Interplay of Catalyst Structure and Temperature for NMR Signal Amplification by Reversible Exchange

SABRE has brought up the many possibilities for chemical and medical researches. However, the current SABRE catalyst has multi-limitations, including the time-consuming activation, activation stability and temperature compatibility. In this report, synthesis of several variants of an iridium-based organometallic catalyst showed accelerated activation performance and enhanced stability, during NMR Signal Amplification By Reversible Exchange (SABRE) in solution under upon administration of parahydrogen (pH2)-enriched gas in methanol mixture containing the “variant” catalyst and the substrate (pyridine or nicotinamide). Furthermore, such series of newly discovered SABRE catalysts are opening a door to a much high activation efficiency and higher low temperature performances for the potential future applications in larger and more challenging application fields, as well the relevant theoretical study of SABRE mechanism.