Using signal amplification by reversible exchange (SABRE) to hyperpolarise 119Sn and 29Si NMR nuclei† †Data created during this research are available by request from the University of York Data Catalogue http://dx.doi.org/10.15124/12345. ‡ ‡Electronic supplementary information (ESI) available: General procedures and experimental conditions, sample preparation, performing SABRE experiments, ligand exchange rates, field dependent polarisation transfer studies, synthetic methods. CCDC 1501636 and

• Published in: Chemical communications (Cambridge, England) Vol. 52; no. 100; pp. 14482 - 14485
• Main Authors: Olaru, Alexandra M., Burt, Alister, Rayner, Peter J., Hart, Sam J., Whitwood, Adrian C., Green, Gary G. R., Duckett, Simon B.
• Format: Journal Article
• Language: English
• Published: Royal Society of Chemistry 23.11.2016
• Subjects: Chemistry
• ISSN: 1359-7345; 1364-548X
• DOI: 10.1039/c6cc07109k

The hyperpolarisation of the 119 Sn and 29 Si nuclei in 5-(tributylstannyl)pyrimidine ( A Sn ) and 5-(trimethylsilyl)pyrimidine ( B Si ) is achieved through their reaction with [IrCl(COD)(IMes)] ( 1a ) or [IrCl(COD)(SIMes)] ( 1b ) and para hydrogen via the SABRE process. The hyperpolarisation of the 119 Sn and 29 Si nuclei in 5-(tributylstannyl)pyrimidine ( A Sn ) and 5-(trimethylsilyl)pyrimidine ( B Si ) is achieved through their reaction with [IrCl(COD)(IMes)] ( 1a ) or [IrCl(COD)(SIMes)] ( 1b ) and para hydrogen via the SABRE process. 1a exhibits superior activity in both cases. The two inequivalent pyrimidine proton environments of A Sn readily yielded signal enhancements totalling ∼2300-fold in its 1 H NMR spectrum at a field strength of 9.4 T, with the corresponding 119 Sn signal being 700 times stronger than normal. In contrast, B Si produced analogous 1 H signal gains of ∼2400-fold and a 29 Si signal that could be detected with a signal to noise ratio of 200 in a single scan. These sensitivity improvements allow NMR detection within seconds using micromole amounts of substrate and illustrate the analytical potential of this approach for high-sensitivity screening. Furthermore, after extended reaction times, a series of novel iridium trimers of general form [Ir(H) 2 Cl(NHC)(μ-pyrimidine-κ N :κ N ′)] 3 precipitate from these solutions whose identity was confirmed crystallographically for B Si .