dynamic Nuclear Polarization ◽  
Solid State Nmr ◽  
Nuclear Polarization ◽  
Sensitivity Enhancement ◽  
Nmr Sensitivity

Enhancing benchtop NMR spectroscopy by means of sample shifting

The Analyst ◽  
2020 ◽  
Vol 145 (22) ◽  
pp. 7406-7411
Author(s):  
Javier A. Romero ◽  
Krzysztof Kazimierczuk ◽  
Dariusz Gołowicz
Keyword(s):  
Nmr Spectroscopy ◽  
Spin Polarization ◽  
Nuclear Spin ◽  
Sensitivity Enhancement ◽  
Nuclear Spin Polarization ◽  
Nmr Sensitivity

Benchtop NMR sensitivity enhancement by cyclic, mechanical shifting of a sample to preserve high nuclear spin polarization.

Low field CIDNP of amino acids and proteins: characterization of transient radicals and NMR sensitivity enhancement

2002 ◽  
Vol 100 (8) ◽  
pp. 1261-1269 ◽  
Author(s):  
CHARLES E. LYON ◽  
JAKOB J. LOPEZ ◽  
BYUNG-MUN CHO ◽  
P. J. HORE
Keyword(s):  
Amino Acids ◽  
Sensitivity Enhancement ◽  
Low Field ◽  
Nmr Sensitivity

scholarly journals NNB-Type Tridentate Boryl Ligands Enabling a Highly Active Iridium Catalyst for C–H Borylation

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1434 ◽  
Author(s):  
Siyi Ding ◽  
Linghua Wang ◽  
Zongcheng Miao ◽  
Pengfei Li
Keyword(s):  
Active Catalyst ◽  
High Electron ◽  
Tridentate Ligands ◽  
Highly Active ◽  
Iridium Catalyst ◽  
Organometallic Catalysis ◽  
Sterically Hindered ◽  
Very High

Boryl ligands play a very important role in catalysis because of their very high electron-donating property. In this paper, NNB-type boryl anions were designed as tridentate ligands to promote aryl C–H borylation. In combination with [IrCl(COD)]2, they generate a highly active catalyst for a broad range of (hetero)arene substrates, including highly electron-rich and/or sterically hindered ones. This work provides a new NNB-type tridentate boryl ligand to support homogeneous organometallic catalysis.

scholarly journals Neutral iridium catalysts with chiral phosphine-carboxy ligands for asymmetric hydrogenation of unsaturated carboxylic acids

2017 ◽  
Vol 8 (3) ◽  
pp. 1977-1980 ◽  
Author(s):  
Shuang Yang ◽  
Wen Che ◽  
Hui-Ling Wu ◽  
Shou-Fei Zhu ◽  
Qi-Lin Zhou
Keyword(s):  
Carboxylic Acids ◽  
Asymmetric Hydrogenation ◽  
Iridium Catalysts ◽  
Iridium Catalyst ◽  
Unsaturated Carboxylic Acids

The new neutral iridium catalyst with chiral spiro phosphine-carboxy ligand exhibited exceptionally high enantioselectivity in the hydrogenation of 3-alkyl-3-methylenepropionic acids.

A High Resolution Study of Alumina Supported Iridium Catalysts

1980 ◽  
Vol 38 ◽  
pp. 202-203
Author(s):  
C. Stoeckert ◽  
B. Etherton ◽  
M. Beer ◽  
J. Gryder
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Metal Particles ◽  
Optical Transfer Function ◽  
Particle Sizes ◽  
Iridium Catalysts ◽  
Transmission Electron ◽  
Optical Transfer ◽  
Conventional Transmission Electron Microscope ◽  
Resolution Study

The interpretation of the activity of catalysts requires information about the sizes of the metal particles, since this has implications for the number of surface atoms available for reaction. To determine the particle dimensions we used a high resolution STEM1. Such an instrument with its simple optical transfer function is far more suitable than a conventional transmission electron microscope for the establishment of particle sizes. We report here our study on the size and number distribution of Ir particles supported on Al2O3 and also examine simple geometric models for the shape of Ir particles.

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