All the chemicals were purchased from Sigma Aldrich. In a solution of 50 mM disodium [1- 13 C]acetylene dicarboxylate and 100 mM sodium sulphite in D2O, the ruthenium catalyst [RuCp*(CH3CN)3]PF6 was dissolved by gentle heating and sonication. The solution was filtered using a PTFE syringe filter (Whatman UNIFLO) with 0.22 µm diameter pores, with a final catalyst concentration of 8 mM. 300 µl of the filtered solution was frozen in a 5 mm pressurisable NMR tube equipped with a J. Young valve. The tube was held in a liquid nitrogen bath (77 K) and pressurized with 2.1 bar of para-enriched hydrogen (86% enriched). The sample was kept at 77 K to prevent any chemical reaction before the start of the hyperpolarization experiment.