Nanoscale Catalysts for NMR Signal Enhancement by Reversible Exchange
نویسندگان
چکیده
منابع مشابه
Nanoscale Catalysts for NMR Signal Enhancement by Reversible Exchange
Two types of nanoscale catalysts were created to explore NMR signal enhancement via reversible exchange (SABRE) at the interface between heterogeneous and homogeneous conditions. Nanoparticle and polymer comb variants were synthesized by covalently tethering Ir-based organometallic catalysts to support materials comprised of TiO2/PMAA (poly methacrylic acid) and PVP (polyvinyl pyridine), respec...
متن کاملAqueous NMR Signal Enhancement by Reversible Exchange in a Single Step Using Water-Soluble Catalysts
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 approa...
متن کاملHeterogeneous solution NMR signal amplification by reversible exchange.
A novel variant of an iridium-based organometallic catalyst was synthesized and used to enhance the NMR signals of pyridine in a heterogeneous phase by immobilization on polymer microbead solid supports. Upon administration of parahydrogen (pH2) gas to a methanol mixture containing the HET-SABRE catalyst particles and the pyridine, up to fivefold enhancements were observed in the (1)H NMR spect...
متن کاملUtilisation of water soluble iridium catalysts for signal amplification by reversible exchange.
The catalytic hyperpolarisation of pyridine, 3-hydroxypyridine and oxazole by the Signal Amplification By Reversible Exchange (SABRE) process is achieved by a series of water soluble iridium phosphine and N-heterocyclic carbene dihydride complexes. While the efficiency of the SABRE process in methanol-d4 solution or ethanol-d6 solution is high, with over 400-fold (1)H polarisation of pyridine b...
متن کاملIrreversible Catalyst Activation Enables Hyperpolarization and Water Solubility for NMR Signal Amplification by Reversible Exchange
Activation of a catalyst [IrCl(COD)(IMes)] (IMes = 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene; COD = cyclooctadiene)] for signal amplification by reversible exchange (SABRE) was monitored by in situ hyperpolarized proton NMR at 9.4 T. During the catalyst-activation process, the COD moiety undergoes hydrogenation that leads to its complete removal from the Ir complex. A transient hydride i...
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ژورنال
عنوان ژورنال: The Journal of Physical Chemistry C
سال: 2015
ISSN: 1932-7447,1932-7455
DOI: 10.1021/acs.jpcc.5b02036