Fig. 1. (a) Schematic of the SABRE process which brings protons that were previously located in p-H2 into spin–spin contact with the substrate (sub). Upon dissociation the NMR signals for the substrate become catalytically enhanced beyond their normal Boltzmann determined intensity levels. The SABRE-active species is [Ir(H)2(1)(L)3]Cl where substrates L, A–D, are differentiated according to R which is Cl, Me, OMe and CH(OH)(OCD3) respectively. (b) Typical 1H NMR spectrum resulting from hyperpolarisation (bottom) with thermal reference spectrum (top), recorded at 9.4 T for a 50 mM loading of 4-methylpyridine (C) with 5 mM of the [IrCl(COD)(1)] pre-catalyst in methanol-d4.
