“…Covalent tagging of metal complexes has been studied for cell lineage tracing in embryonic cells, to understand the dynamic activities of living cells, probes of phagocytosis and immunoassay and immunofluorescence [ 8 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. The labelling of the proteins has been carried out either by using isothiocyanate complexes for albumins or maleimide complexes for conjugation with cysteine based biomolecules [ 24 ]. Aldehyde-based multiple reactive sites in the ligands of cyclometalated Ir(III) complexes have been used for the crosslinking of primary amines of two proteins [ 10 ].…”