Table 1.

A summary of IC₅₀ values, luminescent properties, and special features of iridium complexes: half sandwich complex IR13, where N^N = L1 [34]; half sandwich complex IR6, where N^N = L2 [24]; cyclometallated complexes IR2 [19], IR15 [37], IR16 [38], IR5 [39], IR21 [46]; dinuclear iridium(III) complex IR22 [47]; TRAIL-mimicking peptide complex IR23 [48]; and micelle multi-action prodrug IR24 [49].

Ir Complex	HeLa IC50		A549 IC50		Luminescence		Special Features
	Dark	Light (Irradiation nm)	Dark	Light (Irradiation nm)	λEm (nm)	λEx (nm)
IR2	2.1 ± 0.2		1.7 ± 0.1		630–690	405	Could cause concentration-dependent cell cycle arrest, pro-death autophagy, and caspase-dependent apoptosis in A549 cells.
IR6	11.3 ± 0.1		15.6 ± 1.2				Could induce cancer cell death in a variety of ways and had a good antimetastatic ability to cancer cells.
IR13	3.6 ± 0.8		2.6 ± 0.3		500–600	488	Fluorescence could be used for cellular imaging under both acidic and neutral conditions.
IR15	>100	0.21 ± 0.01 (425)	>100	0.31 ± 0.02 (425)	670	405	Had enhanced emission in lysosomes and could inhibit several key cancerous events, including cell migration, invasion, colony formation, and in vivo angiogenesis.
IR16			4.34 ± 0.01		591	488	Potential anticancer agents with dual functions, including metastasis-inhibition and lysosomal damage.
IR17			62.3 ± 2.6	1.1 ± 0.3 (465)	580–630	563	Photo-selective and cancer-selective in cell and spheroids.
IR21	11.5 ± 0.2	0.044 ± 0.006 (420)			557	381	The first iridium complexes to induce cancer cell death by inhibition of translation targeting the endoplasmic reticulum.
IR22	49.9 ± 0.1 *	0.75 ± 0.01 (visible)			608	405	Nanomolar photocytotoxicity and visible PI > 280.
IR23					506	366	The first example of an artificial TRAIL mimic that induced apoptosis-like cell death.
IR24					460–510	400	Folate targeted multi-action micelle, activated by GHS and irradiation at 400nm.

* IC₅₀ values in SK-MEL-28 cells, as neither HeLa nor A549 have been published.