Intracellular distribution and stability of a luminescent rhenium(i) tricarbonyl tetrazolato complex using epifluorescence microscopy in conjunction with X-ray fluorescence imagingElectronic supplementary information (ESI) available: Details of X-ray crystallography and UV-Vis absorption/emission spectra. CCDC 1510599. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6mt00243a

Optical epifluorescence microscopy was used in conjunction with X-ray fluorescence imaging to monitor the stability and intracellular distribution of the luminescent rhenium( i ) complex fac -[Re(CO) 3 (phen)L], where phen = 1,10-phenathroline and L = 5-(4-iodophenyl)tetrazolato, in 22Rv1 cells. The rhenium complex showed no signs of ancillary ligand dissociation, a conclusion based on data obtained via X-ray fluorescence imaging aligning iodine and rhenium distributions. A diffuse reticular localisation was detected for the complex in the nuclear/perinuclear region of cells, by either optical or X-ray fluorescence imaging techniques. X-ray fluorescence also showed that the rhenium complex disrupted the homeostasis of some biologically relevant elements, such as chlorine, potassium and zinc. The cellular distribution of a Re( i ) complex has been imaged using X-ray fluorescence and correlated to its inherent luminescence.