Mass spectrometry (see the SI for full details) of the initial reaction solution indicates that the [Fe30] species is formed quickly with the t = 0 spectrum showing peaks corresponding to the [[M30]-(3,4lut)+2(MeCN)] 2+ and [[M30]-2(lut)+2(MeCN)] 2+ fragments. The cluster continues to be present throughout the reaction time with measurements at t = 2 hours and t = 4 hours also showing these peaks (Figure ). Mass spectrometry of crystalline 1 redissolved in a 20/80 mix of lut/MeCN shows the [Fe30] cage is present with one, two and three ligands removed, with measurements repeated over a period of 24 hours showing that the molecule is present in solution for at least 1 day (Figures ).