Centre for Hyperpolarization in Magnetic Resonance, University of York, Heslington YO10 5NY, United Kingdom Department of Chemistry, University of York, Heslington YO10 5DD, United Kingdom Centre for ...

Tetrahydrofuran (THF) (Wako Chemical, Osaka, Japan, 99%) and pyridine (Kanto Chemical, Tokyo, Japan, 99.5%) were distilled over sodium wire before use. Other materials were used without any ...