A different iridium compound doesn't work well for hyperpolarization at room temperature because it holds onto pyridine too tightly, but it shows a little activity when warmed up.

The iridium compound loses a pyridine molecule to form a simpler structure that helps transfer polarization during the SABRE process.

The iridium compound has parts that move around quickly at room temperature, with pyridine molecules leaving at about 8 times per second and hydrogen atoms swapping positions about 3.6 times per second.