Mass spectrometry was performed on a 7 T SolariXr FT-ICR MS (Bruker Daltonics, Bremen, Germany) with an ESI source. The spectrum was acquired in positive ion mode (ESI+). The broadband spectrum was acquired with 16 summed scans between 101 -6000 m/z. Samples were solubilized in a 20/80 3,4-lutidine/acetonitrile mix at 230 µM and sprayed by direct infusion into the ESI source. Data were analysed using Bruker Compass DataAnalysis software. Time resolved mass spectrometry was performed on the preparatory mixture used to make 1, under the same conditions as the re-dissolved crystalline sample. Aliquots of the reaction were taken at t = 0, t = 2 hours and t = 4 hours. The latter spectrum was measured after filtering the solution to remove some precipitated material. Aliquots were diluted to 230 µM (wrt FeBr3) with a 20/80 mix of 3,4-lutidine and acetonitrile.