The Journal of Physical Chemistry C
American Chemical Society (ACS)
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Aqueous NMR Signal Enhancement by Reversible Exchange in a Single Step Using Water-Soluble Catalysts
Volume: 120, Issue: 22
DOI 10.1021/acs.jpcc.6b04484

Highlights

Notes

Abstract

jp-2016-04484p_0006

Two synthetic strategies are investigated for the preparation of water-soluble iridium-based catalysts for NMR signal amplification by reversible exchange (SABRE). In one approach, PEGylation of a variant N-heterocyclic carbene provided a novel catalyst with excellent water solubility. However, while SABRE-active in ethanol solutions, the catalyst lost activity in >50% water. In a second approach, synthesis of a novel di-iridium complex precursor where the cyclooctadiene (COD) rings have been replaced by CODDA (1,2-dihydroxy-3,7-cyclooctadiene) leads to the creation of a catalyst [IrCl(CODDA)IMes] that can be dissolved and activated in water—enabling aqueous SABRE in a single step, without need for either an organic cosolvent or solvent removal followed by aqueous reconstitution. The potential utility of the CODDA catalyst for aqueous SABRE is demonstrated with the ∼(−)32-fold enhancement of 1H signals of pyridine in water with only 1 atm of parahydrogen.

https://www.researchpad.co/tools/openurl?pubtype=article&doi=10.1021/acs.jpcc.6b04484&title=Aqueous NMR Signal Enhancement by Reversible Exchange in a Single Step Using Water-Soluble Catalysts&author=&keyword=&subject=General Energy,Physical and Theoretical Chemistry,Electronic, Optical and Magnetic Materials,Surfaces, Coatings and Films,